CN203632269U - Grid-connected connection equipment and grid-connected power supply system - Google Patents
Grid-connected connection equipment and grid-connected power supply system Download PDFInfo
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- CN203632269U CN203632269U CN201320865414.1U CN201320865414U CN203632269U CN 203632269 U CN203632269 U CN 203632269U CN 201320865414 U CN201320865414 U CN 201320865414U CN 203632269 U CN203632269 U CN 203632269U
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Abstract
The utility model discloses a be incorporated into power networks jointing equipment and be incorporated into power networks power supply system. The apparatus comprises: the bidirectional converter is connected between the grid-connected connecting end and the power grid connecting end, the grid-connected connecting end is used for connecting the direct-current power generation equipment and corresponds to the direct-current end of the bidirectional converter, and the power grid connecting end is used for connecting the alternating-current power grid and corresponds to the alternating-current end of the bidirectional converter; the inverter is connected between the grid-connected connecting end and the load connecting end, and the load connecting end is used for connecting an alternating current load and corresponds to an alternating current end of the inverter; the MPPT controller, MPPT controller's input end is used for connecting respectively and sets up the first check out test set at the link of being incorporated into the power networks, sets up the second check out test set at the electric wire netting link and sets up the third check out test set at the load link, and MPPT controller's output end connects bidirectional current converter and dc-to-ac converter. The utility model provides a current photovoltaic power generation system's MPPT design not be applicable to the technical problem who sends out integrative power supply system that is incorporated into power networks of power consumption.
Description
Technical Field
The utility model relates to a power transmission field particularly, relates to a connecting device and power supply system that is incorporated into the power networks that are incorporated into the power networks.
Background
Solar energy is widely concerned by people as a clean and environment-friendly energy source, and is widely applied to various occasions for more than 20 years. Solar photovoltaic power generation is an important form of solar energy utilization, is a power generation form of converting light energy into electric energy by adopting a photovoltaic module, and is one of power generation technologies with the greatest development prospect probably along with the continuous progress of the technology.
In a photovoltaic power generation system, the utilization rate of a photovoltaic module is affected by factors such as irradiance, load, and stability of the use environment, in addition to being related to the internal characteristics of the photovoltaic cell. Under different ambient conditions, the photovoltaic modules may operate at different and unique maximum power points. Therefore, the mppt (maximum Power Point tracking) is an important technology for converting light energy into electric energy to the maximum.
The existing photovoltaic power generation system completes MPPT control mainly by performing loop design between the output of a photovoltaic module and the current and voltage of a power grid so as to realize synchronous performance indexes of light energy electric energy and the power grid and the like. Therefore, the current photovoltaic power generation system mainly plays a role in power generation, mainly aims at converting light energy into electric energy synchronous with a power grid to the maximum extent, and can be approximately considered as a power grid system; the power consumption of the rear-end load is uniformly scheduled by the power grid after the electric energy is converted by solar energy and is converged into the power grid. Therefore, the key of MPPT control only needs to ensure the synchronization of the photovoltaic electric energy and the power grid.
In the photovoltaic system integrating power generation and power utilization, a load cannot be simply approximated to a power grid, a rear-end load needs to be considered and directly controlled, and a working mode of the photovoltaic system is no longer a pure power generation mode, wherein the photovoltaic system needs to be switched in real time in various modes, however, the stability of intermediate direct-current bus voltage and the control target of power factor sine wave current cannot be guaranteed by maintaining the result of the existing MPPT parameter control, that is, the existing MPPT design of the photovoltaic power generation system is not suitable for a grid-connected power supply system integrating power generation and power utilization. No effective solution to this problem has been proposed.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a connecting equipment is incorporated into power networks and power supply system is incorporated into power networks to solve current photovoltaic power generation system's MPPT design at least and not be applicable to the integrative power supply system's that is incorporated into power networks of electricity generation.
According to an aspect of the embodiment of the utility model provides a connecting equipment is incorporated into power networks, include: the bidirectional converter is connected between a grid-connected connecting end and a power grid connecting end, wherein the grid-connected connecting end is used for connecting direct-current power generation equipment and corresponds to a direct-current end of the bidirectional converter, and the power grid connecting end is used for connecting an alternating-current power grid and corresponds to an alternating-current end of the bidirectional converter; an inverter connected between the grid-connected connection terminal and a load connection terminal, wherein the load connection terminal is used for connecting an alternating current load and corresponds to an alternating current terminal of the inverter; an MPPT controller having an input end for connecting a first detection device provided at the grid-connected end, a second detection device provided at the grid-connected end, and a third detection device provided at the load connection end, respectively, and an output end for connecting the bidirectional converter and the inverter, and controlling the bidirectional converter and/or the inverter according to an electrical parameter detected by the first detection device, the second detection device, and/or the third detection device at a corresponding detection point, wherein the electrical parameter includes at least one of: voltage, current, power.
