Energy storage system

Abstract

We will provide a more economical energy storage system than conventional systems. [Solution] The energy storage system 1A includes a control unit 5 that controls the bidirectional AC / DC converter 2 and the bidirectional DC / DC converter 3, and a storage unit 6B that stores a first set value S1 and a second set value S2 (where S2 ≥ S1) related to the remaining capacity of the energy storage device 10. The control unit 5 (1) if the remaining amount > S2, allows power supply from the energy storage device 10 to the customer load L and power supply from the energy storage device 10 to the electric vehicle EV, and (2) S1

Description

Technical Field

[0001] The present invention relates to a power storage system capable of supplying power stored in a power storage device to a customer load and an electric vehicle.

Background Art

[0002] Conventionally, there is known a power storage system connected to an in-house distribution line for supplying AC power supplied from a commercial power system to a customer load, an electric vehicle charging device for charging an electric vehicle, a power storage device, and a photovoltaic power generation device.

[0003] Some power storage systems have a function of always leaving a certain amount of power in the power storage device in preparation for an abnormality (power outage) in the commercial power system. In other words, when the remaining power storage amount reaches a set value (for example, 30%) predetermined by the user, the system is configured not to perform further discharging (see, for example, p. 26 of "Emergency Safety Settings" in Non-Patent Document 1).

[0004] There are also power storage systems that do not supply the power stored in the power storage device to the customer load except when an abnormality occurs in the commercial power system in order to ensure that an electric vehicle returning from a destination is charged for use the next day.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the conventional energy storage systems described above, where the supply of electricity to consumer loads is limited, a large amount of electricity sometimes remains in the storage device after the electric vehicle has finished charging. This tendency is particularly pronounced on days when solar power generation is high. From the perspective of efficient use of electricity, this system cannot be considered economically efficient.

[0007] This invention has been made in view of these circumstances, and aims to provide a more economical energy storage system than conventional systems. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a power storage system connected to a customer's internal distribution line for supplying AC power supplied from the commercial power grid to the customer's load and an electric vehicle charging device for charging an electric vehicle, comprising: a first bidirectional power converter having AC-side input / output terminals connected to the customer's internal distribution line and DC-side input / output terminals connected to the electric vehicle charging device; a second bidirectional power converter having a first input / output terminal connected to the DC-side input / output terminals and a second input / output terminal connected to the power storage device; a control unit that controls the first bidirectional power converter and the second bidirectional power converter; and a storage unit that stores a first set value and a second set value (where the second set value ≥ the first set value) regarding the remaining capacity of the power storage device, wherein the control unit (1) when the commercial power grid is normal and the remaining capacity > the second set value, the power stored in the power storage device is supplied to the second bidirectional power converter and the first bidirectional power converter The system has the following configuration: (1) It allows power to be supplied to the customer's distribution lines via the power conversion unit, and the power stored in the energy storage device to be supplied to the electric vehicle charging device via the second bidirectional power conversion unit; (2) If the commercial power system is normal and the first set value < remaining amount ≤ second set value, it allows power stored in the energy storage device to be supplied to the electric vehicle charging device via the second bidirectional power conversion unit, while prohibiting power stored in the energy storage device from being supplied to the customer load via the first bidirectional power conversion unit and the second bidirectional power conversion unit; and (3) If the commercial power system is normal and the remaining amount ≤ first set value, it prohibits power stored in the energy storage device from being supplied to the customer's distribution lines via the second bidirectional power conversion unit and the first bidirectional power conversion unit, and prohibits power stored in the energy storage device from being supplied to the electric vehicle charging device via the second bidirectional power conversion unit.

[0009] In this configuration, power is supplied from the energy storage device to the customer's distribution lines (customer load) only when the commercial power grid is functioning normally and the remaining capacity is greater than the second setpoint. Therefore, this configuration makes it possible to realize an economical system in which less power remains stored in the energy storage device than in conventional systems.

[0010] Furthermore, in this configuration, when the remaining charge falls below the second set value, the supply of power from the energy storage device to the customer's internal distribution lines (customer load) is prohibited. Therefore, this configuration makes it possible to retain in the energy storage device the power expected to be needed to charge electric vehicles.

