JP6257388B2 - Power supply system - Google Patents

Description

  The present invention provides a plurality of self-systems having an AC line to which a plurality of power consumers are connected, a power storage device, and a self-supporting inverter device that connects the power storage device and the AC line using a self-connection line. And connecting the power storage device of one self-system and the AC line of the other self-system using interconnection lines so that a plurality of self-systems are electrically connected in series The present invention relates to a power supply system including an inverter device between self systems.

  Conventionally, a power supply system has been proposed that includes a plurality of self-systems having an AC line to which a plurality of power consumers are connected, a power storage device, and a self-supporting inverter device that connects the power storage device and the AC line. Has been. For example, a power supply system described in Patent Document 1 (International Publication No. 2010/103650) includes a power storage device included in one self-system and another one so that a plurality of self-systems are electrically connected in series. The inverter system which connects the alternating current line which one self system has is provided between self systems. Furthermore, each of the self-supporting inverter devices of the plurality of self-systems has a target frequency at which the voltage of the power on the AC line becomes the target voltage and the frequency of the power on the AC line is determined according to the amount of power stored in the power storage device. For two self-systems that are electrically connected via a single inverter device, power is transferred from the self-system with the higher target frequency to the self-system with the lower target frequency. The operation of the connected inverter device is controlled so as to be supplied. That is, since the frequency of the power on the AC line of each self system is a value reflecting the amount of power stored in the power storage device, the connected inverter device is connected to each AC line with respect to the two electrically connected self systems. It is possible to know which power storage amount of the power storage device of the self system is large only by detecting the frequency of. And according to the magnitude of the detected frequency value, it is possible to equalize the amount of power stored in the power storage device of each self system by performing power interchange between the self systems.

International Publication No. 2010/103650

In the conventional power supply system described above, the self-supporting inverter device uses a power storage device to set the voltage and frequency of power on the AC line to predetermined values. That is, while the self-supporting inverter device controls the voltage and frequency of power on the AC line to predetermined values, current flows from the power storage device to the AC line via the self-supporting inverter device, or from the AC line to the power storage device. For example, current flows through the self-supporting inverter device.
In a conventional power supply system, it has been unclear what kind of charging should be performed on a power storage device that is constantly used for such power quality control.

  The present invention has been made in view of the above problems, and an object of the present invention is to be able to charge the power storage device while performing power quality control for maintaining the power quality of the AC line using the power storage device. The point is to provide a supply system.

In order to achieve the above object, the characteristic configuration of the power supply system according to the present invention includes an AC line to which a plurality of power consumers are connected, a power storage device, and a self-connection between the power storage device and the AC line. A plurality of self-systems having a self-supporting inverter device connected using wires,
An interconnection line is used between the power storage device of one self system and the AC line of the other self system so that a plurality of the self systems are electrically connected in series. A power supply system comprising a connected inverter device to be connected between the self systems,
The self-connection line includes a first self-connection line for connecting the self-standing inverter device and the power storage device, and a second self-connection line for connecting the self-standing inverter device and the AC line. ,
The interconnect line includes a first interconnect line for connecting the linked inverter device and the power storage device, and a second interconnect line for connecting the linked inverter device and the AC line. ,
A control device is provided that performs power quality control on the independent inverter device, and performs power interchange control and first charge control on the linked inverter device,
The controller is
As the power quality control, the self-contained inverter device is connected to the self-supporting inverter device included in one self-system using the power storage device included in the single self-system, and the self-supporting inverter device is connected using the second self-connecting line. The control is performed such that the voltage of the power on the AC line is a target voltage and the frequency of the power on the AC line is a target frequency determined according to the amount of power stored in the power storage device, and
As the power interchange control, when power is interchanged between one self system and another self system using the interconnect line, the first interconnect line and the first interconnect line constituting the interconnect line are used. The amount of power stored in the power storage device based on the target frequency on the AC line in each of the one self system and the other self system with respect to the connected inverter device provided between two interconnect lines Power from a relatively large self-system to a self-system with a relatively small amount of power stored in the power storage device, and
When it is determined that the charging start condition for one power storage device is satisfied as the first charge control, the connected inverter device connected to the one power storage device using the first interconnection line On the other hand, the sum of the power supplied from the independent inverter device to the AC line and the target charging power to the one power storage device for the power quality control performed in the self system having the one power storage device Power is supplied from the second interconnect line to the first interconnect line to charge the one power storage device.

According to the above characteristic configuration, the voltage and frequency of the power of the AC line can be controlled to predetermined values by the independent inverter device performing power quality control. In particular, in the power quality control, control is performed so that the frequency of the power of the AC line becomes a target frequency determined according to the amount of power stored in the power storage device. That is, information on the amount of power stored in the power storage device is given to the frequency (target frequency) of power on the AC line of each self system. As a result, when performing power interchange control for accommodating power from a self-system with a relatively large amount of power stored in the power storage device to a self-system with a relatively small amount of power stored in the power storage device, the AC line of each self-system By simply looking at the frequency of the power, it can be easily determined which power storage amount of the power storage device of the own system is large.
Further, the control device, as the first charging control when charging the power storage device while performing the power quality control, the power supplied to the AC line from the independent inverter device for the power quality control and the target to the power storage device Power that is the sum of the charging power is supplied from the second interconnect line to the first interconnect line. That is, the power supplied from the second interconnect line to the first interconnect line is divided into power supplied from the independent inverter device to the AC line for power quality control and target charging power to the power storage device. Used. As a result, it is possible to perform both charging of the target charging power to the power storage device and power quality control using the power storage device.

