JP6771170B2 - Power storage system, power storage device, and operation method of power storage device - Google Patents

Description

The present invention generally relates to an operation method of a power storage system, a power storage device, and a power storage device, and more particularly, an operation method of a power storage system, a power storage device, and a power storage device capable of switching between interconnection operation and independent operation.

Conventionally, there is a system in which power storage devices are operated in parallel to supply electric power to a load.

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

JP-A-2002-110210

Conventionally, there is a power storage system in which a plurality of power storage devices capable of switching between interconnection operation and independent operation are provided, and the independent outputs of the plurality of power storage devices are 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 (the degree of burden on the output current) may be biased to any of the power storage devices. In this case, there may be a power storage device in which the output current increases more than other power storage devices and becomes an overcurrent state, or a power storage device that operates in a charging mode in which the output current has the opposite polarity to the load current may occur. is there.

The present invention has been made in view of the above reasons, and an object of the present invention is to determine the degree of burden on each of the plurality of power storage devices when the outputs of the plurality of power storage devices operating independently are connected in parallel. It is an object of the present invention to provide a power storage system, a power storage device, and an operation method of the power storage device capable of suppressing bias.

The power storage system of the present invention has a storage battery and a power conditioner that converts the DC power of the storage battery into AC power and outputs the power conditioner, and includes a plurality of power storage devices capable of switching between interconnection operation and independent operation. The outputs of the plurality of power storage devices during the self-sustaining operation are connected in parallel between the electric paths to which the loads are connected, and when each of the plurality of power storage devices performs the self-sustaining operation, the plurality of power storage devices One of the power storage devices is set as the master device, and the other power storage device is set as the slave device. The power conditioner 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 that acquires measurement data of the total load current supplied to the load, and the power conditioner of the slave device includes the total load current and the number of power storage devices. There line current control for controlling the output current to the determined target current on the basis of the from the master device performs said voltage control by starting the self-sustained operation, the slave device starts the autonomous operation It is characterized in that the current control is performed .

The power storage device of the present invention is characterized in that it is used in the above-mentioned power storage system.

The operation method of the power storage device of the present invention has a storage battery and a power conditioner that converts the DC power of the storage battery into AC power and outputs the power conditioner, and is capable of switching between interconnection operation and independent operation. A method of operating a power storage device used in a power storage system including the above, wherein each output of the plurality of power storage devices during the self-sustaining operation is connected in parallel between electric currents to which a load is connected, and the plurality of power storage devices are connected in parallel. One of the power storage devices becomes the master device, the other power storage device becomes the slave device, and the power conditioner of the master device performs voltage control for controlling the output voltage to the target voltage, and the slave device. power conditioner may have line current control for controlling the output current to the determined target current on the basis of the total load current supplied to the load and the number of the electric storage device, the master device is the self-sustained operation Is started to perform the voltage control, and then the slave device starts the self-sustaining operation to perform the current control .

As described above, the present invention has an effect that when the outputs of a plurality of self-operating power storage devices are connected in parallel, it is possible to suppress a bias in the degree of burden on each of the plurality of power storage devices. There is.

It is a block diagram which shows the structure of the power storage system of embodiment. It is a block diagram which shows the structure of the power storage device of embodiment. It is a schematic diagram which shows the connection form of a plurality of power storage devices which perform self-sustaining operation of embodiment, and a self-sustaining load. 4A, 4B, 4C, and 4D are waveform diagrams showing current waveforms of each part when self-sustaining output control different from that of the present embodiment is performed. 5A, 5B, 5C, and 5D are waveform diagrams showing current waveforms of each part when the self-sustaining output control of the present embodiment is performed. It is a block diagram which shows the structure of another power storage system of embodiment.

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

(Embodiment 1)
The power storage system of the present embodiment has the configuration shown in FIG. 1, and is used in each dwelling unit, detached house, factory, office, or other building of an apartment house to which commercial power is supplied from an electric power company. This system includes a distribution board 1, a plurality of power storage devices 2, a switching board 3, and a controller 4 as main configurations. When distinguishing a plurality of power storage devices 2, each of the plurality of power storage devices 2 is referred to as power storage devices 21, 22, 23 ,. .. .. Called.