Preferably, the grid-connected connection device further includes: a switching device connected between the grid connection terminal, the load connection terminal and the grid connection terminal; when the switching device is in a first state, the grid-connected connection end is disconnected from the power grid connection end and the load connection end, and the MPPT controller is switched to a no-load mode; and/or, when the switching device is in a second state, the load connection terminal is disconnected from the grid-connected connection terminal and the grid connection terminal, and the MPPT controller switches to a power generation mode for controlling the bidirectional converter according to the electrical parameters detected by the first detection device and the second detection device; and/or, when the switching device is in a third state, the grid connection terminal is disconnected from the grid connection terminal and the load connection terminal, and the MPPT controller switches to a load mode for controlling the inverter according to the electrical parameters detected by the first detection device and the third detection device; and/or, when the switching device is in a fourth state, the grid-connected connection terminal is connected to the grid connection terminal through the bidirectional converter and is connected to the load connection terminal through the inverter, and the MPPT controller switches to a load power generation mode or a load power utilization mode, wherein in the load power generation mode, the MPPT controller is configured to control the bidirectional converter and/or the inverter based on the electrical parameter output from the first detection device, the second detection device, and the third detection device, and/or in the load power utilization mode, the MPPT controller is configured to control the bidirectional converter and/or the inverter based on the electrical parameter detected by the first detection device and the third detection device.
Preferably, the switching device includes at least one of: a first switching device connected between the grid-connected connection terminal and a dc bus, the dc bus being a transmission line between the bidirectional converter and the inverter; a second switching device connected between the grid connection terminal and the grid connection terminal, the second switching device being disposed on the dc bus; and a third switching device connected between the grid connection terminal and the load connection terminal, and disposed on the dc bus.
Preferably, the grid-connected device further includes at least one of: a fourth switching device, one end of which is connected to the input end and the other end of which is connected to the first detection device; a fifth switching device, one end of which is connected to the input end and the other end of which is connected to the second detection device; and a sixth switching device, one end of which is connected to the input end and the other end of which is connected to the third detection device.
Preferably, the grid-connected connection device further includes: a mode controller connecting the switching device and the MPPT controller, the mode controller controlling the switching device to switch between at least one of the following states: the first state, the second state, the third state, and the fourth state, and controls the MPPT controller to switch to a mode corresponding to a state of the switching device.
Preferably, the grid-connected device further includes at least one of: the first detecting device, the second detecting device, and the third detecting device.
Preferably, the grid-connected connection device further includes: and a fourth detecting device disposed on the dc bus, connected to the input end, wherein the dc bus is a transmission line between the bidirectional converter and the inverter, and the MPPT controller is configured to control the bidirectional converter and/or the inverter according to the electrical parameter and a voltage and/or a current detected by the fourth detecting device at a corresponding detection point.
Preferably, the MPPT controller controls the bidirectional converter and/or the inverter by a signal of one of: voltage signal, current signal, pulse width modulation signal.
Preferably, the direct current power generation equipment is photovoltaic power generation equipment; and/or the transmission line connected between the grid connection end and the bidirectional converter is a three-phase power transmission line or a single-phase power transmission line; and/or the transmission line connected between the load connecting end and the inverter is a three-phase power transmission line or a single-phase power transmission line.
According to the utility model discloses on the other hand, still provide a power supply system is incorporated into power networks, include: the grid-connected connection device; the direct current power generation equipment is connected with the grid-connected end of the grid-connected connection equipment; and one or more alternating current loads connected with the load connection end of the grid-connected connection equipment.
First, in the embodiment of the present invention, a new architecture of a power supply system with integrated power generation and utilization is provided, a grid-connected device applied to the architecture may include a bidirectional converter and an inverter sequentially connected between a grid connection end and a load connection end, and a grid-connected connection end led out from between the bidirectional converter and the inverter, wherein the grid connection end may connect a grid, the load connection end may connect a load, and the grid-connected connection end may connect a dc power generation device, so that the dc power generation device may transmit power to the grid in one side direction, and transmit power to an ac load in the other side direction, which forms a system with integrated power generation and utilization, and since the dc power generation device may directly feed power to the ac load, it is possible to improve the utilization rate of the generated power directly.
