JP5626798B2 - Photovoltaic power generation system, switching system, and bypass device - Google Patents

Description

  The present invention provides a photovoltaic power generation system having a bypass current path that bypasses a module group current flowing in a group of solar cell modules in which a plurality of solar cell modules are connected in series, a switching system that switches conduction and non-conduction of current paths, and The present invention relates to a bypass device.

  Solar cells that convert sunlight into electricity have been developed. However, since the generated power (generated voltage, generated current) of one solar cell (solar cell element) is small, a large number of solar cells are connected in series and in parallel, and the power required as a solar cell module Like to get. Further, a solar power generation system is configured by further connecting a plurality of solar cell modules.

  Since solar cells (solar cell modules) generate electricity by sunlight, solar cells that do not contribute to power generation when sunlight is shielded and the surface of the solar cell (solar cell module) is shaded ( Solar cell modules) are connected in series to limit the current to the solar cells (solar cell modules) that maintain the normal power generation state, and the power generation efficiency as a solar power generation system decreases. It will be.

  In addition, a current from a solar battery cell (solar battery module) that maintains a normal power generation state flows to a non-power-generating solar battery cell (solar battery module). Since the solar cell (solar cell module) in a non-power generation state acts as a resistor, for example, a hot spot phenomenon occurs due to heat generation, and there is a possibility that the life and reliability may be reduced.

  Therefore, in the conventional solar power generation system, a bypass diode is connected to a solar cell module configured with an appropriate number of solar cells to avoid the above-described disadvantages. A conventional solar power generation system will be described with reference to FIGS. 5A and 5B.

  FIG. 5A is a block diagram showing a schematic block configuration of a conventional photovoltaic power generation system 101.

  A conventional solar power generation system 101 includes a solar cell module 111 configured by connecting a plurality of solar cells 112 that convert sunlight Ls into electricity (electric power) by photoelectric conversion. A plurality of solar cell modules 111 (for example, a solar cell module 111f and a solar cell module 111s) are connected in series to constitute a solar cell module group 110. The solar cell module group 110 can be configured by connecting more solar cell modules 111, but for convenience of explanation, two solar cell modules 111 (a solar cell module 111f and a solar cell module 111s) are provided. A case of connection will be described.

  In addition, when it is not necessary to particularly distinguish the two solar cell modules 111f and the solar cell module 111s, the solar cell module 111 may be simply used. Moreover, the solar cell 112 arrange | positioned at the solar cell module 111f is set as the solar cell 112f, and the solar cell 112 arrange | positioned at the solar cell module 111s is set as the solar cell 112s. When there is no need to particularly distinguish both (solar cell 112f and solar cell 112s), the solar cell 112 may be simply used. Moreover, in FIG. 5A, the solar cell 112 arrange | positioned at both ends inside the solar cell module 111 is shown, and illustration is abbreviate | omitted about the solar cell 112 arrange | positioned in the middle.

  The solar cell modules 111 irradiated with the sunlight Ls each generate an output voltage by photoelectric conversion, and the voltage added by the series connection of the solar cell modules 111 is used as the output voltage of the solar cell module group 110 as a DC / DC converter 130. Is input to the input terminal.

  A common module group current Ig flows through the solar cells 112 connected in series. Therefore, the solar cell module group 110 supplies the module group current Ig to the input terminal of the DC / DC converter 130 using the solar cell module 111f and the solar cell module 111s as current paths.

  The DC / DC converter 130 converts the output voltage (DC voltage) of the solar cell module group 110 into an appropriate voltage (power) at a preset conversion ratio, and outputs the voltage from the output end toward a load (not shown). .

  The conventional photovoltaic power generation system 101 includes a bypass current path 115 connected in parallel with the solar cell module 111, and a bypass diode 116 that is inserted into the bypass current path 115 and forms a unidirectional current path together with the bypass current path 115. Prepare. Since the bypass current path 115 and the bypass diode 116 are connected to correspond to the solar cell module 111, two bypass current paths 115 and the bypass diode 116 are arranged in the same manner as the solar cell module 111.

  The bypass current path 115f connected in parallel with the solar cell module 111f is a bypass current path 115f, the bypass current path 115 connected in parallel with the solar cell module 111s is a bypass current path 115s, and the bypass current path 115f and the bypass current path 115s. May be simply used as the bypass current path 115.

  A bypass diode 116f is inserted (arranged) in the bypass current path 115f, and a bypass diode 116s is inserted (arranged) in the bypass current path 115s. If it is not necessary to distinguish between the bypass diode 116f and the bypass diode 116s, the bypass diode 116f may be simply used as the bypass diode 116.

  Each solar cell 112 receives the irradiation of sunlight Ls, and performs the same photoelectric conversion, when the same sunlight Ls is irradiated. Accordingly, each solar battery cell 112 outputs the module group current Ig at a generated voltage according to the specification.

  In a normal state in which the sunlight Ls is irradiated substantially uniformly, each solar cell 112 operates in the same manner, and therefore outputs an output voltage and a module group current Ig according to the specifications of the entire solar cell module 111. . Therefore, when n solar cells 112 are connected in series, the generated voltage xn of the solar cells 112 becomes the output voltage of the solar cell module 111.

  The bypass diode 116 is connected so that the output (voltage, current) of the solar cell module 111 is reverse-biased in a normal power generation state. That is, the bypass diode 116 has a cathode side connected to the positive side of the generated voltage of the solar cell module 111 and an anode side connected to the negative side of the generated voltage of the solar cell module 111. Therefore, in a normal power generation state, the module group current Ig flows through the solar cell module 11 and does not flow through the bypass diode 116. In other words, in a normal power generation state, the bypass diode 116 is reverse-biased, and therefore no current flows.

  FIG. 5B is a block diagram showing a schematic block configuration in a state where the module group current Ig flows by bypassing the bypass diode 116s in the conventional photovoltaic power generation system 101 shown in FIG. 5A.

  Since the basic configuration is the same as that in FIG. 5A, different items will be mainly described.

  The sunlight Ls may become sunlight Lss (shown corresponding to the solar cell module 111s) in a state where the sunlight Ls is blocked by the occurrence of a shadow or the like. The sunlight Lss is shown only on the outside of the solar cell module 111s in order to show a state where it is shielded from the sunlight Ls. Hereinafter, for example, a case where the solar cell module 111s (solar cell 112s) is shielded from light and does not generate power will be described.

  The light-shielded solar cell module 111s (solar cell 112s) does not generate electricity as a solar cell because it cannot perform photoelectric conversion. In order to show a state where power generation (function) does not occur as a solar cell, the solar cell module 111s (solar cell 112s) is shown by a broken line in FIG. 5B.

  In a state where power generation is not possible due to light shielding, the solar cell module 111s becomes a passive circuit (resistance circuit). That is, when a module group current Ig flowing by power generation of another solar cell module 111 connected in series (here, the solar cell module 111f) flows, it acts as a resistive load and may generate a hot spot phenomenon due to heat generation. .

  When the module group current Ig flows through the solar cell module 111s without generating power, the potentials at both ends of the solar cell module 111s are reversed unlike the normal power generation state. That is, since the anode side of the bypass diode 116s has a high potential and the cathode side of the bypass diode 116 has a low potential, a forward voltage is applied to the bypass diode 116s, and the module group current as a forward current is obtained. Ig enters a state of flowing to the bypass current path 115s (bypass diode 116s). In this state, since the inflow of the module group current Ig to the solar cell module 111s is eliminated, the hot spot phenomenon is reliably prevented and the reliability of the solar power generation system 101 can be ensured.

  That is, the module group current Ig flows to the solar cell module 111f via the bypass diode 116s, and power consumption at the forward voltage of the bypass diode 116s occurs. Since power consumption leads to a reduction in power generation efficiency of the entire photovoltaic power generation system 101, a Schottky diode having a small forward voltage is used as the bypass diode 116 in order to suppress power consumption in the bypass diode 116s as much as possible. Generally applied. The forward voltage of the Schottky diode is smaller than that of a normal diode, but the forward voltage Vf is 0.45V to 0.65V.

  When the forward voltage Vf is 0.5 V, for example, if the module group current Ig is 10 A, the power consumption of the Schottky diode is 10 A × 0.5 V = 5 W, and the loss increases as the scale of the solar cell module group 10 increases. There is a problem that it can not be ignored.

  For example, Patent Document 1 is known as a technique for taking measures against heat generation due to power consumption in a bypass diode arranged in a terminal box.

JP 2006-286996 A

  Regarding the connection of the bypass diode as a means for eliminating the mixture of the power generation state and the non-power generation state in the solar battery cell and the solar battery module, there is a problem of the occurrence of power consumption by the bypass diode itself. As a countermeasure against heat generation due to power consumption of the bypass diode, a technique as described in Patent Document 1 has been proposed. However, the technique disclosed in Patent Document 1 only discloses the response to the generated heat, and does not reduce the power consumption of the bypass diode itself, and the power consumption of the bypass diode still occurs. was there.

  The present invention has been made in view of such a situation. By replacing the bypass diode with a switching element that hardly generates power, the solar power consumption that has been generated in the conventional bypass diode is reduced (eliminated). An object is to provide a photovoltaic system.

  In addition, the present invention provides a switching system that applies a switching element to control conduction and non-conduction of a current path so that the current path functions as necessary and suppresses power consumption in the current path. To do other purposes.

  Further, in the present invention, the output state of the solar cell module can be easily set as a signal (divided voltage) from the voltage dividing terminal by configuring the control unit with a simple series circuit of a diode and two elements of two resistors. It is another object of the present invention to provide a bypass device that can be extracted with high accuracy and that can easily and accurately control the opening and closing of the switching element based on the potential (divided voltage) of the voltage dividing terminal.

The solar power generation system according to the present invention includes a solar battery module group in which a plurality of solar battery modules in which a plurality of solar battery cells are connected in series, and a solar battery module connected in parallel to each of the solar battery modules. A bypass current path for bypassing a module group current flowing in the solar cell module group when the output voltage of the module is smaller than a specified voltage, and a DC for DC-DC conversion of the power output from the solar cell module group / DC converter comprising: a switching element that is disposed in each bypass current path and switches between conduction and non-conduction of the bypass current path, and is disposed corresponding to each of the switching elements And a control unit that controls opening and closing of the switching element. Wherein, when the output voltage is smaller than the specific voltage, the is a switching element from an open and configured to conduct the bypass current path is switched to the closed, the control unit includes a diode and two resistors A voltage dividing terminal that is connected in parallel to the solar cell module and that divides the output voltage of the solar cell module and outputs the divided voltage. The voltage dividing terminal is connected to a control terminal of the switching element .

Therefore, when the solar cell module according to the present invention enters a non-power generation state in which the solar cell module does not generate power due to, for example, interruption of sunlight, the bypass current path arranged in parallel with the solar cell module that does not generate power is in a conductive state. Since the module group current flowing in the solar cell module group as a (short circuit state) is bypassed, the inflow of the module group current to the solar cell module in the non-power generation state is prevented without applying the bypass diode, and the solar cell module (solar cell) The generation of hot spots in the cell) can be prevented, and the power consumption that occurs when the bypass diode is applied can be suppressed. In other words, the hot spot phenomenon in the solar power generation system (solar cell module, solar cell) is prevented to improve reliability, and the life of the solar power generation system (solar cell module, solar cell) is improved. The power generation efficiency can be improved. In addition, since a series circuit with a simple configuration of a diode and two elements of two resistors is connected in parallel with the solar cell module as a control unit, the output state of the solar cell module is a signal (divided voltage) from the voltage dividing terminal. Therefore, it is possible to easily and accurately control the opening and closing of the switching element based on the potential of the voltage dividing terminal (divided voltage).

  In the photovoltaic power generation system according to the present invention, the control unit is connected to the solar cell module and receives the output voltage, and is connected to the control terminal of the switching element to open and close the switching element. And a comparator having an output terminal for controlling the output.

  Therefore, the solar power generation system according to the present invention detects the non-power generation state of the solar cell module with high accuracy and speed and controls the opening / closing (on / off) of the switching element, so the hot spot phenomenon in the solar cell module Can be reliably prevented.

  In the photovoltaic power generation system according to the present invention, the power of the control unit is supplied from the DC / DC converter.

  Therefore, the photovoltaic power generation system according to the present invention can stabilize the power supply of the control unit and can control the bypass current path (control unit) of the photovoltaic power generation system with high accuracy.

  In the photovoltaic power generation system according to the present invention, the switching element is a MIS field effect transistor.

