WO2016199377A1 - Power storage system, power storage device, and operation method for power storage device - Google Patents

Abstract

The present invention addresses the problem of providing a power storage system, a power storage device, and an operation method for a power storage device with which it is possible to inhibit a bias in the degree of the load of each of a plurality of autonomously operating power storage devices when the outputs from each of the power storage devices are connected in parallel. In a power storage system, a power storage device, and an operation method for a power storage device according to the present invention, a power conditioner (2b) of a master device (21) carries out voltage control that controls an output voltage to a target voltage. Slave devices (22, 23) each acquire measurement data about the total load current that is fed to a second load (72). A power conditioner (2b) of each slave device (22, 23) carries out current control that controls an output current to a target current determined on the basis of the total load current and the number of power storage devices (2).

Description

Power storage system, power storage device, and method of operating power storage device

The present invention generally relates to a power storage system, a power storage device, and a method for operating the power storage device.

Conventionally, there is a system that supplies power to a load by operating power storage devices in parallel.

For example, the technique described in Patent Document 1 includes a second power storage circuit using an electric double layer capacitor in addition to a first power storage circuit using a storage battery. When the power consumption of the external load increases momentarily, the first power storage circuit supplies power after the second power storage circuit supplies power.

Furthermore, the conventional power storage system includes a plurality of power storage devices capable of switching between the grid operation and the independent operation. And each independent output of the some electrical storage apparatus is connected in parallel.

In such a power storage system, when a plurality of power storage devices operate independently, the total load current supplied to the load is shared by the plurality of power storage devices. However, in the conventional technique, the degree of burden (degree of burden of output current) may be biased to any of the power storage devices. In this case, there may occur a power storage device in which an output current is increased as compared with other power storage devices to be in an overcurrent state. Furthermore, a power storage device that operates in a charging mode in which the output current has a polarity opposite to that of the load current may occur.

JP 2002-110210 A

An object of the present invention is to provide a power storage system, a power storage device, a power storage system, and a power storage device capable of suppressing a bias in the degree of burden of each of the plurality of power storage devices when the outputs of the plurality of power storage devices that operate independently are connected in parallel. It is another object of the present invention to provide a method for operating a power storage device.

A power storage system according to an aspect of the present invention includes a storage battery, a power conditioner that converts DC power of the storage battery into AC power and outputs the plurality of power storages capable of switching between grid operation and independent operation. Each output of the plurality of power storage devices at the time of the self-sustained operation is connected in parallel between electric circuits to which a load is connected, and when each of the plurality of power storage devices performs the self-sustained operation, One of the plurality of power storage devices is set as a master device, and the other power storage device is set as a slave device, and the power conditioner of the master device controls the output voltage to a target voltage. The slave device further includes a data acquisition unit that acquires measurement data of a total load current supplied to the load, and the slave device Power conditioner, and performs current control for controlling the output current to the determined target current on the basis of the number of the total load current and the power storage device.

A power storage device according to one embodiment of the present invention is used in the above power storage system.

An operation method of a power storage device according to one aspect of the present invention includes a storage battery, a power conditioner that converts DC power of the storage battery into AC power, and outputs the AC power, and can switch between interconnection operation and independent operation. A method of operating a power storage device used in a power storage system including a plurality of power storage devices, wherein each output of the plurality of power storage devices during the self-sustained operation is connected in parallel between electric circuits to which a load is connected, One of the plurality of power storage devices is a master device and the other power storage device is a slave device, and the power conditioner of the master device performs voltage control to control the output voltage to the target voltage. The power conditioner of the slave device outputs a target current determined based on the total load current supplied to the load and the number of power storage devices. And performing current control for controlling the flow.

It is a block diagram which shows the structure of the electrical storage system of embodiment. It is a block diagram which shows the structure of the electrical storage apparatus of embodiment. It is the schematic which shows the connection form of the some electrical storage apparatus which performs the self-sustained operation of embodiment, and 2nd load. Each of FIG. 4A, FIG. 4B, FIG. 4C, and FIG. 4D is a waveform diagram showing the current waveform of each part when independent output control different from the present embodiment is performed. Each of FIG. 5A, FIG. 5B, FIG. 5C, and FIG. 5D is a waveform diagram showing the current waveform of each part when the self-sustained output control of this embodiment is performed. It is a block diagram which shows the structure of another electrical storage system of embodiment.