Further, in the embodiment of the utility model provides an in, the input end of MPPT controller can with set up respectively at the link of being incorporated into the power networks, the first check out test set of electric wire netting link and load link, second check out test set and third check out test set are connected, in order to acquire the voltage that returns at the check point that corresponds, electric current, electricity parameters such as power, thereby this MPPT controller can be according to the output of one or more among these check out test set, also respectively in direct current power generation equipment one side, one or more among the electric parameters of alternating current electric wire netting one side and alternating current load one side collection realize the effective control to two-way transverter and/or adverse current ware, and then reach more excellent power supply efficiency, thereby solved current photovoltaic power generation system's MPPT design and not be applicable to the technical problem who sends out the integrative power supply system that is incorporated into the power networks of electricity.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without undue limitation to the invention. In the drawings:
fig. 1 is a schematic diagram of an alternative grid-connected connection device according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an MPPT control scheme according to the prior art;
fig. 3 is a schematic diagram of another alternative grid-connected connection device according to an embodiment of the present invention.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
Example 1
According to the embodiment of the utility model provides a connecting device is incorporated into power networks is provided, as shown in FIG. 1, this equipment includes:
1) the bidirectional converter 102 is connected between a grid connection end 104 and a power grid connection end 106, wherein the grid connection end 104 is used for connecting direct-current power generation equipment and corresponds to a direct-current end of the bidirectional converter 102, and the power grid connection end 106 is used for connecting an alternating-current power grid and corresponds to an alternating-current end of the bidirectional converter 102;
2) the inverter 108 is connected between the grid-connected connection end 104 and the load connection end 110, wherein the load connection end 110 is used for connecting an alternating current load and corresponds to an alternating current end of the inverter 108;
3) an MPPT controller 112, an input end of the MPPT controller 112 is configured to connect a first detection device 114 disposed at the grid connection end 104, a second detection device 116 disposed at the grid connection end 106, and a third detection device 118 disposed at the load connection end 110, respectively, an output end of the MPPT controller 112 is connected to the bidirectional converter 102 and the inverter 108, and is configured to control the bidirectional converter 102 and/or the inverter 108 according to an electrical parameter detected by the first detection device 114, and/or the second detection device 116, and/or the third detection device 118 at a corresponding detection point, wherein the electrical parameter includes at least one of: voltage, current, power.
It should be clear that, the utility model discloses one of the problem that technical scheme will solve provides a equipment to realize that direct current power generation equipment is incorporated into the power networks to the electric wire netting, also promptly, can relatively gather into the electric wire netting system with the electric energy that this direct current power generation equipment provided effectively, and make the electric wire netting can schedule these electric energies effectively, and then improve the power supply capacity of electric wire netting.
In order to solve the above problem, according to the embodiment of the present invention, the grid-connected connection device can connect the dc power generation device through the grid-connected connection end 104 thereof, and connect the ac power grid through the grid-connected connection end 106 thereof, wherein, the inverter 108 connected between the dc power generation device and the ac power grid, which is usually adopted in the prior art, is distinguished in the embodiment of the present invention, the bidirectional converter 102 can be connected between the grid-connected connection end 104 and the grid-connected connection end 106, so that the supply of the electric energy to the power grid can be realized through the bidirectional converter 102, specifically, the improvement of the power supply can be expressed, wherein the effect played by this alternative will be elaborated in the following embodiments.
Further, for making the dc power generation equipment reach the synchronization through the alternating current power that bidirectional current converter 102 provided and the electric energy of alternating current network to make dc power generation equipment reach more excellent output power point, in some embodiments of the utility model, can adopt MPPT controller 112 to realize the modulation to the electric energy of dc power generation equipment to alternating current network repayment to the mode that bidirectional current converter 102 controlled, and then realize the promotion to the efficiency of being incorporated into the power networks.
In the embodiment of the present invention, the input parameter of the MPPT controller 112 may be the output from the first detecting device 114 and the second detecting device 116, wherein the output of the first detecting device 114 may be the electrical parameter detected by the first detecting device 114 at the detecting point, i.e. near the grid-connected connection end 104, the output of the second detecting device 116 may be the electrical parameter detected by the second detecting device 116 at the detecting point, i.e. near the grid-connected connection end 106, wherein the electrical parameter may be voltage, current, or the power obtained by the detecting device based on the electrical parameter related to the electrical energy transmitted through the grid-connected connection end 104 and/or the grid-connected connection end 106, and correspondingly, the first detecting device 114 and the second detecting device 116 may include a voltage sensor and/or a current sensor, etc., specifically, the electrical parameters fed back by the detection devices may be represented by electrical signals output by the detection devices, and the MPPT controller 112 may acquire the electrical parameters through input terminals connected to the detection devices. More specifically, in the embodiment of the present invention, the input terminal of the MPPT controller 112 may be a terminal block including at least three connecting terminals, wherein the three connecting terminals may be respectively connected to the first detecting device 114, the second detecting device 116 and the third detecting device 118, the third detecting device 118 is disposed at the load connecting terminal 110, and the specific operation manner thereof is similar to that of the first detecting device 114 and the second detecting device 116, which will not be described herein in a repeated manner.
It is worth noting that the present invention does not limit the internal structure of the above three detecting devices and the specific connection mode in the circuit, for example, in the embodiment of the present invention, the current sensors in these detecting devices can be electromagnetic current transformers connected in series in the detecting circuit, also can be hall sensors, etc., wherein, the specific implementation mode of these detecting devices can not be right the implementation of the technical solution and the realization of the technical effect of the present invention cause influence, also should not be understood as the limitation of the present invention.
