Power supply system

Abstract

To provide a power supply system capable of suppressing supply of power from a system power supply while suppressing variations of a discharge amount in a plurality of storage batteries.SOLUTION: In at least two or more interchange control storage batteries H40a (first storage batteries), a first mode for controlling charge / discharge based on an instruction of EMS 60 is set. In a load follow-up storage battery H40b (second storage battery) provided closer to a system power supply S side than the plurality of interchange control storage batteries H40a (first storage batteries), a second mode for controlling charge / discharge based on power circulating between the system power supply S and a load H10 is set. An EMS 60 can change a charge condition of the plurality of interchange control storage batteries H40a (first storage batteries) based on a prescribed condition including a power storage condition of the load follow-up storage battery H40b (second storage battery).SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a technique for a power supply system including a plurality of storage batteries and a plurality of power generation units. [Background technology]

[0002] Conventionally, a technology for a power supply system in which a plurality of storage batteries and a plurality of power generation units are provided between a system power supply and a load has been publicly known, as described in Patent Document 1, for example.

[0003] Patent Document 1 describes a power supply system in which a plurality of units each including a power storage device and a solar power generation device are connected to a power distribution line that connects a commercial power source and a load.

[0004] In the power supply system described in Patent Document 1, storage batteries and power generation units of multiple residential storage battery systems are provided on a power distribution line connecting a grid power source and a load, and storage batteries and power generation units of a shared storage battery system are provided on the grid power source (upstream) side of the storage batteries of the multiple residential storage battery systems. The storage batteries of the shared storage battery system perform load following operation. With this configuration, the shared storage battery system can adjust the excess or shortage of power of the multiple residential storage battery systems relative to the load, and it is possible to suppress the supply of power from the grid power source, for example.

[0005] However, since the storage batteries of the common storage battery system that performs load following operation depend on the operating conditions of the storage batteries of the multiple residential storage battery systems, there is a possibility that the batteries may be overcharged, which may result in an increase in the amount of discharge. For this reason, there is a possibility that the storage batteries of the multiple storage battery systems (the common storage battery system and the residential storage battery systems) may vary in the amount of discharge from one another. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2018-057150 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and the problem to be solved by this invention is to provide a power supply system that can suppress the supply of power from a system power source while suppressing the variation in the discharge amount among multiple storage batteries. [Means for solving the problem]

[0008] The problem to be solved by the present invention has been described above, and the means for solving this problem will now be described.

[0009] That is, in claim 1, there is provided a power supply system comprising: a plurality of storage batteries connected in series between a system power source and a load, capable of charging power and supplying power to the load by discharging the charged power; a plurality of power generation units connected to the storage batteries and distributing generated power between the system power source and the load; and a control unit capable of controlling charging and discharging of the plurality of storage batteries, wherein at least two or more first storage batteries among the plurality of storage batteries are set to a first mode in which charging and discharging are controlled based on an instruction from the control unit, and charging and discharging are controlled based on a result of comparing a total generated power obtained by adding up the amounts of power generated by the plurality of power generation units with the power consumption consumed by the load, and a second storage battery among the plurality of storage batteries, which is provided closer to the system power source than the plurality of first storage batteries, is set to a second mode in which charging and discharging are controlled based on the power circulating between the system power source and the load, and the control unit is capable of changing the charging conditions of the plurality of first storage batteries based on predetermined conditions including the storage status of the second storage batteries.

[0010] In claim 2, the charge state of the second storage battery includes the charge amount of the second storage battery.

[0011] In claim 3, the control unit can relax charging conditions for the plurality of first storage batteries when the amount of stored electricity in the second storage battery is equal to or greater than a predetermined first value.

[0012] In claim 4, the control unit is capable of lifting the relaxation of the charging conditions for the multiple first storage batteries when the amount of stored electricity in the second storage battery is smaller than a predetermined second value that is smaller than the first value.

[0013] In claim 5, the control unit is capable of strengthening the charging conditions for the plurality of first storage batteries when the amount of stored electricity in the second storage battery is equal to or less than a predetermined third value.

[0014] In claim 6, the specified conditions include the cost of electricity supplied from a grid power source, and when the cost is relatively high during a time period, the charging conditions for the multiple first storage batteries are not strengthened regardless of the amount of electricity stored in the second storage battery.

[0015] In claim 7, the control unit is capable of canceling the tightening of the charging conditions for the multiple first storage batteries when the amount of stored electricity in the second storage battery is greater than a predetermined fourth value that is greater than the third value. Effect of the Invention

[0016] The present invention has the following advantages.

