JP7310427B2 - Electricity storage system and its control method - Google Patents

Description

The present disclosure relates to an electric storage system and a control method thereof.

2. Description of the Related Art A power storage system is known that is connected to a power system and can supply power temporarily stored in a storage battery to a load via a power conversion device during a power failure or the like. A power storage system that is also connected to a photovoltaic power generation system and stores generated power (surplus power) exceeding power supplied to a load in a storage battery is also known.

As for the power storage system, it is conceivable to reduce its size and weight so that it can be installed in a narrow space. When such a power storage system is used and a large power storage capacity is required, a plurality of power storage systems are installed. Therefore, when charging a plurality of storage batteries with a photovoltaic power generation system, it is conceivable to provide the same number of photovoltaic power generation systems as there are storage batteries.

Patent Literature 1 listed below discloses a system in which two solar power generation systems (solar panels) and two storage batteries are installed. This system includes a power conversion system in which two power conditioners corresponding to each set of solar panels and storage batteries are collectively provided in one housing. Each power conditioner includes a DC/AC converter, a storage battery DC/DC converter, a solar battery DC/DC converter, and a controller for controlling these. In the system of Patent Literature 1, the control units of the power conditioners communicate with each other, so that the two storage batteries cooperate to supply power to the load after switching from the system cooperation mode to the independent operation mode due to a power failure or the like.

JP 2017-85769 A

Here, for example, when installing an additional power storage system after one solar system and one power storage system are installed, or when installing two power storage systems simultaneously or sequentially for an existing solar system Consider the case of increasing the number. In such a configuration, a plurality of storage batteries will be installed for one solar system.

In the configuration disclosed in Patent Document 1, the same number of solar systems (solar panels) as the number of storage batteries is required in order to charge the storage batteries with the power generated by the solar system. If there is only one solar system, the storage battery to which the solar system is not connected cannot be charged by the solar system. Therefore, with the configuration disclosed in Patent Document 1, it is difficult to cope with the configuration described above. More specifically, the conventional system disclosed in Patent Literature 1 has a problem that one of the two storage batteries cannot be charged with the surplus power of the solar system after switching to the self-sustained operation mode. Furthermore, in the configuration disclosed in Patent Document 1, when adding a storage battery to an existing solar system, it is necessary to replace the power conversion system as well.

As described above, in the configuration disclosed in Patent Document 1, when the number of power storage units (storage batteries) is larger than that of the solar system due to the additional installation of power storage units (storage batteries), the solar system operates after switching to the self-sustained operation mode. There is a problem that a plurality of power storage units cannot be efficiently charged.

Therefore, the present disclosure provides a power storage system and a control method thereof that can efficiently charge a plurality of power storage units by the solar system during self-sustained operation even when more power storage units are installed than the solar system. With the goal.

A power storage system according to an aspect of the present disclosure is a power storage system including a plurality of power storage units connected to an AC power supply, wherein output power of the AC power supply is supplied to any one of the power storage units. and a control unit that controls the switching unit during self-sustained operation of the power storage unit so that each power storage unit of the plurality of power storage units outputs the input power. an electric circuit, a storage battery connected to the electric circuit, and a conversion unit that converts the DC power and the AC power between each other. The output power of the input AC power supply is supplied to the specific load corresponding to the power storage unit via the electric path of the power storage unit, and the surplus power of the output power of the input AC power supply is used to convert the conversion unit of the power storage unit. If the output power of the AC power supply is not input, the power of the storage battery of the storage unit is supplied to the specific load via the converter and the electric path of the storage unit.

A control method according to another aspect of the present disclosure includes: a plurality of power storage units connected to an AC power supply; Each power storage unit of the plurality of power storage units includes an electric circuit for outputting the input electric power, a storage battery connected to the electric circuit, and a DC power and an AC power. A method for controlling an electricity storage system, including a conversion unit for converting, comprising: a first step of controlling a switching unit during self-sustained operation of the energy storage unit; 2 step, wherein the output power of the AC power supply input to the power storage unit is supplied to the power storage unit through the electric path of the power storage unit according to the supply destination of the output power switched by the switching unit. charging a storage battery of the power storage unit with the surplus power of the output power of the input AC power supply via the converter of the power storage unit; and If not input, causing the electric power of the storage battery of the storage unit to be supplied to the specific load via the converter and the electrical path of the storage unit.

According to the present disclosure, even if more power storage units than AC power sources are installed, multiple power storage units can be efficiently charged by the AC power source during self-sustained operation.

FIG. 1 is a block diagram showing the configuration of a power storage system according to the first embodiment of the present disclosure. FIG. 2 is a block diagram showing the state of the power storage system shown in FIG. FIG. 3 is a flow chart showing the operation of the power storage system shown in FIG. FIG. 4 is a block diagram showing a state of the power storage system shown in FIG. 1 different from that shown in FIG. FIG. 5 is a flowchart showing a modification (first modification) of the operation of the power storage system shown in FIG. FIG. 6 is a block diagram showing the configuration of the power storage system according to the second embodiment of the present disclosure. FIG. 7 is a block diagram showing the state of the power storage system shown in FIG. FIG. 8 is a flow chart showing the operation of the power storage system shown in FIG. 9 is a block diagram showing a state of the power storage system shown in FIG. 6 different from that in FIG. 7. FIG. FIG. 10 is a flowchart showing a modification (second modification) of the operation of the power storage system shown in FIG. FIG. 11 is a flowchart showing a modification (third modification) of the operation of the power storage system shown in FIG. 12 is a block diagram showing a state of the power storage system shown in FIG. 6 that is different from both FIGS. 7 and 9. FIG. FIG. 13 is a flowchart showing a modification (fourth modification) of the operation of the power storage system shown in FIG.

[Description of Embodiments of the Present Disclosure]
First, the contents of the embodiments of the present disclosure will be listed and explained. At least some of the embodiments described below may be combined arbitrarily.

(1) A power storage system according to a first aspect of the present disclosure is a power storage system including a plurality of power storage units connected to an AC power supply, wherein the output power of the AC power supply is any one of the plurality of power storage units. and a control unit that controls the switching unit during self-sustained operation of the power storage unit so that the output power is supplied to one power storage unit. an electric circuit for outputting the electric power supplied to the electric circuit, a storage battery connected to the electric circuit, and a converter for converting between the DC power and the AC power. , during the self-sustained operation, the output power of the input AC power supply is supplied to the specific load corresponding to the power storage unit through the electric circuit of the power storage unit, and the surplus power of the output power of the input AC power supply The storage battery of the storage unit is charged via the conversion section of the unit, and if the output power of the AC power supply is not input, the power of the storage battery of the storage unit is supplied to the specific load via the conversion section of the storage unit and the electric path. supply. As a result, even if there are more power storage units installed than AC power sources, the plurality of power storage units can be efficiently charged by the AC power sources during self-sustained operation.

(2) Preferably, the switching unit includes a switch provided inside each of the plurality of power storage units. This facilitates the addition of power storage units.

(3) More preferably, the power storage system determines whether or not the amount of power stored in one of the plurality of power storage units has reached a predetermined value in a state in which output power is supplied to one power storage unit. In response to the determination by the determination unit that the amount of power stored in one power storage unit has reached a predetermined value, the control unit instructs the switching unit to select the supply destination of the output power from the plurality of power storage units. The unit is switched to a power storage unit that is different from one power storage unit. As a result, a desired power storage unit can be charged preferentially, and the power storage units can be charged sequentially.

(4) More preferably, in a state in which output power is supplied to one of the plurality of power storage units, the power storage system includes a variable value representing variation in the amount of power stored in each of the plurality of power storage units and a predetermined further comprising a determination unit that determines a magnitude relationship with a value, wherein the determination unit determines that the value of the variable has changed from a state greater than a predetermined value to a state that the value of the variable is less than or equal to the predetermined value; or In response to the determination that the value of the variable has changed from the state where the value of the variable is equal to or less than the predetermined value to the state where the value of the variable is greater than the predetermined value, the control unit causes the switching unit to select a plurality of output power supply destinations. One of the power storage units is switched to a different power storage unit. Thereby, a plurality of power storage units can be charged equally. Therefore, by maintaining the storage battery of the specific power storage unit in a nearly fully charged state, it is possible to prevent the progress of deterioration of only the storage battery of the specific power storage unit.