  Therefore, in the photovoltaic power generation system according to the present invention, the switching element is configured by a MIS field effect transistor having a low resistance, so that power consumption generated in the bypass current path (switching element) is reduced and power loss in the bypass current path is reduced. It can suppress and can improve the power generation efficiency as a whole. Further, since power consumption generated in the bypass current path (switching element) is reduced, heat generation due to power consumption is suppressed, so that when the bypass diode is applied, it is necessary in the bypass current path and does not require heat dissipation means. be able to.

The switching system according to the present invention is a switching system including a switching element that is disposed in a current path and switches between conduction and non-conduction of the current path, and a control unit that controls opening and closing of the switching element. The control unit is configured to control opening and closing of the switching element based on a voltage between both ends of the current path, and the control unit is a series circuit in which a diode and two resistors are connected in series to form the current path. A voltage dividing terminal connected in parallel between the two resistors to divide and output the output voltage of the solar cell module, and the voltage dividing terminal is connected to the switching element. It is connected to a control terminal .

Therefore, since the switching system according to the present invention controls the opening and closing of the switching element according to the voltage (potential difference) between both ends of the current path, the conduction of the current path according to the correlation state of the potentials at both ends of the current path. Since it is possible to switch between non-conduction, the current path can be made to function as necessary by short-circuiting (closed) or opening (opening), and the current path is made conductive by applying a switching element. Power consumption at the time can be suppressed. In addition, since a series circuit having a simple configuration of three elements of a diode and two resistors is connected as a control unit in parallel with the current path, the potential state between both ends of the current path is expressed by a signal (divided voltage) from the voltage dividing terminal. ) Can be easily and highly accurately extracted, so that switching of the switching element can be easily and accurately controlled based on the potential (divided voltage) of the voltage dividing terminal.

  In the switching system according to the present invention, the control unit is a comparator including a first input terminal, a second input terminal, and an output terminal, and the first input terminal is a first terminal of the current path. The second input terminal is connected to a second terminal of the current path, and the output terminal is connected to a control terminal of the switching element.

  Therefore, since the switching system according to the present invention is configured by the comparator, the potential state at both ends of the current path can be compared with high accuracy, and the switching of the switching element can be controlled with high accuracy.

  In the switching system according to the present invention, the switching element is a MIS field effect transistor, the source of the MIS field effect transistor is connected to the first terminal, and the drain of the MIS field effect transistor is the second terminal. The gate of the MIS field effect transistor is connected to the output terminal as the control terminal.

  Therefore, since the MIS field effect transistor is applied as the switching element in the switching system according to the present invention, generation of unnecessary power consumption is suppressed by suppressing power consumption when the switching element is conductive (when the current path is conductive). And an efficient switching system.

  In the switching system according to the present invention, the control unit is supplied with power from an external power source disposed outside.

  Therefore, since the switching system according to the present invention operates with external power supply power, stable operation can be realized.

  In the switching system according to the present invention, the external power source is an output of a DC / DC converter that performs DC / DC conversion on the output of the solar cell module.

  Therefore, since the switching system according to the present invention uses the output of the DC / DC converter that adjusts the output of the solar cell module, it can be applied to the control system of the solar cell module, and the bypass circuit of the solar cell module is provided. By replacing the constituent bypass diode with a switching element, it is possible to suppress the occurrence of power consumption, which is a problem with the bypass diode.

  In the solar cell system according to the present invention, the switching element and the control unit are mounted on a single wiring board and built in an output box of the solar cell module.

  Therefore, since the photovoltaic power generation system according to the present invention mounts the switching element and the control unit (series circuit) on one wiring board and incorporates them in the output box, the bypass current path for the solar cell module is highly functionalized. Can do.

  The bypass device according to the present invention is a bypass device that forms a bypass current path by being connected to both ends of the solar cell module, the switching element switching between conduction and non-conduction of the bypass current path, and the switching A control unit that is arranged corresponding to the element and controls opening and closing of the switching element, the control unit is a series circuit in which a diode and two resistors are connected in series, and is connected in parallel to the solar cell module. A voltage dividing terminal that divides and outputs the output voltage of the solar cell module from between the two resistors, and the voltage dividing terminal is connected to a control terminal of the switching element. It is characterized by.

  Therefore, the bypass device according to the present invention connects the solar cell module in parallel with the solar cell module as a control unit using a series circuit of a simple configuration of a diode and two resistors as a control unit. Therefore, the switching element can be easily opened and closed with high accuracy based on the potential of the voltage dividing terminal (divided voltage).

  In the bypass device according to the present invention, the control unit is disposed between the voltage dividing terminal and the control terminal and maintains a potential state of the control terminal when the switching element is switched from OFF to ON. The switching state maintaining circuit is provided.

  Therefore, in the bypass device according to the present invention, even when the voltage applied to the control unit is reduced due to the switching element being switched from OFF to ON, the potential state of the control terminal (signal state; applied to the control terminal). Voltage) is maintained, so that the ON state of the switching element can be maintained.

  In the bypass device according to the present invention, the switching state maintaining circuit includes an anode connected to the voltage dividing terminal, a cathode connected to the control terminal, one end connected to the control terminal, and the other end Comprising a capacitor connected to the module terminal on the positive side in the power generation state of the solar cell module.

  Therefore, even when the voltage applied to the control unit is reduced by switching the switching element from OFF to ON, the bypass device according to the present invention can be applied to the control terminal potential state (applied to the control terminal) with a simple combination of a diode and a capacitor. Can be maintained by the charging voltage to the capacitor, so that the ON state of the switching element can be easily maintained.

  Further, in the bypass device according to the present invention, the control unit includes a discharge diode in which an anode is connected to the one end of the capacitor and a cathode is connected to a module terminal that is a negative side in the power generation state of the solar cell module. It is characterized by providing.

  Therefore, the bypass device according to the present invention discharges the charge stored in the capacitor to the negative module terminal with the discharge diode when the solar cell module is in the power generation state, so that the capacitor is returned to the initial state. Therefore, a stable switching state maintaining circuit can be realized.

  In the bypass device according to the present invention, the switching element and the control unit are mounted on a single wiring board.

  Therefore, since the bypass device according to the present invention mounts the switching element and the control unit (series circuit) on one wiring board and can be downsized, the solar cell module can be easily incorporated in the output box. Become.

  The solar power generation system according to the present invention includes a solar battery module group in which a plurality of solar battery modules in which a plurality of solar battery cells are connected in series, and a solar battery module connected in parallel to each of the solar battery modules. A bypass current path for bypassing a module group current flowing in the solar cell module group when the output voltage of the module is smaller than a specified voltage, and a DC for DC-DC conversion of the power output from the solar cell module group / DC converter comprising: a switching element that is disposed in each bypass current path and switches between conduction and non-conduction of the bypass current path, and is disposed corresponding to each of the switching elements And a control unit that controls opening and closing of the switching element. Wherein, when the output voltage is smaller than the specific voltage, characterized in that it is configured to conduct the bypass current path is switched to the closed the switching device from the open.

  Therefore, when the solar cell module according to the present invention enters a non-power generation state in which the solar cell module does not generate power due to, for example, interruption of sunlight, the bypass current path arranged in parallel with the solar cell module that does not generate power is in a conductive state. Since the module group current flowing in the solar cell module group as a (short circuit state) is bypassed, the inflow of the module group current to the solar cell module in the non-power generation state is prevented without applying the bypass diode, and the solar cell module (solar cell) The generation of hot spots in the cell) can be prevented, and the power consumption that occurs when the bypass diode is applied can be suppressed. In other words, the hot spot phenomenon in the solar power generation system (solar cell module, solar cell) is prevented to improve reliability, and the life of the solar power generation system (solar cell module, solar cell) is improved. The power generation efficiency can be improved.

  The switching system according to the present invention is a switching system including a switching element that is arranged in a current path and switches between conduction and non-conduction of the current path, and a control unit that controls opening and closing of the switching element. The opening and closing of the switching element is controlled based on the voltage across the current path.

  Therefore, the switching system according to the present invention controls the opening and closing of the switching element according to the result of detecting the voltage (potential difference) between both ends of the current path, and therefore according to the correlation state of the potentials at both ends of the current path. Since the conduction and non-conduction of the current path can be switched, the current path can be made to function as necessary by short-circuiting (closing) or opening (opening), and since the switching element is applied, the current path It is possible to suppress power consumption when conducting the.

  A bypass device according to the present invention is a bypass device that forms a bypass current path by being connected to both ends of a solar cell module, and corresponds to the switching element that switches conduction and non-conduction of the bypass current path, and the switching element. And a control unit that controls the opening and closing of the switching element. The control unit is a series circuit in which a diode and two resistors are connected in series, and when connected in parallel to the solar cell module, the two resistors A voltage dividing terminal that divides and outputs the output voltage of the solar cell module is provided, and the voltage dividing terminal is connected to the control terminal of the switching element.

  Therefore, the bypass device according to the present invention connects the solar cell module in parallel with the solar cell module as a control unit using a series circuit of a simple configuration of a diode and two resistors as a control unit. Therefore, the switching element can be easily opened and closed with high accuracy based on the potential of the voltage dividing terminal (divided voltage).

It is a block diagram which shows the schematic block structure of the solar energy power generation system which concerns on Embodiment 1 of this invention. It is an equivalent circuit diagram which shows the equivalent circuit of the solar cell module in the photovoltaic power generation system shown to FIG. 1A, and a photovoltaic cell. FIG. 1B is a block diagram showing a schematic block configuration when the bypass power path is made to function in the photovoltaic power generation system shown in FIG. 1A. It is an equivalent circuit diagram which shows the equivalent circuit of the solar cell module in the photovoltaic power generation system shown to FIG. 2A, and a photovoltaic cell. It is a circuit symbol figure which shows the circuit symbol of the MIS field effect transistor which is a specific example of the switching element in the solar energy power generation system shown to FIG. 1A. FIG. 3B is an equivalent circuit diagram showing an off state (open state) of the MIS field effect transistor shown in FIG. 3A with an equivalent switch symbol. FIG. 3B is an equivalent circuit diagram showing an ON state (closed state) of the MIS field effect transistor shown in FIG. 3A with an equivalent switch symbol. It is an electric power characteristic figure explaining the electric power generation characteristic in the photovoltaic power generation system shown in Drawing 1A, and an operation of a bypass current course. It is a block diagram which shows the schematic block structure of the conventional solar power generation system. FIG. 5B is a block diagram showing a schematic block configuration in a state where the module group current flows through the bypass diode in the conventional photovoltaic power generation system shown in FIG. 5A. It is a block diagram which shows the schematic block structure of the solar energy power generation system which concerns on Embodiment 2 of this invention. FIG. 6B is a block diagram showing a schematic block configuration when the bypass current path is made to function in the photovoltaic power generation system shown in FIG. 6A. It is a circuit diagram which shows the modification circuit example 1 of the control part (series circuit) in the photovoltaic power generation system shown to FIG. 6A. It is a circuit diagram which shows the modification circuit example 2 of the control part (series circuit) in the photovoltaic power generation system shown to FIG. 6A. It is a circuit diagram which shows the modification circuit example 3 of the control part (series circuit) in the photovoltaic power generation system shown to FIG. 6A. It is a circuit diagram which shows the more specific circuit example of the control part in the solar energy power generation system shown to FIG. 6A.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Embodiment 1>
A photovoltaic power generation system and a switching system according to Embodiment 1 of the present invention will be described with reference to FIGS. 1A to 4. The switching system will be described collectively at the end of the present embodiment for the convenience of description.

  FIG. 1A is a block diagram showing a schematic block configuration of a photovoltaic power generation system 1 according to Embodiment 1 of the present invention.

  Note that the components of the switching system 14 are included as some components of the photovoltaic power generation system 1. For example, the bypass current path 15, the switching element 16, and the control unit 20 constitute the switching system 14.

  The photovoltaic power generation system 1 according to the present embodiment includes a solar cell module 11 configured by connecting a plurality of solar cells 12 that convert sunlight Ls into electricity (electric power) by photoelectric conversion. A plurality of solar cell modules 11 (for example, a solar cell module 11f and a solar cell module 11s) are connected in series to constitute a solar cell module group 10. The solar cell module group 10 can be configured by connecting a larger number of solar cell modules 11. However, for convenience of explanation, two solar cell modules 11 (a solar cell module 11f and a solar cell module 11s) are provided. A case of connection will be described.

  In addition, when it is not necessary to particularly distinguish the two solar cell modules 11f and the solar cell module 11s, the solar cell module 11 may be simply used. Moreover, let the solar cell 12 arrange | positioned at the solar cell module 11f be the solar cell 12f, and let the solar cell 12 arrange | positioned at the solar cell module 11s be the solar cell 12s. When there is no need to distinguish both (solar battery cell 12f and solar battery cell 12s), the solar battery cell 12 may be used. Moreover, in FIG. 1A, the solar cell 12 arrange | positioned at both ends inside the solar cell module 11 is shown, and illustration is abbreviate | omitted about the solar cell 12 arrange | positioned in the middle.