[0017] In the present invention, it is possible to suppress the supply of power from the system power supply while suppressing the variation in the discharge amount among a plurality of storage batteries. [Brief description of the drawings]

[0018] [Figure 1] 1 is a block diagram showing a configuration of a power supply system according to an embodiment of the present invention; [Diagram 2] FIG. 4 is a block diagram showing an example of a power supply mode. [Diagram 3]1 is a block diagram showing an example of a power supply system in which a first mode and a second mode are set for a storage battery; [Figure 4] 4 is a flowchart showing a charge / discharge control process. [Diagram 5] 4 is a flowchart showing an interchange control process among the charge / discharge control processes. [Figure 6] 4 is a flowchart showing a pre-control process of the charge / discharge control process. [Figure 7] 7 is a flowchart showing a continuation of FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] A power supply system 1 according to an embodiment of the present invention will be described below with reference to FIG.

[0020] The power supply system 1 is applied to a residential block T having a plurality of detached houses (houses H) and various facilities. In this embodiment, the residential block T includes four houses H (a first house H1, a second house H2, a third house H3, and a fourth house H4) as the plurality of (detached) houses H. In the residential block T, an electricity retailer purchases electricity in bulk from an electric power company (a power grid S), and the purchased electricity is supplied (sold) to each house H as appropriate.

[0021] The power supply system 1 is a system for appropriately supplying (accommodating) power that an electricity retailer purchases in bulk from an electric power company to multiple residences H (a first residence H1, a second residence H2, a third residence H3, and a fourth residence H4).

[0022] In the power supply system 1, a plurality of power storage systems H20 are connected to a power path L (between the power system S and the load H10 of each house H) that supplies power from a power system S to a load H10 (such as an appropriate electrical appliance) of each house H. The power storage system H20 is owned by each of the plurality of houses H (a first house H1, a second house H2, a third house H3, and a fourth house H4). In the power supply system 1, the power storage system H20 of the first house H1, the power storage system H20 of the second house H2, the power storage system H20 of the third house H3, and the power storage system H20 of the fourth house H4 are connected in series with each other in that order from upstream to downstream on the power path L.

[0023] The power supply system 1 is configured to allow electric power stored in one residence to be shared among residences each having a power storage system H20. In this embodiment, the power supply system 1 includes a plurality of power storage systems H20 and an EMS 60.

[0024] The power storage system H20 stores power generated by utilizing sunlight and supplies the power to a load H10. The power storage system H20 includes a solar power generation unit H30, a storage battery H40, and a hybrid power conditioner H50.

[0025] The solar power generation unit H30 is a device that generates power by utilizing sunlight. The solar power generation unit H30 is composed of a solar panel or the like. The solar power generation unit H30 is connected to a storage battery H40 that is similarly provided in the same house H. The solar power generation unit H30 is installed in a sunny location, such as on the roof of the house H. The power generated by the solar power generation unit H30 can be charged into the corresponding storage battery H40 (similarly provided in the same house H).

[0026] The storage battery H40 appropriately charges and discharges power from the power grid S and power (generated power) from the solar power generation unit H30. The storage battery H40 is, for example, a lithium-ion battery. The storage battery H40 is connected to the solar power generation unit H30 by a predetermined power distribution line via a hybrid power conditioner H50 (described later) or the like.

[0027] In this embodiment, the storage battery H40 has a maximum discharge power of 2000 W. The maximum discharge power refers to the maximum amount of power that the storage battery H40 can discharge per unit time. The maximum charging power of the storage battery H40 (the maximum amount of power that the storage battery H40 can charge per unit time) is also 2000 W.

[0028] In addition, in preparation for a power outage, the storage battery H40 is set so that when the amount of stored electricity reaches a dischargeable amount (a predetermined value relative to the capacity, in this embodiment, 30% or less), it will not discharge even if it is in a dischargeable state.

[0029] The storage battery H40 has a plurality of modes for charging and discharging power. The plurality of modes include a first mode (charge and discharge control mode) and a second mode (eco mode). The first mode and the second mode are set (switched) by the EMS 60 described later.

[0030] When the first mode is executed, the storage battery H40 is in a state in which it can execute an operation instructed by the EMS 60, which will be described later. Specifically, when a discharge instruction is given, the storage battery H40 is in a state in which it can discharge, and is in a discharging state or a standby state depending on the power consumption of the load H10. Also, when a standby instruction is given, the storage battery H40 is in a standby state in which it does not perform charging or discharging.

[0031] Furthermore, when a charging instruction is issued, the storage battery H40 operates to charge with 2000 W of power. That is, when a charging instruction is issued, the storage battery H40 first operates to charge with the power generated by the solar power generation unit H30 of the same power storage system H20, and if the generated power alone is insufficient to reach 2000 W, it operates to charge with the power circulating through the power path L (including the power supplied from the system power source S).