(5) Preferably, the control unit causes the switching unit to switch the supply destination of the output power of the AC power supply based on the output power of the AC power supply and the power consumption of the specific load. As a result, when the output power of the AC power supply becomes smaller than the power consumption of the specific load to which the output power of the AC power supply is supplied, the output power of the AC power supply can be supplied to another specific load, and the surplus of the AC power supply The power can charge a storage unit connected to another specific load. Therefore, the output power of the AC power supply can be used effectively without wasting it.

(6) More preferably, the AC power supply is a solar system, and the solar system includes a solar panel and a power converter that converts DC power generated by the solar panel into AC power and outputs it as output power. including the part. As a result, a plurality of power storage units can be charged with power generated by the photovoltaic system during self-sustained operation.

(7) A control method according to a second aspect of the present disclosure includes a plurality of power storage units connected to an AC power supply, and output power of the AC power supply being supplied to any one power storage unit of the plurality of power storage units. , each power storage unit of the plurality of power storage units includes an electric path for outputting the input electric power, a storage battery connected to the electric path, DC power and AC power. A control method for a power storage system including a conversion unit that mutually converts electric power, comprising: a first step of controlling a switching unit during self-sustained operation of the power storage unit; wherein the second step controls the output power of the AC power supply input to the storage unit according to the supply destination of the output power switched by the switching unit, and the electric path of the storage unit. charging a storage battery of the storage unit with the surplus power of the input output power of the AC power supply via the converter of the storage unit; If the output power of the power supply is not input, the power of the storage battery of the storage unit is supplied to the specific load via the converter and the electrical path of the storage unit. As a result, even if there are more power storage units installed than AC power sources, the plurality of power storage units can be efficiently charged by the AC power sources during self-sustained operation.

[Details of the embodiment of the present disclosure]
In the following embodiments, identical parts are provided with identical reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

(First embodiment)
[overall structure]
Referring to FIG. 1 , a power storage system 100 according to the first embodiment of the present disclosure includes a first power storage unit 102, a second power storage unit 104, a controller 106, a first switching section 108, a second switching section 110, a third A switching unit 112 , a first sensor 114 and a second sensor 116 are included. The first power storage unit 102 and the second power storage unit 104 are connected to the solar system 180 via the first switching section 108 . The first power storage unit 102 is connected to the first specific load 194 via the second switching section 110 , and the second power storage unit 104 is connected to the second specific load 196 via the third switching section 112 . The power storage system 100 performs self-sustained operation when the power grid 190 is cut off.

The first specific load 194 and the second specific load 196 are loads to which power should be supplied not only when there is no power failure in the power system 190 (hereinafter also referred to as normal time) but also when the power system 190 has power failure. is. A general load 192 is a load to which power is normally supplied, but to which power is not supplied during a power outage. Although there are actually a plurality of distribution lines (two-phase or three-phase), only one line is shown in FIG.

Solar system 180 includes solar panel 182 and solar PCS 184 . The solar panel 182 is a power device that generates power by converting light energy into power. The solar PCS 184 converts the DC power (DC voltage) generated by the solar panel 182 into AC power (AC voltage) and outputs the AC power (AC voltage). The solar PCS 184 normally supplies power to a general load 192 , a first specific load 194 and a second specific load 196 via distribution lines that supply commercial power from the power grid 190 . At this time, the terminals 150 and 154 are connected in the second switching section 110 , and the terminals 160 and 164 are connected in the third switching section 112 . During a power outage, the solar PCS 184 stops supplying power to distribution lines that supply commercial power, and supplies power from the independent output terminal 186 . Occurrence of a power failure can be detected, for example, by observing a detection value of a sensor (not shown) that detects power supply from the power system 190 . If the detected value of the sensor becomes equal to or less than a predetermined value, it can be determined that a power failure has occurred.

The first power storage unit 102 includes a first PCS 120 and a first storage battery 122 . The first PCS 120 includes a control unit (CPU, microcomputer, etc.), a storage unit (eg, rewritable nonvolatile memory), and a conversion circuit that converts DC power and AC power between each other. The first PCS 120 further includes a communication section and communicates with the communication section of the controller 106 . The first storage battery 122 is a chargeable/dischargeable storage battery such as a lithium ion secondary battery. The first power storage unit 102 outputs the AC power input from the auxiliary input terminal 124 directly from the output terminal 126 . The first PCS 120 operates under the control of the controller 106 , converts the power (DC voltage) stored in the first storage battery 122 into AC power (AC voltage), and outputs the AC power (AC voltage) from the output terminal 126 . The first PCS 120 also converts AC power input from the auxiliary input terminal 124 into DC power to charge the first storage battery 122 .

Similarly, the second power storage unit 104 includes a second PCS 130 and a second storage battery 132 . The second PCS 130 includes a control unit, a storage unit, and a conversion circuit that mutually converts DC power and AC power. The second PCS 130 further includes a communication section and communicates with the communication section of the controller 106 . The second storage battery 132 is a chargeable/dischargeable storage battery such as a lithium ion secondary battery. The second power storage unit 104 outputs the AC power input from the auxiliary input terminal 134 directly from the output terminal 136 . The second PCS 130 operates under the control of the controller 106 , converts the power (DC voltage) stored in the second storage battery 132 into AC power (AC voltage), and outputs the AC power (AC voltage) from the output terminal 136 . Second PCS 130 also converts AC power input from auxiliary input terminal 134 into DC power to charge second storage battery 132 .

The controller 106 includes a control unit (CPU, microcomputer, etc.), a storage unit (for example, a rewritable nonvolatile memory), and a communication unit. It controls the first PCS 120 and the second PCS 130 . The controller 106 causes each of the first switching unit 108, the second switching unit 110, the third switching unit 112, the first PCS 120, and the second PCS 130 to perform a predetermined operation during a power failure, as will be described later.

In the first switching unit 108, the terminal 140 is connected to the independent output terminal 186 of the solar PCS 184, the terminal 142 is connected to the auxiliary input terminal 124 of the first power storage unit 102, and the terminal 144 is connected to the auxiliary input of the second power storage unit 104. It is connected to terminal 134 . The first switching unit 108 normally connects the terminal 140 to neither the terminal 142 nor the terminal 144, but connects the terminal 140 to the terminal 142 or the terminal 144 under the control of the controller 106 during a power failure. The first switching unit 108 is implemented by, for example, a relay.

In second switching unit 110 , terminal 150 is connected to a distribution line to which commercial power is supplied, terminal 152 is connected to output terminal 126 of first power storage unit 102 , and terminal 154 is connected to first specific load 194 . It is connected. The second switching unit 110 normally connects the terminals 150 and 154 as described above, and changes the connection state under the control of the controller 106 to connect the terminals 152 and 154 in the event of a power failure. Similarly, in the third switching unit 112, the terminal 160 is connected to the distribution line to which commercial power is supplied, the terminal 162 is connected to the output terminal 136 of the second power storage unit 104, and the terminal 164 is connected to the second specific power storage unit 104. It is connected to load 196 . The third switching unit 112 normally connects the terminals 160 and 164 as described above, and changes the connection state under the control of the controller 106 to connect the terminals 162 and 164 in the event of a power failure. The second switching unit 110 and the third switching unit 112 are realized by relays, for example.

The first sensor 114 and the second sensor 116 are, for example, current sensors, measure the current (alternating current) flowing through the electric wire at the installed position, and output the corresponding information (current value, etc.). The first sensor 114 measures the current supplied to the first specific load 194 and the measurements are output to the first PCS 120 . Similarly, the second sensor 116 measures the current supplied to the second specific load 196 and the measurements are output to the second PCS 130 . The first PCS 120 and the second PCS 130 receive the measured values of the first sensor 114 and the second sensor 116, respectively, and obtain the amount of power (power consumption) supplied to the first specific load 194 and the second specific load 196, which will be described later. It is used in the processing to do.