  The solar cell modules 11 irradiated with sunlight Ls are each converted into an output voltage Vm (the output voltage Vm of the solar cell module 11f is an output voltage Vmf and the output voltage Vm of the solar cell module 11s is an output voltage Vms) by photoelectric conversion. When it is not necessary to distinguish between the voltage Vmf and the output voltage Vms, the output voltage Vm may be simply generated.) And the voltage added by the series connection of the solar cell modules 11 is the output of the solar cell module group 10. The voltage Vg is input to the input terminal 31 of the DC / DC converter 30.

  Specifically, in the solar cell module 11f, the output voltage Vmf is between the module terminal 13f and the module terminal 13s, the module terminal 13f is on the positive side, the module terminal 13s is on the negative side, and the module group current Ig is the module terminal. 13f is supplied to the DC / DC converter 30. The solar cell module 11s has an output voltage Vms between the module terminal 13s and the module terminal 13t, the module terminal 13s is on the plus side, the module terminal 13t is on the minus side, and the module group current Ig is transmitted from the module terminal 13s to the sun. It is supplied to the DC / DC converter 30 via the battery module 11f.

  A common module group current Ig flows through each of the solar cells 12 connected in series. Therefore, the solar cell module group 10 supplies the module group current Ig to the input end 31 of the DC / DC converter 30 using the solar cell module 11f and the solar cell module 11s as current paths.

  The DC / DC converter 30 converts the output voltage Vg (DC voltage) of the solar cell module group 10 into an output voltage Vs (DC voltage) at a preset conversion ratio, and loads the output voltage Vs from the output terminal 32 (non-load). Output toward (illustration).

  The photovoltaic power generation system 1 according to the present embodiment includes a bypass current path 15 connected in parallel with the solar cell module 11 and a switching element 16 that is inserted into the bypass current path 15 and switches between conduction / non-conduction of the bypass current path 15. The control unit 20 controls the opening / closing of the switching element 16 (on / off. For example, the on state corresponds to the closed state and the off state corresponds to the open state).

  Since the bypass current path 15 is connected in correspondence with the solar cell module 11, two bypass current paths 15 are arranged in the present embodiment, similarly to the solar cell module 11.

  The bypass current path 15 connected in parallel to the solar cell module 11f is referred to as a bypass current path 15f, and the bypass current path 15 connected in parallel to the solar cell module 11s is referred to as a bypass current path 15s. If it is not necessary to distinguish between the bypass current path 15f and the bypass current path 15s, the bypass current path 15 may be simply used.

  A switching element 16f is inserted (arranged) in the bypass current path 15f, and a switching element 16s is inserted (arranged) in the bypass current path 15s. When it is not necessary to distinguish the switching element 16f and the switching element 16s, the switching element 16 may be simply used.

  The switching element 16 is preferably formed of a MIS (Metal-Insulator-Semiconductor) field effect transistor. More specifically, it is an enhancement type n-channel MOS (Metal-Oxide-Semiconductor) field effect transistor. The source of the MOS field-effect transistor is connected to the positive side of the output of the solar cell module 11 (positive in the state where power is effectively generated. The positive side of the specification), and the drain is the negative side of the solar cell module 11. (Minus in the state of generating power effectively. Minus on the specification) side. The gate of the MOS field effect transistor is connected to the output terminal 23 of the control unit 20 (the gate of the switching element 16f is connected to the output terminal 23f, and the gate of the switching element 16s is output terminal 23s).

  The control terminal 17 of the switching element 16 (the gate of the MOS field effect element) controls the operating state of the switching element 16. The control terminal 17 corresponding to the switching element 16f is referred to as a control terminal 17f, and the control terminal 17 corresponding to the switching element 16s is referred to as a control terminal 17s. If there is no need to distinguish between the control terminal 17f and the control terminal 17s, the control terminal 17 may be simply used.

  Since the control unit 20 is connected corresponding to the solar cell module 11 similarly to the bypass current path 15 and the switching element 16, two control units 20 are arranged similarly to the bypass current path 15 and the switching element 16.

  The control unit 20 that is connected in parallel to the solar cell module 11f and controls the switching element 16f is referred to as a control unit 20f, and the control unit 20 that is connected in parallel to the solar cell module 11s and controls the switching element 16s is referred to as a control unit 20s. When it is not necessary to distinguish between the control unit 20f and the control unit 20s, the control unit 20 may be simply used.

  The control unit 20 includes a comparator having two input terminals 21 and an input terminal 22. That is, the input terminal 21 and the input terminal 22 are connected to both ends of the solar cell module 11, and the control unit 20 compares the voltage applied to the input terminal 21 with the voltage applied to the input terminal 22, and results of comparison Is output from the output terminal 23 to control on / off (opening / closing) of the switching element 16.

  Since the power supply of the comparator (control unit 20) is supplied from the output of the DC / DC converter 30, a stable comparison operation can be realized. The power source of the control unit 20 is a stable power source, and can be configured not to be supplied from the DC / DC converter 30 as long as the potential difference between both ends of the solar cell module 11 can be compared as a comparator.

  The input terminal 21 connected to the solar cell module 11f is referred to as an input terminal 21f, the similarly connected input terminal 22 is referred to as an input terminal 22f, and the output terminal 23 connected to the switching element 16f is referred to as an output terminal 23f. In addition, the input terminal 21 connected to the solar cell module 11s is referred to as an input terminal 21s, the similarly connected input terminal 22 is referred to as an input terminal 22s, and the output terminal 23 connected to the switching element 16s is referred to as an output terminal 23s. When there is no need to distinguish between the input terminal 21f and the input terminal 21s, the input terminal 22f and the input terminal 22s, the output terminal 23f and the output terminal 23s, they may be simply referred to as the input terminal 21, the input terminal 22, and the output terminal 23. .

  When the voltage applied to the input terminal 21 is higher than the voltage applied to the input terminal 22, the solar cell module 11 is in a normal power generation state, so that the level L from the output terminal 23 (the level at which the switching element 16 is turned off). ) Is output to the control terminal 17 of the switching element 16 to turn the switching element 16 off (open), and the bypass current path 15 is turned off.

  Further, when the voltage applied to the input terminal 22 is higher than the voltage applied to the input terminal 21, the solar cell module 11 is in a non-power generation state, so that the level H (switching element 16 is turned on) from the output terminal 23. Level) signal is output to the control terminal 17 of the switching element 16 so that the switching element 16 is turned on (closed) and the bypass current path 15 is turned on.

  As described above, when the voltage applied from the solar cell module 11 to the input terminal 22 is higher than the voltage applied to the input terminal 21, power generation in the solar cell module 11 is not performed, and the solar cell module 11 is in a power generation state. Since it acts as a resistor instead of acting as a solar cell, a hot spot phenomenon may occur, so that the bypass current path 15 is conducted to bypass the module group current Ig to the bypass current path 15. Note that the operation of the bypass current path 15 in the non-power generation state will be described in more detail with reference to FIG. 2A.

  FIG. 1B is an equivalent circuit diagram showing an equivalent circuit of the solar battery module 11 and the solar battery cell 12 in the photovoltaic power generation system 1 shown in FIG. 1A.

  Since the basic configuration is the same as that of FIG. 1A, different items will be mainly described.

  The solar battery cell 12 is provided with a photoelectric conversion current source Iph that photoelectrically converts the sunlight Ls when it is irradiated with sunlight Ls as irradiation light, and includes a diode Di and a leakage current as other circuit elements. A parallel resistance Rsh caused by the resistance and a series resistance Rs caused by the resistance of the connection portion are provided.

  When the same sunlight Ls is irradiated, each photovoltaic cell 12 receives the irradiation of sunlight Ls, and performs the same photoelectric conversion (photoelectric power generation). Accordingly, in each solar battery cell 12, the photoelectric conversion current source Iph functions to output the generated current Ic (module group current Ig) and the generated voltage Vc.

  In a normal state in which the sunlight Ls is irradiated substantially uniformly, each solar battery cell 12 operates in the same manner, and therefore outputs the output voltage Vm and the module group current Ig in the entire solar battery module 11. When n solar cells 12 are connected in series, the generated voltage Vc × n = the output voltage Vm.

  FIG. 2A is a block diagram showing a schematic block configuration when the bypass power path 15s is made to function by the photovoltaic power generation system 1 shown in FIG. 1A.

  Since the basic configuration is the same as that of FIG. 1A, different items will be mainly described.

  The sunlight Ls may become sunlight Lss (showing a state corresponding to the solar cell module 11s) in a state where the sunlight Ls is shielded by generation of a shadow or the like. The sunlight Lss is shown only outside the solar cell module 11s in order to show a state where the sunlight Ls is shielded compared to the sunlight Ls. Below, the case where the solar cell module 11s (solar cell 12s), for example, is shielded from light and does not generate power will be described.

  Since the light-shielded solar cell module 11s (solar cell 12s) cannot perform photoelectric conversion, it does not generate power as a solar cell. In order to show a state where power generation (function) does not occur as a solar cell, the solar cell module 11s (solar cell 12s) is shown by a broken line in FIG. 2A.

  In a normal power generation state, an output voltage Vms is generated between the module terminal 13s that is the positive terminal of the solar cell module 11s and the module terminal 13t that is the negative terminal. That is, in a normal power generation state, the potential of the module terminal 13s is higher than the potential of the module terminal 13t.

  However, in a state where power generation is not possible due to light shielding, the solar cell module 11s becomes a passive circuit including a series resistance Rs and a parallel resistance Rsh (see FIGS. 1B and 2B). That is, when a module group current Ig flowing by power generation of another solar cell module 11 connected in series (here, the solar cell module 11f) flows, the solar cell module 11s acts as a resistance load, and the potential of the module terminal 13s. On the other hand, the potential of the module terminal 13t becomes higher, and the potential difference between the module terminal 13s and the module terminal 13t is opposite to that in the power generation state. Further, if this state is continued, there is a risk of causing a hot spot phenomenon.

  In the prior art, when the solar cell module 11s is in a non-power generation state, the bypass diode connected between the module terminal 13s and the module terminal 13t is forward biased, so that the module group current Ig is supplied to the solar cell module 11s. The current is passed through the bypass diode without flowing, thereby preventing the influence of the non-power generation state (for example, hot spot phenomenon). However, since power consumption occurs in the bypass diode and power generation efficiency is lowered, in the present embodiment, the switching element 16 in which power consumption is not a problem is arranged in the bypass current path 15 instead of the bypass diode.

  That is, when the potential difference (output voltage Vms) between the module terminal 13s and the module terminal 13t is in a reverse direction different from the normal power generation state (the potential of the module terminal 13t is higher than the potential of the module terminal 13s). Is detected by the control unit 20s. In other words, the output voltage Vms (see FIG. 1A) is smaller than a specific voltage (for example, output voltage Vms = 0) specified in advance (for example, the output voltage Vms is in a direction different from the normal power generation state). ) Is detected by the control unit 20s.

  Specifically, the control unit 20s includes, for example, a comparator having two input terminals 21s and 22s, where one input terminal 21s is connected to the module terminal 13s and the other input terminal 22s is a module terminal. Since it is connected to 13t, it can be detected that the output voltage Vms has become smaller than a specific voltage (for example, the output voltage Vms = 0V).

  When the output voltage Vms input between the input terminal 21s and the input terminal 22s is smaller than a specific voltage, the control unit 20s configured with a comparator (for example, a voltage in the reverse direction with respect to the voltage during normal power generation) The switching element 16s is output from the output terminal 23s to the switching element 16s (control terminal 17s), and the switching element 16s is turned on ( Closed), the bypass current path 15s is turned on.

  The bypass current path 15s that is in the conductive state (the switching element 16s that is in the on state) switches the current path through which the module group current Ig flows from the solar cell module 11s to the bypass current path 15s and bypasses the module group current Ig. Is prevented from flowing into the solar cell module 11s.

  That is, the bypass current path 15s is connected to the solar cell module 11s in parallel, and the output voltage Vms of the solar cell module 11s is specified in advance (for example, the output voltage Vms = 0V can be set as the specific voltage). When it is smaller, the module group current Ig flowing in the solar cell module group 10 is bypassed. When the output voltage Vm (Vms) becomes smaller than the specific voltage, the control unit 20s detects that the output voltage Vm (Vms) is smaller than the specific voltage, and closes the switching element 16s from open (off) to on (on). ) And the bypass current path 15s is made conductive. Since the operation of the comparator applied as the control unit 20s is the same as that of a general comparator, detailed description thereof is omitted.