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

Then, the main electric circuit 81 branches into a plurality of branch electric circuits 82 via each branch breaker 1b. System loads 71 of lighting equipment, air conditioning equipment, home appliances, etc. are connected to each of the branch electric lines 82, and AC power is supplied to these system loads 71. However, one of the plurality of branch electric circuits 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, and is connected to the power conditioner 2b. The power conditioner 2b includes an AC / DC conversion function that converts AC power into DC power to charge the storage battery 2a, and a DC / AC conversion function that converts the DC power of the storage battery 2a into AC power and outputs it.

The interconnection connection 2f of the power conditioner 2b receives commercial power from the commercial power supply 9 via the breaker 1c for distributed power supply, and the power conditioner 2b converts the received commercial power into DC power to convert the received commercial power into DC power to convert the received commercial power into DC power to store the storage battery 2a. It can be charged.

Further, the discharge power of the storage battery 2a is supplied to the power conditioner 2b, and is converted into AC power by the power conditioner 2b. The power conditioner 2b operates so as to be able to switch between interconnection operation and independent operation. By detecting the AC voltage input to the interconnection connection 2f, the power conditioner 2b stops the supply of commercial power from the commercial power supply 9 during normal times when the commercial power supply 9 is supplying commercial power and when the commercial power supply 9 stops supplying commercial power. Determine when there is a power outage.

Specifically, the power conditioner 2b performs interconnection operation when the commercial power source 9 is energized, and operates independently when the commercial power source 9 has a power failure. Then, the power conditioner 2b interconnects with the commercial power source 9 (commercial power system) during the interconnection operation, and outputs the AC power generated from the discharge power of the storage battery 2a from the interconnection connection unit 2f. Further, the power conditioner 2b outputs AC power generated from the discharge power of the storage battery 2a from the self-sustaining connection unit 2g without being connected to the commercial power system during self-sustaining operation.

The AC power output from the interconnection connection 2f is called an interconnection output, and the AC power output from the self-supporting connection 2g is called a self-sustaining output.

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

Further, the self-supporting connection unit 2g is connected to the AC electric circuit 84, and the self-sustaining output is input to the switching board 3 via the AC electric circuit 84. The switching board 3 switches the connection destination of the self-supporting electric circuit 85 to either the branch electric circuit 82a or the AC electric circuit 84. The self-supporting electric circuit 85 is connected to a self-sustaining load 72 such as a lighting device, an air-conditioning device, and a home electric appliance.

Then, the connection state of the switching board 3 is switched and controlled by the controller 4. The controller 4 detects the voltage on the primary side of the main power breaker 1a, for example, during a normal time when the commercial power supply 9 is supplying commercial power and during a power failure when the commercial power supply 9 is stopped supplying commercial power. Is determined. Then, when the controller 4 determines that it is in the normal state, it switches and controls the switching board 3 to connect the self-supporting electric circuit 85 to the branch electric circuit 82a. If the controller 4 determines that a power failure has occurred, the controller 4 switches and controls the switching panel 3 to connect the self-supporting electric circuit 85 to the AC electric circuit 84.

When the self-sustaining 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 self-sustaining electric circuit 85 is conducted, and the electric power (sum of commercial power and interconnection output) of the main electric circuit 81 is the self-sustaining electric circuit 85. Is supplied to. Further, 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 the independent electric circuit is supplied to the independent electric circuit 85.

In this system, the system load 71 connected to the branch electric circuit 82 is a load to which electric power is supplied only when the commercial power source 9 is energized. On the other hand, the self-sustaining load 72 connected to the self-sustaining electric circuit 85 is a load to which power is supplied both in the normal state when the commercial power source 9 is energized and in the 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 self-supporting load 72 is electrically connected. The current sensors 51 to 53 measure the total load current, which is the total load current supplied to the self-supporting load 72, by measuring the current flowing through the self-supporting electric circuit 85. The current sensor 51 outputs the measurement data of the total load current to the power storage device 21, the current sensor 52 outputs the measurement data of the total load current to the power storage device 22, and the current sensor 53 outputs the measurement data of the total load current to the power storage device 23. Output to. Each data acquisition unit 2e of the power storage device 2 receives the measurement data transmitted to its 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, and the control unit 2d controls the communication of the communication unit 2c.

Hereinafter, independent operation by the power storage device 2 in the event of a power failure will be described with reference to FIG. FIG. 3 is a schematic view showing only a connection mode between a plurality of power storage devices 2 that perform independent operation and an independent load 72.