By being configured in this way, the power storage system 100 normally transfers the power generated by the solar system 180 to the general load 192 via the distribution line that supplies commercial power from the power system 190 as shown in FIG. , to the first specific load 194 via the second switching section 110 , and to the second specific load 196 via the third switching section 112 . At the time of power failure, the power storage system 100 performs self-sustained operation, and as described above with reference to FIG. be. FIG. 2 shows a case where the power generated by solar system 180 is greater than the power consumed by first specific load 194 , and first switching unit 108 connects terminal 140 to terminal 142 . In FIG. 2, arrows indicate the direction of current flow. As described above, during a power failure, the photovoltaic system 180 stops supplying generated power to the distribution line that supplies commercial power, and outputs the generated power from the independent output terminal 186. Therefore, the generated power of the photovoltaic system 180 is The power is supplied to the first specific load 194 via the first power storage unit 102 . Since the power generated by the solar system 180 is greater than the power consumed by the first specific load 194 , the first PCS 120 of the first power storage unit 102 charges the first storage battery 122 with the surplus power of the solar system 180 . On the other hand, AC power obtained by converting the power stored in the second storage battery 132 by the second PCS 130 is supplied to the second specific load 196 from the output terminal 136 of the second power storage unit 104 .

[Control action]
The operation of power storage system 100 during a power outage in power system 190 will be described below with reference to FIG. 3 . The flow chart of FIG. 3 is executed by controller 106 . Specifically, when detecting that a power failure has occurred, the control unit of the controller 106 sets the second switching unit 110 and the third switching unit 112 to the state at the time of the power failure, and After disconnecting the load 196 from the electric power system 190, a predetermined program is read from the storage unit inside the controller 106 and executed. Here, it is assumed that the first power storage unit 102 is charged preferentially over the second power storage unit 104 with the surplus power of the solar system 180 .

In step 300, the controller 106 acquires the amount of charge (hereinafter referred to as SOC (State Of Charge)) of the first storage battery 122 and the second storage battery 132 inside each from the first storage unit 102 and the second storage unit 104. do. Specifically, the controller 106 acquires SOC (%) from the first PCS 120 and the second PCS 130 . Control then passes to step 302 . The SOCs of the first storage battery 122 and the second storage battery 132 are represented by SOC1 (%) and SOC2 (%), respectively.

At step 302, the controller 106 determines whether the SOC1 acquired at step 300 is 100% (the first storage battery 122 is fully charged). If SOC1 is determined to be 100%, control passes to step 308 , else control passes to step 304 .

At step 304 , controller 106 connects stand-alone output terminal 186 of solar PCS 184 to first power storage unit 102 . That is, as described above, the controller 106 controls the first switching section 108 to connect the terminals 140 and 142 (see FIG. 2). As a result, the first power storage unit 102 outputs the power generated by the solar system 180 input to the auxiliary input terminal 124 from the output terminal 126 . The power output from the output terminal 126 is supplied to the first specific load 194 via the second switching section 110 . Control then passes to step 306 .

At step 306 , the controller 106 instructs the first power storage unit 102 to charge and the second power storage unit 104 to discharge. That is, the controller 106 causes the first PCS 120 to start charging and the second PCS 130 to start discharging. Thereby, the first PCS 120 charges the first storage battery 122 with the surplus power of the solar system 180 . The presence or absence of surplus power can be determined by whether or not the amount of power input to auxiliary input terminal 124 is greater than the amount of power supplied to first specific load 194 . First PCS 120 calculates the amount of power input to auxiliary input terminal 124 from the detection value of the current sensor inside first power storage unit 102 , and calculates the amount of power supplied to first specific load 194 from first sensor 114 . Calculated from the input current value. On the other hand, the second PCS 130 of the second power storage unit 104 converts the power stored in the second storage battery 132 into alternating current and outputs it from the output terminal 136 . The power output from the output terminal 136 is supplied to the second specific load 196 via the third switching section 112 . Control then passes to step 316 .

On the other hand, if SOC1 is 100%, controller 106 connects stand-alone output terminal 186 of solar system 180 to second power storage unit 104 in step 308 . That is, the controller 106 controls the first switching section 108 to connect the terminals 140 and 144 . Thereby, the second power storage unit 104 outputs from the output terminal 136 the power generated by the solar system 180 that is input to the auxiliary input terminal 134 . The power output from the output terminal 136 is supplied to the second specific load 196 via the third switching section 112 . Control then passes to step 310 .

At step 310 , the controller 106 instructs the first power storage unit 102 to discharge and the second power storage unit 104 to charge. That is, the controller 106 causes the first PCS 120 to start discharging and the second PCS 130 to start charging. Thereby, the first PCS 120 converts the power stored in the first storage battery 122 into alternating current and outputs the alternating current from the output terminal 126 . The power output from the output terminal 126 is supplied to the first specific load 194 via the second switching section 110 . On the other hand, the second PCS 130 charges the second storage battery 132 with the surplus power of the solar system 180 . The presence or absence of surplus power can be determined by whether or not the amount of power input to auxiliary input terminal 134 is greater than the amount of power supplied to second specific load 196 . Second PCS 130 calculates the amount of power input to auxiliary input terminal 134 from the detection value of the current sensor inside second power storage unit 104 , and calculates the amount of power supplied to second specific load 196 from second sensor 116 . Calculated from the input current value. Control then passes to step 312 .

At step 312 , the controller 106 acquires the SOC (SOC2) of the internal second storage battery 132 from the second power storage unit 104 . Control then passes to step 314 .

At step 314, the controller 106 determines whether the SOC2 acquired at step 312 is 100% (the second storage battery 132 is fully charged). If SOC2 is determined to be 100%, control passes to step 316 . Otherwise control returns to step 312 .

At step 316, the controller 106 determines whether to terminate. For example, when the power failure of the power system 190 is resolved and the supply of power from the power system 190 is started, the controller 106 determines that the power supply has ended. When it is determined to end, the controller 106 changes the first switching unit 108, the second switching unit 110, and the third switching unit 112 to the normal state, and the first power storage unit 102 and the second power storage unit 104 command to stop. After that, the program ends. Otherwise, control returns to step 300, and the processing from step 300 onwards is repeated until it is determined that the process is finished.

As described above, when the power grid 190 fails, the controller 106 controls the second switching unit 110 and the third switching unit 112 to disconnect the first specific load 194 and the second specific load 196 from the power grid 190. The first switching section 108 is controlled so that the output terminal 186 is connected to the auxiliary input terminal 124 or the auxiliary input terminal 134 . Then, controller 106 causes first power storage unit 102 and second power storage unit 104 to start charging or discharging according to the SOC of the storage battery inside each of first power storage unit 102 and second power storage unit 104 . The controller 106 determines whether the SOC (SOC1) received from the first power storage unit 102 is 100% (the first storage battery 122 is fully charged). Then, the first storage battery 122 is charged with the surplus power of the solar system 180 (step 306). After that, when the SOC (SOC1) received from the first power storage unit 102 reaches 100%, as shown in FIG. 4, the second storage battery 132 is charged with the surplus power of the solar system 180 (step 310). In FIG. 4 , the power generated by the solar system 180 output from the independent output terminal 186 is input to the auxiliary input terminal 134 and output from the output terminal 136 . The power output from the auxiliary input terminal 134 is supplied to the second specific load 196 via the third switching section 112 . Electric power output from the output terminal 126 of the first power storage unit 102 (AC power obtained by converting the power stored in the first storage battery 122 by the first PCS 120 ) is supplied to the first specific load 194 via the second switching unit 110 . supplied. In this way, one solar system 180 can charge the first power storage unit 102 and the second power storage unit 104 .

Although the case where the first storage battery 122 of the first power storage unit 102 is preferentially charged over the second storage battery 132 of the second power storage unit 104 has been described above, the present invention is not limited to this. The second storage battery 132 of the second power storage unit 104 may be charged preferentially over the first storage battery 122 of the first power storage unit 102 .

(First modification)
In the above description, the case where one of the storage batteries of the first power storage unit 102 and the second power storage unit 104 is preferentially charged has been described. is not limited to When one of the storage batteries is preferentially charged, the power storage unit that is preferentially charged may be more likely to be maintained at a high SOC. In this case, it may lead to deterioration of the storage battery. In order to prevent this, it is preferable to charge the storage batteries of the first power storage unit 102 and the second power storage unit 104 equally. In this modification, if the difference (variation) in the SOC (%) between the first power storage unit 102 and the second power storage unit 104 exceeds a predetermined value, the power generation of the solar system 180 is transferred to the power storage unit with the smaller SOC. Power and charge. When the difference becomes equal to or less than a predetermined value, the supply destination of the power generated by the solar system 180 is switched to another power storage unit, and control is performed to charge the other power storage unit. Specifically, the power storage system is controlled as shown in FIG.