  Although the case where the output voltage Vms = 0 V is exemplified as the specific voltage, the present invention is not limited to this, and an appropriate voltage value can be set.

  When a MOS field effect transistor is applied as the switching element 16s, the MOS field effect transistor is turned on compared to the module terminal 13s (source) in order to turn on the switching element 16 (MOS field effect transistor). A voltage higher than the threshold value (for example, 2V) may be output from the output terminal 23s and applied to the control terminal 17s (gate). Further, in order to turn off the switching element 16 (MOS field effect transistor) (non-conducting state), a voltage lower than the threshold value (for example, 2 V) of the MOS field effect transistor compared to the module terminal 13s (source) is output terminal. What is necessary is just to output from 23s and to apply to the control terminal 17s (gate).

  FIG. 2B is an equivalent circuit diagram showing an equivalent circuit of the solar cell module 11s and the solar cell 12s in the solar power generation system 1 shown in FIG. 2A.

  Since the basic configuration is the same as that in FIGS. 1B and 2A, different items will be mainly described.

  The solar battery cell 12s is sunlight Lss that is shielded without being irradiated with sunlight Ls as irradiation light. Therefore, sunlight Lss is not irradiated to the solar cell module 11s, and the photoelectric conversion current source Iph is not generated in the solar cell 12s. In FIG. 2B, a state where the photoelectric conversion current source Iph does not function is indicated by a broken line.

  That is, in the solar cell 12s in the non-power generation state, the photoelectric conversion current source Iph does not operate, so the diode Di, the parallel resistor Rsh arranged in parallel with the diode Di, and the series resistor Rs arranged in series with the parallel resistor Rsh. It is in a state equipped with. In this state, the equivalent circuit of the solar battery cell 12s is configured by a resistance circuit (a series resistance circuit of a series resistance Rs and a parallel resistance Rsh), and the generated voltage Vc obtained in a normal power generation state cannot be obtained. In FIG. 2B, it is indicated by a broken line that the normal generated voltage Vc cannot be obtained.

  The solar battery cell 12s in the non-power generation state does not generate the power generation voltage Vc. Therefore, the solar cell module 11s in which the plurality of solar cells 12s are connected in series does not generate the output voltage Vms. In FIG. 2B, since the power generation voltage Vc at the solar battery cell 12s cannot be obtained, the output voltage Vms at the solar battery module 11s cannot be obtained by a broken line.

  When the solar cell module 11s is in a non-power generation state, in the state where the bypass current path 15s is not conducted, the solar cell 12s is connected to another solar cell module 11 (here, the solar cell module 11f) connected in series. The module group current Ig generated by the electric current flows.

  Therefore, the solar cell module 11s causes a voltage drop due to the module group current Ig flowing through the resistors (series resistor Rs, parallel resistor Rsh). Since a large number of solar cells 12s are connected, the voltage drop in the solar cell module 11s is a large value that cannot be ignored compared to the voltage drop in the solar cells 12s.

  Since a voltage drop occurs in the resistance (series resistance Rs, parallel resistance Rsh) due to the module group current Ig, the voltage relationship between the module terminal 13t and the module terminal 13s is compared with the module terminal 13s. Becomes higher voltage.

  That is, when the solar cell module 11s is in a non-power generation state, the module group current Ig flows through the other solar cell modules 11, so that the potential difference between the module terminal 13s and the module terminal 13t is reversed. That is, in the normal power generation state, the potential of the module terminal 13s is higher than the potential of the module terminal 13t, whereas in the non-power generation state, the potential of the module terminal 13s is lower than the potential of the module terminal 13t.

  In the power generation state, the potential difference between the module terminal 13s and the module terminal 13t is the output voltage Vms, but in the non-power generation state, a voltage drop due to resistance occurs. For convenience of explanation, the potential difference between the module terminal 13s and the module terminal 13t is defined as the output voltage Vms even in the non-power generation state. In other words, when the solar cell module 11s is in a non-power generation state, the output voltage Vms (potential difference between the module terminal 13s and the module terminal 13t) is a specific voltage specified in advance (for example, the output voltage Vms = 0V). ) Smaller.

  When the potential difference between the module terminal 13s and the module terminal 13t changes due to the change from the power generation state to the non-power generation state (for example, when the output voltage Vms becomes 0 V indicating the non-power generation state from the voltage in the power generation state). The control unit 20s (comparator) detects a change in input between the input terminal 21s and the input terminal 22s. When the control unit 20s detects a change in input at the input terminal 21s and the input terminal 22s, the control unit 20s converts the signal output from the output terminal 23s.

  That is, the control unit 20s in the power generation state outputs a signal for turning off (opening) the switching element 16s (MOS field effect transistor) from the output terminal 23s and applies the signal to the control terminal 17s (gate). The control unit 20s in the non-power generation state applies a signal (voltage) for turning on (closing) the switching element 16s (MOS field effect transistor) from the output terminal 23s to the control terminal 17s (gate).

  Therefore, when the solar cell module 11s shifts from the power generation state to the non-power generation state, the control unit 20s switches the switching element 16s from the non-conduction state to the conduction state, and switches the bypass current path 15s from the non-conduction state to the conduction state. The module group current Ig is bypassed.

  After the switching element 16s is switched by the control unit 20s (output terminal 23s), the module group current Ig flows through the bypass current path 15s and does not flow into the solar cell module 11s. In FIG. 2B, a state where the module group current Ig no longer flows in the solar cell module 11s is indicated by a broken line.

  Since the module group current Ig flows through the bypass current path 15s configured as a bypass path, the solar cell module 11s is substantially separated from the solar cell module group 10, and the module group current Ig does not flow. . Further, since the switching element 16s is equivalently replaced with a simple switch, power consumption does not occur (see FIGS. 3A to 3C). Therefore, there is no possibility that a hot spot phenomenon will occur, and it acts in the same way as a bypass diode, and it is possible to prevent power consumption that has become a problem with the bypass diode.

  Note that the threshold of fluctuation of the output voltage Vms detected by the control unit 20s can be adjusted by appropriately setting circuit constants of the control unit 20s and changing the detection levels at the input terminal 21s and the input terminal 22s. In other words, the output voltage Vms has been described as switching the signal output from the output terminal 23s when the output voltage Vms fluctuates from the power generation voltage to the output voltage Vms = 0V. It is possible to use a different value.

  In the above description, the case where the bypass current path 15s is switched from the non-conduction state to the conduction state when the solar cell module 11s changes from the power generation state to the non-power generation state has been described. The same control can be performed for returning the bypass current path 15s from the conductive state to the non-conductive state when the state changes. That is, when the control unit 20s detects that the output voltage Vms has become a normal power generation voltage (for example, the output voltage Vms has become a positive voltage), the control unit 20s brings the bypass current path 15s from the conductive state. It is possible to return to a non-conduction state.

  In FIG. 2A and FIG. 2B, the operation state of the bypass current path 15s, the switching element 16s, and the control unit 20s when the solar cell module 11s is in the non-power generation state has been described. Since the operations of the current path 15f, the switching element 16f, and the control unit 20f are the same, description thereof is omitted.

  FIG. 3A is a circuit symbol diagram showing a circuit symbol of a MIS field effect transistor which is a specific example of the switching element 16 in the photovoltaic power generation system 1 shown in FIG. 1A.

  FIG. 3B is an equivalent circuit diagram showing an off state (open state) of the MIS field effect transistor shown in FIG. 3A with an equivalent switch symbol.

  FIG. 3C is an equivalent circuit diagram illustrating an ON state (closed state) of the MIS field effect transistor illustrated in FIG. 3A with an equivalent switch symbol.

  When the switching element 16 is composed of a MOS field effect transistor (MIS field effect transistor), the source and drain of the MOS field effect transistor are connected to the bypass current path 15 and the gate is connected to the output terminal 23.

  In the off state (FIG. 3B) of the MOS field effect transistor, the bypass current path 15 is disconnected, that is, opened, and the module group current Ig does not flow. Further, in the ON state of the MOS field effect transistor (FIG. 3C), the bypass current path 15 is in a conductive state, that is, a closed state, and the module group current Ig flows.

  Therefore, by turning on the MOS field effect transistor, the bypass current path 15 can be conducted to bypass the module group current Ig.

  When the module group current Ig is 8.4 A (ampere), for example, the voltage drop in the MOS field effect transistor used in the present embodiment is, for example, depending on the characteristics of the MOS field effect transistor used. It is about 0.1 V (volt), and the power consumption can be as close as possible to 0 W, so that the switch does not substantially cause a voltage drop (power consumption).

  FIG. 4 is a power characteristic diagram for explaining the power generation characteristics and the operation of the bypass current path 15 in the photovoltaic power generation system 1 shown in FIG. 1A.

  The power generation characteristics in the photovoltaic power generation system 1 are shown with the horizontal axis representing voltage (V) and the vertical axis representing current (A). That is, the horizontal axis corresponds to the output voltage Vm, and the vertical axis corresponds to the module group current Ig.

  Assuming that the irradiation state of the sunlight Ls is equal and the power generation states in the solar cell module 11f and the solar cell module 11s are equal, the power characteristic curve PCf of the solar cell module 11f and the power characteristic curve PCs of the solar cell module 11s are It is obtained as a similar equal curve.

  Since the solar power generation system 1 is configured by connecting the solar cell module 11f and the solar cell module 11s in series, the power obtained as a whole (power of the solar power generation system 1) is constant in the module group current Ig. The output voltage Vg is obtained by adding the output voltage Vm (output voltage Vmf, output voltage Vms), and is represented by a power characteristic curve PCt (power characteristic curve PCf + power characteristic curve PCs).

  When the maximum power (maximum power point) is indicated by a rectangular power area, the solar cell module 11f is indicated as a rectangular power area RAf, and the solar cell module 11s is indicated as a rectangular power area RAs. Since the rectangular power area RAf and the rectangular power area RAs are in the same power generation state, they are the rectangular power area RAf and the rectangular power area RAs having the same area. Accordingly, the rectangular power area of the solar cell module group 10 is an area (rectangular power area RAt) obtained by adding the rectangular power area RAf of the solar cell module 11f and the rectangular power area RAs of the solar cell module 11s.

  The rectangular power area RAf and the rectangular power area RAs are such that the output voltage Vm at the maximum power (maximum power point) is about 13.5 V, and the module group current Ig at the maximum power is about 8.4 A. The power (maximum power) obtained by each is about 113.4W.

  In the photovoltaic power generation system 1, assuming that the power conversion efficiency of the DC / DC converter 30 is 100%, the output (output power) of the DC / DC converter 30 is equal to the input (input power) to the DC / DC converter 30. .

  When the output voltage Vs of the DC / DC converter 30 is adjusted to the output voltage Vm (about 13.5 V) of the solar cell module 11, the rectangular power area RAt as the output power of the DC / DC converter 30 is set in the current direction. Can be replaced. That is, the rectangular power area RAt is the rectangular power area RAtc (vertical axis direction in the state where the rectangular power area RAf and the rectangular power area RAs are stacked in the current direction. The voltage is adjusted to the output voltage Vm = 13.5V and the current is adjusted. Doubled state).

  The rectangular power area RAtc (output power of the DC / DC converter 30) is approximately 226.8W (twice 113.4W).

  Since the rectangular power area RAtc (output power of the DC / DC converter 30) is converted in the vertical axis direction (current direction) with the output voltage Vm being about 13.5 V, the replaced current is power (about 226.8 W). ) And a voltage of 13.5 V, the result is approximately 16.8 A (approximately 8.4 A × 2).

  When a conventional bypass diode is applied to the bypass current path 15, the solar cell module 11s is in a non-power generation state, the bypass diode operates with respect to the solar cell module 11s, and only the solar cell module 11f is in a power generation state. Assume the time. At this time, since the power is generated only by the solar cell module 11f, the module group current Ig is about 8.4A. The power consumption in the bypass diode at this time is obtained as follows.

  Generally, a Schottky diode with a low forward voltage is applied as the bypass diode. The forward voltage of the Schottky diode is usually about 0.45V to 0.65V. When the forward voltage is about 0.55, the module group current Ig = 8.4 A flows through the Schottky diode, and the power consumption of the Schottky diode is about 8.4 A × 0.55 V = 4.6 W. It becomes.

  When the solar cell module 11s is in a non-power generation state, the output power of the entire solar power generation system 1 is about 113.4 W (output of only the solar cell module 11f), and therefore the ratio of the power consumption of the Schottky diode is 4.6W / 113.4W = 0.04 (4%). That is, the power consumption of the bypass diode is as large as 4%, and is a large value that cannot be ignored as an absolute value.