Another characteristic configuration of the power supply system according to the present invention includes an AC line to which a plurality of power consumers are connected, a power storage device, and a connection between the power storage device and the AC line using a self-connection line. A plurality of self-systems having a self-standing inverter device
An interconnection line is used between the power storage device of one self system and the AC line of the other self system so that a plurality of the self systems are electrically connected in series. A power supply system comprising a connected inverter device to be connected between the self systems,
The self-connection line includes a first self-connection line for connecting the self-standing inverter device and the power storage device, and a second self-connection line for connecting the self-standing inverter device and the AC line. ,
The interconnect line includes a first interconnect line for connecting the linked inverter device and the power storage device, and a second interconnect line for connecting the linked inverter device and the AC line. ,
An inverter device for charging that uses an external connection line to connect between the power storage device of one of the plurality of self systems and an external power system;
A control device for performing power quality control on the independent inverter device, performing power interchange control on the connected inverter device, and performing second charge control on the charging inverter device;
The external connection line includes a first external connection line for connecting the charging inverter device and the power system, and a second external connection line for connecting the charging inverter device and the power storage device. Configured,
The controller is
As the power quality control, the self-contained inverter device is connected to the self-supporting inverter device included in one self-system using the power storage device included in the single self-system, and the self-supporting inverter device is connected using the second self-connecting line. The control is performed such that the voltage of the power on the AC line is a target voltage and the frequency of the power on the AC line is a target frequency determined according to the amount of power stored in the power storage device, and
As the power interchange control, when power is interchanged between one self system and another self system using the interconnect line, the first interconnect line and the first interconnect line constituting the interconnect line are used. The amount of power stored in the power storage device based on the target frequency on the AC line in each of the one self system and the other self system with respect to the connected inverter device provided between two interconnect lines Power from a relatively large self-system to a self-system with a relatively small amount of power stored in the power storage device, and
When it is determined that the charging start condition for one power storage device connected to the charging inverter device using the second external connection line is satisfied as the second charging control, the charging inverter device In contrast, for the power quality control performed in the self-system having the one power storage device, the power supplied from the independent inverter device to the AC line and the target charging power to the one power storage device The sum of electric power is supplied from the first external connection line to the second external connection line to charge the one power storage device.

According to the above characteristic configuration, the voltage and frequency of the power of the AC line can be controlled to predetermined values by the independent inverter device performing power quality control. In particular, in the power quality control, control is performed so that the frequency of the power of the AC line becomes a target frequency determined according to the amount of power stored in the power storage device. That is, information on the amount of power stored in the power storage device is given to the frequency (target frequency) of power on the AC line of each self system. As a result, when performing power interchange control for accommodating power from a self-system with a relatively large amount of power stored in the power storage device to a self-system with a relatively small amount of power stored in the power storage device, the AC line of each self-system By simply looking at the frequency of the power, it can be easily determined which power storage amount of the power storage device of the own system is large.
Further, the control device, as the second charging control when charging the power storage device while performing the power quality control, the power supplied from the independent inverter device to the AC line for the power quality control and the target to the power storage device Electric power that is the sum of the charging power is supplied from the first external connection line to the second external connection line. That is, the power supplied from the first external connection line to the second external connection line is divided into power supplied from the independent inverter device to the AC line for power quality control and target charging power to the power storage device. Used. As a result, it is possible to perform both charging of the target charging power to the power storage device and power quality control using the power storage device.

  Still another characteristic configuration of the power supply system according to the present invention is that, when the total voltage by a plurality of cells constituting the power storage device is less than a reference voltage, the control device supplies the target charging power to the power storage device, Constant current charging derived by the product of the total voltage and a constant reference current is performed, and when the total voltage is equal to or higher than the reference voltage, the target charging power to the power storage device is expressed as the reference voltage and the target charging current. The target charging current is determined by a current curve that decreases the current with the lapse of time using the constant reference current as an initial value, and the current curve is configured as the power storage device. The determination is based on at least one of the degree of deterioration of the cell and the temperature.

According to the above characteristic configuration, in a state where the total voltage by the plurality of cells is less than the reference voltage, that is, in a state where the total amount of electricity stored by the plurality of cells is relatively small, a relatively large constant reference current is supplied Charging can be performed rapidly by performing constant current charging. On the other hand, in a state where the total voltage by the plurality of cells is equal to or higher than the reference voltage, that is, in a state where the total amount of electricity stored by the plurality of cells is relatively large, the current is decreased with the passage of time using the reference current as an initial value. Overcharge can be suppressed by performing constant voltage charging.
Furthermore, since the current curve is determined according to at least one of the actual cell deterioration degree and the cell temperature related to the ease of cell deterioration, the cell deterioration during charging is suppressed. It is possible to set to

  Still another characteristic configuration of the power supply system according to the present invention is that the control device is based on a relational expression between the highest cell voltage and the target charging current among the cell voltages of the plurality of cells constituting the power storage device. A target charging current corresponding to the current highest cell voltage is determined, and a product of the target charging current and a total voltage of a plurality of cells constituting the power storage device is derived as the target charging power to the power storage device. In the relational expression, there is a relation that the target charging current decreases as the maximum cell voltage increases.

  According to the above characteristic configuration, when the product of the target charging current and the total voltage of a plurality of cells is used as the target charging power, the target charging current is set such that the target charging current decreases as the maximum cell voltage increases. It is determined according to the relational expression. In other words, among the plurality of cells, the cell with the highest cell voltage (the cell with the highest cell voltage) is the cell with the largest amount of power storage, and is intended to suppress overcharging of the cell. All the cells are charged.

  Yet another characteristic configuration of the power supply system according to the present invention is that the control device determines that the charging start condition is satisfied when a set time is reached.

  According to the above characteristic configuration, it is possible to charge the power storage device by determining that the charging start condition is periodically satisfied at the set time. For example, if the set time is set before the time period in which the power demand increases during the day, it is determined that the charging start condition is satisfied prior to the time period in which the power demand increases, and the power storage device Is stored. As a result, it is possible to increase the power supply capacity for the power consumer prior to the time period when the power demand increases.

  Still another characteristic configuration of the power supply system according to the present invention is that the control device determines that the charging start condition is satisfied when a power storage amount of the power storage device becomes less than a lower limit power storage amount.

  According to the above characteristic configuration, it is determined that the charging start condition is satisfied at a timing when the amount of power stored in the power storage device becomes less than the lower limit power storage amount, that is, at a timing when the power supply capacity from the power storage device to the power consumer decreases. The power storage device can be charged.