A control method for equally charging the storage batteries of the first power storage unit 102 and the second power storage unit 104 during a power failure in the power system 190 will be described with reference to FIG. 5 . The flow chart of FIG. 5 is executed by controller 106 . Specifically, when detecting that a power failure has occurred, the control unit of the controller 106 sets the second switching unit 110 and the third switching unit 112 to the state at the time of the power failure, and After disconnecting the load 196 from the electric power system 190, a predetermined program is read from the storage unit inside the controller 106 and executed.

At step 400 , the controller 106 acquires the SOC (%) of the first storage battery 122 and the second storage battery 132 inside each from the first storage unit 102 and the second storage unit 104 . Specifically, the controller 106 acquires SOCs from the first PCS 120 and the second PCS 130 . Control then passes to step 402 . The SOCs of the first storage battery 122 and the second storage battery 132 are represented by SOC1 (%) and SOC2 (%), respectively.

At step 402, controller 106 determines whether the difference obtained by subtracting SOC2 from SOC1 (hereinafter referred to as the subtraction value) is greater than 5%. If the subtraction value is determined to be greater than 5%, control passes to step 404 , else control passes to step 408 .

At step 404 , the controller 106 connects the self-contained output terminal 186 of the solar system 180 to the second storage unit 104 . That is, the controller 106 controls the first switching section 108 to connect the terminals 140 and 144 . Thereby, the second power storage unit 104 outputs from the output terminal 136 the power generated by the solar system 180 that is input to the auxiliary input terminal 134 . The power output from the output terminal 136 is supplied to the second specific load 196 via the third switching section 112 . Control then passes to step 406 .

At step 406 , the controller 106 instructs the first power storage unit 102 to discharge and the second power storage unit 104 to charge. That is, the controller 106 causes the first PCS 120 to start discharging and the second PCS 130 to start charging. Thereby, the first PCS 120 converts the power stored in the first storage battery 122 into AC power and outputs the AC power from the output terminal 126 . The AC power output from the output terminal 126 is supplied to the first specific load 194 via the second switching section 110 . On the other hand, the second PCS 130 charges the second storage battery 132 with the surplus power of the solar system 180 . Control then passes to step 414 .

If the value obtained by subtracting SOC2 from SOC1 is 5% or less, in step 408 controller 106 determines whether SOC1 is 100% (first storage battery 122 is fully charged). If SOC1 is determined to be 100%, control passes to step 404;

At step 410 , the controller 106 connects the self-contained output terminal 186 of the solar PCS 184 to the first power storage unit 102 . That is, the controller 106 controls the first switching section 108 to connect the terminals 140 and 142 as described above. As a result, the first power storage unit 102 outputs the power generated by the solar system 180 input to the auxiliary input terminal 124 from the output terminal 126 . The power output from the output terminal 126 is supplied to the first specific load 194 via the second switching section 110 . Control then passes to step 412 .

At step 412 , the controller 106 instructs the first power storage unit 102 to charge and the second power storage unit 104 to discharge. That is, the controller 106 causes the first PCS 120 to start charging and the second PCS 130 to start discharging. Thereby, the first PCS 120 of the first power storage unit 102 charges the first storage battery 122 with the surplus power of the solar system 180 . On the other hand, the second PCS 130 of the second power storage unit 104 converts the power stored in the second storage battery 132 into AC power and outputs it from the output terminal 136 . The AC power output from the output terminal 136 is supplied to the second specific load 196 via the third switching section 112 . Control then passes to step 414 .

At step 414, the controller 106 determines whether to terminate. When it is determined to end, the controller 106 changes the first switching unit 108, the second switching unit 110, and the third switching unit 112 to the normal state, and the first power storage unit 102 and the second power storage unit 104 to send a stop instruction. After that, the program ends. Otherwise, control returns to step 400, and the processing from step 400 onwards is repeated until it is determined that the process is finished.

As described above, when the power grid 190 fails, the controller 106 controls the second switching unit 110 and the third switching unit 112 to disconnect the first specific load 194 and the second specific load 196 from the power grid 190. The first switching section 108 is controlled so that the output terminal 186 is connected to the auxiliary input terminal 124 or the auxiliary input terminal 134 . Then, controller 106 causes first power storage unit 102 and second power storage unit 104 to start charging or discharging according to the difference in SOC of the storage batteries inside each of first power storage unit 102 and second power storage unit 104 . That is, the controller 106 determines whether the SOC subtraction value (SOC1-SOC2) received from each of the first power storage unit 102 and the second power storage unit 104 is greater than 5%. If it is greater than 5%, as shown in FIG. 4, the surplus power of the solar system 180 is used to charge the second storage battery 132 of the second storage unit 104 having a smaller storage amount (step 406). After that, when the amount of electricity stored in the second storage battery 132 increases and the subtraction value becomes 5% or less, and the first storage battery 122 of the first storage battery 102 is not fully charged, the controller 106 performs the operation as shown in FIG. , the first storage battery 122 is charged with the surplus power of the solar system 180 (step 412).

In the initial state, if the subtraction value is less than or equal to 5% and the first storage battery 122 of the first storage unit 102 is not fully charged, the controller 106 controls the surplus power of the solar system 180 as shown in FIG. to charge the first storage battery 122 (step 412). After that, when the amount of power stored in the first storage battery 122 increases and the subtraction value becomes greater than 5%, the controller 106 charges the second storage battery 132 with the surplus power of the solar system 180 as shown in FIG. (step 406).

In this way, every time the magnitude relationship between the subtraction value representing the variation and the predetermined value (for example, 5%) changes after charging is started, by changing the supply destination of the power generated by the solar system 180, 1 With one solar system 180, charging can be performed such that the difference in the amount of storage of the storage batteries inside the first power storage unit 102 and the second power storage unit 104 is reduced. That is, the storage batteries inside the first power storage unit 102 and the second power storage unit 104 can be charged equally. As a result, it is possible to prevent the deterioration of only the storage battery of one of the storage units from progressing.

(Second embodiment)
[overall structure]
In the first embodiment (see FIG. 1), the case where the power storage system 100 includes the first switching unit 108 provided outside the first power storage unit 102 and the second power storage unit 104 has been described, but the present invention is not limited to this. In the second embodiment of the present disclosure, a switch substituting the function of the first switching section 108 is included inside each of the two power storage units. 6, a power storage system 200 according to the second embodiment of the present disclosure is the power storage system 100 of FIG. The controller 106 is replaced by the first power storage unit 202, the second power storage unit 204, and the controller 206, respectively. In FIG. 6, the elements denoted by the same reference numerals as those in FIG. 1 have the same functions as those of the power storage system 100, so redundant description will be omitted, and different points will be mainly described.

The first storage unit 202 includes a first PCS 120 , a first storage battery 122 and a first internal switch 208 . The first PCS 120 includes a control unit, a storage unit, and a conversion circuit that mutually converts DC power and AC power. The first PCS 120 further includes a communication section and communicates with the communication section of the controller 206 . The first power storage unit 202 outputs the AC power input from the auxiliary input terminal 124 directly from the output terminal 126 . The first PCS 120 operates under the control of the controller 206, converts the power (DC voltage) stored in the first storage battery 122 into AC power (AC voltage), outputs it from the output terminal 126, and inputs it from the auxiliary input terminal 124. The received AC power is converted into DC power to charge the first storage battery 122 . The first PCS 120 also controls ON/OFF of the first internal switch 208 .

Similarly, the second storage unit 204 includes a second PCS 130 , a second storage battery 132 and a second internal switch 210 . The second PCS 130 includes a control unit, a storage unit, and a conversion circuit that mutually converts DC power and AC power. The second PCS 130 further includes a communication section and communicates with the communication section of the controller 206 . The second power storage unit 204 outputs the AC power input from the auxiliary input terminal 134 directly from the output terminal 136 . The second PCS 130 operates under the control of the controller 206, converts the power (DC voltage) stored in the second storage battery 132 into AC power (AC voltage), outputs it from the output terminal 136, and inputs it from the auxiliary input terminal 134. The received AC power is converted into DC power to charge the second storage battery 132 . The second PCS 130 also controls ON/OFF of the second internal switch 210 .