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

The following embodiments generally relate to a power storage system, a power storage device, and a method for operating the power storage device. More specifically, the present invention relates to a power storage system, a power storage device, and a method for operating the power storage device that can switch between a grid operation and a self-sustained operation.

The power storage system 100 of the present embodiment has the configuration shown in FIG. This power storage system 100 is used in each building such as a dwelling unit, a detached house, a factory, and an office of an apartment house supplied with commercial power from an electric power company. The power storage system 100 includes a distribution board 1, a plurality of power storage devices 2, a switching board 3, and a controller 4 as main components. When distinguishing a plurality of power storage devices 2, each of the plurality of power storage devices 2 is connected to power storage devices 21, 22, 23,. . . Call it.

The distribution board 1 is connected to a main line 81 drawn into the building, and commercial power is supplied from the commercial power source 9 of the power company through the main line 81. The distribution board 1 stores a main power breaker 1a, a branch breaker 1b, and a distributed power breaker 1c. The main line 81 is connected to each of the plurality of branch breakers 1b and the distributed power breakers 1c via the main power breaker 1a.

Then, the main line 81 branches into a plurality of branch lines 82 via each branch breaker 1b. A first load 71 is connected to each branch electric circuit 82. The first load 71 is composed of one or more electric devices 710 including lighting devices, air conditioning devices, home appliances, and the like. The branch electric circuit 82 supplies AC power to the first load 71.

Further, the main line 81 branches to one branch circuit 82a via one branch breaker 1b. The branch electric circuit 82 a is connected to the switching board 3.

As shown in FIG. 2, each of the plurality of power storage devices 2 includes a storage battery 2a, a power conditioner 2b, a communication unit 2c, a control unit 2d, and a data acquisition unit 2e.

The storage battery 2a is composed of a secondary battery such as a lithium ion battery. The storage battery 2a is connected to the power conditioner 2b. The power conditioner 2b has an AC / DC conversion function and a DC / AC conversion function. The AC / DC conversion function is a function of charging the storage battery 2a by converting AC power into DC power. The DC / AC conversion function is a function of converting the direct current power of the storage battery 2a into alternating current power and outputting it.

It is preferable that the power conditioner 2b charges the storage battery 2a when the charge level of the storage battery 2a decreases to the set value. Moreover, the power conditioner 2b can also charge the storage battery 2a regularly using late-night electric power.

The interconnection connection part 2f of the power conditioner 2b receives commercial power from the commercial power source 9 via the distributed power circuit breaker 1c. The power conditioner 2b can charge the storage battery 2a by converting the received commercial power into DC power.

Further, the discharge power of the storage battery 2a is supplied to the power conditioner 2b and converted into AC power by the power conditioner 2b. The power conditioner 2b operates so as to be able to switch between the grid operation and the independent operation. The power conditioner 2b discriminates between the normal time and the power failure time by detecting the AC voltage input to the interconnection connection portion 2f. At normal times, the commercial power supply 9 supplies commercial power. At the time of a power failure, the supply of commercial power from the commercial power source 9 is stopped.

Specifically, the power conditioner 2b performs a grid-connected operation at normal times when the commercial power source 9 is energized. The power conditioner 2b performs a self-sustained operation when the commercial power source 9 fails. And the power conditioner 2b is connected with the commercial power supply 9 (commercial power system) at the time of a grid connection operation, and outputs the alternating current power produced | generated from the discharge power of the storage battery 2a from the grid connection part 2f. Moreover, the power conditioner 2b outputs the alternating current power produced | generated from the discharge power of the storage battery 2a from the independent connection part 2g, without connecting with a commercial power system at the time of an autonomous operation.

In addition, the alternating current power output from the interconnection connection part 2f is called an interconnection output, and the alternating current power output from the independent connection part 2g is called an independent output.