It is a figure which shows the structure of the electric power supply system of 1st Embodiment. It is a figure which shows the schematic structure of an electrical storage apparatus. It is a figure explaining 1st charge control. It is a graph which shows the example of each electric power Pa, Pb, Pc. It is a graph which shows the example of target charge electric power. It is a graph which shows the example of the relational expression of the highest cell voltage and target charging current among the cell voltages of the some cell which comprises an electrical storage apparatus. It is a figure which shows the structure of the electric power supply system of 3rd Embodiment. It is a figure explaining 2nd charge control.

<First Embodiment>
The configuration of the power supply system according to the first embodiment will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating a configuration of a power supply system according to the first embodiment. This power supply system includes an AC line 1 to which a plurality of power consumers D are connected, a power storage device 4, and a self-standing inverter device that connects the power storage device 4 and the AC line 1 using a self-connection line 2. The power storage device 4 of one self-system 10 and the alternating current of the other self-system 10 are provided so that the plurality of self-systems 10 are electrically connected in series. A connected inverter device 9 for connecting the line 1 with the interconnect line 3 is provided between the self systems 10. Self-connecting line 2 includes first self-connecting line 2 a (2) for connecting self-standing inverter device 5 and power storage device 4, and second self-connecting line for connecting self-standing inverter device 5 and AC line 1. 2b (2). The interconnection line 3 includes a first interconnection line 3 a (3) for connecting the linked inverter device 9 and the power storage device 4, and a second interconnection line for connecting the linked inverter device 9 and the AC line 1. 3b (3). In addition, the power supply system includes a control device C that causes the independent inverter device 5 to perform power quality control and causes the linked inverter device 9 to perform power interchange control and first charging control.
Although FIG. 1 illustrates a state in which two self systems 10, that is, the self system 10 </ b> A (10) and the self system 10 </ b> B (10) are connected via the linked inverter device 9, the self system provided in the power supply system There is no limit to the number of ten.

  The power consumer D has a power consuming device 6 that consumes the power supplied from the AC line 1. Alternatively, the power consumer D may have the power generation device 7 in addition to the power consumption device 6. As the power consuming device 6, not only a general device such as a lighting device or an air conditioner, but also various devices that consume power for its operation can be used. As the power generation device 7, various devices such as a solar power generation device and a wind power generation device that generate power using natural energy such as sunlight and wind power, and a fuel cell that generates power using fuel can be used. As shown in FIG. 1, in the self system 10, the power generator 7 may be connected to the AC line 1 as a single unit. Further, the number of power consumers D connected to the AC line 1 and the numbers and combinations of the power consuming devices 6 and the power generators 7 included in the power consumers D are not limited to the illustrated example.

  The power storage device 4 can use a storage battery (chemical battery) such as a lithium ion battery, a nickel metal hydride battery, or a lead battery.

  The self-supporting inverter device 5 and the linked inverter device 9 are power conversion devices that can convert input power into power having a desired voltage, frequency, and phase and output the converted power. For example, the self-supporting inverter device 5 and the linked inverter device 9 include a circuit unit (not shown) having a semiconductor switching element and a control unit (not shown) that controls the switching operation of the semiconductor switching element. The And the power conversion operation | movement from input electric power to output electric power is performed by switching on / off of those semiconductor switching elements.

  The control device C is a device capable of controlling operations of the self-supporting inverter device 5 and the linked inverter device 9. For example, the control device C is a device having an information input / output function, a storage function, an arithmetic processing function, and the like. The function of the control device C is that any one of the control units (not shown) included in each of the self-supporting inverter device 5 and the linked inverter device 9 functions as a master control unit, and the other control unit is a master control unit. This can be realized by functioning as a slave control unit while performing information communication. Or the function of the control apparatus C is provided separately from the control part (not shown) which each of the independent inverter apparatus 5 and the connection inverter apparatus 9 has, and the master control part comprised so that information communication with those control parts is possible Can be realized.

  Then, the control device C performs power quality control in each self system 10 and power interchange control among the plurality of self systems 10. The power quality control is control for the purpose of keeping constant the quality of power on the AC line 1 of the own system 10. The power interchange control is control for the purpose of equalizing the amount of power stored in the power storage device 4 of each self system 10.

  Supplementing the power quality control, the power of the AC line 1 is consumed by the power consuming device 6 of the power consumer D. The power consuming device 6 is usually an external commercial power system separate from this power supply system. It is assumed that it operates with the electric power supplied from. That is, the power consuming apparatus 6 is designed to operate according to the frequency of power supplied from the commercial power system. Therefore, if the frequency of the power supplied to the power consuming device 6 is different, strictly speaking, the operation of these devices will also be different. Therefore, it is necessary to perform power quality control that keeps the frequency of power on the AC line 1 of each self system 10 within a predetermined range.

  Therefore, as power quality control, the control device C uses the power storage device 4 of the one self system 10 for the self inverter device 5 of the one self system 10, and the self inverter device 5 The voltage of power on the AC line 1 connected using the self-connection line 2b is set as the target voltage, and the frequency of power on the AC line 1 is set as the target frequency determined according to the amount of power stored in the power storage device 4. Let control take place. Information on the amount of power stored in the power storage device 4 may be transmitted from the power storage device 4 to the self-supporting inverter device 5, or may be transmitted from the power storage device 4 to the control device C and further from the control device C to the self-supporting inverter device. 5 may be configured to be transmitted.

For example, in one self-system 10, the power supplied from the power generation device 7 to the AC line 1 is less than the received power (load power) from the power consumption device 6 from the AC line 1 (that is, the AC line 1 is loaded). In the excessive state), the voltage of the power of the AC line 1 is smaller than the target voltage. In that case, the control device C supplies power to the AC line 1 from the self-supporting inverter device 5 (that is, causes discharge from the power storage device 4 side to the AC line 1 side via the self-supporting inverter device 5. ), Power quality control is performed to increase the voltage on the AC line 1.
On the other hand, in one self-system 10, the power supplied from the power generation device 7 to the AC line 1 is greater than the power received by the power consumption device 6 from the AC line 1 (that is, the AC line 1 has excessive power generation). In this state, the voltage of the power of the AC line 1 is larger than the target voltage. In that case, the control device C draws electric power from the AC line 1 to the self-supporting inverter device 5 (that is, by charging the power storage device 4 from the AC line 1 via the self-supporting inverter device 5). Power quality control is performed to reduce the voltage on the AC line 1.