[0011] Furthermore, in this configuration, when the remaining charge falls below the first set value, power supply from the energy storage device to the electric vehicle charging device (electric vehicle) is also prohibited. Therefore, this configuration makes it possible to retain the necessary power in the energy storage device in the event of an abnormality (power outage) in the commercial power grid.

[0012] Preferably, the control unit of the above-mentioned energy storage system has the following configuration: (4) If an abnormality occurs in the commercial power grid, regardless of the remaining amount, the power stored in the energy storage device is supplied to the customer's distribution line via the first bidirectional power converter and the second bidirectional power converter.

[0013] This configuration makes it possible to keep consumer loads running even if an anomaly occurs in the commercial power grid.

[0014] The above-described energy storage system may further include a setting value input unit that accepts input of a third setting value and a fourth setting value related to the remaining amount, and is configured to store the third setting value as a first setting value in the storage unit, and to store the sum of the third setting value and the fourth setting value as a second setting value in the storage unit.

[0015] This configuration allows users to change the first and second setting values.

[0016] The memory unit of the above-mentioned energy storage system may further store priority information indicating which of the following should take priority: supplying the power stored in the energy storage device to the electric vehicle charging device, or supplying the power stored in the energy storage device to the distribution lines within the customer's premises in the event of an abnormality in the commercial power grid.

[0017] According to this configuration, when the sum of the third set value and the fourth set value exceeds 100%, it is possible to adjust the sum to be 100% or less by reducing at least one of the third set value and the fourth set value based on the priority information. That is, according to this configuration, it is possible to automatically correct an input error by the user.

[0018] The above power storage system may further include a third power conversion unit having an output terminal connected to the DC side input / output terminal and an input terminal connected to the solar power generation device.

Effects of the Invention

[0019] According to the present invention, it is possible to provide a power storage system with better economic efficiency than before.

Brief Description of the Drawings

[0020] [Figure 1] It is a diagram showing a power storage system according to a first embodiment of the present invention and its surroundings. [Figure 2] It is a diagram showing an operation example of the power storage system according to the first embodiment. [Figure 3] It is a diagram showing a power storage system according to a second embodiment of the present invention and its surroundings. [Figure 4] It is a diagram showing a first operation example of the power storage system according to the second embodiment. [Figure 5] It is a diagram showing a second operation example of the power storage system according to the second embodiment. [Figure 6] It is a diagram showing a third operation example of the power storage system according to the second embodiment. [Figure 7] It is a diagram showing a fourth operation example of the power storage system according to the second embodiment. [Figure 8] It is a diagram showing a fifth operation example of the power storage system according to the second embodiment.

Modes for Carrying Out the Invention

[0021] The first and second embodiments of the energy storage system according to the present invention will be described below with reference to the attached drawings. The dashed arrows in Figures 1 and 3 indicate some of the communications performed by the energy storage system according to the present invention.

[0022] [First Embodiment] Figure 1 shows a first embodiment of the present invention, a power storage system 1A. The power storage system 1A is used in conjunction with a customer's internal distribution line 20 for supplying AC power supplied from the commercial power grid G ​​to customer loads L, L..., a power storage device 10 consisting of a secondary battery with a capacity of approximately 5 to 15 kWh, a solar power generation device (panel) 11, and an electric vehicle charging device 12 for charging electric vehicles (EVs). The system includes a bidirectional AC / DC converter 2, a bidirectional DC / DC converter 3, a DC / DC converter 4, a control unit 5, and a memory unit 6A. Note that electric vehicles (EVs) include not only electric vehicles (EVs) but also plug-in hybrid electric vehicles (PHEVs). The electric vehicle charging device 12 is also called a V2H (Vehicle to Home) device and can also discharge electric vehicles (EVs).