The interconnection connection part 2 f is connected to the AC circuit 83. The interconnection output is supplied from the AC electric circuit 83 to the main electric circuit 81 via the distributed power circuit breaker 1 c of the distribution board 1. Thus, the interconnection output is supplied from the main line 81 to the branch circuit 82 via the branch breaker 1b. The power conditioner 2b has a grid connection function. The grid interconnection function is a function for coordinating the grid output with the commercial power supplied by the commercial power supply 9.

In addition, the self-supporting connection 2g is connected to the AC circuit 84. The self-sustained output is input to the switching board 3 via the AC electric circuit 84. The switching board 3 switches the connection destination of the independent electric circuit 85 to either the branch electric circuit 82 a or the AC electric circuit 84. A second load 72 is connected to the self-supporting electric circuit 85. The second load 72 is composed of one or more electric devices 720 including lighting devices, air conditioning devices, home appliances, and the like.

Then, the controller 4 controls switching of the connection state of the switching board 3. For example, the controller 4 detects the primary side voltage of the main power breaker 1a to determine whether it is normal or during a power failure. If the controller 4 determines that it is normal, the controller 4 controls the switching panel 3 to connect the self-supporting electric circuit 85 to the branch electric circuit 82a. Further, when the controller 4 determines that the power failure has occurred, the controller 4 controls the switching panel 3 to connect the self-supporting electric circuit 85 to the AC electric circuit 84.

When the independent electric circuit 85 is connected to the branch electric circuit 82a by the switching board 3, the electric circuit from the branch electric circuit 82a to the independent electric circuit 85 is conducted, and the power of the trunk electric circuit 81 (sum of commercial power and interconnection output) is the independent electric circuit. 85. In addition, when the independent electric circuit 85 is connected to the AC electric circuit 84 by the switching board 3, the electric circuit from the AC electric circuit 84 to the independent electric circuit 85 is conducted, and an independent output is supplied to the independent electric circuit 85.

In the power storage system 100, the first load 71 connected to the branch circuit 82 is a load that is supplied with power only during normal times when the commercial power supply 9 is in an energized state. On the other hand, the second load 72 connected to the self-supporting electric circuit 85 is a load to which electric power is supplied both during normal times when the commercial power source 9 is in an energized state and during a power failure of the commercial power source 9.

Current sensors 51 to 53 are provided in the self-supporting electric circuit 85 to which the second load 72 is electrically connected. The current sensors 51 to 53 measure the total load current by measuring the current flowing through the self-supporting electric circuit 85. The total load current is the sum of the load currents supplied to the second load 72. Current sensor 51 outputs measurement data of the total load current to power storage device 21. Current sensor 52 outputs measurement data of the total load current to power storage device 22. The current sensor 53 outputs the measurement data of the total load current to the power storage device 23. Each data acquisition unit 2e of the power storage device 2 receives the measurement data transmitted to the own device and delivers the measurement data to the control unit 2d.

Further, the communication unit 2c of the power storage device 2 can perform wired or wireless communication with the communication unit 2c of the other power storage device 2. The control unit 2d performs communication control of the communication unit 2c.

Hereinafter, the independent operation by the power storage device 2 during a power failure will be described with reference to FIG. FIG. 3 is a schematic diagram showing only a connection form between the plurality of power storage devices 2 performing the self-sustained operation and the second load 72.

The AC electric circuit 84 connected to the self-supporting connection part 2g of the power storage device 2 is two wires L1 and L2. The self-supporting electric circuit 85 is composed of two lines L11 and L12, and the second load 72 is electrically connected between the lines L11 and L12. The wiring L1 and the wiring L11 are electrically connected via the switching board 3. The wiring L2 and the wiring L12 are electrically connected via the switching board 3. That is, each output (self-supporting connection part 2g) of the plurality of power storage devices 2 (power conditioner 2b) during the self-sustaining operation is electrically connected in parallel between the electric circuits to which the second load 72 is connected. In the present embodiment, the outputs of the three power storage devices 21, 22, and 23 are connected in parallel.