  Supplementing the power interchange control, in each self system 10, the function of maintaining the power quality of the AC line 1 is performed by the power quality control of the independent inverter device 5 using the power storage device 4. As a result, how much the amount of power stored in the power storage device 4 increases or decreases varies among the plurality of self-systems 10. Therefore, with the passage of time, a difference may occur in the amount of power stored in the power storage device 4 of each self system 10. In such a case, if power can be exchanged from the self system 10 having a large amount of power stored in the power storage device 4 to the self system 10 having a small amount of power stored in the power storage device 4, the power storage devices 4 between the self systems 10. Is preferable for equalizing the amount of electricity stored.

  Therefore, as power interchange control, when the control device C uses the interconnect line 3 to exchange power between one self system 10 and another self system 10, the control device C configures the first interconnect line 3. The AC line 1 in each of the one self-system 10 and the other self-system 10 with respect to the connected inverter device 9 provided between the interconnection line 3a (3) and the second interconnection line 3b (3). Based on the target frequency at, power is accommodated from the self system 10 in which the power storage amount of the power storage device 4 is relatively large to the self system 10 in which the power storage amount of the power storage device 4 is relatively small.

  For example, as shown in FIG. 1, with respect to two self-systems 10A and 10B that are electrically connected through one linked inverter device 9 and are adjacent to each other, the one linked inverter device 9 Based on the target frequency determined according to the amount of power stored in the power storage device 4, the self system 10 in which the power storage amount of the power storage device 4 is relatively large changes to the self system 10 in which the power storage amount of the power storage device 4 is relatively small. And power interchange. Specifically, the linked inverter device 9 acquires information on the frequency fA of the AC line 1 of the own system 10A and information on the frequency fB of the AC line 1 of the own system 10B, compares the values, Electric power is accommodated from the self-system 10 in which the power storage amount of the power storage device 4 is relatively large, which is found by frequency comparison, to the self system 10 in which the power storage amount of the power storage device 4 is relatively small. Here, the information regarding the frequency of the AC line 1 acquired by the connected inverter device 9 is a value obtained by detecting the frequency (= target frequency) of the actual power in the AC line 1 of each of the own systems 10A and 10B. Alternatively, it may be a target frequency value transmitted from the self-supporting inverter device 5 that determines the target frequency.

Next, how the target frequency is determined in the power quality control described above will be described.
In the present embodiment, the self-supporting inverter device 5 performs control so that the frequency of power on the AC line 1 becomes a target frequency that is determined so as to increase as the amount of power stored in the power storage device 4 increases. As an example of this relational expression, a frequency fluctuation value determined by a function of the amount of power stored in the power storage device 4 (for example, a relationship in which the frequency fluctuation value increases as the power storage amount increases) is set to the reference frequency (for example, 60 Hz) of the AC line 1 In some cases, the target frequency is a value obtained by addition. In this case, the relationship between the target frequency: f, the reference frequency: f0, and the frequency fluctuation value: Δf can be expressed by the following (Formula 1). Further, the frequency variation: Δf can be expressed by the following (Equation 2) using the state of charge: [SOC] and constants A and B.

f = f0 + Δf (Equation 1)
Δf = A × [SOC] + B (Formula 2)

  The independent inverter device 5 stores the above relational expression in advance in an internal memory or the like so that the target frequency of the AC line 1 increases as the amount of power stored in the power storage apparatus 4 increases, and performs control according to the relational expression. Thus, the actual frequency of the AC line 1 (that is, the target frequency) reflects the amount of power stored in the power storage device 4 connected to the AC line 1 via the self-standing inverter device 5.

Next, the 1st charge control which charges the electrical storage apparatus 4 is demonstrated.
FIG. 2 is a diagram illustrating a schematic structure of the power storage device 4. As illustrated, the power storage device 4 is configured by connecting a plurality of cells 4a in series and in parallel. Note that the structure of the power storage device 4 shown in FIG. 2 is described for illustrative purposes, and can be changed as appropriate. For example, the number of series connections and the number of parallel connections of the cells 4a can be changed as appropriate. In addition, the power storage device 4 of the present embodiment includes a cell management unit 4b that detects the voltage and temperature of each cell 4a, a current sensor 4c that measures current flowing through all cells, a current sensor 4c, and a cell management unit 4b. And a control unit 4d for determining the state of the power storage device 4 based on the information (for example, the above-described power storage amount: SOC).

The cell management unit 4b has a function as voltage measuring means 4bv for measuring the voltage of each cell 4a and a function as temperature measuring means 4bt for detecting the temperature of each cell 4a.
Further, the control unit 4d can obtain information about the current measured by the current sensor 4c and information about the voltage measured by the voltage measuring unit 4bv (cell management unit 4b), and as a result, the power storage device An internal resistance of 4 can be derived. When power storage device 4 is deteriorated (the degree of progress of deterioration is large), its internal resistance increases. That is, the control unit 4d can know the degree of deterioration of the power storage device 4 based on the information about the internal resistance of the power storage device 4 derived as described above.

  Information on the voltage and temperature of each cell 4a obtained by the cell management unit 4b and information on the current measured by the current sensor 4c are transmitted to the control unit 4d. Further, it is transmitted from the power storage device 4 to the control device C as necessary. Information about the internal resistance of the power storage device 4 (information about the degree of deterioration of the power storage device 4) is also transmitted from the power storage device 4 to the control device C as necessary.