[0023] The bidirectional AC / DC converter 2 corresponds to the "first bidirectional power conversion unit" of the present invention. The bidirectional AC / DC converter 2 has an AC-side input / output terminal connected to the customer's internal power distribution line 20 and a DC-side input / output terminal connected to the electric vehicle charging device 12. Under the control of the control unit 5, the bidirectional AC / DC converter 2 can convert AC power input to the AC-side input / output terminal into predetermined DC power and output it from the DC-side input / output terminal, or convert DC power input to the DC-side input / output terminal into predetermined AC power and output it from the AC-side input / output terminal.

[0024] The bidirectional DC / DC converter 3 corresponds to the "second bidirectional power conversion unit" of the present invention. The bidirectional DC / DC converter 3 has a first input / output terminal connected to the DC side input / output terminal of the bidirectional AC / DC converter 2, and a second input / output terminal connected to the energy storage device 10. Under the control of the control unit 5, the bidirectional DC / DC converter 3 can convert the DC power input to the first input / output terminal into a predetermined DC power and output it from the second input / output terminal, or convert the DC power input to the second input / output terminal into a predetermined DC power and output it from the first input / output terminal. In other words, the bidirectional DC / DC converter 3 can charge and discharge the energy storage device 10.

[0025] The DC / DC converter 4 corresponds to the "third power conversion unit" of the present invention. The DC / DC converter 4 has an output terminal connected to the DC-side input / output terminal of the bidirectional AC / DC converter 2 and an input terminal connected to the photovoltaic power generation device 11. Under the control of the control unit 5, the DC / DC converter 4 can convert the DC power (generated power) input to the input terminal into a predetermined DC power and output it from the output terminal.

[0026] The control unit 5 is composed of a microcomputer and the like. Based on the information stored in the memory unit 6A and the information obtained from the energy storage device 10, the control unit 5 can control at least the bidirectional AC / DC converter 2 and the bidirectional DC / DC converter 3. More specifically, the control unit 5 can control at least two converters 2 and 3 based on the first set value S1 and the second set value S2 stored in the memory unit 6A and the remaining amount (%) obtained from the energy storage device 10.

[0027] The memory unit 6A stores various setting values, including the first setting value S1 and the second setting value S2. In this embodiment, the first setting value S1 and the second setting value S2 are stored in the memory unit 6A at the time of factory shipment or when the energy storage system 10A is installed.

[0028] The first setting value S1 is a setting value related to the remaining capacity (%) of the energy storage device 10. For example, if you want to always keep 30% of the power in the energy storage device 10 in preparation for a power outage in the commercial power grid G, you should set the first setting value S1 to 30%. The first setting value S1 corresponds to the setting value for emergency safety settings (see Non-Patent Document 1).

[0029] The second setting value S2 is also a setting value related to the remaining capacity (%) of the energy storage device 10. For example, if it is estimated that 40% of the power will be needed to charge an electric vehicle (EV) returning from an outing, the second setting value S2 should be set to 70% (=30% + 40%).

[0030] Next, with reference to Figure 2, the control of the bidirectional AC / DC converter 2 and the bidirectional DC / DC converter 3 by the control unit 5 will be explained.

[0031] (i) When the commercial power grid G ​​is functioning normally and the remaining amount > the second setting value S2 (70%) In this case, the control unit 5 allows the power stored in the energy storage device 10 to be supplied to the customer's internal distribution line 20 (customer loads L, L...) via the bidirectional DC / DC converter 3 and the bidirectional AC / DC converter 2, and also allows the power stored in the energy storage device 10 to be supplied to the electric vehicle charging device 12 (electric vehicle EV) via the bidirectional DC / DC converter 3. As a result, when customer loads L, L... require power, power is supplied from the energy storage device 10 to customer loads L, L..., and when electric vehicle EV requires power, power is supplied from the energy storage device 10 to electric vehicle EV.

[0032] (ii) When the commercial power grid G ​​is functioning normally and the first set value (30%) < remaining amount ≤ second set value S2 (70%) In this case, the control unit 5 allows power supply from the energy storage device 10 to the electric vehicle (EV), while prohibiting power supply from the energy storage device 10 to the customer loads L,L.... This prevents a shortage of power for charging the electric vehicle (EV) due to power being supplied to the customer loads L,L.... In other words, 40% of the power expected to be needed to charge the electric vehicle (EV) can be left in the energy storage device 10.