Each control unit 2d of power storage devices 21, 22, and 23 periodically exchanges remaining capacity data with other power storage devices 2 via communication unit 2c during both the grid operation and the independent operation. Do it. The remaining capacity data represents the charge level of the storage battery 2a. Each control unit 2d of the power storage devices 21, 22, and 23 can know the current remaining capacity (charge level) of the other power storage devices 2. Each control unit 2d of the power storage devices 21, 22, and 23 compares the remaining capacity of the own device and the other power storage device 2, and sets the own device as the master device if the remaining capacity of the own device is the largest. preferable. Each control unit 2d of the power storage devices 21, 22, and 23 compares the remaining capacity of the own device and the other power storage device 2, and if the remaining capacity of the own device is not the largest (there is more remaining capacity than the own device). If there is another power storage device 2), it is preferable to set the own device as a slave device.

That is, the setting unit 6 is configured by the control units 2 d of the power storage devices 21, 22, and 23. When each of the plurality of power storage devices 2 performs a self-sustained operation, the setting unit 6 uses any one power storage device 2 among the plurality of power storage devices 2 as a master device and other power storage devices 2 as slave devices. It has a function. Thus, each of the plurality of power storage devices 2 is switched to either the master device or the slave device by being set as a master device or a slave device by the setting unit 6 periodically.

Hereinafter, the power storage device 2 that is a master device is referred to as a master device 2, and the power storage device 2 that is a slave device is referred to as a slave device 2. Here, it is assumed that the power storage device 21 is the master device 21 and the power storage devices 22 and 23 are the slave devices 22 and 23.

In addition, the control unit 2d can recognize the number of power storage devices 2 in the power storage system 100 when periodically transferring remaining capacity data to and from other power storage devices 2. The control unit 2d holds data on the number of power storage devices 2 in the power storage system 100.

Then, when each of the master device 21 and the slave devices 22 and 23 starts independent operation, in the master device 21, the control unit 2d instructs the power conditioner 2b to perform constant voltage operation. Specifically, the control unit 2d of the master device 21 notifies the target voltage to the power conditioner 2b. The power conditioner 2b instructed to operate at a constant voltage performs voltage control so that the voltage of the independent output matches the target voltage. The target voltage is set to the nominal voltage of commercial power, and is set to 100V or 200V here.

In each of the slave devices 22 and 23 that have started independent operation, the control unit 2d instructs the power conditioner 2b to perform constant current operation. Specifically, each control unit 2d of the slave devices 22 and 23 notifies the target current to the power conditioner 2b. The power conditioner 2b instructed to perform the constant current operation performs current control so that the current of the self-sustained output matches the target current. In the power conditioner 2b instructed to operate at constant current, the voltage of the self-sustained output is close to the nominal voltage of commercial power.

In addition, after the master apparatus 21 starts a self-sustained operation and performs voltage control, each of the slave apparatuses 22 and 23 starts a self-sustained operation and performs current control, so that the self-sustained output can be synchronized. Alternatively, the master device 21 and the slave devices 22 and 23 can communicate with each other to synchronize independent outputs.

Specifically, each control unit 2d of the slave devices 22 and 23 can know the total load current I0 from the measurement data of the total load current. Therefore, the control unit 2d preferably uses a value obtained by dividing the total load current I0 by the number of power storage devices 2 (in this case, three) as a target current. That is, each of the slave devices 22 and 23 sets the target current so that each of the power storage devices 2 in the power storage system 100 equally divides and bears the total load current I0. Therefore, the current values and waveforms of the independent outputs of the slave devices 22 and 23 are the same, and the independent output of the master device 21 that performs voltage control is the same as the independent outputs of the slave devices 22 and 23 as a result. Current value and waveform.

4A, FIG. 4B, FIG. 4C, and FIG. 4D show current waveforms of respective parts when the master device 21 performs voltage control and each of the slave devices 22 and 23 performs current control different from that of the present embodiment. In this case, the current control performed by each of the slave devices 22 and 23 differs from the current control of the present embodiment in that the current waveform of the self-supporting output is a sine wave.