Controller 206 includes a control unit, a storage unit, and a communication unit, and controls second switching unit 110 , third switching unit 112 , first PCS 120 and second PCS 130 . The controller 206 causes each of the second switching unit 110, the third switching unit 112, the first PCS 120, and the second PCS 130 to perform a predetermined operation during a power failure, as will be described later.

By being configured in this manner, the power storage system 200 normally transfers the power generated by the solar system 180 to the general load 192 via the distribution line that supplies commercial power from the power grid 190, as shown in FIG. , to the first specific load 194 via the second switching section 110 , and to the second specific load 196 via the third switching section 112 . Referring to FIG. 7 , in power storage system 200 during a power failure, controller 206 changes the connection states of second switching unit 110 and third switching unit 112 as described above. FIG. 7 shows a case where the power generated by solar system 180 is greater than the power consumed by first specific load 194 . In FIG. 7, arrows indicate currents. As described above, during a power failure, the photovoltaic system 180 stops supplying generated power to the distribution line that supplies commercial power, and outputs the generated power from the independent output terminal 186. Therefore, the generated power of the photovoltaic system 180 is The power is supplied to the first specific load 194 via the first power storage unit 202 . Since the power generated by the solar system 180 is greater than the power consumed by the first specific load 194 , the first PCS 120 of the first power storage unit 202 charges the first storage battery 122 with the surplus power of the solar system 180 . On the other hand, AC power obtained by converting the power stored in the second storage battery 132 by the second PCS 130 is supplied to the second specific load 196 from the output terminal 136 of the second power storage unit 204 .

[Control action]
The operation of power storage system 200 during a power outage in power system 190 will be described below with reference to FIG. 8 . The flow chart of FIG. 8 is executed by controller 206 . Specifically, when detecting that a power failure has occurred, the control unit of the controller 206 sets the second switching unit 110 and the third switching unit 112 to the state at the time of the power failure, and switches the first specific load 194 and the second specific load 194 After disconnecting the load 196 from the electric power system 190, a predetermined program is read from the storage unit inside the controller 206 and executed. Here, it is assumed that the first power storage unit 202 is preferentially charged over the second power storage unit 204 with the surplus power of the solar system 180 .

The flowchart of FIG. 8 is obtained by replacing steps 304, 306, 308 and 310 in the flowchart of FIG. 3 with steps 320, 322, 324 and 326, respectively. In FIG. 8, the processing of steps denoted by the same reference numerals as in FIG. 3 is the same as the processing of the steps in FIG. However, the main body is changed from the controller 106 to the controller 206, and the first power storage unit 102 and the second power storage unit 104 are replaced with the first power storage unit 202 and the second power storage unit 204, respectively. Here, redundant description will be omitted, and different points will be mainly described.

The controller 206 acquires the respective SOCs (SOC1 and SOC2) from the first power storage unit 202 and the second power storage unit 204 (step 300), and determines whether the SOC1 is 100% (step 302). If it is determined in step 302 that it is not 100%, in step 320 the controller 206 instructs the first power storage unit 202 (first PCS 120) to turn on the first internal switch 208 and charge. Thereby, the first PCS 120 turns on the first internal switch 208 and charges the first storage battery 122 with the surplus power of the solar system 180 . Control then passes to step 322 . When the first internal switch 208 is ON, the power generated by the solar system 180 input to the auxiliary input terminal 124 is output from the output terminal 126 and supplied to the first specific load 194 via the second switching section 110. be done.

At step 322, the controller 206 instructs the second power storage unit 204 (second PCS 130) to turn off the second internal switch 210 and discharge. As a result, the second PCS 130 turns off the second internal switch 210 and starts discharging. Control then passes to step 316 . If the second internal switch 210 is OFF, the power generated by the solar system 180 input to the auxiliary input terminal 134 will not be output from the output terminal 136 . The AC power obtained by converting the power of the second storage battery 132 by the second PCS 130 is output from the output terminal 136 and supplied to the second specific load 196 via the third switching unit 112 .

On the other hand, if it is determined in step 302 that the SOC1 is 100%, in step 324 the controller 206 instructs the first power storage unit 202 (first PCS 120) to turn off the first internal switch 208 and discharge. . This causes the first PCS 120 to turn off the first internal switch 208 and start discharging. Control then passes to step 326 . If the first internal switch 208 is OFF, the power generated by the solar system 180 input to the auxiliary input terminal 124 will not be output from the output terminal 126 . The AC power obtained by converting the power of the first storage battery 122 by the first PCS 120 is output from the output terminal 126 and supplied to the first specific load 194 via the second switching unit 110 .

At step 326, the controller 206 instructs the second power storage unit 204 (second PCS 130) to set the second internal switch 210 to ON and charge. Thereby, the second PCS 130 turns on the second internal switch 210 and charges the second storage battery 132 with the surplus power of the solar system 180 . Control then passes to step 316 . When the second internal switch 210 is ON, the power generated by the solar system 180 input to the auxiliary input terminal 134 is output from the output terminal 136 and supplied to the second specific load 196 via the third switching section 112. be done.

At step 316, the controller 206 determines whether or not to end, and the processing from step 300 onward is repeated until it is determined to end.

As described above, the controller 206 disconnects the first specific load 194 and the second specific load 196 from the power system 190 by controlling the second switching unit 110 and the third switching unit 112 when the power system 190 fails. Then, the controller 206 sets the internal switches of the first power storage unit 202 and the second power storage unit 204 according to the SOC of the storage battery inside each of the first power storage unit 202 and the second power storage unit 204, and Instructs the start of charging or discharging. The controller 206 determines whether the SOC (SOC1) received from the first power storage unit 202 is 100% (the first storage battery 122 is fully charged). Then, the first storage battery 122 is charged with the surplus power of the solar system 180 (step 320). After that, when the SOC (SOC1) received from the first power storage unit 202 reaches 100%, as shown in FIG. 9, the second storage battery 132 is charged with the surplus power of the solar system 180 (step 326). In FIG. 9 , the power generated by the solar system 180 output from the independent output terminal 186 is input to the auxiliary input terminal 134 and output from the output terminal 136 . The power output from the output terminal 136 is supplied to the second specific load 196 via the third switching section 112 . Electric power output from the output terminal 126 of the first power storage unit 202 is supplied to the first specific load 194 via the second switching section 110 . Thus, one solar system 180 can charge the first power storage unit 202 and the second power storage unit 204 .

Further, by providing an internal switch in each power storage unit, it is easier to add power storage units than when a switching unit (first switching unit 108 in FIG. 1) is provided outside the power storage unit. In addition, although the case where the first storage battery 122 of the first power storage unit 202 is preferentially charged over the second storage battery 132 of the second power storage unit 204 has been described above, the present invention is not limited to this. The second storage battery 132 of the second power storage unit 204 may be charged preferentially over the first storage battery 122 of the first power storage unit 202 .

(Second modification)
In the above description, the case of preferentially charging the storage battery of either the first power storage unit 202 or the second power storage unit 204 has been described. is not limited to As described above, in the power storage system 200 of FIG. 6, the storage batteries of the first power storage unit 202 and the second power storage unit 204 are evenly charged in order to prevent the deterioration of only one of the power storage units. You may

With reference to FIG. 10, a control method for evenly charging the storage batteries of the first power storage unit 202 and the second power storage unit 204 during a power outage in the power system 190 will be described. The flow chart of FIG. 10 is executed by controller 206 . Specifically, when detecting that a power failure has occurred, the control unit of the controller 206 sets the second switching unit 110 and the third switching unit 112 to the state at the time of the power failure, and switches the first specific load 194 and the second specific load 194 After disconnecting the load 196 from the electric power system 190, a predetermined program is read from the storage unit inside the controller 206 and executed.

The flowchart of FIG. 10 is obtained by replacing steps 404, 406, 410 and 412 in the flowchart of FIG. 5 with steps 420, 422, 424 and 426, respectively. In FIG. 10, the processing of steps denoted by the same reference numerals as in FIG. 5 is the same as the processing of the steps in FIG. However, the main body is changed from the controller 106 to the controller 206, and the first power storage unit 102 and the second power storage unit 104 are replaced with the first power storage unit 202 and the second power storage unit 204, respectively. Here, redundant description will be omitted, and different points will be mainly described.