FIG. 3 is a diagram illustrating the first charging control. As illustrated, when the control device C determines that the charging start condition for one power storage device 4 is satisfied as the first charge control, the control device C uses the first interconnection line 3 a for the one power storage device 4. Power Pc supplied from the independent inverter device 5 to the AC line 1 for power quality control performed in the self system 10 having the one power storage device 4 for the connected inverter device 9 connected thereto Power Pa that is the sum of the target charging power Pb for one power storage device 4 is supplied from the second interconnect line 3b to the first interconnect line 3a so that the one power storage device 4 is charged. It is configured. By performing such control, each self system 10 can charge the power storage device 4 in parallel while performing power quality control. In addition, the control apparatus C is the electric current Pc supplied to the alternating current line 1 from the independent inverter apparatus 5 for electric power quality control, for example, the electric current value which flows into the alternating current line 1 from the independent inverter apparatus 5, It is possible to know by deriving the product of the voltage values.
In the present embodiment, for each power Pa, Pb, Pc, the direction indicated by the arrow in FIG. 3 is the positive direction. That is, the relationship “Pa = Pb + Pc” is established.

  FIG. 4 is a graph showing an example of each power Pa, Pb, Pc described above. In FIG. 4, the electric power Pc is expressed as “regulated electric power in the independent inverter device 5: Pc”. As indicated by an arrow in FIG. 3, the electric power Pc has a positive direction from the power storage device 4 side to the AC line 1 side via the self-standing inverter device 5. In FIG. 4, the electric power Pa is described as “regulated electric power in the linked inverter device 9: Pa”. As indicated by an arrow in FIG. 3, the electric power Pa has a positive direction from the second interconnection line 3 b side to the first interconnection line 3 a side via the connected inverter device 9.

  In this first charge control, “regulated power in the linked inverter device 9: Pa” becomes negative power, that is, the second interconnect from the first interconnect line 3a side via the linked inverter device 9. Electric power may go to the line 3b side. In addition, “regulated power in the self-supporting inverter device 5: Pc” may be negative power, that is, power may flow from the AC line 1 side to the power storage device 4 side via the self-supporting inverter device 5.

For example, in one self-system 10, the power supplied from the power generator 7 to the AC line 1 is greater than the power received by the power consuming device 6 from the AC line 1 (that is, the AC line 1 has excessive power generation). ), As described above, the control device C operates the independent inverter device 5 so as to draw power from the AC line 1 to the independent inverter device 5 (that is, from the AC line 1 to the independent inverter device). Power quality control is performed such that the power storage device 4 side is charged via 5). That is, “adjusted power in the self-standing inverter device 5: Pc” becomes negative power in the direction opposite to the direction indicated by the arrow in FIG. 3, that is, in the relational expression “Pa = Pb + Pc”: Becomes negative power. Therefore, if the target charging power Pb to the power storage device 4 is smaller than the power Pc, the power Pa is also negative power. Specifically, in this case, since “adjusted power in the self-supporting inverter device 5: Pc” is directed toward the power storage device 4, the surplus power is generated if the power Pc is larger than the target charging power Pb to the power storage device 4. (= Pc−Pb) occurs. And the magnitude | size of this surplus electric power (= Pc-Pb) is "adjustment electric power in the connection inverter apparatus 9 which goes to the 2nd interconnection line 3b side from the 1st interconnection line 3a side via the connection inverter apparatus 9." : Pa (negative power) ".
Even if “adjusted power in self-supporting inverter device 5: Pc” becomes negative power in the direction opposite to the direction indicated by the arrow in FIG. 3, target charging power Pb to power storage device 4 is If it is larger than the electric power Pc, the electric power Pa becomes a positive electric power in the relational expression “Pa = Pb + Pc”. Therefore, the electric power Pa is directed from the second interconnect line 3b side to the first interconnect line 3a side via the connected inverter device 9.
As described above, the magnitude and the sign of the power Pa are determined according to the magnitude and the sign of the power Pc and the magnitude of the power Pb.

The charge start condition described above is a condition related to time, a condition related to the amount of power stored in the power storage device 4, or both of them.
Specifically, in the former case, the control device C determines that the charging start condition is satisfied when the set time is reached. In this manner, by adopting the time-related condition as the charge start condition, it is possible to determine that the charge start condition is periodically satisfied at the set time, and to charge the power storage device 4 by the first charge control. For example, if the set time is set before the time period in which the power demand increases during the day, it is determined that the charging start condition is satisfied prior to the time period in which the power demand increases, and the power storage device 4 is charged. As a result, the power supply capacity for the power consumer D can be increased prior to the time period when the power demand increases.
In the latter case, the control device C determines that the charging start condition is satisfied when the amount of power stored in the power storage device 4 is less than the lower limit power storage amount. The level of the lower limit storage amount can be set as appropriate. As described above, by adopting the condition related to the storage amount of the power storage device 4 as the charging start condition, the timing when the storage amount of the power storage device 4 becomes less than the lower limit storage amount, that is, the power from the power storage device 4 to the power consumer D It is determined that the charging start condition is satisfied at the timing when the supply surplus capacity decreases, and the power storage device 4 can be charged by the first charging control.

Next, the target charging power Pb for the power storage device 4 will be described.
FIG. 5 is a graph showing an example of the target charging power Pb. In the present embodiment, when the total voltage by the plurality of cells 4a constituting the power storage device 4 is less than the reference voltage, the control device C calculates the target charging power Pb to the power storage device 4 between the total voltage and a constant reference current. Constant current charging derived by product is performed, and when the total voltage is equal to or higher than the reference voltage, target charging power Pb to the power storage device 4 is performed by constant voltage charging derived by the product of the reference voltage and the target charging current. The current is determined by a current curve in which a constant reference current is set as an initial value and the current is decreased over time. The current curve is based on at least one of the temperature and the degree of deterioration of the cell 4a constituting the power storage device 4. To decide.

  In this way, in a state where the total voltage by the plurality of cells 4a is less than the reference voltage, that is, in a state where the total amount of electricity stored by the plurality of cells 4a is relatively small, it is assumed that a relatively large constant reference current flows. Charging can be performed rapidly by performing current charging. On the other hand, in a state in which the total voltage by the plurality of cells 4a is equal to or higher than the reference voltage, that is, in a state in which the total amount of electricity stored by the plurality of cells 4a is relatively large, Overcharge can be suppressed by performing constant voltage charging to reduce the power consumption.