FIG. 4A shows the waveform of the total load current I0. FIG. 4B shows the waveform of the current (self-supporting current) I1 of the self-supporting output of the master device 21. FIG. 4C shows a waveform of the free-standing current I2 of the slave device 22. FIG. 4D shows a waveform of the self-supporting current I3 of the slave device 23.

In this case, the second load 72 includes a capacitive load (for example, a capacitor input type load). Therefore, the total load current I0 increases rapidly in the vicinity of the voltage peak, and the waveform is distorted. When each of the slave devices 22 and 23 performs current control in which the current waveform of the self-supporting output is a sine wave, the master device 21 bears most of the waveform distortion component, and the master device 21, the slave device 22, There is a possibility that output deviation occurs between the two. For example, as shown in FIG. 4B, when the self-supporting current I1 of the master device 21 bears most of the waveform distortion component of the total load current I0, the self-supporting current I1 is distorted and becomes an overcurrent state (region X1 in FIG. 4B). The operation of the master device 21 becomes unstable. In addition, the self-supporting current I1 of the master device 21 may be in a charging mode in which the polarity is opposite to that of the total load current I0 (region X2 in FIG. 4B), which may affect the safety of the system.

Therefore, in the present embodiment, as described above, the master device 21 performs voltage control, and each of the slave devices 22 and 23 performs current control with a value obtained by dividing the total load current I0 by the number of power storage devices 2 as a target current. I do.

5A, FIG. 5B, FIG. 5C, and FIG. 5D show current waveforms of respective parts when the master device 21 performs voltage control and each of the slave devices 22 and 23 performs current control using the above-described target current. . FIG. 5A shows the waveform of the total load current I0. FIG. 5B shows a waveform of the self-supporting current I1 of the master device 21. FIG. 5C shows a waveform of the free-standing current I2 of the slave device 22. FIG. 5D shows a waveform of the self-supporting current I3 of the slave device 23.

Also in this case, the second load 72 includes a capacitive load. Therefore, the total load current I0 increases rapidly in the vicinity of the voltage peak, and the waveform is distorted. However, when the master device 21 performs the above-described voltage control and each of the slave devices 22 and 23 performs the current control using the above-described target current, each of the independent currents I1 of the master device 21 and the slave devices 22 and 23 is obtained. , I2 and I3 have substantially the same current values and waveforms. As a result, the self-supporting currents I1, I2, and I3 are almost unbiased.

Therefore, the waveform distortion component of the total load current I0 is also borne by the independent currents I1, I2, and I3 almost equally, and the occurrence of a charging mode having a polarity opposite to that of the total load current I0 can be suppressed. That is, in the power storage system 100 of the present embodiment, when the outputs of the plurality of power storage devices 2 that are independently operated are connected in parallel, it is possible to suppress a bias in the degree of the burden on each of the plurality of power storage devices 2. it can.

In this embodiment, the power storage device 21 is a master device, and the power storage devices 22 and 23 are slave devices. However, the settings of the master device and the slave device are periodically updated based on the remaining capacity data.

That is, the power storage device 2 includes the storage battery 2a and the power conditioner 2b that converts the DC power of the storage battery 2a into AC power and outputs it, and can switch between the grid operation and the independent operation. And the electrical storage apparatus 2 becomes a master apparatus or a slave apparatus, when performing a self-sustained operation. When the power storage device 2 becomes a master device, the power conditioner 2b performs voltage control for controlling the output voltage to the target voltage. When power storage device 2 becomes a slave device, power conditioner 2b outputs a target current determined based on the total load current supplied to the load (second load) and the number of power storage devices 2. Perform current control to control current.

Alternatively, the setting of the master device or the slave device is fixed for each power storage device 2, and the power storage system 100 includes the power storage device 2 dedicated to the master device and the power storage device 2 dedicated to the slave device. May be.

Also, even during normal times, the master device performs a linked operation by voltage control, and the slave device performs a linked operation by current control. Alternatively, during normal times, not only the slave device but also the master device may perform a linked operation by current control.