Controller 206 acquires the respective SOCs (SOC1 and SOC2) from first power storage unit 202 and second power storage unit 204 (step 400), and the value obtained by subtracting SOC2 from SOC1 (subtraction value) is 5%. It is determined whether it is greater than (step 402). If it is determined in step 402 that the subtraction value is greater than 5%, in step 420 the controller 206 turns off the first internal switch 208 of the first power storage unit 202 (first PCS 120) to instruct discharge. This causes the first PCS 120 to turn off the first internal switch 208 and start discharging. Control then passes to step 422 . If the first internal switch 208 is OFF, the power generated by the solar system 180 input to the auxiliary input terminal 124 will not be output from the output terminal 126 . The AC power obtained by converting the power of the first storage battery 122 by the first PCS 120 is output from the output terminal 126 and supplied to the first specific load 194 via the second switching unit 110 .

At step 422, the controller 206 instructs the second power storage unit 204 (second PCS 130) to set the second internal switch 210 to ON and charge. Thereby, the second PCS 130 turns on the second internal switch 210 and charges the second storage battery 132 with the surplus power of the solar system 180 . Control then passes to step 414 . When the second internal switch 210 is ON, the power generated by the solar system 180 input to the auxiliary input terminal 134 is output from the output terminal 136 and supplied to the second specific load 196 via the third switching section 112. be done.

Even if it is determined in step 402 that the subtraction value is 5% or less, if it is determined in step 408 that the SOC (SOC1) of first power storage unit 202 is 100%, steps 420 and 422 are executed. be.

On the other hand, if it is determined in step 402 that the subtraction value is 5% or less and if it is determined in step 408 that the SOC (SOC1) of the first power storage unit 202 is not 100%, then in step 424 the controller 206 instructs the first power storage unit 202 (first PCS 120) to set the first internal switch 208 to ON and charge. Thereby, the first PCS 120 turns on the first internal switch 208 and charges the first storage battery 122 with the surplus power of the solar system 180 . Control then passes to step 426 . When the first internal switch 208 is ON, the power generated by the solar system 180 input to the auxiliary input terminal 124 is output from the output terminal 126 and supplied to the first specific load 194 via the second switching section 110. be done.

At step 426, the controller 206 instructs the second power storage unit 204 (second PCS 130) to turn off the second internal switch 210 and discharge. As a result, the second PCS 130 turns off the second internal switch 210 and starts discharging. Control then passes to step 414 . If the second internal switch 210 is OFF, the power generated by the solar system 180 input to the auxiliary input terminal 134 will not be output from the output terminal 136 . The AC power obtained by converting the power of the second storage battery 132 by the second PCS 130 is output from the output terminal 136 and supplied to the second specific load 196 via the third switching unit 112 .

At step 414, the controller 206 determines whether or not to end, and the processing from step 400 onward is repeated until it is determined to end.

As described above, the controller 206 disconnects the first specific load 194 and the second specific load 196 from the power system 190 by controlling the second switching unit 110 and the third switching unit 112 when the power system 190 fails. Then, the controller 206 causes the first power storage unit 202 and the second power storage unit 204 to start charging or discharging according to the difference in the SOC of the storage batteries inside each of the first power storage unit 202 and the second power storage unit 204 . That is, the controller 206 determines whether the SOC subtraction value (SOC1-SOC2) received from each of the first power storage unit 202 and the second power storage unit 204 is greater than 5%. For example, as shown in FIG. 9, the second storage battery 132 is charged with the surplus power of the solar system 180 (step 422). If the subtraction value is 5% or less, the controller 206 charges the first storage battery 122 with the surplus power of the solar system 180 as shown in FIG. 7 (step 424).

Therefore, as in the first modification described above, every time the magnitude relationship between the subtraction value representing the variation and the predetermined value (for example, 5%) changes after charging is started, the power generated by the solar system 180 is supplied. By changing the destination, one solar system 180 can evenly charge the storage batteries inside the first power storage unit 202 and the second power storage unit 204 . As a result, it is possible to prevent the deterioration of only the storage battery of one of the storage units from progressing.

(Third modification)
In the power storage system 200, when the power generated by the solar system 180 decreases and becomes smaller than the power consumption of the specific load (for example, the first specific load 194) to which the generated power is currently supplied, the generated power is transferred to the specific load. can no longer be supplied. In that case, the power storage system (first power storage unit 202) connected to the specific load turns off the internal switch (first internal switch 208) and supplies power to the specific load by discharging. After that, the controller 206 continues to instruct that power storage unit (first power storage unit 202) to be charged. The switch (first internal switch 208) is turned on. If the power generation amount of the solar system 180 is still smaller than the power consumption of the specific load (first specific load 194), the corresponding power storage unit (first power storage unit 202) turns the internal switch (first internal switch 208) again. Turn off. That is, if the connection between the solar system 180 and the power storage unit is maintained, and the instruction to charge the power storage unit from the controller 206 is maintained, the internal switch of the power storage unit is repeatedly turned ON/OFF.

At this time, power is supplied to the other specific load (second specific load 196) by discharging the other power storage system (second power storage unit 204). However, even if the power generated by the solar system 180 is smaller than the power consumption of the specific load (first specific load 194) to which the power is supplied, if it is larger than the power consumption of the other specific load (second specific load 196). For example, the power generated by the solar system 180 can be supplied to the other specific load.

Therefore, in this modified example, the control as shown in FIG. 11 is performed in consideration of the above matter. It is assumed that the power consumption of the first specific load 194 is greater than the power consumption of the second specific load 196 . The flowchart of FIG. 11 is obtained by adding steps 340, 342, 344 and 346 to the flowchart of FIG. In FIG. 11, the processing of steps denoted by the same reference numerals as in FIG. 8 is the same as the processing of the steps in FIG. Therefore, redundant description will be omitted, and different points will be mainly described.

The controller 206 acquires the respective SOCs (SOC1 and SOC2) from the first power storage unit 202 and the second power storage unit 204 (step 300), and determines whether the SOC1 is 100% (step 302). If step 302 determines that it is not 100%, controller 206 performs steps 320 and 322 . As a result, the first internal switch 208 is turned ON, the second internal switch 210 is turned OFF, and the first power storage unit 202 supplies the input power generated by the solar system 180 to the first specific load 194, The surplus power of 180 is used to charge the first storage battery 122 . On the other hand, the second power storage unit 204 supplies power to the second specific load 196 by discharging.

Subsequently, at step 340 , the controller 206 determines whether or not the power generated by the solar system 180 is less than the power consumed by the first specific load 194 . Specifically, the controller 206 acquires the generated power of the solar system 180 and the power consumption of the first specific load 194 from the first PCS 120 and determines them. As described above, the first PCS 120 determines whether or not there is surplus power in the solar system 180 in order to charge the first storage battery 122. Therefore, the power generated by the solar system 180 and the power consumption of the first specific load 194 are can be provided to controller 206 . If it is determined that the power generated by the solar system 180 is less than the power consumption of the first specific load 194 , control proceeds to step 324 . Otherwise control passes to step 316 .

On the other hand, if step 302 determines that SOC1 is 100%, controller 206 performs steps 324 and 326 . As a result, the first internal switch 208 is turned OFF, the second internal switch 210 is turned ON, and the first power storage unit 202 supplies power to the first specific load 194 by discharging. On the other hand, the second power storage unit 204 supplies the input power generated by the solar system 180 to the second specific load 196 and charges the second storage battery 132 with the surplus power of the solar system 180 .

Subsequently, at step 342 , the controller 206 determines whether or not the power generated by the solar system 180 is less than the power consumed by the second specific load 196 . Specifically, the controller 206 acquires the generated power of the solar system 180 and the power consumption of the second specific load 196 from the second PCS 130 and determines them. As described above, the second PCS 130 determines whether there is surplus power in the solar system 180 in order to charge the second storage battery 132. Therefore, the power generated by the solar system 180 and the power consumption of the second specific load 196 are can be provided to controller 206 . If it is determined that the power generated by solar system 180 is less than the power consumption of second specific load 196 , control proceeds to step 344 . Otherwise, control passes to step 312 .