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

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

That is, the setting unit 6 is configured by the control units 2d of the power storage devices 21, 22, and 23, respectively. When each of the plurality of power storage devices 2 operates independently, the setting unit 6 uses any one of the plurality of power storage devices 2 as the master device and the other power storage device 2 as the slave device. It has a function. In this way, each of the plurality of power storage devices 2 is switched to either the master device or the slave device by being periodically set to the master device or the slave device by the setting unit 6.

Hereinafter, the power storage device 2 which is a master device is referred to as a master device 2, and the power storage device 2 which 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.

Further, the control unit 2d can recognize the number of power storage devices 2 in the system when periodically exchanging the remaining capacity data with and from the other power storage devices 2, and the power storage devices 2 in the system can be recognized. Hold the data of the number of units.

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

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

After the master device 21 starts the self-sustaining operation and performs voltage control, each of the slave devices 22 and 23 starts the self-sustaining operation and performs current control, so that the self-sustaining output can be synchronized. Alternatively, the master device 21, the slave devices 22, and 23 can communicate with each other to synchronize the independent outputs.

Specifically, the control units 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 sets the value obtained by dividing the total load current I0 by the number of power storage devices 2 (three in this case) as the 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 system bears the total load current I0 evenly divided. Therefore, the current values and waveforms of the independent outputs of the slave devices 22 and 23 are the same as each other, and the independent outputs of the master device 21 that controls the voltage are also the same as the independent outputs of the slave devices 22 and 23 as a result. It becomes the current value and the waveform.

4A, 4B, 4C, and 4D show current waveforms of each part when the master device 21 performs voltage control and the slave devices 22 and 23 each perform 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 is different from the current control of the present embodiment in that the current waveform of the independent output is a sine wave.

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

In this case, the self-supporting load 72 includes a capacitive load (for example, a capacitor input type load), and the total load current I0 rapidly increases in the vicinity of the voltage peak, and the waveform is distorted. .. Then, when each of the slave devices 22 and 23 performs current control in which the current waveform of the self-sustaining 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 the output will be biased between 23. For example, as shown in FIG. 4B, when the independent current I1 of the master device 21 bears most of the waveform distortion components of the total load current I0, the independent current I1 is distorted and becomes an overcurrent state (region X1 in FIG. 4B). The operation of the master device 21 becomes unstable. Further, the self-sustaining current I1 of the master device 21 may be in a charging mode having the opposite polarity to 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 controls the voltage, and each of the slave devices 22 and 23 sets the value obtained by dividing the total load current I0 by the number of power storage devices 2 as the target current. I do.

5A, 5B, 5C, and 5D show current waveforms of each part when the master device 21 performs voltage control and each of the slave devices 22 and 23 performs current control using the above-mentioned target current. .. 5A shows the waveform of the total load current I0, FIG. 5B shows the waveform of the independent current I1 of the master device 21, FIG. 5C shows the waveform of the independent current I2 of the slave device 22, and FIG. 5D shows the slave. The waveform of the self-sustaining current I3 of the apparatus 23 is shown.

In this case as well, the self-sustaining load 72 includes a capacitive load, and the total load current I0 rapidly increases in the vicinity of the voltage peak, and the waveform is distorted. However, the master device 21 performs the above-mentioned voltage control, and each of the slave devices 22 and 23 performs the current control using the above-mentioned target current, so that the independent currents I1 of the master device 21, the slave devices 22, and 23 are respectively. , I2, I3 have almost the same current value and waveform, and the independent currents I1, I2, I3 are in a state where there is almost no bias.

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

Further, in the present embodiment, the power storage device 21 is used as the master device and the power storage devices 22 and 23 are used as slave devices, but 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 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 conditioner 2b, and can switch between interconnection operation and independent operation. The power storage device 2 is preferably a master device or a slave device when performing self-sustaining operation. When the power storage device 2 becomes the master device, the power conditioner 2b performs voltage control for controlling the output voltage to the target voltage. When the power storage device 2 becomes a slave device, the power conditioner 2b sets the output current to the target current determined based on the total load current supplied to the load (self-sustaining load) and the number of storage batteries 2. Performs current control to be controlled.

Alternatively, the master device or the slave device is fixedly set for each power storage device 2, and the storage battery system includes a power storage device 2 dedicated to the master device and a power storage device 2 dedicated to the slave device. May be good.