Similarly, in the embodiment of the present invention, the specific implementation manner of the MPPT controller 112 may also adopt a circuit or a device similar to those in the prior art for implementing the above-mentioned control function, for example, a typical three-loop control structure for MPPT control may be as shown in fig. 2, wherein the input parameters of the MPPT controller 112 may be the voltage and current collected at the side of the DC power generation device and the voltage and/or current collected at the side of the AC power grid as a synchronization signal, and the output parameters thereof may be the pulse width modulation signals for controlling the DC/DC converter and the DC/AC converter in the inverter 202, so that the MPPT can adjust the pulse width modulation signals, such as the duty ratio thereof, according to the synchronization condition, thereby implementing the adjustment of the AC output generated by the inverter 202. Of course, the above is only an example, and the present invention is not limited thereto, for example, in some embodiments of the present invention, the output of the MPPT controller 112 may not be limited to the form of pulse, for example, the control of the output of the inverter 202 connected to the dc power generating equipment may be realized by analog signals such as voltage signals or current signals, that is, in the present invention, the MPPT controller 112 controls the bidirectional converter 102 and/or the inverter 108 by one of the following signals: voltage signal, current signal, pulse width modulation signal. Furthermore, the MPPT controller 112 may also track the maximum power point in conjunction with control logic written into the controller chip, such as dynamic tracking of the maximum power point through scanning of the amplitude and/or phase of the output voltage and/or current, etc. It should be understood that the above embodiments of the present invention should be considered as being within the scope of the present invention.
Through the technical scheme of the embodiment, effective grid connection of the direct current power generation equipment to the alternating current power grid can be achieved, wherein the framework provided by the scheme similar to the prior art can be summarized that the direct current power generation equipment supplies power to the alternating current power grid, and then the expanded alternating current power grid is connected with each alternating current load. In a traditional power generation system, the framework can achieve ideal power supply efficiency, however, in a system integrating power generation and power utilization, because the load of a direct current power generation device cannot be simply approximated to a power grid, and the influence of a rear-end load on the power supply efficiency of the direct current power generation device needs to be considered, the traditional MPPT design cannot meet the design requirement that a converter is effectively controlled in the system integrating power generation and power utilization with more complex influence factors to achieve better power supply efficiency.
To this problem, in the embodiment of the present invention, a new architecture is firstly proposed, specifically, the grid-connected connection device may further be provided with a load connection end 110, the load connection end 110 is used for connecting an ac load, wherein an inverter 108 may be connected between the grid-connected connection end 104 and the load connection end 110, so that the dc power generation device may transmit electric energy to the grid in one side and transmit electric energy to the ac load in the other side, which forms an integrated system for generating and using electricity, and since the dc power generation device may directly feed energy to the ac load, the direct-drive utilization rate of the generated electric energy may be improved. Further, in the embodiment of the present invention, the input end of the MPPT controller 112 may be further connected to the third detection device 118 disposed at the load connection end 110 to collect the aforementioned electrical parameters such as voltage, current and power fed back by the load connection end 110, so that the MPPT controller 112 may effectively control the bidirectional inverter 102 and/or the reverse-current inverter according to the output of one or more of these detection devices, that is, one or more of the electrical parameters collected at the dc power generation device side, the ac power grid side and the ac load side, and further achieve better power supply efficiency.
On the basis of the above description, for further realizing the more effective control to the integrative system of electricity generation and utilization, according to the utility model discloses can also be provided with switching device among the above-mentioned connecting device that is incorporated into the power networks that provides, and then can realize the switching of the integrative system of electricity generation and utilization between the application mode of difference through this switching device to reach the purpose of carrying out nimble matching between the capacity of direct current power generation equipment, the capacity of alternating current electric wire netting and the capacity of alternating current load. On the other hand, MPPT controller 112 may also cooperate with the switching device to execute a control strategy corresponding to the application mode, so that better power supply efficiency may be achieved. Specifically, in the embodiment of the present invention, the grid-connected connection device may include:
1) the switching device is connected among the grid connection end 106, the load connection end 110 and the grid connection end 104;
wherein,
when the switching device is in the first state, the grid-connected connection end 104 is disconnected from the grid connection end 106 and the load connection end 110, and the MPPT controller 112 is switched to the no-load mode; and/or the presence of a gas in the gas,
when the switching device is in the second state, the load connection terminal 110 is disconnected from the grid connection terminal 104 and the grid connection terminal 106, and the MPPT controller 112 switches to the power generation mode to control the bidirectional converter 102 according to the electrical parameters detected by the first detection device 114 and the second detection device 116; and/or the presence of a gas in the gas,
when the switching device is in the third state, the grid connection terminal 106 is disconnected from the grid connection terminal 104 and the load connection terminal 110, and the MPPT controller 112 switches to the load mode for controlling the inverter 108 according to the electrical parameters detected by the first detection device 114 and the third detection device 118; and/or the presence of a gas in the gas,
when the switching device is in the fourth state, the grid connection terminal 104 is connected to the grid connection terminal 106 through the bidirectional converter 102 and is connected to the load connection terminal 110 through the inverter 108, and the MPPT controller 112 switches to the load power generation mode or the load power utilization mode, wherein,
the MPPT controller 112 is operable to control the bidirectional converter 102 and/or the inverter 108 based on the electrical parameters output by the first, second, and third detection devices 114, 116, and 118 in the load power mode, and/or the MPPT controller 112 is operable to control the bidirectional converter 102 and/or the inverter 108 based on the electrical parameters detected by the first and third detection devices 114 and 118 in the load power mode.