At step 344, the controller 206 instructs the second power storage unit 204 (second PCS 130) to turn off the second internal switch 210 and discharge. As a result, the second PCS 130 turns off the second internal switch 210 and starts discharging. Control then passes to step 346 . If the second internal switch 210 is OFF, the power generated by the solar system 180 input to the auxiliary input terminal 134 will not be output from the output terminal 136 . The AC power obtained by converting the power of the second storage battery 132 by the second PCS 130 is output from the output terminal 136 and supplied to the second specific load 196 via the third switching unit 112 . At this time, the first power storage unit 202 maintains the state of supplying power to the first specific load 194 by discharging (step 324).

At step 346 , the controller 206 determines whether or not the power generated by the solar system 180 is greater than or equal to the power consumed by the second specific load 196 . Specifically, the controller 206 acquires the power generated by the solar system 180 and the power consumption of the second specific load 196 from the second PCS 130 and determines them, as in step 342 . If it is determined that the power generated by the solar system 180 is greater than or equal to the power consumption of the second specific load 196 , control proceeds to step 316 . Otherwise control returns to step 344 .

At step 316, the controller 206 determines whether or not to end, and the processing from step 300 onward is repeated until it is determined to end.

As described above, the controller 206 disconnects the first specific load 194 and the second specific load 196 from the power system 190 by controlling the second switching unit 110 and the third switching unit 112 when the power system 190 fails. Then, the controller 206 sets the internal switches of the first power storage unit 202 and the second power storage unit 204 according to the SOC of the storage battery inside each of the first power storage unit 202 and the second power storage unit 204, and Instructs the start of charging or discharging. The controller 206 determines whether the SOC (SOC1) received from the first power storage unit 202 is 100% (the first storage battery 122 is fully charged). Then, the first storage battery 122 is charged with the surplus power of the solar system 180 (step 320). After that, when the SOC (SOC1) received from the first power storage unit 202 reaches 100%, as shown in FIG. 9, the second storage battery 132 is charged with the surplus power of the solar system 180 (step 326).

As shown in FIG. 7, in a state where the SOC1 is less than 100% and the first storage battery 122 is being charged with the surplus power of the solar system 180, the power generated by the solar system 180 decreases and the first specific It is conceivable that it will be less than the power consumption of the load 194 (the decision result in step 340 is YES). In that case, as shown in FIG. 9, the first internal switch 208 is turned off, the first power storage unit 202 supplies power to the first specific load 194 by discharging (step 324), and the second internal switch 210 is turned off. is turned on, and the second power storage unit 204 charges the second storage battery 132 with the surplus power of the solar system 180 (step 326).

In the state of FIG. 9, it is conceivable that the power generated by the solar system 180 will further decrease and become smaller than the power consumption of the second specific load 196 (the determination result in step 342 is YES). In that case, as shown in FIG. 12, the second internal switch 210 is turned off, and the second power storage unit 204 discharges to supply power to the second specific load 196 (step 344). The first internal switch 208 remains OFF, and the first storage unit 202 is supplying power to the first specific load 194 by discharging (step 324).

In the state of FIG. 12, it is conceivable that the power generated by the solar system 180 will increase and exceed the power consumption of the second specific load 196 (the determination result in step 346 is YES). In that case, the state shown in FIG. 7 or 9 is restored. That is, as described above, depending on whether the SOC1 is 100% (step 302) and whether the power generation amount of the solar system 180 is smaller than the power consumption of the first specific load 194 (step 340), The first power storage unit 202 is charged with the surplus power of the solar system 180 (see FIG. 7), or the second power storage unit 204 is charged with the surplus power of the solar system 180 (see FIG. 9).

Therefore, when the power generated by solar system 180 becomes smaller than the power consumption of the specific load (first specific load 194) to which power is supplied, the internal switch (first It is possible to prevent the internal switch 208) from repeatedly turning ON/OFF. Moreover, even if the power generated by the solar system 180 is less than the power consumption of the specific load (first specific load 194) to which the power is supplied, it is less than the power consumption of the other specific load (second specific load 196). If it is larger, the power generated by the solar system 180 can be supplied to the other specific load, and the surplus power of the solar system 180 can be used to charge the power storage system (second power storage unit 204) corresponding to the other specific load. Therefore, the power generated by the solar system 180 can be used effectively without wasting it.

Note that FIG. 11 is a flowchart when the power consumption of the first specific load 194 is greater than the power consumption of the second specific load 196, and the power consumption of the second specific load 196 is greater than the power consumption of the first specific load 194. 11, the first power storage unit 202 and the second power storage unit 204 may be replaced.

(Fourth modification)
Steps 340, 342, 344 and 346 can be added to the flowchart shown in FIG. 10 as well as in FIG. That is, the controller 206 can execute the control shown in FIG.

13, in the flowchart of FIG. 10, step 340 is added after step 426 (corresponding to step 322 in FIG. 11), and steps 342, 344 and 344 are added after step 422 (corresponding to step 326 in FIG. 11). 346 was added. Therefore, according to the flowchart of FIG. 13, similarly to the flowchart of FIG. 11, the power storage system 200 is changed from the state of FIG. state can be changed to the state shown in FIG. Also, if the power generated by the solar system 180 increases, the power storage system 200 can be changed from the state shown in FIG. 11 to the state shown in FIG. 7 or 9 . Therefore, it is possible to prevent the internal switch inside the power storage unit from repeatedly turning ON/OFF, and the power generated by solar system 180 can be used effectively without wasting it.

In the above description, in the power storage system 200, the processing when the power generated by the solar system 180 becomes smaller than the power consumption of the specific load has been described. can play For example, steps 340, 342, 344 and 346 may be added to the flow charts shown in FIGS. 3 and 5 in the same manner as in FIGS. 11 and 13, respectively.

In the above, it is determined whether or not the SOC is 100%, but the present invention is not limited to this. It is sufficient if it is possible to determine whether or not the storage battery inside the power storage unit is charged with a predetermined amount or more (for example, whether or not the battery is in a nearly fully charged state). For example, the value may be in the range of 100% or less and 80% or more.

In addition, in the control of evenly charging the two power storage units (FIGS. 5, 10, and 13), the reference value for determining which of the two power storage units is charged is 5%, but the present invention is not limited to this. . The reference value for determination may be set so that the two storage units can be charged so that the storage amounts of the two storage units are as even as possible. For example, the value may be in the range of more than 0% and 20% or less. If the reference value for determination is small, the first switching unit 108 will be switched frequently. Therefore, the reference value for determination should be set to an appropriate value in consideration of the life of the switching times of the first switching unit 108 (for example, a relay). is preferably set to

Also, in the above description, the case where the difference (subtraction value) between the SOCs of the two power storage units is used to determine which of the two power storage units is to be charged has been described, but the present invention is not limited to this. Any variable (function of SOC1 and SOC2) representing the degree of difference in the amount of stored electricity calculated from the SOC of each of the two storage units may be used. For example, the ratio of SOC1 to SOC2 (SOC1/SOC2) may be used. The reference value for determination may be set according to the variables used for determination. For example, when using SOC1/SOC2, 1.05 may be used as the reference value corresponding to the above 5%.

Although the case where there are two power storage units has been described above, the present invention is not limited to this. Three or more power storage units may be charged by one solar system. In that case, for example, a priority order is set in advance for a plurality of power storage units, and power generated by the solar system is supplied one by one to reach a predetermined storage amount (for example, fully charged) in descending order of priority. to charge. The number of solar systems is not limited to one, and the number of solar systems may be less than the number of power storage systems installed.

In addition, the electric power generated by the solar system is supplied to the power storage units one by one in descending order of the power storage amount so that the value of the variable representing the variation in the power storage amount of the plurality of power storage units is within a predetermined range. may For example, the storage unit with the smallest storage amount is charged first, and when the storage amount of that storage unit becomes less than the minimum storage amount, another storage unit with the smallest storage amount is charged repeatedly. Keep it within the specified range. After that, when the value of the variable representing the variation exceeds the predetermined range again, the power storage unit to be charged is changed. After that, even when the value of the variable representing the variation falls within the predetermined range again, the power storage unit to be charged is changed.

In the above description, the case of charging a plurality of power storage units with AC power supplied from the solar system has been described, but the present invention is not limited to this. Any AC power supply may be used, and the plurality of power storage units may be charged with AC power supplied from a power generation system other than the solar system.