  In the present embodiment, the control device C stores four types of current curves (pattern A to pattern D) in storage means (not shown) such as an internal memory. Then, control device C determines a current curve used for determining the target charging current among the four types of current curves based on at least one of the temperature and the degree of deterioration of cell 4a constituting power storage device 4. That is, in the present embodiment, the current curve is determined according to at least one of the actual degree of deterioration of the cell 4a and the temperature of the cell 4a related to the ease of progress of the deterioration of the cell 4a. Setting that suppresses deterioration of the cell 4a during charging is possible. In any current curve (Pattern A to Pattern D), from the start of charging until time ta (that is, while the total voltage of the plurality of cells 4a constituting the power storage device 4 is less than the reference voltage Vr). The constant reference current Ir becomes the charging current. Then, by continuing such charging, the total voltage gradually increases. The reference current Ir and the reference voltage Vr are the same regardless of the current curve (pattern A to pattern D). From the start of charging until the time ta, the target charging power Pb is derived by the product of the total voltage V1 and the reference current Ir (= I1).

  Specifically, as illustrated in Table 1 below, when the control device C selects a current curve based only on the temperature of the cell 4a, the temperature measured by the temperature measuring unit 4bt is relatively low ( When the deterioration of the cell 4a is relatively difficult to proceed), the current curve of the pattern A is selected. When the temperature is relatively high (when the deterioration of the cell 4a is relatively easy to proceed), the pattern C Select the current curve. As can be seen from the current curve of the pattern A shown in FIG. 5A and the current curve of the pattern C shown in FIG. 5C, the current curve of the pattern C is more time ta than the current curve of the pattern A. Thereafter, the reduction rate of the target charging current with the passage of time is set to be large. That is, after the time ta, the target charging power is derived by the product of the reference voltage Vr (V2)) and the target charging current I2, and therefore the pattern C is charged with time as compared with the pattern A. The power reduction rate is set to be large. As described above, the power supply system includes the temperature measurement unit 4bt that measures the temperature of the power storage device 4, and the control device C selects the temperature among the plurality of current curves prepared in advance according to the temperature of the power storage device 4. A current curve corresponding to the temperature of power storage device 4 measured by measuring means 4bt is selected.

  Further, when the control device C selects a current curve based only on the degree of deterioration of the cell 4a (for example, the above-mentioned “internal resistance”), the degree of deterioration of the cell 4a is relatively low (the internal resistance is relatively low). If low, the pattern A current curve is selected, and if the degree of deterioration is relatively high, the pattern B current curve is selected. As described above, the power supply system includes the control unit 4d as a deterioration measurement unit that measures the degree of deterioration of the power storage device 4, and the control device C includes a plurality of preparations prepared in advance according to the degree of deterioration of the power storage device 4. Among the current curves, a current curve corresponding to the degree of deterioration of the power storage device 4 measured by the control unit 4d as the deterioration measuring means is selected.

  Alternatively, when the control device C selects a current curve based on the combination of the temperature and the degree of deterioration of the cell 4a, the current of the pattern A when the temperature of the cell 4a is relatively low and the degree of deterioration is relatively low. A curve is selected, and when the temperature of the cell 4a is relatively low and the degree of deterioration is relatively high, the current curve of the pattern B is selected, and the temperature of the cell 4a is relatively high and the degree of deterioration is relatively When the temperature is low, the current curve of the pattern C is selected, and when the temperature of the cell 4a is relatively high and the degree of deterioration is relatively high, the current curve of the pattern D is selected. As described above, the power supply system includes the temperature measurement unit 4bt that measures the temperature of the power storage device 4 and the control unit 4d that serves as a deterioration measurement unit that measures the degree of deterioration of the power storage device 4. Of a plurality of current curves prepared in advance according to the combination of the temperature and the degree of deterioration of the device 4, the temperature and the deterioration measuring means (control unit 4d) of the power storage device 4 measured by the temperature measuring means 4bt are measured. A current curve corresponding to a combination of deterioration degrees of the power storage device 4 is selected.

  As described above, the control device C determines the target charging power Pb in which the deterioration of the cell 4a is unlikely to proceed based on at least one of the temperature and the degree of deterioration of the cell 4a constituting the power storage device 4. Thus, the target charging power Pb can be charged to the power storage device 4 while performing power quality control.

Second Embodiment
The power supply system of the second embodiment is different from the first embodiment in the method for determining the target charging power Pb. The power supply system according to the second embodiment will be described below, but the description of the same configuration as that of the first embodiment will be omitted.

  The power supply system of the present embodiment is the same as the configuration shown in FIG. 1, but the contents of the first charge control (the method for determining the target charge power Pb) performed by the control device C are different from those of the first embodiment. Yes. Specifically, in the present embodiment, the control device C stores the cell voltages of the plurality of cells 4a constituting the power storage device 4 (that is, the individual voltages of the cells 4a) in storage means (not shown) such as an internal memory. The relational expression between the highest cell voltage and the target charging current is stored. Then, the control device C determines a target charging current corresponding to the current highest cell voltage based on the relational expression, and multiplies the target charging current by the total voltage of the plurality of cells 4a constituting the power storage device 4. Is derived as the target charging power Pb to the power storage device 4. In the present embodiment, information on the voltage of each cell 4a obtained by the cell management unit 4b is transmitted to the control unit 4d, and further transmitted from the power storage device 4 to the control device C.

  FIG. 6 is a graph showing an example of a relational expression between the highest cell voltage and the target charging current among the cell voltages of the plurality of cells 4a constituting the power storage device 4. As shown in the figure, in this relational expression, a relationship is set such that the target charging current decreases as the maximum cell voltage increases. As described above, when the product of the target charging current and the total voltage of the plurality of cells 4a is used as the target charging power, the target charging current is set so that the target charging current decreases as the maximum cell voltage increases. It is determined according to the relational expression. That is, among the plurality of cells 4a, the cell with the highest cell voltage (the cell with the highest cell voltage) 4a is the cell with the largest amount of stored electricity, and is therefore intended to suppress overcharging of the cell. On the other hand, all the cells are charged. In other words, the fact that the target charging power Pa to the power storage device 4 is derived from the product of the target charging current determined based on the above relational expression and the total voltage of the plurality of cells 4a constitutes the power storage device 4. This means that the other cells 4a are also charged in accordance with the charging current to the cell 4a having the highest cell voltage (that is, the cell 4a having the largest amount of stored electricity) among the plurality of cells 4a.