In the embodiment of the present invention, when the switching device is in the first state, the grid connection end 106 and the load connection end 110 are connected through the bidirectional converter 102 and the inverter 108, wherein the electric energy can be firstly converted from ac to dc through the bidirectional converter 102, and then converted from dc to ac through the inverter 108 to supply ac to the load, and in this scenario, the bidirectional converter 102 works as a rectifier. The grid-connected connection end 104, the grid connection end 106 and the load connection end 110 are disconnected, the ac power grid completely bears the power supply to the ac load, the dc power generation device does not output electric energy, and therefore only the matching between the characteristics of the ac load and the ac power grid needs to be considered, the adjusting effect of the MPPT controller 112 on the power supply efficiency of the dc power generation device does not need to be exerted, and the MPPT controller 112 can work in a standby state or an idle state.
When the switching device is in the second state, the grid-connected connection 104 is connected to the grid connection 106 via the bidirectional converter 102, wherein the electrical energy may be converted from dc to ac via the bidirectional converter 102, so as to feed the dc power plant to the ac grid, and in this scenario, the bidirectional converter 102 operates as an inverter 108. The load connection terminal 110, the grid connection terminal 104 and the grid connection terminal 106 are disconnected, the ac load does not use electricity, and the electric energy generated by the dc power generation device is completely converged into the ac power grid, so that only the synchronization between the dc power generation device and the ac power grid and the maximization of the power supply efficiency need to be considered, and the MPPT controller 112 may operate in a conventional mode or a power generation mode, where the control parameters of the MPPT are the output parameters of the dc power generation device and the grid synchronization parameters, that is, the outputs of the first detection device 114 and the second detection device 116.
When the switching device is in the second state, the grid connection terminal 104 is connected to the grid connection terminal 106 via an inverter 108, wherein electrical energy can be converted from direct current to alternating current via the inverter 108, so that the direct current power generation device supplies power to the alternating current load. The grid connection end 106, the grid connection end 104, and the load connection end 110 are both disconnected, the ac grid neither sinks electric energy from the dc power generation device nor supplies power to the ac load, and the electric energy generated by the dc power generation device is completely used for driving the ac load, so that only the matching between the dc power generation device and the ac load needs to be considered, and the MPPT controller 112 can operate in a load mode, where the control parameters of the MPPT are the output parameters of the dc power generation device and the load-related parameters, that is, the outputs of the first detection device 114 and the third detection device 118.
When the switching device is in the fourth state, the grid-connected terminal 104 is connected to the grid terminal 106 through the bidirectional converter 102 and to the load terminal 110 through the inverter 108, and this connection corresponds to two application modes of the power generation and utilization integrated system: 1) in the load power utilization mode, the capacity of the direct current power generation system is smaller than that of the alternating current load, the alternating current network also needs to supply power to the alternating current load, and the bidirectional converter 102 works as a rectifier; 2) in the load power generation mode, the capacity of the dc power generation system is larger than that of the ac load, and the electric energy generated by the dc power generation system may be partially supplied to the ac load and partially collected into the ac grid, and the bidirectional converter 102 operates as the inverter 108. Correspondingly, the MPPT controller 112 may also operate in two modes: 1) in the load power utilization mode, since the dc power generation device does not feed energy to the ac power grid, the output parameters of the dc power generation device do not need to be synchronized with the ac power grid, but it still needs to ensure matching between the dc power generation device and the ac load, where the control parameters of the MPPT may be the output of the dc power generation device and the load related parameters, that is, the outputs of the first detection device 114 and the third detection device 118; 2) in the load power generation mode, since the dc power generation device needs to feed energy to the ac power grid while supplying the ac load, the target of the MPPT control needs not only matching between the dc power generation device and the ac power grid but also matching between the dc power generation device and the ac load, so that the control parameters of the MPPT may include the output of the dc power generation device, the relevant parameters of the ac power grid, and the relevant parameters of the ac load, that is, the outputs of the first to third detection devices.