As is clear from the embodiment described above, the power storage system 100 according to the first aspect of the present invention includes a plurality of power storage devices (2). Each of the plurality of power storage devices (2) includes a storage battery (2a), a power conditioner (2b) that converts the DC power of the storage battery (2a) into AC power and outputs the power, and performs interconnected operation and independent operation. Can be switched. The outputs of the plurality of power storage devices (2) during the self-sustaining operation are connected in parallel between the electric circuits to which the load (second load (72)) is connected. When each of a plurality of power storage devices (2) performs a self-sustained operation, any one power storage device (2) among the plurality of power storage devices (2) is set as a master device, and the other power storage device (2) Is set as a slave device.

And the power conditioner (2b) of the master device performs voltage control for controlling the output voltage to the target voltage. The slave device further includes a data acquisition unit (2e) that acquires measurement data of the total load current supplied to the load. The power conditioner (2b) of the slave device performs current control for controlling the output current to the target current determined based on the total load current and the number of power storage devices (2).

According to the power storage system (100) of the first aspect, the target current is determined based on the total load current and the number of power storage devices (2), and the slave device performs current control for controlling the output current to the target current. Do. Therefore, the power storage system (100) suppresses the unevenness of the degree of burden of each of the plurality of power storage devices (2) when the outputs of the plurality of power storage devices (2) that are operated independently are connected in parallel. be able to.

In the power storage system (100) according to the second aspect of the present invention, in the first aspect, the power storage device (2) having the largest remaining capacity of the storage battery (2a) among the plurality of power storage devices (2) is the master device. It is preferable that

According to the power storage system (100) of the second aspect, by using the power storage device (2) having the largest remaining capacity of the storage battery (2a) as the master device, stable voltage control is performed and applied to the load. Voltage stability is improved.

In the power storage system (100) according to the third aspect of the present invention, in the first or second aspect, each of the plurality of power storage devices (2) communicates with another power storage device (2). It is preferable to further include a communication unit (2c) capable of performing the above.

According to the power storage system (100) of the third aspect, it is possible to share data among the plurality of power storage devices (2), and according to the respective states of the plurality of power storage devices (2) as a system Control can be performed.

In the power storage system (100) according to the fourth aspect of the present invention, in the third aspect, each of the plurality of power storage devices (2) preferably further includes a control unit (2d). The control unit (2d) transmits the remaining capacity data of the storage battery (2a) of its own device to the other power storage apparatus (2), and is based on the remaining capacity of each storage battery (2a) of the plurality of power storage apparatuses (2). To set the device as a master device or a slave device. Then, among the plurality of power storage devices (2), the control unit (2d) of the power storage device (2) having the largest remaining capacity of the storage battery (2a) sets its own device as the master device, and the other power storage device (2) The control unit (2d) sets its own device as a slave device.

According to the power storage system (100) of the fourth aspect, since the function of the setting unit (6) is realized by the power storage device (2), there is no need to provide a separate setting unit, and the system configuration is simplified. Can do.

In the power storage system (100) according to the fifth aspect of the present invention, in any one of the first to fourth aspects, the power conditioner (2b) of the slave device converts the total load current to a plurality of power storage devices (2 ) Is preferably the target current.

According to the power storage system (100) of the fifth aspect, the current values and the waveforms of the outputs of the plurality of power storage devices (2) are substantially the same, and the outputs are in an almost non-biased state.

Further, as described above, each control unit 2d of power storage devices 21, 22, and 23 periodically exchanges remaining capacity data with other power storage devices 2 via communication unit 2c. . Therefore, the control unit 2d of the master device 21 can derive a weighting coefficient for weighting each target current of the slave devices 22 and 23 based on the remaining capacity data of the own device and the slave devices 22 and 23. preferable.