[0033] (iii) When the commercial power grid G ​​is functioning normally and the remaining amount ≤ the first set value (30%) In this case, the control unit 5 prohibits the supply of power from the energy storage device 10 to customer loads L,L... and the supply of power from the energy storage device 10 to electric vehicles (EVs). This allows 30% of the power needed in the event of an abnormality (power outage) in the commercial power grid G ​​to be retained in the energy storage device 10.

[0034] (iv) If an abnormality occurs in the commercial power grid G In this case, the control unit 5 allows power supply from the energy storage device 10 to the customer loads L,L... regardless of the remaining charge. This allows the customer loads L,L... to continue operating. In this embodiment, power supply from the energy storage device 10 to the electric vehicle EV is allowed if the first set value (30%) < remaining charge, but this is optional. That is, if an abnormality occurs in the commercial power grid G, power supply from the energy storage device 10 to the electric vehicle EV may be prohibited regardless of the remaining charge.

[0035] Thus, in the energy storage system 10A according to this embodiment, power is supplied from the energy storage device 10 to the customer loads L,L... when the commercial power grid G ​​is functioning normally and the remaining amount > the second set value S2. For this reason, the energy storage system 10A is an economical system in which less power remains in the energy storage device 10 than in conventional systems.

[0036] Furthermore, in the energy storage system 10A according to this embodiment, when the remaining amount is less than or equal to the second set value S2, the supply of power from the energy storage device 10 to the customer load L,L... is prohibited, so that the power expected to be needed to charge electric vehicles (EVs) can be left in the energy storage device 10.

[0037] Furthermore, in the energy storage system 10A according to this embodiment, when the remaining amount is less than or equal to the first set value S2, the supply of power from the energy storage device 10 to the electric vehicle EV is also prohibited, so that power that will be needed when an abnormality (power outage) occurs in the commercial power grid G ​​can be left in the energy storage device 10.

[0038] [Second Example] Figure 3 shows a second embodiment of the present invention, a power storage system 1B. The power storage system 1B differs from the power storage system 1A in that it has a storage unit 6B instead of a storage unit 6A, and further includes a set value input unit 7, but is otherwise common to the power storage system 1A.

[0039] In addition to the first set value S1 and the second set value S2, the memory unit 6B also stores priority information indicating which of the following should be prioritized when an abnormality occurs in the commercial power grid G: power supply from the energy storage device 10 to customer loads L, L..., or power supply from the energy storage device 10 to electric vehicles (EVs).

[0040] The setting value input unit 7 is a remote control installed in a different location from the main enclosure of the energy storage system 1B, which houses the bidirectional AC / DC converter 2, the bidirectional DC / DC converter 3, and the DC / DC converter 4. The setting value input unit 7 accepts input of a third setting value S3 and a fourth setting value S4 from the user, and stores the first setting value S1 and the second setting value S2 obtained from these in the storage unit 6B. In other words, in this embodiment, the user can change the first setting value S1 and the second setting value S2.

[0041] The third setting value S3 is a setting value related to the remaining capacity (%) of the energy storage device 10. For example, if the user wants to always keep 30% of the power in the energy storage device 10 in preparation for a power outage in the commercial power grid G, the user should enter 30% as the third setting value S3.

[0042] The fourth setting value S4 is also a setting value related to the remaining charge (%) of the energy storage device 10. For example, if it is estimated that 40% of the power is needed to charge an electric vehicle (EV) returning from an outing, the user should enter 40% as the fourth setting value S4.

[0043] <Example of operation 1> If the input setting values ​​S3 and S4 are 30% and 40%, the setting value input unit 7 stores the third setting value S3 (30%) as the first setting value S1 in the storage unit 6B, and also stores the sum of the third setting value S3 (30%) and the fourth setting value S4 (40%) (70%) as the second setting value S2 in the storage unit 6B. In this case, the control unit 5 allows / prohibits the supply of power from the energy storage device 10 to customer loads L, L... and the supply of power from the energy storage device 10 to electric vehicles EV, as shown in Figure 4.