Through the switching device in the grid-connected connection equipment, the power generation and utilization integrated system can work in one or more modes. More specifically, in the embodiment of the present invention, the above switching device may have various implementations, for example, at most basically, the switching device may be implemented by a switch device, for example, as shown in fig. 3, and the switching device may include at least one of the following:
1) a first switching device 302 connected between the grid-connected connection end 104 and a dc bus, the dc bus being a transmission line between the bidirectional converter 102 and the inverter 108;
2) the second switching device 304 is connected between the grid-connected connecting end 104 and the power grid connecting end 106, and the second switching device 304 is arranged on the direct-current bus;
3) and a third switching device 306 connected between the grid-connection terminal 104 and the load connection terminal 110, wherein the third switching device 306 is disposed on the dc bus.
The first switching device 302, the second switching device 304 and the third switching device 306 correspond to the grid connection terminal 104, the grid connection terminal 106 and the load connection terminal 110 of the grid connection device, respectively, so that when the first switching device 302 is disconnected, the grid connection terminal 104 is disconnected, the switching device can be switched to the first state, when the second switching device 304 is disconnected, the grid connection terminal 106 is disconnected, the switching device can be switched to the third state, when the third switching device 306 is disconnected, the load connection terminal 110 is disconnected, and the switching device can be switched to the second state. More specifically, the switching devices may be semiconductor switches such as IGBTs driven by push-pull amplifiers, or may include high-power switches controlled by chips, such as relays, contactors, and the like, which the present invention is not limited to.
It is to be noted that the implementation of the above-mentioned switching means by one or more of the above-mentioned three switching devices is not the only embodiment of the present invention, and should not be understood as limiting the present invention, for example, in some embodiments of the present invention, the above-mentioned three switching devices may also be formed as one body, such as being replaced by a selector switch or selector, etc. It is to be understood that such equivalent or obvious modifications of the embodiments of the present invention are deemed to be within the scope of the present invention.
Further, in order to reduce the power consumption of the first to third detection devices and/or the MPPT controller 112, in an embodiment of the present invention, the grid-connected connection device may further include at least one of:
1) a fourth switching device having one end connected to the input terminal and the other end for connecting to the first detecting device 114;
2) a fifth switching device, one end of which is connected to the input terminal and the other end of which is connected to the second detection device 116;
3) and a sixth switching device having one end connected to the input terminal and the other end connected to the third detecting device 118.
The fourth to sixth switches can connect the corresponding detection device to the input end of the MPPT controller 112 in a certain state and mode, which can save energy consumption, and cut off unnecessary signal transmission lines to reduce interference to the signal transmission lines transmitting required electrical parameters, thereby further optimizing the power generation and utilization integrated system.
Furthermore, in an embodiment of the present invention, the grid-connected connection device may further include:
1) a mode controller connected to the switching device and the MPPT controller 112, the mode controller for controlling the switching device to switch between at least one of the following states: a first state, a second state, a third state, and a fourth state, and controls the MPPT controller 112 to switch to a mode corresponding to the state of the switching device.
In general, in the embodiment of the present invention, the mode controller may adopt a design of combining the control loop with the power element, however, the present invention is not limited thereto, wherein the mode controller and the MPPT controller 112 may be independent from each other or may be integrated into one body, for example, may appear as one integrated controller, wherein the integrated controller may also include a two-stage control loop. Specifically, for the foregoing embodiment, the mode controller may control the first to third switching devices, and further, the mode controller may control the fourth to sixth switches in a lump, which depends on the requirement of the control integration level in the specific implementation of the present invention, which is not limited by the present invention. Furthermore, in the embodiment of the present invention, the grid-connected connection device may further include one or more of the first to third detection devices, which depends on the requirement of the integration level of the product of the grid-connected connection device in the specific embodiment of the present invention, which is not limited by the present invention.
On the basis of the above description, further considering that the dc transmission line connected between the bidirectional converter 102 and the inverter 108 in the framework provided by the embodiment of the present invention, or the electric energy stability requirement transmitted on the dc bus that plays a role of shunting or converging, in the embodiment of the present invention, the above grid-connected connection device may further include:
1) and a fourth detection device disposed on the dc bus, which is a transmission line between the bidirectional converter 102 and the inverter 108, and connected to an input end of the MPPT controller 112, wherein the MPPT controller 112 is configured to control the bidirectional converter 102 and/or the inverter 108 according to the electrical parameter and the voltage and/or current detected by the fourth detection device at the corresponding detection point.
In the embodiment of the present invention, the electrical parameters on the dc bus as the MPPT control target and other aforementioned input parameters of the MPPT controller 112 may be simultaneously from one or more of the first to fourth detection devices, and the control target may still be the bidirectional converter 102 and/or the inverter 108, wherein the specific control strategy may generally adopt a state space control manner, however, the present invention is not limited thereto.
Through the above embodiments, the technical solution and the working principle of the present invention are explained, however, it is worth noting that the above embodiments are only used for understanding the technical solution of the present invention, and it is not limited to any unnecessary limitations of the present invention, for example, fig. 3 shows a feasible connection relationship between the first to the third switching devices, however, in other embodiments of the present invention, the second switching device 304 and the third switching device 306 can also be respectively disposed outside the bidirectional connector and the inverter 108, and so on.