  Further, the power consumption (about 4.6 W) in the Schottky diode is a loss with respect to the generated power of the solar cell module 11f. When the power consumption 4.6 W is superimposed on the rectangular power area RAf (rectangular power area RAs), the rectangular power area RAbpd (4.6 W / 13.5 V = 0.34 A. That is, it is the value at the upper end of the rectangular power area RAf. 4A minus 0.34A minus a value equal to the area between 8.06A and 8.4A.)

  The power consumption of the bypass diode increases as the scale of the solar cell module 11 increases, and cannot be ignored. In addition, it is necessary to design heat dissipation against loss and to use an actual heat dissipation member. Moreover, even if a heat dissipation design is made, generation of heat cannot be avoided. It is known that the power generation efficiency of the solar battery cell 12 decreases with increasing temperature, and the power generation efficiency of the solar battery cell 12 decreases with the generation of heat. Therefore, the adoption of the bypass diode is a negative factor because it causes unnecessary power consumption.

  In the photovoltaic power generation system 1 according to the present embodiment, since the switching element 16 controlled by the control unit 20 is applied instead of the bypass diode, the power consumption in the bypass current path 15 (switching element 16) is significantly increased. Can be reduced. In particular, by applying a MIS field effect transistor (MOS field effect transistor) as the switching element 16, power consumption in the switching element 16 can be almost eliminated and a greater effect can be achieved.

  Specifically, the power consumption in the MOS field effect transistor when the MOS field effect transistor is applied is, for example, 0.84 W (for example, 8.4 A × 0.1 V), and the power consumption in the bypass diode (4. Compared to 6W), the power consumption is significantly reduced (1 / 5.5).

  As described with reference to FIGS. 1A to 4, the solar power generation system 1 according to the present embodiment is a solar cell module in which a plurality of solar cell modules 11 in which a plurality of solar cells 12 are connected in series are connected in series. Bypass current path that bypasses module group current Ig that flows through solar cell module group 10 when the output voltage of solar cell module 11 is smaller than a specific voltage that is connected in parallel to group 10 and each solar cell module 11 15 and a DC / DC converter 30 that performs DC-DC conversion on the electric power output from the solar cell module group 10, and is arranged in each bypass current path 15 to be bypass current paths A switching element 16 that switches between conduction and non-conduction of 15 and a switching element 16 And a control unit 20 that is arranged corresponding to each and controls the opening and closing of the switching element 16. When the output voltage of the solar cell module 11 becomes smaller than a specific voltage, the control unit 20 closes the switching element 16 from opening to closing. And the bypass current path 15 is made conductive.

  Therefore, the solar power generation system 1 according to the present embodiment is arranged in parallel with the solar cell module 11 that does not generate power when the solar cell module 11 enters a non-power generation state in which power generation is not performed, for example, due to interruption of sunlight Ls. The module current Ig flowing in the solar cell module group 10 is bypassed with the bypass current path 15 in a conductive state (short-circuit state), so that the module to the solar cell module 11 in the non-power generation state without applying the bypass diode (conventional technology) Inflow of the group current Ig can be prevented to prevent generation of hot spots in the solar cell module 11 (solar cell 12), and power consumption that occurs when a bypass diode is applied can be suppressed. . That is, the occurrence of a hot spot phenomenon in the solar power generation system 1 (solar cell module 11, solar cell 12) is prevented to improve reliability, and the solar power generation system 1 (solar cell module 11, solar cell). The life of the cell 12) can be extended and the power generation efficiency can be improved.

  Moreover, in the solar power generation system 1 which concerns on this Embodiment, the control part 20 (control part 20f, control part 20s) is connected to the solar cell module 11 (solar cell module 11f, solar cell module 11s), and is output voltage. Input terminals to which Vm (output voltage Vmf, output voltage Vms) is input (input terminal 21 and input terminal 22. For example, input terminal 21f and input terminal 22f for solar cell module 11f. Input terminal 21s and input for solar cell module 11s Terminal 22s.) And control terminal 17 of switching element 16 (switching element 16f, switching element 16s) (control terminal 17f for switching element 16f, control terminal 17s for switching element 16s) and connected to control opening and closing of switching element 16. Output terminal 2 Characterized in that it is constituted by a comparator and a (output terminal 23s to the output terminal 23f. Control terminal 17s with respect to the control terminal 17f).

  Therefore, the solar power generation system 1 according to the present embodiment detects the non-power generation state of the solar cell module 11 with high accuracy and speed and controls the opening / closing (on / off) of the switching element 16. 11 can be reliably prevented from occurring.

  Moreover, in the solar power generation system 1 which concerns on this Embodiment, the power supply of the control part 20 is supplied from the DC / DC converter 30, It is characterized by the above-mentioned. Therefore, the photovoltaic power generation system 1 according to the present embodiment stabilizes the power supply of the control unit 20 and makes the control of the bypass current path 15 (control unit 20) of the photovoltaic power generation system 1 highly accurate. Can do.

  In the photovoltaic power generation system 1 according to the present embodiment, the switching element 16 is a MIS field effect transistor. Therefore, in the photovoltaic power generation system 1 according to the present embodiment, the switching element 16 is configured by a MIS field effect transistor (generally, a MOS field effect transistor) having a low resistance, and thus the bypass current path 15 (switching element 16). ) Can be reduced, power loss in the bypass current path 15 can be suppressed, and overall power generation efficiency can be improved. Further, since power consumption generated in the bypass current path 15 (switching element 16) is reduced, heat generation due to power consumption is suppressed, so that when the bypass diode is applied, it is necessary in the bypass current path 15 and a heat dissipation means is provided. It can be unnecessary.

  Although the solar power generation system 1 has been mainly described above, the bypass current path 15 (current path), the switching element 16, and the control unit 20 are extracted from the solar power generation system 1 and switching according to the present embodiment (the present invention) is performed. The system 14 will be described.

  Hereinafter, although the switching system 14 is demonstrated applying the relationship with the solar power generation system 1 mentioned above, the switching system 14 which concerns on this Embodiment is not restricted to the case where it is applied to the solar power generation system 1. However, the present invention can be applied to other cases where switching in a general current path is required.

  As described below, two switching systems 14 according to the present embodiment are arranged in correspondence with the solar cell module 11 (solar cell module 11f, solar cell module 11s). In the case of corresponding to the solar cell module 11f, in the case of corresponding to the solar cell module 11s, the configuration is completely the same, so that the switching system 14 will be described without any particular distinction.

  The switching system 14 according to the present embodiment is arranged in a current path (for example, the bypass current path 15 can be exemplified. Also, the bypass current path 15f and the bypass current path 15s can be similarly exemplified) and the current path (bypass current). A switching element 16 that switches between conduction and non-conduction of the path 15) (switching element 16f in the case of the bypass current path 15f; switching element 16s in the case of the bypass current path 15s) and a control unit that controls opening and closing of the switching element 16 20 is a switching system 14.

  Further, in the switching system 14 according to the present embodiment, the control unit 20 has a current path (bypass current path 15) between both ends (in the case of the bypass current path 15f, between the module terminal 13f and the module terminal 13s). In the case of the path 15s, the voltage (between the module terminal 13s and the module terminal 13t) (corresponding to the output voltage Vm in the case of the photovoltaic power generation system. In the case of the bypass current path 15f, it corresponds to the output voltage Vmf. Bypass current path 15s. In this case, the switching of the switching element 16 is controlled based on the output voltage Vms).

  Therefore, the switching system 14 according to the present embodiment controls the opening and closing of the switching element 16 according to the voltage (potential difference) between both ends of the current path (for example, the bypass current path 15). Since the conduction and non-conduction of the current path can be switched according to the correlation state of the potential, the current path can be made to function as necessary by short-circuiting (closing) or opening (opening), and the switching element Since 16 is applied, power consumption when the current path is made conductive can be suppressed.

  In the switching system 14 according to the present embodiment, the control unit 20 is a comparator including a first input terminal (input terminal 21), a second input terminal (input terminal 22), and an output terminal 23. The input terminal (input terminal 21) is the first terminal of the current path (when the current path is, for example, the bypass current path 15f, the module terminal 13f. When the current path is, for example, the bypass current path 15s, the module terminal 13s) And the second input terminal (input terminal 22) is the second terminal of the current path (when the current path is, for example, the bypass current path 15f, the module terminal 13s. When the current path is, for example, the bypass current path 15s, Is connected to the module terminal 13t, and the output terminal (output terminal 23) is connected to the control terminal (control terminal 17) of the switching element 16. It has been.

  Therefore, since the switching system 14 according to the present embodiment includes the control unit 20 as a comparator, both ends of the current path (bypass current path 15) (the module terminal 13f and the module terminal 13s in the bypass current path 15f). The potential states at the module terminal 13s and the module terminal 13t) in the bypass current path 15s can be compared with high accuracy, and the switching of the switching element 16 can be controlled with high accuracy.

  In the switching system 14 according to the present embodiment, the switching element 16 is a MIS field effect transistor (specifically, for example, a MOS field effect transistor), and the source of the MIS field effect transistor is the first terminal (bypass current path 15f). The module terminal 13f is connected to the module terminal 13s in the case of the bypass current path 15s, and the drain of the MIS field effect transistor is the second terminal (the module terminal 13s in the case of the bypass current path 15f. The bypass current path). In the case of 15s, it is connected to the module terminal 13t), and the gate of the MIS field effect transistor is the control terminal (control terminal 17, control terminal 17f in the case of the switching element 16f, control terminal 17s in the case of the switching element 16s). Output terminal (output terminal And it is connected to 23).

  Therefore, since the switching system 14 according to the present embodiment uses the MIS field effect transistor as the switching element 16, it is unnecessary to suppress power consumption when the switching element 16 is conductive (when the current path is conductive). Generation of high power consumption is prevented and an efficient switching system is obtained.

  In the switching system 14 according to the present embodiment, the control unit 20 is supplied with power from an external power supply (for example, a DC / DC converter 30) disposed outside.

  Therefore, since the switching system 14 according to the present embodiment operates with external power supply power, stable operation can be realized.

  In the switching system 14 according to the present embodiment, the external power supply is the output of a DC / DC converter (DC / DC converter 30) that performs DC / DC conversion on the output of the solar cell module (solar cell module 11).

  Therefore, the switching system 14 according to the present embodiment uses the output of the DC / DC converter (DC / DC converter 30) that adjusts the output of the solar cell module (solar cell module 11). Application to a control system provided is possible, and the bypass diode constituting the bypass circuit of the solar cell module can be replaced with the switching element 16 to suppress the occurrence of power consumption, which is a problem with the bypass diode.

  The switching element 16 and the control unit 20 can be mounted on a common printed circuit board (not shown) and mounted on a terminal box (not shown) of the solar cell module 11 or the like.

<Embodiment 2>
Hereinafter, a photovoltaic power generation system, a switching system, and a bypass device according to Embodiment 2 of the present invention will be described with reference to FIGS. 6A to 7C. Since the basic configuration of the photovoltaic power generation system and the switching system according to the present embodiment is the same as that of the first embodiment described above (FIGS. 1A to 4), the reference numerals are used mainly, Explain the different points.

  FIG. 6A is a block diagram showing a schematic block configuration of the photovoltaic power generation system 1 according to Embodiment 2 of the present invention.

  Note that the components of the switching system 14 are included as some components of the photovoltaic power generation system 1. For example, the bypass current path 15, the switching element 16, and the control unit 26 constitute the switching system 14. A control unit 26f is arranged for the solar cell module 11f, and a control unit 26s is arranged for the solar cell module 11s. Hereinafter, the control unit 26f and the control unit 26s may be simply referred to as the control unit 26 when it is not necessary to distinguish between them.

  The switching element 16 is composed of a MOS field effect transistor (enhanced n-channel) as in the first embodiment.

  In the first embodiment, the control unit 20 is configured by a comparator. However, the control unit 26 according to the present embodiment particularly distinguishes the diode Ds, the resistor R1, and the resistor R2 (hereinafter, the resistor R1 and the resistor R2). When there is no need, it may be simply a resistor R.).

  The photovoltaic power generation system 1 according to the present embodiment includes a solar cell module 11 configured by connecting a plurality of solar cells 12 that convert sunlight Ls into electricity (electric power) by photoelectric conversion. A plurality of solar cell modules 11 (for example, a solar cell module 11f and a solar cell module 11s) are connected in series to constitute a solar cell module group 10. The solar cell module group 10 can be configured by connecting a larger number of solar cell modules 11. However, for convenience of explanation, two solar cell modules 11 (a solar cell module 11f and a solar cell module 11s) are provided. A case of connection will be described.