<Third Embodiment>
The power supply system according to the third embodiment is different from the above-described embodiment in that the self-system includes a charging inverter device that connects the external power system. Hereinafter, the power supply system of the third embodiment will be described, but the description of the same configuration as that of the above embodiment will be omitted.

  FIG. 7 is a diagram illustrating a configuration of a power supply system according to the third embodiment. As shown in the figure, the power supply system of the present embodiment connects the power storage device 4 of one self-system 10B of the plurality of self-systems 10 and an external power system 20 using an external connection line 22. The charging inverter device 21 is provided. The power system 20 is, for example, a system that is used for power supply by a power company that conducts power supply business. Further, as will be described later, the control device C causes the self-standing inverter device 5 to perform power quality control, causes the linked inverter device 9 to perform power interchange control, and causes the charging inverter device 21 to perform power interchange control. On the other hand, the second charging control is performed. The external connection line 22 includes a first external connection line 22a for connecting the charging inverter device 21 and the power system 20, and a second external connection line 22b for connecting the charging inverter device 21 and the power storage device 4. It consists of.

  Also in the present embodiment, the control device C uses the power storage device 4 included in one self system 10 for the self-standing inverter device 5 included in one self system 10 as power quality control, as in the above embodiment. Thus, the voltage of power on the AC line 1 to which the self-standing inverter device 5 is connected using the second self-connecting line 2b is set as a target voltage, and the frequency of power on the AC line 1 is set as the amount of power stored in the power storage device 4. When performing power control using the interconnection line 3 between one self-system 10 and another self-system 10 as a power interchange control, and performing a control with a target frequency determined according to With respect to the connected inverter device 9 provided between the first interconnect line 3a and the second interconnect line 3b constituting the interconnect line 3, the connection of one self system 10 and the other self system 10 is performed. Based on the target frequency on each AC line 1, power is accommodated from the self system 10 in which the power storage amount of the power storage device 4 is relatively large to the self system 10 in which the power storage amount of the power storage device 4 is relatively small. .

Next, the second charging control will be described.
FIG. 8 is a diagram illustrating the second charging control. As shown in the drawing, the control device C satisfies the charge start condition for one power storage device 4 connected to the charging inverter device 21 using the second external connection line 22b as the second charge control. The power inverter Pc supplied to the AC line 1 from the self-standing inverter device 5 for the power quality control performed in the self-system 10B having the one power storage device 4 with respect to the charging inverter device 21. The power Pa that is the sum of the target charging power Pb to the power storage device 4 is supplied from the first external connection line 22a to the second external connection line 22b to charge the single power storage device 4. Has been. Also in this embodiment, for each power Pa, Pb, Pc, the direction indicated by the arrow in FIG. 8 is the positive direction. That is, the relationship “Pa = Pb + Pc” is established. In the second charging control, the power Pa and the power Pc may be negative power as described in the first embodiment.

In the second charging control of the present embodiment, the method for determining the target charging power Pb is the same as the method for determining the target charging power Pb described in the first and second embodiments.
That is, according to the method for determining the target charging power Pb described in the first embodiment, the control device C supplies power to the power storage device 4 when the total voltage by the plurality of cells 4a constituting the power storage device 4 is less than the reference voltage. Constant current charging is performed by deriving the target charging power Pb by the product of the total voltage and a constant reference current. When the total voltage is equal to or higher than the reference voltage, the target charging power Pb to the power storage device 4 is converted to the reference voltage. The constant voltage charging derived by the product of the target charging current is performed, the target charging current is determined by a current curve having a constant reference current as an initial value, and the current is decreased over time. This is determined based on at least one of the degree of deterioration of the cell 4a and the temperature.

  Alternatively, according to the method for determining the target charging power Pb described in the second embodiment, the control device C calculates the maximum cell voltage and the target charging current among the cell voltages of the plurality of cells 4a constituting the power storage device 4. Based on the relational expression, the target charging current corresponding to the current highest cell voltage is determined, and the product of the target charging current and the total voltage of the plurality of cells 4a constituting the power storage device 4 is determined as the target for the power storage device 4. Derived as charging power Pb, in the above relational expression, a relationship is set in which the target charging current decreases as the maximum cell voltage increases.

<Another embodiment>
In the said embodiment, the number of the self systems with which an electric power supply system is provided can be changed suitably. For example, the number of self systems can be set as appropriate, such as 2, tens, hundreds, etc., and can be freely added / deleted.

  In the above embodiment, the relational expression (Formula 2) for deriving the frequency variation value: “Δf = A × [SOC] + B” is described for the purpose of illustration, and can be changed as appropriate. Moreover, in the said embodiment, the relationship where the frequency of the electric power in the alternating current line 1 becomes high as the electrical storage amount of the electrical storage apparatus 4 becomes large (that is, when the coefficient A takes a positive value in Formula 2) in the said embodiment. ), The self-sustained inverter device 5 decreases the frequency of power on the AC line 1 as the power storage amount of the power storage device 4 increases. Control may be performed so that the target frequency is determined by the following relationship (that is, when the coefficient A takes a negative value in Equation 2).

  In the said embodiment, the timing of the charge stop in 1st charge control and 2nd charge control can be set suitably. For example, the control device C performs control such that charging by the first charge control or the second charge control is stopped when the total voltage by the plurality of cells 4a constituting the power storage device 4 reaches the upper limit total voltage. Can do. Alternatively, the control device C is charged by the first charge control or the second charge control when the highest cell voltage among the individual cell voltages of the plurality of cells 4a constituting the power storage device 4 becomes the upper limit individual cell voltage. It is possible to perform control to stop the operation.

  In the above embodiment, the relational expression between the maximum cell voltage and the target charging current shown in FIG. 6 can be changed as appropriate. For example, FIG. 6 shows an example in which the maximum cell voltage and the target charging current are set in a non-linear relationship, but both may be set in a linear relationship.