It should be further noted that, in the embodiment of the present invention, the grid-connected end 104, the grid-connected end 106, and the load-connected end 110 are referred to as interfaces for connecting the dc power generation device, the ac power grid, and the ac load, respectively, any one of these connected ends is not limited to only corresponding to one connecting line, wherein the grid-connected end 104 may be a pair of connected ends for connecting a pair of dc transmission lines in general, and the grid-connected end 106 and the load-connected end 110 may be three or four connected ends for connecting a set of three-phase cables, etc., without limitation. Correspondingly, the connection lines in fig. 1 and 3 are only used as an illustration of the connection relationship between the devices, and it is not meant that the transmission lines corresponding to these connection lines in the embodiment of the present invention are limited to only one, specifically, in the embodiment of the present invention, the transmission lines connected between the grid connection end 106 and the bidirectional converter 102 and between the load connection end 110 and the inverter 108 may be three-phase power transmission lines, and the transmission lines connected between the bidirectional converter 102 and the counter-current device and between the two and the grid connection end 104 may be direct current transmission lines. Of course, this is merely an example, and in some embodiments of the present invention, the transmission lines connected between the grid connection end 106 and the bidirectional converter 102 and between the load connection end 110 and the inverter 108 may also be carriers of other ac power transmission lines such as single-phase power transmission lines, which is not limited by the present invention.
It should be further noted that, in the embodiments of the present invention, the above-mentioned dc power generation device is used to indicate a device capable of generating dc power, wherein the device may be a complete device, or a combination of a plurality of specific devices, or even a distributed device, and the present invention is not limited thereto. Further, the dc power generation facility may provide a dc power output directly, for example, from a photovoltaic module or the like, or indirectly, for example, from the electric power stored in the battery pack from the wind turbine generator. It should be understood that these embodiments do not affect the implementation of the technical solution of the present invention and the achievement of the technical effect, and the present invention is not limited thereto.
Example 2
According to the embodiment of the utility model provides a, still provide a power supply system that is incorporated into power networks, this system includes:
1) the grid-connected device according to embodiment 1;
2) the direct current power generation equipment is connected with the grid-connected end of the grid-connected connection equipment;
3) and one or more alternating current loads connected with the load connection end of the grid-connected equipment.
The embodiment of the utility model provides an in, a new framework of power supply system is incorporated into power networks is proposed, be applied to the connection equipment that is incorporated into power networks of this framework can be including connecting gradually two-way transverter and the dc-to-ac converter between electric wire netting link and the load link, and the connection end that is incorporated into power networks of drawing forth between two-way transverter and the dc-to-ac converter, wherein, the electric wire netting can be connected to the electric wire netting link, load link can the connection load, direct current power generation equipment can be connected to the connection end that is incorporated into power networks, thereby this direct current power generation equipment can be in one side to the electric wire netting transport electric energy, carry the electric energy in another side to alternating current load, this has just formed the integrative power supply system that is incorporated into power networks of electricity.
Further, in the embodiment of the utility model provides an in, the input end of MPPT controller can with set up respectively at the link of being incorporated into the power networks, the first check out test set of electric wire netting link and load link, second check out test set and third check out test set are connected, in order to acquire the voltage that returns at the check point that corresponds, electric current, electricity parameters such as power, thereby this MPPT controller can be according to the output of one or more among these check out test set, also respectively in direct current power generation equipment one side, one or more among the electric parameters of alternating current electric wire netting one side and alternating current load one side collection realize the effective control to two-way transverter and/or adverse current ware, and then reach more excellent power supply efficiency, thereby solved current photovoltaic power generation system's MPPT design and not be applicable to the technical problem who sends out the integrative power supply system that is incorporated into the power networks of electricity.
Furthermore, in the embodiment of the present invention, the various improvements to the grid-connected connection device described in embodiment 1 can also be combined, and the grid-connected power supply system using the grid-connected connection device can achieve the effect similar to that described in embodiment 1, and the present invention is not described herein.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A grid-connected connection device, comprising:
the bidirectional converter is connected between a grid-connected connecting end and a power grid connecting end, wherein the grid-connected connecting end is used for connecting direct-current power generation equipment and corresponds to a direct-current end of the bidirectional converter, and the power grid connecting end is used for connecting an alternating-current power grid and corresponds to an alternating-current end of the bidirectional converter;
the inverter is connected between the grid-connected connecting end and the load connecting end, wherein the load connecting end is used for connecting an alternating current load and corresponds to an alternating current end of the inverter;
an MPPT controller, an input end of the MPPT controller is used for respectively connecting a first detection device arranged at the grid-connected connection end, a second detection device arranged at the power grid connection end and a third detection device arranged at the load connection end, an output end of the MPPT controller is connected with the bidirectional converter and the inverter and is used for controlling the bidirectional converter and/or the inverter according to electrical parameters detected by the first detection device, the second detection device and/or the third detection device at corresponding detection points, wherein the electrical parameters comprise at least one of the following parameters: voltage, current, power.