  The solar cell modules 11 irradiated with sunlight Ls are each converted into an output voltage Vm (the output voltage Vm of the solar cell module 11f is an output voltage Vmf and the output voltage Vm of the solar cell module 11s is an output voltage Vms) by photoelectric conversion. When it is not necessary to distinguish between the voltage Vmf and the output voltage Vms, the output voltage Vm may be simply generated.) And the voltage added by the series connection of the solar cell modules 11 is the output of the solar cell module group 10. The voltage Vg is input to the input terminal 31 of the DC / DC converter 30.

  A common module group current Ig flows through each of the solar cells 12 connected in series. Therefore, the solar cell module group 10 supplies the module group current Ig to the input end 31 of the DC / DC converter 30 using the solar cell module 11f and the solar cell module 11s as current paths.

  The photovoltaic power generation system 1 includes a bypass current path 15 connected in parallel with the solar cell module 11, a switching element 16 inserted in the bypass current path 15 to switch conduction / non-conduction of the bypass current path 15, and opening / closing of the switching element 16 (On / off. For example, an on state corresponds to a closed state, and an off state corresponds to an open state.)

  Since the bypass current path 15 is connected in correspondence with the solar cell module 11, two bypass current paths 15f corresponding to the solar cell module 11f and the solar cell module 11s are associated with the solar cell module 11. The bypass current path 15s) is arranged. Hereinafter, when there is no need to particularly distinguish the bypass current path 15f and the bypass current path 15s, the bypass current path 15 may be simply used.

  The bypass current path 15f is connected in parallel to the solar cell module 11f, and the bypass current path 15s is connected in parallel to the solar cell module 11s. That is, the bypass current path 15f is connected between the module terminal 13f and the module terminal 13s, and the bypass current path 15s is connected between the module terminal 13s and the module terminal 13t.

  A switching element 16f is inserted (arranged) in the bypass current path 15f, and a switching element 16s is inserted (arranged) in the bypass current path 15s. When it is not necessary to distinguish the switching element 16f and the switching element 16s, the switching element 16 may be simply used.

  Moreover, since the control part 26 is connected corresponding to the solar cell module 11 and the bypass current path | route 15, it is the same as the solar cell module 11 (control corresponding to the solar cell module 11f and the bypass current path | route 15f). 26f, the solar cell module 11s, and the control unit 26s) corresponding to the bypass current path 15s. That is, the control unit 26f is connected between the module terminal 13f and the module terminal 13s, and the control unit 26s is connected between the module terminal 13s and the module terminal 13t. Hereinafter, the control unit 26f and the control unit 26s may be simply referred to as the control unit 26 when it is not necessary to distinguish between them.

  The control unit 26f and the control unit 26s have the same configuration. Specifically, the control unit 26f is configured by a series circuit of a diode Dsf (diode Ds), a resistor R1f (resistor R1), and a resistor R2f (resistor R2). The control unit 26s includes a series circuit of a diode Dss (diode Ds), a resistor R1s (resistor R1), and a resistor R2s (resistor R2).

  Hereinafter, the diode Dsf and the diode Dss may be simply referred to as the diode Ds when it is not necessary to distinguish between them. In addition, when there is no need to distinguish between the resistor R1f and the resistor R1s, the resistor R1 may be simply used as the resistor R1. In addition, when there is no need to distinguish between the resistor R2f and the resistor R2s, the resistor R2 may be simply used as the resistor R2.

  That is, the control unit 26 is configured as a series circuit of a diode Ds, a resistor R1, and a resistor R2. Note that various modifications can be applied to the arrangement relationship (connection relationship) of the diode Ds, the resistor R1, and the resistor R2. A modification will be described with reference to FIGS. 7A to 7C.

  The diode Dsf has a cathode side connected to the module terminal 13f and an anode side connected to the module terminal 13s. The diode Dss has a cathode side connected to the module terminal 13s and an anode side connected to the module terminal 13t. A resistor R1 and a resistor R2 are connected in series to the diode Ds. Since the resistor R1 and the resistor R2 are connected in series, the same current flows and a voltage drop corresponding to the resistance (resistance value) is generated. Therefore, by setting the resistance value to an appropriate value, Can be divided into a voltage having a desired ratio.

  The control unit 26 includes a voltage dividing terminal 27 that outputs a divided voltage. That is, the voltage dividing terminal 27 (the voltage dividing terminal 27f in the control unit 26f and the voltage dividing terminal 27s in the control unit 26s) is connected between the resistor R1 and the resistor R2, and the ratio of the resistance values of the resistor R1 and the resistor R2 The divided voltage Vd determined by is output. In the control unit 26f, the divided terminal 27f is an output terminal and the divided voltage Vdf is output, and in the control unit 26s, the divided terminal 27s is the output terminal and the divided voltage Vds is output. Hereinafter, when there is no need to distinguish between the voltage dividing terminal 27f and the voltage dividing terminal 27s, the voltage dividing terminal 27 may be simply used. In addition, when it is not necessary to distinguish between the divided voltage Vdf and the divided voltage Vds, the divided voltage Vd may be simply used.

  The voltage dividing terminal 27 is connected to the control terminal 17. The voltage dividing terminal 27f is connected to the control terminal 17f, and the voltage dividing terminal 27s is connected to the control terminal 17s. Therefore, the voltage dividing terminal 27f and the voltage dividing terminal 27s can control the switching element 16 by the potential (divided voltage Vd) output to each. Hereinafter, when it is not necessary to distinguish between the control terminal 17f and the control terminal 17s, the control terminal 17 may be simply referred to as the control terminal 17.

  In the present embodiment, the divided voltage Vdf output to the voltage dividing terminal 27f of the control unit 26f is set with reference to the module terminal 13f of the solar cell module 11f, and is output to the voltage dividing terminal 27s of the control unit 26s. The divided voltage Vds is set with reference to the module terminal 13s of the solar cell module 11s.

  The divided voltage Vd is merely defined for convenience in order to explain the voltage (potential) applied to the control terminal 17 and the operating state of the switching element 16, and the other resistor (resistor R2) side is used as a reference. It is also possible to define (based on the module terminal 13s of the solar cell module 11f and the module terminal 13t of the solar cell module 11s).

  When the solar cell module 11f is in a normal power generation state, the module terminal 13f has a positive output voltage Vmf between the module terminal 13f and the module terminal 13s with respect to the module terminal 13s. That is, since the potential of the module terminal 13f becomes higher than the potential of the module terminal 13s, the diode Dsf is reverse-biased and no current flows through the series circuit (control unit 26f). Therefore, in the normal power generation state, the potential of the module terminal 13s is output as the divided voltage Vdf with respect to the potential of the module terminal 13f. That is, the divided voltage Vdf (potential of the voltage dividing terminal 27f) is negative with respect to the potential of the module terminal 13f.

  As described above, the switching element 16f is composed of a MOS field effect transistor, the source of the MOS field effect transistor is connected to the module terminal 13f, the drain is connected to the module terminal 13s, and the gate (control terminal 17f) is the split terminal. It is connected to the pressure terminal 27f. Therefore, in a normal power generation state, the potential of the gate (divided voltage Vdf: potential of the divided terminal 27f) is negative with respect to the potential of the source (potential of the module terminal 13f), and the MOS field effect transistor, that is, the switching element 16f. Is opened (off), and the bypass current path 15f does not function (a state in which no current flows).

  When the solar cell module 11s is in a normal power generation state, the module terminal 13s has a positive output voltage Vms between the module terminal 13s and the module terminal 13t with respect to the module terminal 13t. That is, since the potential of the module terminal 13s is higher than the potential of the module terminal 13t, the diode Dss is reverse-biased and no current flows through the series circuit (control unit 26s). Therefore, in the normal power generation state, the potential of the module terminal 13t is output as the divided voltage Vds with respect to the potential of the module terminal 13s. That is, the divided voltage Vds (potential of the voltage dividing terminal 27s) is negative with respect to the potential of the module terminal 13s.

  The switching element 16s is composed of a MOS field effect transistor, the source of the MOS field effect transistor is connected to the module terminal 13s, the drain is connected to the module terminal 13t, and the gate (control terminal 17s) is connected to the voltage dividing terminal 27s. It is connected. Therefore, in a normal power generation state, the potential of the gate (divided voltage Vds: potential of the divided terminal 27s) is negative with respect to the source potential (potential of the module terminal 13s), and the MOS field effect transistor, that is, the switching element 16s. Is opened (off), and the bypass current path 15s does not function (a state in which no current flows).

  The reverse breakdown voltage of the diode Ds (diode Dsf, diode Dss) may be a value that exceeds the output voltage Vm (output voltage Vmf, output voltage Vms) in a normal power generation state. That is, if the reverse breakdown voltage of the diode Ds exceeds the output voltage Vm, the diode Ds can block the reverse current, so that no current flows through the control unit 26 (series circuit).

  6B is a block diagram showing a schematic block configuration when the bypass current path 15s is made to function by the photovoltaic power generation system 1 shown in FIG. 6A.

  Since the basic configuration is the same as that in FIG. 6A, a mode when the bypass current path 15s and the control unit 26s are mainly operated will be described. Note that the bypass current path 15f and the control unit 26f operate in the same manner as the bypass current path 15s and the control unit 26s, and thus the description when the bypass current path 15f and the control unit 26f operate is omitted.

  The sunlight Ls may become sunlight Lss (showing a state corresponding to the solar cell module 11s) in a state where the sunlight Ls is shielded by generation of a shadow or the like. The sunlight Lss is shown only outside the solar cell module 11s in order to show a state where the sunlight Ls is shielded compared to the sunlight Ls. Below, the case where the solar cell module 11s (solar cell 12s), for example, is shielded from light and does not generate power will be described.

  Since the light-shielded solar cell module 11s (solar cell 12s) cannot perform photoelectric conversion, it does not generate power as a solar cell. In order to show a state in which power generation (function) does not occur as a solar cell, the solar cell module 11s (solar cell 12s) is shown by a broken line in FIG. 6B.

  In a normal power generation state, as described above, the output voltage Vms is generated between the module terminal 13s that is the positive terminal of the solar cell module 11s and the module terminal 13t that is the negative terminal. That is, in a normal power generation state, the potential of the module terminal 13s is higher than the potential of the module terminal 13t.

  However, in a state where power generation is not possible due to light shielding, the solar cell module 11s becomes a passive circuit (see FIGS. 1B and 2B). That is, when a module group current Ig flowing by power generation of another solar cell module 11 connected in series (here, the solar cell module 11f) flows, the solar cell module 11s acts as a resistance load, and the potential of the module terminal 13s. On the other hand, the potential of the module terminal 13t becomes higher, and the potential difference between the module terminal 13s and the module terminal 13t is opposite to that in the power generation state.

  That is, in the non-power generation state, the module terminal 13t is at a higher potential than the module terminal 13s, and the diode Dss flows a forward current. Therefore, a current (a shunt current Igb) corresponding to the potential difference between the module terminal 13s and the module terminal 13t flows through the series circuit (control unit 26s) of the diode Dss, the resistor R1s, and the resistor R2s.

  In the control unit 26s (series circuit), a voltage drop at the resistors R1s and R2s and a forward voltage drop at the diode Dss are generated by the shunt current Igb, and a divided voltage Vds is generated. In the series circuit (control unit 26) when the solar cell module 11s is in the non-power generation state (FIG. 6B), the divided voltage Vds is a value determined by the forward voltage drop of the diode Dss and the voltage drop at the resistor R1s. The divided voltage Vdf can be similarly defined for the control unit 26f. Hereinafter, when it is not necessary to distinguish between the divided voltage Vds and the divided voltage Vdf, the divided voltage Vds may be simply referred to as a divided voltage Vd.

  The circuit design is such that the value of the divided voltage Vds is a value sufficient to bring the switching element 16s into an on state (closed state) (specifically, a value exceeding the threshold of the switching element 16s (MOS field effect transistor)). By performing (setting element constants), the control unit 26s generates the divided voltage Vds. Further, the divided voltage Vds is applied from the voltage dividing terminal 27s to the control terminal 17s (gate) to turn on (close) the switching element 16s (MOS field effect transistor), so that the bypass current path 15s becomes conductive. .

  In addition, the concrete numerical value of resistance R1s, resistance R2s, and diode Dss which comprise a series circuit (control part 26) can be set suitably.

  For example, when the divided voltage Vds is set to be the threshold value of the MOS field effect transistor (switching element 16) and the switching element 16 is turned on when the divided current Igb flows 20 mA, the threshold value of the MOS field effect transistor is set to For example, assuming that the voltage is 2V and the forward voltage of the diode Dss is ignored for simplicity, the resistance value required for the resistor R1s is 2V / 20 mA = 100Ω. For simplicity, if the voltage dividing ratio between the resistor R1 and the resistor R2 is 1, the resistor R2s can have the same resistance value as that of the resistor R1.