The control unit 2d of the master device 21 obtains the weighting coefficient α based on the remaining capacity data of the own device and the slave devices 22 and 23. Specifically, the control unit 2d of the master device 21 obtains a ratio [remaining capacity of the slave device / remaining capacity of the master device] of each remaining capacity of the slave devices 22 and 23 to the remaining capacity of the own device as the weighting coefficient α. That is, the weighting coefficient α2 of the slave device 22 is [remaining capacity of the slave device 22 / remaining capacity of the master device 21]. The weighting coefficient α3 of the slave device 23 is [remaining capacity of the slave device 23 / remaining capacity of the master device 21]. Then, the control unit 2d of the master device 21 transmits the data of the weighting coefficient α2 to the slave device 22, and transmits the data of the weighting coefficient α3 to the slave device 23.

The control unit 2d of the slave device 22 sets the result obtained by multiplying the value obtained by dividing the total load current I0 by the number of the power storage devices 2 by the weighting coefficient α2 as the target current. In addition, the control unit 2d of the slave device 23 sets a result obtained by multiplying the value obtained by dividing the total load current I0 by the number of the power storage devices 2 by the weighting coefficient α3 as the target current.

In the power storage system (100) of the sixth aspect according to the present invention, in the third or fourth aspect, the slave device uses the remaining capacity data, which is data relating to the remaining capacity of the storage battery (2a) of the own apparatus, as a master device. Send to. Based on the remaining capacity data of the slave device and the remaining capacity data of the own device, the master device sets a coefficient (weighting coefficient) that increases as the remaining capacity increases for each power storage device (2). The data of the coefficient corresponding to each of is transmitted. The power conditioner (2b) of the slave device preferably uses a value obtained by dividing the total load current by the number of power storage devices (2) multiplied by a coefficient as the target current.

According to the power storage system (100) of the sixth aspect, the self-sustained current supplied from the power storage device (2) with a large remaining capacity increases, and the self-supporting current supplied from the power storage device (2) with a small remaining capacity decreases. Become. Therefore, the power storage system (100) can suppress the bias of the AC power output from each of the plurality of power storage devices (2), and each of the power storage devices (2) as a current burden corresponding to the remaining capacity of each power storage device (2). The remaining capacity of the storage battery (2a) of 2) can be equalized.

Further, the power storage system (100) may include a setting unit 6A separately from the power storage device 2, as shown in FIG. In this case, setting unit 6A periodically obtains remaining capacity data from each of the plurality of power storage devices 2, uses power storage device 2 having the largest remaining capacity of storage battery 2a as a master device, and sets other power storage devices 2 as slave devices. And Setting unit 6A transmits a master device setting instruction or a slave device setting instruction to each of the plurality of power storage devices 2. Control unit 2d of power storage device 2 sets itself as a master device or a slave device in response to a setting instruction.

Further, the power storage device (2) according to the first aspect of the present invention is used in any one of the power storage systems (100) according to the first to sixth aspects.

According to the power storage device (2) of the first aspect, the power storage device (2) also has a plurality of power storage devices (2) when the outputs of the plurality of power storage devices (2) that operate independently are connected in parallel. ) Can be prevented from being biased.

Moreover, the operation method of the power storage device according to the first aspect of the present invention is an operation method of the power storage device (2) used in the power storage system (100). The power storage system (100) includes a storage battery (2a) and a power conditioner (2b) that converts the DC power of the storage battery (2a) into AC power and outputs the power, and can switch between grid operation and independent operation. A plurality of power storage devices (2) are provided. The outputs of the plurality of power storage devices (2) during the self-sustaining operation are connected in parallel between the electric circuits to which the load (second load (72)) is connected. Then, any one of the plurality of power storage devices (2) is a master device, and the other power storage device (2) is a slave device. The power conditioner (2b) of the master device performs voltage control for controlling the output voltage to the target voltage. The power conditioner (2b) of the slave device performs current control for controlling the output current to the target current determined based on the total load current supplied to the load and the number of power storage devices (2).

According to the operation method of the power storage device of the first aspect, when the outputs of the plurality of power storage devices (2) that are independently operated are connected in parallel, the degree of each burden of the plurality of power storage devices (2) Can be suppressed.