2. The grid-tie connection apparatus according to claim 1, further comprising:
the switching device is connected among the power grid connecting end, the load connecting end and the grid-connected connecting end;
wherein,
when the switching device is in a first state, the grid-connected connecting end is disconnected from the power grid connecting end and the load connecting end, and the MPPT controller is switched to a no-load mode; and/or the presence of a gas in the gas,
when the switching device is in a second state, the load connecting end is disconnected from the grid-connected connecting end and the power grid connecting end, and the MPPT controller is switched to a power generation mode and used for controlling the bidirectional converter according to the electrical parameters detected by the first detection equipment and the second detection equipment; and/or the presence of a gas in the gas,
when the switching device is in a third state, the grid connection end is disconnected from the grid connection end and the load connection end, and the MPPT controller is switched to a load mode and used for controlling the inverter according to the electrical parameters detected by the first detection equipment and the third detection equipment; and/or the presence of a gas in the gas,
when the switching device is in a fourth state, the grid-connected connection end is connected with the grid connection end through the bidirectional converter and is connected with the load connection end through the inverter, the MPPT controller is switched to a load power generation mode or a load power utilization mode, wherein,
in the load power generation mode, the MPPT controller is configured to control the bidirectional converter and/or the inverter according to the electrical parameter output by the first detection device, the second detection device, and the third detection device, and/or in the load power mode, the MPPT controller is configured to control the bidirectional converter and/or the inverter according to the electrical parameter detected by the first detection device and the third detection device.
3. The grid-tie connection apparatus according to claim 2, wherein the switching device includes at least one of:
the first switching device is connected between the grid-connected connecting end and a direct current bus, and the direct current bus is a transmission line between the bidirectional converter and the inverter;
the second switching device is connected between the grid-connected connecting end and the power grid connecting end and arranged on the direct current bus;
and the third switching device is connected between the grid-connected connecting end and the load connecting end and is arranged on the direct current bus.
4. The grid-tie connection apparatus according to claim 2, further comprising at least one of:
one end of the fourth switching device is connected with the input end part, and the other end of the fourth switching device is used for being connected with the first detection equipment;
one end of the fifth switching device is connected with the input end part, and the other end of the fifth switching device is connected with the second detection equipment;
and one end of the sixth switching device is connected with the input end part, and the other end of the sixth switching device is connected with the third detection equipment.
5. The grid-tie connection apparatus according to claim 2, further comprising:
a mode controller connected to the switching device and the MPPT controller, the mode controller configured to control the switching device to switch between at least one of the following states: the first state, the second state, the third state, and the fourth state, and controls the MPPT controller to switch to a mode corresponding to a state of the switching device.
6. The grid-tie connection apparatus according to any one of claims 1 to 5, further comprising at least one of: the first detection device, the second detection device, the third detection device.
7. The grid-tie connection apparatus according to any one of claims 1 to 5, characterized by further comprising:
and a fourth detection device arranged on a direct current bus connected with the input end, wherein the direct current bus is a transmission line between the bidirectional converter and the inverter, and the MPPT controller is used for controlling the bidirectional converter and/or the inverter according to the electrical parameters and the voltage and/or current detected by the fourth detection device at the corresponding detection point.
8. The grid-tie connection apparatus according to any one of claims 1 to 5, wherein the MPPT controller controls the bidirectional converter and/or the inverter by a signal of one of: voltage signal, current signal, pulse width modulation signal.
9. The grid-tie connection apparatus according to any one of claims 1 to 5,
the direct current power generation equipment is photovoltaic power generation equipment; and/or the presence of a gas in the gas,
the transmission line connected between the grid connection end and the bidirectional converter is a three-phase power transmission line or a single-phase power transmission line; and/or the presence of a gas in the gas,
the transmission line connected between the load connection end and the inverter is a three-phase power transmission line or a single-phase power transmission line.
10. A grid-connected power supply system, comprising:
the grid-tie connection apparatus according to any one of claims 1 to 9;
the direct current power generation equipment is connected with the grid-connected end of the grid-connected connection equipment;
and one or more alternating current loads connected with the load connection end of the grid-connected connection equipment.
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| CN201320865414.1U CN203632269U (en) | 2013-12-24 | 2013-12-24 | Grid-connected connection equipment and grid-connected power supply system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016004896A1 (en) * | 2014-07-11 | 2016-01-14 | 珠海格力电器股份有限公司 | Photovoltaic inverter and air conditioner |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016004896A1 (en) * | 2014-07-11 | 2016-01-14 | 珠海格力电器股份有限公司 | Photovoltaic inverter and air conditioner |
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