  That is, when the solar cell module 11s enters the non-power generation state, the shunt current Igb (initially, the transient module group current Ig flows as the shunt current Igb) flows out, and the shunt current Igb becomes 20 mA. The divided voltage Vds exceeds 2 V (in practice, a forward voltage drop of the diode Dss is further added). Note that the potential difference between the module terminal 13t and the module terminal 13s at this time is as follows: a voltage drop at the resistor R1 (2V), a voltage drop at the resistor R2 (2V), and a quasi-directional voltage drop at the diode Dss (Vf: For example, Vf is a value obtained by adding 0.5 V).

  When the shunt current Igb becomes 20 mA and the voltage drop at the resistor R1s becomes 2V, the divided voltage Vds (2V + 0.5V = 2.5V) is applied to the control terminal 17s, and the switching element 16s is reliably turned on. Since the module group current Ig flows through the bypass current path 15s after the switching element 16s is turned on, the same operational effects as those of the first embodiment can be obtained.

  As for the shunt current Igb, the module group current Ig flowing in the solar cell module group 10 flows in a transitional state when the solar cell module 11s is in the non-power generation state until the switching element 16s is turned on. Further, in a state immediately before the switching element 16s is turned on, the module group current Ig in a transient state flows as the shunt current Igb as it is.

  After the switching element 16s is turned on, a part of the module group current Ig flows in the shunt current Igb according to the voltage between the module terminal 13s and the module terminal 13t. That is, a current (module group current Ig−divided current Igb) having a value obtained by subtracting the shunt current Igb from the module group current Ig flows through the switching element 16s.

  Since the shunt current Igb only needs to generate the divided voltage Vds to turn on the switching element 16s, the shunt current Igb is set to a small value so that power consumption in the resistor R (resistor R1, resistor R2) can be suppressed. ing. Specifically, the shunt current Igb is, for example, about 1/100 to 1/500 of the module group current Ig after the switching element 16s is switched on (for example, when the module group current Ig is 8.4 A). The shunt current Igb can be set to 20 mA, for example.

  The switching element 16 once turned on is set to an element configuration that maintains the on state, and the switching element 16 is turned off when the solar cell module 11 returns to the normal power generation state. In such a case, it is possible to control the on / off (open / close) of the switching element 16 by connecting the voltage dividing terminal 27 of the control unit 26 (series circuit) to the control terminal 17.

  In this embodiment, since the switching element 16 is composed of a MOS field effect transistor (MIS field effect transistor), when the switching element 16 (MOS field effect transistor) is turned on, the source-drain voltage Is substantially 0 V (for example, 0.1 V), and the voltage between the source and the drain is directly the voltage (potential difference) across the series circuit (control unit 26). At this time, the voltage dividing terminal 27 divides and outputs approximately 0 V (for example, 0.1 V), which is a source-drain voltage, and therefore has a value smaller than approximately 0 V (0.1 V).

  That is, as described above, the threshold voltage of the MOS field-effect transistor is 2 V, for example. Therefore, when the switching element 16 is turned on, the gate voltage (the voltage at the voltage dividing terminal 27 and the voltage at the control terminal 17) is As a result, the MOS field-effect transistor returns to the off state.

  Therefore, in the photovoltaic power generation system 1 and the switching system 14 according to the present embodiment, since the MOS field effect transistor (MIS field effect transistor) is applied as the switching element 16, the circuit that maintains the ON state of the MOS field effect transistor. (A switching state maintaining circuit 26c (see FIG. 8) for maintaining the potential state of the control terminal 17 when the switching element 16 is switched from OFF to ON) is separately required. For convenience of explanation, the switching state maintaining circuit 26c will be described separately with reference to FIG.

  As described above, in the photovoltaic power generation system 1 according to the present embodiment, the control unit 26 is a series circuit in which the diode Ds and the two resistors R (resistors R1 and R2) are connected in series, and is a solar cell module. 11 is connected in parallel to the two resistors R1 and R2, and includes a voltage dividing terminal 27 that divides and outputs the output voltage Vm of the solar cell module 11, and the voltage dividing terminal 27 is a switching device. It is connected to the control terminal 17 of the element 16.

  Therefore, the solar power generation system 1 is connected in parallel with the solar cell module 11 as a control unit 26, which is a series circuit of a simple configuration of three elements of the diode Ds and the two resistors R (resistor R1, resistor R2). Since the output state of the solar cell module 11 can be easily and accurately extracted as a signal (divided voltage Vd) from the voltage dividing terminal 27, the switching element 16 is based on the potential (divided voltage Vd) of the voltage dividing terminal 27. Can be easily and accurately controlled.

  Further, since the control unit 26 that is a series circuit is connected to the solar cell module 11 in parallel, a signal for controlling the opening and closing of the switching element 16 without using an external power source (a power source other than the solar cell module 11) is connected to the series circuit. It can be easily obtained as an output (divided voltage Vd) from the voltage dividing terminal 27 of the (control unit 26).

  In the solar power generation system 1, the switching element 16 and the control unit 26 are mounted on a single wiring board 40 and are built in the output box 60 of the solar cell module 11. Therefore, since the photovoltaic power generation system 1 mounts the switching element 16 and the control unit 26 (series circuit) on one wiring board 40 and incorporates them in the output box 60, the bypass current path 15 for the solar cell module 11 is highly functional. Can be The output box 60 is normally disposed on the back surface (surface opposite to the light receiving surface) of the solar cell module 11 and the like, and a cable necessary for connection with another solar cell module 11 is connected thereto.

  In the present embodiment, the switching system 14 is provided as in the first embodiment. In the present embodiment, two switching systems 14 are arranged corresponding to the solar cell modules 11 (the solar cell module 11f and the solar cell module 11s) as in the first embodiment. Since the configuration is exactly the same, the switching system 14 will be described without particular distinction.

  The switching system 14 is not limited to the application to the solar cell module 11 but can be applied to on / off of a general current path. In the present embodiment, the switching system 14 includes a bypass current path 15, a switching element 16, and a control unit 26. The difference from the switching system 14 in the first embodiment is that a control unit 26 is applied instead of the control unit 20. Therefore, the control unit 26 will be mainly described.

  In the switching system 14 according to the present embodiment, the control unit 26 is a series circuit in which the diode Ds and two resistors (resistor R1, resistor R2) are connected in series, and is connected to both ends of the current path (bypass current path 15). The voltage dividing terminal 27 is connected in parallel and connected between the two resistors R1 and R2 to divide and output the output voltage Vm of the solar cell module 11, and the voltage dividing terminal 27 is connected to the switching element 16. The control terminal 17 is connected.

  Therefore, the switching system 14 according to the present embodiment is connected in parallel with the current path (bypass current path 15) using the simple circuit series circuit including the diode Ds and the two elements R1 and R2 as the control unit 26. As a result, the potential state between both ends of the current path can be easily and accurately extracted as a signal (divided voltage Vd) from the voltage dividing terminal 27, so that the potential of the voltage dividing terminal 27 (divided voltage Vd) is obtained. Based on this, the opening and closing of the switching element 16 can be easily and accurately controlled.

  Further, since the control unit 26 configured as a series circuit is connected in parallel to the current path, a signal for controlling the opening / closing of the switching element 16 without using an external power source (a power source other than the current path) is transmitted to the series circuit (control unit 26). ) Can be easily obtained as an output (divided voltage Vd) from the voltage dividing terminal 27.

  In the present embodiment, an external power supply is not required for the control unit 26s (it is only necessary to connect to both ends of the bypass current path 15s as a control target), so that the bypass current path 15s, the switching element 16s, The self-operation type (self-standing type) bypass device 25s including the control unit 26s can be extracted as an individual device.

  Further, the control unit 26f is arranged in the same manner as the control unit 26s. That is, in the present embodiment, an external power supply for the control unit 26f is not necessary (it is only necessary to connect to both ends of the bypass current path 15f as a control target), so that the bypass current path 15f, the switching element 16f, The self-acting (self-standing) bypass device 25f including the control unit 26f can be extracted as an individual device.

  Hereinafter, when there is no particular need to distinguish between the bypass device 25f and the bypass device 25s, the bypass device 25 may be simply referred to as the bypass device 25.

  The bypass device 25 according to the present embodiment is a bypass device 25 that configures the bypass current path 15 by being connected to both ends of the solar cell module 11, and is a switching element that switches between conduction and non-conduction of the bypass current path 15. 16 and a control unit 26 that is arranged corresponding to the switching element 16 and controls the opening and closing of the switching element 16. The control unit 26 includes a series circuit in which a diode Ds and two resistors R1 and R2 are connected in series. And a voltage dividing terminal 27 for dividing and outputting the output voltage Vm of the solar cell module 11 from between the two resistors R1 and R2 when connected in parallel to the solar cell module 11. The terminal 27 is connected to the control terminal 17 of the switching element 16.

  Therefore, the bypass device 25 according to the present embodiment connects a series circuit having a simple configuration of three elements of the diode Ds and the two resistors R1 and R2 in parallel with the solar cell module 11 as the control unit 26. Since the output state of the solar cell module 11 can be easily and accurately extracted as a signal (divided voltage Vd) from the voltage dividing terminal 27, the switching element 16 is based on the potential (divided voltage Vd) of the voltage dividing terminal 27. Can be easily and accurately controlled.

  The bypass device 25 only needs to connect the switching element 16 and the control unit 26 to both ends of the bypass current path 15 and does not require a separate power supply, and can be mounted on a single wiring board. That is, in the bypass device 25, the switching element 16 and the control unit 26 are mounted on a single wiring board 40. Further, since it can be mounted on a single wiring board, it can be housed in a single package, and productivity and reliability can be improved.

  Therefore, since the bypass device 25 according to the present embodiment mounts the switching element 16 and the control unit 26 (series circuit) on one wiring board 40, the bypass device 25 can be reduced in size, so that the output of the solar cell module 11 can be reduced. The box 60 can be easily incorporated.

  In the present embodiment, two wiring boards 40 and output boxes 60 are arranged corresponding to the solar cell module 11 (solar cell module 11f, solar cell module 11s). Since the configuration is exactly the same, the description will be made simply as the wiring board 40 and the output box 60 without particular distinction.

  In the block diagrams (FIGS. 6A and 6B), the module terminal 13s is described in common on the bypass current path 15f (control unit 26f) side and the bypass current path 15s (control unit 26s) side. However, since the wiring board 40 and the output box 60 are arranged with respect to the solar cell module 11, wiring for the module terminal 13s on the bypass current path 15f side and wiring for the module terminal 13s on the bypass current path 15s May be arranged independently, but they are described in common for the sake of simplicity.

  A modified example (modified circuit example 1 to modified circuit example 3) of the control unit 26 (series circuit) will be described with reference to FIGS. 7A to 7C. Since the basic configuration is the same as in the case of FIGS. 6A and 6B, different items will be mainly described.

  FIG. 7A is a circuit diagram showing a modified circuit example 1 of the control unit 26 (series circuit) in the photovoltaic power generation system 1 shown in FIG. 6A.

  FIG. 7B is a circuit diagram illustrating a modified circuit example 2 of the control unit 26 (series circuit) in the photovoltaic power generation system 1 illustrated in FIG. 6A.

  FIG. 7C is a circuit diagram illustrating a modified circuit example 3 of the control unit 26 (series circuit) in the photovoltaic power generation system 1 illustrated in FIG. 6A.

  In the modified circuit example 1 to the modified circuit example 3, in order to simplify the description, the solar cell module 11 and the control unit 26 are described as one each. Therefore, the module terminal 13f, the module terminal 13s, and the module terminal 13t when the two solar cell modules 11 are arranged are simplified when the number of the solar cell modules 11 is one, and the terminals (module terminals) that are on the plus side in the normal power generation state 13p) and a negative terminal (module terminal 13m). That is, in the normal power generation state of the solar cell module 11, the module terminal 13p is on the positive side and the module terminal 13m is on the negative side. The “normal power generation state” refers to a state where the bypass current path 15 and the switching element 16 do not need to be turned on (closed state).

  The control unit 26 includes a module terminal 13p (for example, the module terminal 13s corresponds to the solar cell module 11s) and a module terminal 13m (for example, the module terminal 13t corresponds to the solar cell module 11s). .) Is connected between. The divided voltage Vd is defined by the potential (divided voltage Vd) of the divided terminal 27 with respect to the module terminal 13p.