Further, even in the normal state, the master device performs the interconnection operation by the voltage control, and the slave device performs the interconnection operation by the current control. Alternatively, in the normal state, not only the slave device but also the master device may perform the interconnection operation by current control.

The above-mentioned power storage system includes a plurality of power storage devices 2. Each of the plurality of power storage devices 2 has a power conditioner 2b that converts the DC power of the storage battery 2a and the storage battery 2a into AC power and outputs the power conditioner 2b, and can switch between interconnection operation and independent operation. Each output of the plurality of power storage devices 2 during the self-sustaining operation is connected in parallel between the electric circuits to which the load (self-sustaining load 72) is connected. When each of the plurality of power storage devices 2 operates independently, any one of the plurality of power storage devices 2 is set as the master device, and the other power storage device 2 is set as the slave device.

Then, 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 a target current determined based on the total load current and the number of power storage devices 2.

That is, 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. Therefore, when the outputs of the plurality of power storage devices 2 that operate independently are connected in parallel, the power storage system can suppress a bias in the degree of burden on each of the plurality of power storage devices 2.

Further, among the plurality of power storage devices 2, the power storage device 2 having the largest remaining capacity of the storage battery 2a is preferably the master device.

Therefore, 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 the stability of the voltage applied to the load is improved.

Further, it is preferable that each of the plurality of power storage devices 2 further includes a communication unit 2c capable of communicating with another power storage device 2.

Therefore, data can be shared between the plurality of power storage devices 2, and the system can perform control according to each state of the plurality of power storage devices 2.

Further, each of the plurality of power storage devices 2 transmits data of the remaining capacity of the storage battery 2a of the own device to the other power storage device 2, and based on the remaining capacity of each storage battery 2a of the plurality of power storage devices 2, the own device It is preferable to further include a control unit 2d for setting the above in the master device or the 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 control unit 2d of the other power storage device 2 sets its own device as the slave device. Set to.

Therefore, since the function of the setting unit 6 is realized by the power storage device 2, it is not necessary to separately provide the setting unit, and the system configuration can be simplified.

Further, the power conditioner 2b of the slave device preferably has a value obtained by dividing the total load current by the number of the plurality of power storage devices 2 as the target current.

Therefore, the current values and waveforms of the respective outputs of the plurality of power storage devices 2 are substantially the same, and the respective outputs are in a state of being substantially unbiased.

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

Specifically, the control unit 2d of the master device 21 determines the ratio of the remaining capacity of the slave devices 22 and 23 to the remaining capacity of the own device based on the remaining capacity data of the own device and the slave devices 22 and 23 [slave device]. Remaining capacity of / Master device] is obtained as a 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 target current as the result of multiplying the value obtained by dividing the total load current I0 by the number of power storage devices 2 by the weighting coefficient α2. Further, the control unit 2d of the slave device 23 sets the result of multiplying the value obtained by dividing the total load current I0 by the number of power storage devices 2 by the weighting coefficient α3 as the target current.

That is, the slave device transmits the remaining capacity data, which is the data related to the remaining capacity of the storage battery 2a 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 (weighting coefficient) that becomes higher as the remaining capacity increases for each power storage device 2, and each of the slave devices Send the data of the corresponding coefficient to. The power conditioner 2b of the slave device sets the target current as a value obtained by multiplying the total load current by the number of the plurality of power storage devices 2 by a coefficient.

That is, the self-sustaining current supplied from the power storage device 2 having a large remaining capacity increases, and the self-sustaining current supplied from the power storage device 2 having a small remaining capacity decreases. Therefore, the power storage system can suppress the bias of the AC power output by each of the plurality of power storage devices 2, and the remaining capacity of the storage battery 2a of each power storage device 2 is set as the current burden according to the remaining capacity of each power storage device 2. Equalization can be achieved.

Further, as shown in FIG. 6, the power storage system may include a setting unit 6A separately from the power storage device 2. In this case, the setting unit 6A periodically acquires the remaining capacity data from each of the plurality of power storage devices 2, the power storage device 2 having the largest remaining capacity of the storage battery 2a is used as the master device, and the other power storage devices 2 are slave devices. And. The setting unit 6A transmits a setting instruction of the master device or a setting instruction of the slave device to each of the plurality of power storage devices 2. The control unit 2d of the power storage device 2 sets its own device as a master device or a slave device in response to a setting instruction.