[0044] Note that the operation of energy storage system 1B shown in Figure 4 is the same as the operation of energy storage system 1A shown in Figure 2.

[0045] <Example of second action> If the input setting values ​​S3 and S4 are 40% and 0%, the setting value input unit 7 stores the third setting value S3 (40%) as the first setting value S1 in the storage unit 6B, and also stores the sum of the third setting value S3 (40%) and the fourth setting value S4 (0%) (40%) as the second setting value S2 in the storage unit 6B. In this case, the control unit 5 allows / prohibits the supply of power from the energy storage device 10 to customer loads L, L... and the supply of power from the energy storage device 10 to electric vehicles EV as shown in Figure 5. In other words, the control unit 5 performs the following control.

[0046] (i) When the commercial power grid G ​​is functioning normally and the remaining amount > the second setting value S2 (40%) In this case, the control unit 5 allows power supply from the energy storage device 10 to customer loads L,L... and power supply from the energy storage device 10 to electric vehicles (EVs).

[0047] (ii) When the commercial power grid G ​​is functioning normally and the remaining amount ≤ the first set value (40%) In this case, the control unit 5 prohibits the supply of power from the energy storage device 10 to the customer loads L,L··· and the supply of power from the energy storage device 10 to the electric vehicle EV.

[0048] (iii) If an abnormality occurs in the commercial power grid G In this case, the control unit 5 allows power supply from the energy storage device 10 to the customer loads L,L... regardless of the remaining capacity. Whether or not to allow power supply from the energy storage device 10 to the electric vehicle EV when the first set value (40%) < remaining capacity is optional.

[0049] <Example of the third action> If the input setting values ​​S3 and S4 are 40% and 80%, and the priority information indicates that priority should be given to supplying power from the energy storage device 10 to customer loads L, L... when an abnormality occurs in the commercial power grid G, the setting value input unit 7 stores the third setting value S3 (40%) as the first setting value S1 in the storage unit 6B, and stores the sum of the value obtained by subtracting 20% ​​from the fourth setting value S4 (80%) and the third setting value S3 (40%) (100%) as the second setting value S2 in the storage unit 6B. In this case, the control unit 5 allows / prohibits the supply of power from the energy storage device 10 to customer loads L, L... and the supply of power from the energy storage device 10 to electric vehicles EV as shown in Figure 6. In other words, the control unit 5 performs the following control.

[0050] (i) When the commercial power grid G ​​is functioning normally and the first set value (40%) < remaining amount ≤ second set value S2 (100%) In this case, the control unit 5 allows power supply from the energy storage device 10 to the electric vehicle EV, while prohibiting power supply from the energy storage device 10 to the customer loads L,L...

[0051] (ii) When the commercial power grid G ​​is functioning normally and the remaining amount ≤ the first set value (40%) In this case, the control unit 5 prohibits the supply of power from the energy storage device 10 to the customer loads L,L··· and the supply of power from the energy storage device 10 to the electric vehicle EV.

[0052] (iii) If an abnormality occurs in the commercial power grid G In this case, the control unit 5 allows power supply from the energy storage device 10 to the customer loads L,L... regardless of the remaining capacity. Whether or not to allow power supply from the energy storage device 10 to the electric vehicle EV when the first set value (40%) < remaining capacity is optional.

[0053] Thus, in this example, the third setting value S3 and the fourth setting value S4 are adjusted to sum to 100%. As a result, in this example, 40% of the power is left in preparation for a power outage in the commercial power grid G, while the power left for charging the electric vehicle (EV) returning from an outing is 60%, not 80%.

[0054] <Example of the fourth action> If the input setting values ​​S3 and S4 are 40% and 80%, and the priority information indicates that power supply from the energy storage device 10 to the electric vehicle EV should be prioritized, the setting value input unit 7 stores the value obtained by subtracting 20% ​​from the third setting value S3 (40%) as the first setting value S1 in the storage unit 6B, and also stores the sum of the value obtained by subtracting 20% ​​from the third setting value S3 (40%) and the fourth setting value S4 (80%) (100%) as the second setting value S2 in the storage unit 6B. In this case, the control unit 5 allows / prohibits power supply from the energy storage device 10 to customer loads L, L... and power supply from the energy storage device 10 to the electric vehicle EV as shown in Figure 7. In other words, the control unit 5 performs the following control.