  INDUSTRIAL APPLICABILITY The present invention can be used for a power supply system that can charge a power storage device while performing power quality control that maintains the power quality of an AC line using the power storage device.

1: AC line 2: Self-connection line 2a: First self-connection line 2b: Second self-connection line 3: Interconnection line 4: Power storage device 4a: Cell 4b: Cell management unit 4bt: Temperature measurement means 4bv: Voltage measurement means 4c: current sensor 4d: control unit 5: self-supporting inverter device 6: power consuming device 7: power generation device 9: linked inverter device 10: self system 20: power system 21: charging inverter device 22: external connection line 22a: first External connection line 22b: Second external connection line C: Control device D: Electric power consumer

Claims (6)

A plurality of self-systems including an AC line to which a plurality of power consumers are connected, a power storage device, and a self-standing inverter device that connects the power storage device and the AC line using a self-connection line,
An interconnection line is used between the power storage device of one self system and the AC line of the other self system so that a plurality of the self systems are electrically connected in series. A power supply system comprising a connected inverter device to be connected between the self systems,
The self-connection line includes a first self-connection line for connecting the self-standing inverter device and the power storage device, and a second self-connection line for connecting the self-standing inverter device and the AC line. ,
The interconnect line includes a first interconnect line for connecting the linked inverter device and the power storage device, and a second interconnect line for connecting the linked inverter device and the AC line. ,
A control device is provided that performs power quality control on the independent inverter device, and performs power interchange control and first charge control on the connected inverter device,
The controller is
As the power quality control, the self-contained inverter device is connected to the self-supporting inverter device included in one self-system using the power storage device included in the single self-system, and the self-supporting inverter device is connected using the second self-connecting line. The control is performed such that the voltage of the power on the AC line is a target voltage and the frequency of the power on the AC line is a target frequency determined according to the amount of power stored in the power storage device, and
As the power interchange control, when power is interchanged between one self system and another self system using the interconnect line, the first interconnect line and the first interconnect line constituting the interconnect line are used. The amount of power stored in the power storage device based on the target frequency on the AC line in each of the one self system and the other self system with respect to the connected inverter device provided between two interconnect lines Power from a relatively large self-system to a self-system with a relatively small amount of power stored in the power storage device, and
When it is determined that the charging start condition for one power storage device is satisfied as the first charge control, the connected inverter device connected to the one power storage device using the first interconnection line On the other hand, the sum of the power supplied from the independent inverter device to the AC line and the target charging power to the one power storage device for the power quality control performed in the self system having the one power storage device The power supply system is configured to supply the power from the second interconnection line to the first interconnection line to charge the one power storage device. A plurality of self-systems including an AC line to which a plurality of power consumers are connected, a power storage device, and a self-standing inverter device that connects the power storage device and the AC line using a self-connection line,
An interconnection line is used between the power storage device of one self system and the AC line of the other self system so that a plurality of the self systems are electrically connected in series. A power supply system comprising a connected inverter device to be connected between the self systems,
The self-connection line includes a first self-connection line for connecting the self-standing inverter device and the power storage device, and a second self-connection line for connecting the self-standing inverter device and the AC line. ,
The interconnect line includes a first interconnect line for connecting the linked inverter device and the power storage device, and a second interconnect line for connecting the linked inverter device and the AC line. ,
An inverter device for charging that uses an external connection line to connect between the power storage device of one of the plurality of self systems and an external power system;
A control device for performing power quality control on the independent inverter device, performing power interchange control on the connected inverter device, and performing second charge control on the charging inverter device;
The external connection line includes a first external connection line for connecting the charging inverter device and the power system, and a second external connection line for connecting the charging inverter device and the power storage device. Configured,
The controller is
As the power quality control, the self-contained inverter device is connected to the self-supporting inverter device included in one self-system using the power storage device included in the single self-system, and the self-supporting inverter device is connected using the second self-connecting line. The control is performed such that the voltage of the power on the AC line is a target voltage and the frequency of the power on the AC line is a target frequency determined according to the amount of power stored in the power storage device, and
As the power interchange control, when power is interchanged between one self system and another self system using the interconnect line, the first interconnect line and the first interconnect line constituting the interconnect line are used. The amount of power stored in the power storage device based on the target frequency on the AC line in each of the one self system and the other self system with respect to the connected inverter device provided between two interconnect lines Power from a relatively large self-system to a self-system with a relatively small amount of power stored in the power storage device, and
When it is determined that the charging start condition for one power storage device connected to the charging inverter device using the second external connection line is satisfied as the second charging control, the charging inverter device In contrast, for the power quality control performed in the self-system having the one power storage device, the power supplied from the independent inverter device to the AC line and the target charging power to the one power storage device A power supply system configured to supply a sum of electric power from the first external connection line to the second external connection line to charge the one power storage device. The controller is
When the total voltage by a plurality of cells constituting the power storage device is less than a reference voltage, the target charging power to the power storage device is subjected to constant current charging derived by a product of the total voltage and a constant reference current,
When the total voltage is equal to or higher than the reference voltage, the target charging power to the power storage device is subjected to constant voltage charging derived by a product of the reference voltage and the target charging current,
The target charging current is determined by a current curve in which the constant reference current is set as an initial value and the current is decreased over time, and the current curve is determined by at least one of a deterioration degree and a temperature of a cell constituting the power storage device. The power supply system according to claim 1, wherein the power supply system is determined based on one of the two. The control device determines a target charging current corresponding to the current highest cell voltage based on a relational expression between a highest cell voltage and a target charging current among cell voltages of a plurality of cells constituting the power storage device. The product of the target charging current and the total voltage of a plurality of cells constituting the power storage device is derived as the target charging power to the power storage device,
3. The power supply system according to claim 1, wherein in the relational expression, a relationship is set such that the target charging current decreases as the highest cell voltage increases.   The power supply system according to any one of claims 1 to 4, wherein the control device determines that the charging start condition is satisfied when a set time is reached.   The power supply system according to any one of claims 1 to 5, wherein the control device determines that the charging start condition is satisfied when a storage amount of the power storage device is less than a lower limit storage amount.

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