Although the present invention has been described above by describing the embodiments, the above-described embodiments are examples, and the present invention is not limited only to the above-described embodiments. The scope of the present invention is indicated by each claim in the scope of claims after taking into account the description of the detailed description of the invention, and all changes within the meaning and range of equivalents to the wording described therein include.

100, 200 power storage systems 102, 202 first power storage units 104, 204 second power storage units 106, 206 controller 108 first switching section 110 second switching section 112 third switching section 114 first sensor 116 second sensor 120 first PCS
122 first storage batteries 124, 134 auxiliary input terminals 126, 136 output terminal 130 second PCS
132 second storage battery 140, 142, 144, 150, 152, 154, 160, 162, 164 terminal 180 solar system 182 solar panel 184 solar PCS
186 isolated output terminal 190 power system 192 general load 194 first specific load 196 second specific load 208 first internal switch 210 second internal switch 300, 302, 304, 306, 308, 310, 312, 314, 316, 320, 322,324,326,340,342,344,346,400,402,404,406,408,410,412,414,420,422,424,426 Step

Claims (6)

An electricity storage system including a plurality of electricity storage units connected to an AC power supply,
a switching unit that switches a supply destination of the output power so that the output power of the AC power supply is supplied to any one of the plurality of power storage units;
a control unit that controls the switching unit during self-sustained operation of the power storage unit;
each power storage unit of the plurality of power storage units,
an electric circuit for outputting input electric power;
a storage battery connected to the electrical circuit;
a conversion unit that mutually converts DC power and AC power,
According to the supply destination of the output power switched by the switching unit, the power storage unit, during self-sustained operation,
supplying the output power of the input AC power supply to a specific load corresponding to the power storage unit through the electrical path of the power storage unit;
charging the storage battery of the power storage unit via the conversion unit of the power storage unit with surplus power of the output power of the input AC power supply;
if the output power of the AC power supply is not input, the power of the storage battery of the power storage unit is supplied to the specific load via the conversion unit and the electric line of the power storage unit;
In a state in which the output power is supplied to one of the plurality of power storage units, a magnitude relationship between a value of a variable representing variation in the amount of power stored in each of the plurality of power storage units and a predetermined value is determined. further comprising a determination unit;
The determining unit causes the value of the variable to change from a state in which the value of the variable is greater than the predetermined value to a state in which the value of the variable is equal to or less than the predetermined value, and the one power storage unit among the plurality of power storage units is determined that the amount of electricity stored in a different storage unit is less than a predetermined amount , or that the value of the variable has changed from being equal to or less than the predetermined value to being greater than the predetermined value In response to the determination, the control unit causes the switching unit to switch the supply destination of the output power to the power storage unit different from the one power storage unit among the plurality of power storage units. system. An electricity storage system including a plurality of electricity storage units connected to an AC power supply,
A switch that is provided inside each of the plurality of power storage units and switches a supply destination of the output power so that the output power of the AC power supply is supplied to any one of the plurality of power storage units. and,
a control unit that controls the plurality of power storage units during self-sustained operation of the power storage units;
each power storage unit of the plurality of power storage units,
an electric circuit for outputting input electric power;
a storage battery connected to the electrical circuit;
a conversion unit that mutually converts DC power and AC power,
According to the supply destination of the output power switched by the switch, the power storage unit, during self-sustained operation,
supplying the output power of the input AC power supply to a specific load corresponding to the power storage unit through the electrical path of the power storage unit;
charging the storage battery of the power storage unit via the conversion unit of the power storage unit with surplus power of the output power of the input AC power supply;
if the output power of the AC power supply is not input, the power of the storage battery of the power storage unit is supplied to the specific load via the conversion unit and the electric line of the power storage unit;
In a state in which the output power is supplied to one of the plurality of power storage units, a magnitude relationship between a value of a variable representing variation in the amount of power stored in each of the plurality of power storage units and a predetermined value is determined. further comprising a determination unit;
The determining unit causes the value of the variable to change from a state in which the value of the variable is greater than the predetermined value to a state in which the value of the variable is equal to or less than the predetermined value, and the one power storage unit among the plurality of power storage units is determined that the amount of electricity stored in a different storage unit is less than a predetermined amount, or that the value of the variable has changed from being equal to or less than the predetermined value to being greater than the predetermined value In response to the determination, the controller controls the one power storage unit and the one power storage unit so that the supply destination of the output power is switched to the power storage unit different from the one power storage unit. An electric storage system that causes each of the different electric storage units to control the switch provided therein . In a state in which the output power is supplied to one power storage unit of the plurality of power storage units during the self-sustained operation, and the storage battery of the power storage unit is charged with the surplus power of the output power, In response to the fact that the output power has become smaller than the power consumption of the specific load corresponding to the one power storage unit , the output power is supplied to the one power storage unit among the plurality of power storage units. 3. The switch according to claim 2 , wherein each of the one power storage unit and the power storage unit different from the one power storage unit controls the switch provided therein so as to switch to the power storage unit different from the unit. The electrical storage system described. The AC power supply is a solar system,
The solar system is
solar panel and
The power storage system according to any one of claims 1 to 3 , further comprising a power converter that converts DC power generated by the solar panel into AC power and outputs the AC power as the output power. An electricity storage system including a plurality of electricity storage units connected to an AC power supply,
A switch that is provided inside each of the plurality of power storage units and switches a supply destination of the output power so that the output power of the AC power supply is supplied to any one of the plurality of power storage units. and,
a control unit that controls the switching unit during self-sustained operation of the power storage unit;
each power storage unit of the plurality of power storage units,
an electric circuit for outputting input electric power;
a storage battery connected to the electrical circuit;
a conversion unit that mutually converts DC power and AC power,
According to the supply destination of the output power switched by the switching unit, the power storage unit, during self-sustained operation,
supplying the output power of the input AC power supply to a specific load corresponding to the power storage unit through the electrical path of the power storage unit;
charging the storage battery of the power storage unit via the conversion unit of the power storage unit with surplus power of the output power of the input AC power supply;
if the output power of the AC power supply is not input, the power of the storage battery of the power storage unit is supplied to the specific load via the conversion unit and the electric line of the power storage unit;
In a state in which the output power is supplied to one power storage unit of the plurality of power storage units during the self-sustained operation, and the storage battery of the power storage unit is charged with the surplus power of the output power, In response to the fact that the output power has become smaller than the power consumption of the specific load corresponding to the one power storage unit , the output power is supplied to the one power storage unit among the plurality of power storage units. An electric storage system, wherein each of the one electric storage unit and an electric storage unit different from the one electric storage unit controls the switch provided therein so as to switch to an electric storage unit different from the unit. a plurality of power storage units connected to an AC power supply; and a switching unit for switching a supply destination of the output power so that the output power of the AC power supply is supplied to any one power storage unit of the plurality of power storage units. and each power storage unit of the plurality of power storage units includes an electric line for outputting input electric power, a storage battery connected to the electric line, and a conversion unit for mutually converting DC power and AC power. , a control method for a power storage system,
a first step of controlling the switching unit during self-sustained operation of the power storage unit;
a second step of controlling each power storage unit of the plurality of power storage units during the self-sustained operation;
In the second step, according to the supply destination of the output power switched by the switching unit, the power storage unit
a step of supplying the output power of the input AC power supply to a specific load corresponding to the power storage unit through the electric path of the power storage unit;
a step of charging the storage battery of the power storage unit with surplus power of the output power of the input AC power supply via the conversion unit of the power storage unit;
If the output power of the AC power supply is not input, the power of the storage battery of the power storage unit is supplied to the specific load via the conversion unit of the power storage unit and the electric line,
In a state in which the output power is supplied to one of the plurality of power storage units, a magnitude relationship between a value of a variable representing variation in the amount of power stored in each of the plurality of power storage units and a predetermined value is determined. a determination step;
By the determining step, the value of the variable changes from a state in which the value of the variable is greater than the predetermined value to a state in which the value of the variable is equal to or less than the predetermined value, and the one power storage unit among the plurality of power storage units is determined that the amount of electricity stored in a different storage unit is less than a predetermined amount , or that the value of the variable has changed from being equal to or less than the predetermined value to being greater than the predetermined value and causing the switching unit to switch a supply destination of the output power to the power storage unit different from the one power storage unit, among the plurality of power storage units, in response to the determination . Method.

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