  In the modified circuit example 1, a resistor R1, a diode Ds, and a resistor R2 are connected in series in this order from the module terminal 13p side to the module terminal 13m to form a series circuit (control unit 26) ( The position of the diode Ds is different compared to FIG. 6A). The voltage dividing terminal 27 is taken out between the resistor R1 and the diode Ds (cathode side). Therefore, the divided voltage Vd is defined by the ratio between the voltage drop at the resistor R1 due to the shunt current Igb and the sum of the forward voltage drop at the diode Ds due to the shunt current Igb and the voltage drop at the resistor R2 due to the shunt current Igb. Is done.

  Although the voltage dividing ratio by the resistors R1 and R2 has been described as 1 in FIG. 6A, the voltage dividing ratio is set appropriately in consideration of the forward voltage drop of the divided current Igb, the divided voltage Vd, the resistor R, and the diode Ds. can do.

  In the modified circuit example 2, the resistor R1, the diode Ds, and the resistor R2 are connected in series in this order from the module terminal 13p side to the module terminal 13m to form a series circuit (control unit 26) ( Same as modified circuit example 1). Further, the voltage dividing terminal 27 is taken out from between the resistor R1 and the diode Ds (anode side) (the taking-out position of the voltage dividing terminal 27 is different from the modified circuit example 1). Therefore, the divided voltage Vd is defined by the ratio of the sum of the voltage drop at the resistor R1 due to the shunt current Igb and the forward voltage drop at the diode Ds due to the shunt current Igb and the voltage drop at the resistor R2 due to the shunt current Igb. Is done.

  In the modified circuit example 3, the resistor R1, the resistor R2, and the diode Ds are connected (arranged) in order from the module terminal 13p side to the module terminal 13m to form a series circuit (control unit 26) ( 6A, the position of the diode Ds is different from that of the modified circuit example 1 and the modified circuit example 2, and the diode Ds is disposed on the module terminal 13m side. The voltage dividing terminal 27 is taken out from between the resistor R1 and the resistor R2 (similar to FIG. 6A). Therefore, the divided voltage Vd is defined by the ratio of the voltage drop at the resistor R1 due to the shunt current Igb to the sum of the voltage drop at the resistor R2 due to the shunt current Igb and the forward voltage drop at the diode Ds due to the shunt current Igb. Is done.

  The photovoltaic power generation system 1 and the switching system 14 according to the present embodiment operate in the same manner as in the first embodiment. Further, the bypass device 25 operates as described above. That is, there exists an effect as demonstrated in FIG.

  FIG. 8 is a circuit diagram showing a more specific circuit example of the control unit 26 in the photovoltaic power generation system 1 shown in FIG. 6A.

  As described above, in the present embodiment, the switching element 16 is configured by a MOS field effect transistor (MIS field effect transistor). Therefore, when the switching element 16 is turned on (closed state), the potential difference between both ends of the solar cell module 11 becomes equal to the on voltage of the switching element 16. In general, the on-voltage of a MOS field effect transistor is a very low value of approximately 0 V (for example, 0.1 V). That is, the divided voltage Vd that has acted when switching the switching element 16 to the on state is reduced to be smaller than the threshold value of the switching element 16 (MOS field effect transistor), and the switching element 16 is turned off again. Therefore, a case where a circuit (switching state maintaining circuit 26c) for maintaining the ON state of the switching element 16 is required will be described.

  Since the switching element 16 and the control unit 26 (series circuit of the diode Ds, the resistor R1, and the resistor R2) are as described above, description thereof may be omitted as appropriate.

  The control unit 26 includes a switching state maintaining circuit 26 c between the voltage dividing terminal 27 and the control terminal 17. The switching state maintaining circuit 26 c has a diode Dc having an anode connected to the voltage dividing terminal 27, a cathode connected to the control terminal 17, one end connected to the control terminal 17, and the other end in the power generation state of the solar cell module 11. And a capacitor Cg connected to the module terminal 13p on the positive side.

  When the switching element 16 switches from the off state to the on state, the shunt current Igb flows to the control unit 26, but a part of the shunt current Igb flows to the capacitor Cg via the diode Dc, and charges the capacitor Cg. As a result of the charging, the charging voltage of the capacitor Cg becomes a charging voltage Vh (maintenance voltage) equal to the divided voltage Vd. Actually, since the forward voltage Vf of the diode Dc is interposed, the divided voltage Vd = charge voltage Vh + Vf. When the charging voltage Vh becomes equal to or higher than the threshold value of the switching element 16 (MOS field effect transistor), the switching element 16 is switched from the off state to the on state.

  When the switching element 16 is switched from the off state to the on state, the potential difference between both ends of the switching element 16 (potential difference between the module terminal 13p and the module terminal 13m) becomes approximately 0V (for example, 0.1V). Therefore, the divided voltage Vd is approximately 0 V (for example, 0.1 V) or less because the potential difference between both ends of the switching element 16 is divided. At this time, since the diode Dc connected between the control terminal 17 and the voltage dividing terminal 27 is in a reverse bias state, the control terminal 17 supplies the charging voltage Vh to the divided voltage Vd of approximately 0V. Can be maintained. Note that the reverse withstand voltage of the diode Dc needs to be larger than the power reception voltage Vh.

  Since the switching state maintaining circuit 26c can secure the potential (charging voltage Vh) when the switching element 16 is switched from OFF to ON by the charge accumulated in the capacitor Cg, the potential of the control terminal 17 can be secured. The state (the voltage applied to the control terminal 17, that is, the charging voltage Vh) can be maintained. That is, the switching state maintaining circuit 26c performs charging on the capacitor Cg according to the potential (divided voltage Vd) of the voltage dividing terminal 27 in the forward direction of the diode Dc, and discharges the charge charged in the capacitor Cg. This is prevented by the reverse breakdown voltage of the diode Dc. Therefore, the switching state maintaining circuit 26c can maintain the potential state of the control terminal 17 by maintaining the charging voltage Vh of the capacitor Cg with high accuracy.

  That is, the influence caused by the decrease in the divided voltage Vd due to the switching element 16 switching from OFF to ON (the influence caused by the potential difference between the charging voltage Vh and the divided voltage Vd) is ignored by the reverse withstand voltage of the diode Dc. Since the charge of the capacitor Cg is maintained as it is, the ON state of the switching element 16 can be maintained. In other words, the switching state maintaining circuit 26c configured by the diode Dc and the capacitor Cg maintains the potential state of the control terminal 17 when the switching element 16 is switched from OFF to ON. Can be maintained.

  The control unit 26 further includes a discharging diode Ddc in addition to the switching state maintaining circuit 26c. The discharge diode Ddc has an anode connected to the control terminal 17 and a cathode connected to the module terminal 13m.

  Therefore, when the solar cell module 11 returns to the normal power generation state with the capacitor Cg charged with the charging voltage Vh, and the module terminal 13p becomes positive with respect to the module terminal 13m, the capacitor Cg is charged. The electric charge is discharged to the module terminal 13m by the discharging diode Ddc. That is, the switching state maintaining circuit 26c is provided with the discharging diode Ddc, so that the charged charge of the capacitor Cg can be surely discharged and stable switching with high reliability can be executed.

  As described above, in the bypass device 25 according to the present embodiment, the control unit 26 is disposed between the voltage dividing terminal 27 and the control terminal 17 and the control terminal 17 when the switching element 16 is switched from OFF to ON. The switching state maintaining circuit 26c is maintained.

  Therefore, the bypass device 25 has the potential state (signal state) of the control terminal 17 even when the voltage (divided voltage Vd) applied to the control unit 26 is reduced due to the switching element 16 being switched from OFF to ON. Since the voltage applied to the control terminal 17 is maintained, the ON state of the switching element 16 can be maintained.

  The switching state maintaining circuit 26c has a diode Dc whose anode is connected to the voltage dividing terminal 27, cathode is connected to the control terminal 17, one end is connected to the control terminal 17, and the other end is a power generator of the solar cell module 11. And a capacitor Cg connected to the module terminal 13p on the plus side in the state.

  Therefore, even when the voltage applied to the control unit 26 is reduced by switching the switching element 16 from OFF to ON, the bypass device 25 can be configured with the potential state (control terminal) of the control terminal 17 with a simple combination of the diode Dc and the capacitor Cg. Since the voltage applied to the switching element 16 can be maintained by the charging voltage Vh applied to the capacitor Cg, the ON state of the switching element 16 can be easily maintained.

  The control unit 26 includes a discharge diode Ddc whose anode is connected to one end of the capacitor Cg and whose cathode is connected to the module terminal 13m that is on the negative side in the power generation state of the solar cell module 11.

  Therefore, when the solar cell module 11 is in a power generation state, the bypass device 25 discharges the charge stored in the capacitor Cg to the negative module terminal 13m by the discharging diode Ddc, so that the capacitor Cg is in the initial state ( The switching element 16 can be returned to the state of the capacitor Cg when the switching element 16 is off, and a stable switching state maintaining circuit 26c can be realized.

  The switching state maintaining circuit 26c and the discharging diode Ddc shown in FIG. 8 can be similarly applied to the modified circuit examples 1 to 3 in FIGS. 7A to 7C.

DESCRIPTION OF SYMBOLS 1 Photovoltaic power generation system 10 Solar cell module group 11, 11f, 11s Solar cell module 12, 12f, 12s Solar cell 13f, 13s, 13t Module terminal (The 1st terminal in a switching system, 2nd terminal)
14 Switching system 15, 15f, 15s Bypass current path (current path in switching system)
16, 16f, 16s switching element (MIS field effect transistor)
17, 17f, 17s Control terminal 20, 20f, 20s Control unit (comparator)
21, 21f, 21s Input terminal (first input terminal)
22, 22f, 22s Input terminal (second input terminal)
23, 23f, 23s Output terminal 25, 25f, 25s Bypass device 26, 26f, 26s Control unit (series circuit)
26c switching state maintaining circuit 27, 27f, 27s voltage dividing terminal 30 DC / DC converter 31 input terminal 32 output terminal 40 wiring board 60 output box Cg capacitor Dc diode Ddc discharging diode Di diode Ds, Dsf, Dss diode (series circuit)
Ic Power generation current Ig Module group current Igb Shunt current Iph Photoelectric conversion current source Ls, Lss Sunlight PCf, PCs, PCt Power characteristic curve R1, R1f, R1s, R2, R2f, R2s Resistance RAf, RAs, RAt, RAtc, RAbpd Rectangle Power area Rs Series resistance Rsh Parallel resistance Vc Generated voltage Vd, Vdf, Vds Divided voltage Vg, Vs Output voltage Vh Received voltage Vm, Vmf, Vms Output voltage (voltage across the current path in the switching system)

Claims (4)

A plurality of solar cell modules in which a plurality of solar cells are connected in series, and a specification in which the output voltage of the solar cell module connected in parallel to each of the solar cell modules is specified in advance Photovoltaic power generation comprising a bypass current path for bypassing a module group current flowing in the solar cell module group when the voltage is smaller than a voltage, and a DC / DC converter for DC-DC conversion of the power output from the solar cell module group A system,
A switching element that is arranged in each of the bypass current paths and switches between conduction and non-conduction of the bypass current path, and a control unit that is arranged corresponding to each of the switching elements and controls opening and closing of the switching elements,
When the output voltage is lower than the specific voltage, the control unit is configured to switch the switching element from open to closed and to conduct the bypass current path ,
The control unit is a series circuit in which a diode and two resistors are connected in series and is connected in parallel to the solar cell module, and is connected between the two resistors to output the output voltage of the solar cell module. It has a voltage dividing terminal that divides and outputs,
The solar power generation system , wherein the voltage dividing terminal is connected to a control terminal of the switching element .   The photovoltaic power generation system according to claim 1,
  The switching element and the control unit are mounted on a single wiring board and built in the output box of the solar cell module.
  A solar power generation system characterized by A switching system comprising a switching element that is arranged in a current path and switches between conduction and non-conduction of the current path, and a control unit that controls opening and closing of the switching element,
The control unit is configured to control opening and closing of the switching element based on a voltage between both ends of the current path ,
The control unit is a series circuit in which a diode and two resistors are connected in series, and is connected in parallel to both ends of the current path, and is connected between the two resistors to output the solar cell module. It has a voltage dividing terminal that divides the voltage and outputs it,
The switching system , wherein the voltage dividing terminal is connected to a control terminal of the switching element . A bypass device that forms a bypass current path by being connected to both ends of a solar cell module,
A switching element that switches between conduction and non-conduction of the bypass current path, and a control unit that is arranged corresponding to the switching element and controls opening and closing of the switching element,
The control unit is a series circuit in which a diode and two resistors are connected in series, and when connected in parallel to the solar cell module, the control unit divides the output voltage of the solar cell module from between the two resistors. Voltage divider terminal to output
The bypass device, wherein the voltage dividing terminal is connected to a control terminal of the switching element.

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