Further, the above-mentioned power storage device 2 is characterized in that it is used in the power storage system of the present embodiment. Therefore, the power storage device 2 can also suppress a bias in the degree of burden on each of the plurality of power storage devices 2 when the outputs of the plurality of power storage devices 2 that operate independently are connected in parallel.

Further, the above-mentioned operation method of the power storage device is an operation method of the power storage device 2 used in the power storage system. The power storage system 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 conditioner 2b, and includes a plurality of power storage devices 2 capable of switching between interconnection operation and independent operation. Each output of the plurality of power storage devices 2 during the self-sustaining operation is connected in parallel between the electric circuits to which the load (self-sustaining load 72) is connected. Then, any one of the plurality of power storage devices 2 becomes the master device, and the other power storage device 2 becomes the 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 a target current determined based on the total load current supplied to the load and the number of power storage devices 2.

Therefore, this method of operating the power storage device can also suppress a bias in the degree of burden on each of the plurality of power storage devices 2 when the outputs of the plurality of power storage devices 2 that operate independently are connected in parallel. ..

Further, 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 executing the program by the computer. A computer is mainly composed of a device having a processor for executing a program, a device for an interface for exchanging data between other devices, and a device for storing data. Be prepared. The device provided with the processor may be either a CPU (Central Processing Unit) or MPU (Micro Processing Unit) that is separate from the semiconductor memory, or a microcomputer that is integrally provided with the semiconductor memory. As the 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.

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

The above-described embodiment is an example of the present invention. Therefore, the present invention is not limited to the above-described embodiment, and even if it is not the embodiment, it varies depending on the design and the like as long as it does not deviate from the technical idea of the present invention. Of course, it is possible to change.

1 Distribution board 2 (21, 22, 23) Power storage device 2a Storage battery 2b Power conditioner 2c Communication unit 2d Control unit 2e Data acquisition unit 2f Interconnection connection unit 2g Independent connection unit 3 Switching board 4 Controller 51, 52, 53 Current Sensor 6 Setting unit 71 System load 72 Independent load 81 Main line line 82 Branch line line 83 AC line line 84 AC line line 85 Independent line line

Claims (8)

It has a storage battery, a power conditioner that converts the DC power of the storage battery into AC power and outputs it, and is equipped with a plurality of power storage devices that can switch between interconnection operation and independent operation.
Each output of the plurality of power storage devices during the self-sustaining operation is connected in parallel between the electric circuits to which the loads are connected.
When each of the plurality of power storage devices performs the self-sustaining operation, any one of the plurality of power storage devices is set as the master device, and the other power storage device is set as the slave device.
The power conditioner 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 that acquires measurement data of the total load current supplied to the load, and the power conditioner of the slave device includes the total load current and the number of power storage devices. There line current control for controlling the output current to the determined target current on the basis of,
A power storage system characterized in that after the master device starts the self-sustaining operation and performs the voltage control, the slave device starts the self-sustaining operation and performs the current control . The power storage system according to claim 1, wherein the power storage device having the largest remaining capacity of the storage battery is the master device among the plurality of power storage devices. The power storage system according to claim 1 or 2, 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 of 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, the own device is used as the master device or It further includes a control unit to be set 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 the other power storage device sets its own device as the slave device. The power storage system according to claim 3, which is characterized. The power storage system according to any one of claims 1 to 4, wherein the power conditioner of the slave device has 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 the remaining capacity data, which is data related to the remaining capacity of the storage battery owned by 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, and each of the slave devices Send the data of the coefficient corresponding to
The power conditioner of the slave device according to claim 3 or 4, wherein the target current is a value obtained by multiplying the total load current by the number of the plurality of power storage devices by the coefficient. 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 used in a power storage system having a power conditioner that converts the DC power of the storage battery into AC power and outputs the power conditioner, and has a plurality of power storage devices capable of switching between interconnection operation and independent operation. It ’s a driving method,
Each output of the plurality of power storage devices during the self-sustaining operation is connected in parallel between the electric circuits to which the loads are connected.
One of the plurality of power storage devices serves as a master device, and the other power storage device serves as a slave device.
The power conditioner of the master device performs voltage control for controlling the output voltage to the target voltage.
The power conditioner of the slave device have line current control for controlling the output current to the determined target current on the basis of the total load current supplied to the load and the number of said power storage device,
A method of operating a power storage device, wherein the master device starts the self-sustaining operation to perform the voltage control, and then the slave device starts the self-sustaining operation to perform the current control .

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