[0055] (i) When the commercial power grid G ​​is functioning normally and the first set value (20%) < remaining amount ≤ second set value S2 (100%) In this case, the control unit 5 allows power supply from the energy storage device 10 to the electric vehicle EV, while prohibiting power supply from the energy storage device 10 to the customer loads L,L...

[0056] (ii) When the commercial power grid G ​​is functioning normally and the remaining amount ≤ the first set value (20%) In this case, the control unit 5 prohibits the supply of power from the energy storage device 10 to the customer loads L,L··· and the supply of power from the energy storage device 10 to the electric vehicle EV.

[0057] (iii) If an abnormality occurs in the commercial power grid G In this case, the control unit 5 allows power supply from the energy storage device 10 to the customer loads L,L... regardless of the remaining capacity. Whether or not to allow power supply from the energy storage device 10 to the electric vehicle EV when the first set value (20%) < remaining capacity is optional.

[0058] Thus, in this example, the third setting value S3 and the fourth setting value S4 are adjusted so that their sum equals 100%. As a result, in this example, 80% of the power is left for charging the electric vehicle (EV) returning from an outing, while the power left in preparation for a power outage in the commercial power grid G ​​is 20%, not 40%.

[0059] <Example of the fifth action> If the input setting values ​​S3 and S4 are 40% and 80%, and the priority information indicates that both power supplies should be given priority, the setting value input unit 7 stores in the storage unit 6B as the first setting value S1, which is the value obtained by subtracting 6.7% (≒40 × (1 - 100 / 120)) from the third setting value S3 (40%), and also stores in the storage unit 6B as the second setting value S2, which is the sum (100%) of the value obtained by subtracting 6.7% from the third setting value S3 (40%) and the value obtained by subtracting 13.3% (≒80 × (1 - 100 / 120)) from the fourth setting value S4 (80%). In this case, the control unit 5 allows / denies the supply of power from the energy storage device 10 to the customer loads L, L... and the supply of power from the energy storage device 10 to the electric vehicle EV as shown in Figure 8. In other words, the control unit 5 performs the following control.

[0060] (i) When the commercial power grid G ​​is functioning normally and the first set value (33.3%) < remaining amount ≤ second set value S2 (100%) In this case, the control unit 5 allows power supply from the energy storage device 10 to the electric vehicle EV, while prohibiting power supply from the energy storage device 10 to the customer loads L,L...

[0061] (ii) When the commercial power grid G ​​is functioning normally and the remaining amount ≤ the first set value (33.3%) In this case, the control unit 5 prohibits the supply of power from the energy storage device 10 to the customer loads L,L··· and the supply of power from the energy storage device 10 to the electric vehicle EV.

[0062] (iii) If an abnormality occurs in the commercial power grid G In this case, the control unit 5 allows power supply from the energy storage device 10 to the customer loads L,L... regardless of the remaining capacity. Whether or not to allow power supply from the energy storage device 10 to the electric vehicle EV when the first set value (33.3%) < remaining capacity is optional.

[0063] Thus, in this example, the third setting value S3 and the fourth setting value S4 are adjusted to sum to 100%. As a result, in this example, the amount of power remaining in preparation for a power outage in the commercial power grid G ​​is 33.3% instead of 40%, and the amount of power remaining for charging an electric vehicle (EV) returning from an outing is 66.7% instead of 80%.

[0064] [Differentiation] Although the first and second embodiments of the energy storage system according to the present invention have been described above, the configuration of the energy storage system according to the present invention is not limited to these.

[0065] For example, the energy storage system according to the present invention does not need to include a DC / DC converter 4, or a power generation device that uses renewable energy other than solar power may be connected to the DC / DC converter 4.