The power storage device 2 is equipped with a computer, and the function of the control unit 2d of the power storage device 2 described above is realized by the computer executing a program. A computer mainly includes a device having a processor for executing a program, an interface device for transmitting / receiving data to / from other apparatuses, and a storage device for storing data. Prepare. The device provided with the processor may be a CPU (Central Processing Unit) or MPU (Micro Processing Unit) which is a separate body from the semiconductor memory, or a microcomputer integrally including a semiconductor memory. As a storage device, a storage device having a short access time such as a semiconductor memory and a large-capacity storage device such as a hard disk device are used in combination.

As a program providing form, a computer-readable ROM (Read Only Memory), a form stored in advance in a recording medium such as an optical disc, a form supplied to a recording medium via a wide area communication network including the Internet, etc. There is.

The above embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and various modifications can be made depending on the design and the like as long as the technical idea according to the present invention is not deviated from this embodiment. Of course, it is possible to change.

DESCRIPTION OF SYMBOLS 100 Power storage system 1 Distribution board 2 (21, 22, 23) Power storage device 2a Storage battery 2b Power conditioner 2c Communication part 2d Control part 2e Data acquisition part 2f Interconnection connection part 2g Independent connection part 3 Switching panel 4 Controller 51,52 , 53 Current sensor 6 Setting unit 71 First load 72 Second load 81 Trunk line 82 Branch line 83 AC line 84 AC line 85 Stand-alone line

Claims (8)

A storage battery, having a power conditioner that converts and outputs DC power of the storage battery into AC power, and includes a plurality of power storage devices capable of switching between interconnection operation and independent operation,
Each output of the plurality of power storage devices during the self-sustained operation is connected in parallel between electric circuits to which a load is connected,
When each of the plurality of power storage devices performs the independent operation, any one power storage device among the plurality of power storage devices is set as a master device, and the other power storage device is set as a slave device,
The power conditioner of the master device performs voltage control to control the output voltage to the target voltage,
The slave device further includes a data acquisition unit that acquires measurement data of a total load current supplied to the load, and the power conditioner of the slave device includes the total load current, the number of power storage devices, A power storage system, wherein current control is performed to control an output current to a target current determined based on. The power storage system according to claim 1, wherein the power storage device having the largest remaining capacity of the storage battery among the plurality of power storage devices is the master device. 3. The power storage system according to claim 1, wherein each of the plurality of power storage devices further includes a communication unit capable of communicating with another power storage device. Each of the plurality of power storage devices transmits data on the remaining capacity of the storage battery of the own device to another power storage device, and based on the remaining capacity of each storage battery of the plurality of power storage devices, It further comprises a control unit for setting in the slave device,
Among the plurality of power storage devices, the control unit of the power storage device having the largest remaining capacity of the storage battery sets its own device as the master device, and the control unit of another power storage device sets its own device as the slave device. The power storage system according to claim 3, characterized in that: The power storage system according to any one of claims 1 to 4, wherein the power conditioner of the slave device uses a value obtained by dividing the total load current by the number of the plurality of power storage devices as a target current. The slave device transmits remaining capacity data, which is data related to the remaining capacity of the storage battery of the own device, to the master device,
Based on the remaining capacity data of the slave device and the remaining capacity data of the own device, the master device sets a coefficient that becomes higher as the remaining capacity increases for each power storage device, Send the coefficient data corresponding to
5. The power conditioner of the slave device uses the value obtained by dividing the total load current by the number of the plurality of power storage devices multiplied by the coefficient as the target current. 6. Power storage system. A power storage device used in the power storage system according to any one of claims 1 to 6. A storage battery, a power storage device that includes a power conditioner that converts DC power of the storage battery into AC power and outputs the power, and includes a plurality of power storage devices that can switch between interconnection operation and independent operation. Driving method,
Each output of the plurality of power storage devices during the self-sustained operation is connected in parallel between electric circuits to which a load is connected,
One of the plurality of power storage devices is a master device, and the other power storage device is a slave device,
The power conditioner of the master device performs voltage control to control the output voltage to the target voltage,
The power conditioner of the slave device performs current control for controlling an output current to a target current determined based on a total load current supplied to the load and the number of the power storage devices. How to operate the device.

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