[0066] Furthermore, the setting value input unit 7 of the energy storage system according to the present invention may notify the user by some means if at least one of the third setting value S3 and the fourth setting value S4 is reduced.

[0067] Furthermore, the adjustment by the setting value input unit 7 of the energy storage system according to the present invention is not limited to adjusting the sum of the third setting value S3 and the fourth setting value S4 to 100%, but may be adjusted to, for example, 95%. In other words, if the sum of the third setting value S3 and the fourth setting value S4 exceeds 100%, the setting value input unit 7 should adjust it so that the sum becomes 100% or less.

[0068] Furthermore, the setting value input unit 7 of the energy storage system according to the present invention is not limited to a remote control operated by a user, but may also be, for example, a receiving device that receives the optimal third setting value S3 and fourth setting value S4 derived by AI from historical and forecast information regarding weather and the use of electric vehicles (EVs). [Explanation of Symbols]

[0069] 1A, 1B Energy Storage System 2. Bidirectional AC / DC converter (first bidirectional power conversion unit) 3. Bidirectional DC / DC converter (second bidirectional power conversion unit) 4. DC / DC converter (third power conversion section) 5. Control Unit 6A,6B Storage section 7. Input section for setting values 10 Energy storage device 11. Solar power generation equipment 12 Electric vehicle charging device 20 In-consumer distribution line EV electric vehicle G Commercial power system L Consumer load

Claims

1. A power storage system connected to a customer's internal distribution line for supplying AC power from the commercial power grid to the customer's load, and an electric vehicle charging device for charging electric vehicles, A first bidirectional power converter having AC-side input / output terminals connected to the customer's internal power distribution line and DC-side input / output terminals connected to the electric vehicle charging device, A second bidirectional power converter having a first input / output terminal connected to the DC side input / output terminal and a second input / output terminal connected to the energy storage device, A control unit that controls the first bidirectional power conversion unit and the second bidirectional power conversion unit, A storage unit that stores a first set value and a second set value (where the second set value ≥ the first set value) related to the remaining capacity of the energy storage device, Equipped with, The control unit (1) allows the power stored in the energy storage device to be supplied to the customer's internal distribution line via the second bidirectional power converter and the first bidirectional power converter, and the power stored in the energy storage device to be supplied to the electric vehicle charging device via the second bidirectional power converter, if the commercial power system is functioning normally and the remaining amount > the second setting value, and the power stored in the energy storage device to be supplied to the electric vehicle charging device via the second bidirectional power converter. (3) If the commercial power system is normal and the remaining amount is less than or equal to the first set value, then it is prohibited that the power stored in the power storage device be supplied to the customer's internal distribution line via the second bidirectional power conversion unit and the first bidirectional power conversion unit, and that the power stored in the power storage device be supplied to the electric vehicle charging device via the second bidirectional power conversion unit. A power storage system characterized by the following features.

2. The control unit (4) If an abnormality occurs in the commercial power system, regardless of the remaining amount, the power stored in the energy storage device is supplied to the customer's distribution line via the first bidirectional power converter and the second bidirectional power converter. The energy storage system according to claim 1.

3. The system further includes a setting value input unit that accepts input of a third setting value and a fourth setting value related to the remaining amount, The setting value input unit stores the third setting value as the first setting value in the storage unit, and stores the sum of the third setting value and the fourth setting value as the second setting value in the storage unit. The energy storage system according to claim 2, characterized in that it is as described above.

4. The memory unit further stores priority information indicating which of the following should be prioritized: supplying the power stored in the energy storage device to the electric vehicle charging device, or supplying the power stored in the energy storage device to the customer's distribution line in the event of an abnormality in the commercial power grid. If the sum of the third and fourth setting values ​​exceeds 100%, the setting value input unit adjusts the sum to 100% or less by subtracting at least one of the third and fourth setting values ​​based on the priority information, and then stores the first and second setting values ​​in the storage unit. The energy storage system according to claim 3.

5. The third power conversion unit further comprises an output terminal connected to the DC input / output terminal and an input terminal connected to a photovoltaic power generation device. The energy storage system according to any one of claims 1 to 4.

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