[0032] Furthermore, when the second mode is executed, the storage battery H40 controls charging and discharging through a load following operation based on the power flowing through the power path L. In this embodiment, the storage battery H40 charges and discharges an adjusted amount of power according to the detection result of a predetermined sensor (not shown) that detects the power flowing through the power path L. The predetermined sensor is configured to be able to detect the power flowing through a connection point P, which will be described later, on the power path L.

[0033] In this way, when the second mode is executed, the storage battery H40 discharges power according to the detection result of the predetermined sensor when the power generated by the solar power generation unit H30 is insufficient to cover the power consumed by the load H10. The storage battery H40 also charges with surplus power (surplus power with respect to the power consumed by the load H10) among the power generated by the solar power generation unit H30.

[0034] In addition, even in the first mode, when a discharge command is issued, the storage battery H40 performs load following operation. When performing load following operation, the storage battery H40 discharges an amount of power adjusted according to the detection result of the predetermined sensor.

[0035] The hybrid power conditioner H50 is a device that appropriately converts electric power (hybrid power conditioner). The hybrid power conditioner H50 is configured to be capable of outputting electric power generated by the solar power generation unit H30 and electric power discharged from the storage battery H40 to the load H10, and to be capable of outputting electric power generated by the solar power generation unit H30 and electric power from the system power source S to the storage battery H40. The hybrid power conditioner H50 is also connected to a connection point P of the electric power path L via a predetermined distribution line.

[0036] The hybrid power conditioner H50 is capable of controlling the operation of the storage battery H40. In this embodiment, the setting of the mode (first mode, second mode, etc.) of the storage battery H40 by the EMS 60 described later is performed via the hybrid power conditioner H50.

[0037] The EMS 60 is an energy management system that manages the operation of the power supply system 1. The EMS 60 includes a storage unit such as a RAM or a ROM, an arithmetic processing unit such as a CPU, an input / output unit such as an I / O, and the like. The EMS 60 can perform predetermined arithmetic processing, storage processing, and the like. Various information, programs, and the like used when controlling the operation of the power supply system 1 are stored in advance in the EMS 60.

[0038] Specifically, the EMS 60 is electrically connected (either wired or wirelessly) to the hybrid power conditioner H50 of each residence H. The EMS 60 can acquire various information such as the operating status of the storage battery H40 (e.g., the set mode, whether discharging is occurring, etc.), the amount of stored power, the amount of discharged power, and the amount of chargeable power. The EMS 60 can also acquire various information such as the operating status of the solar power generation unit H30 and the amount of generated power via the hybrid power conditioner H50. The EMS 60 may acquire the information directly from the solar power generation unit H30, rather than via the hybrid power conditioner H50.

[0039] Furthermore, the EMS 60 can determine the mode of the storage battery H40 in each residence H based on the acquired information, etc., and can cause the storage battery H40 to execute the determined mode. Furthermore, when the EMS 60 causes the storage battery H40 to execute the first mode, the EMS 60 can issue a discharge instruction, a charge instruction, or a standby instruction based on the acquired information, etc.

[0040] In addition, the EMS 60 can issue discharge instructions, charge instructions, and standby instructions based on the total power generated by all solar power generation units H30 shown in A in Figure 1 (hereinafter referred to as the "total PV power generation") and the total power consumption of all loads H10 shown in B (hereinafter referred to as the "total residential load").

[0041] Furthermore, the EMS 60 can determine a discharge priority order (to be described later) for the storage battery H40 based on the acquired information, etc. The discharge priority order is used mainly when the first mode is executed, and is a priority order for discharge among the storage battery H40 in which the first mode is executed.

[0042] In setting the discharge priority order, the battery H40 in which the first mode is executed may be determined to have a higher priority if the amount of discharge on the previous day is smaller. The discharge priority order is not limited to being determined based on the amount of discharge on the previous day, and may be determined based on various information. For example, the battery H40 in which the first mode is executed may be determined to have a higher priority if the accumulated amount of discharged power is smaller. The accumulated amount of discharged power is a total accumulated value for a predetermined period (for example, from the time when each battery H40 is installed until 23:00 on the previous day). The predetermined period is not limited to this, and may be any period. The discharge priority order may be determined to have a higher priority if the amount of stored power is larger among the batteries H40 in which the first mode is executed.

[0043] Furthermore, the EMS 60 can determine a charging priority order (to be described later) for the storage battery H40 based on the acquired information, etc. The charging priority order is used mainly when the first mode is executed, and is the charging priority order for the storage battery H40 in which the first mode is executed.

[0044] In setting the charging priority order, it can be determined that the lower the amount of stored electricity, the higher the priority order of the storage battery H40 in which the first mode is executed. Note that the charging priority order is not limited to being determined based on the amount of stored electricity, and can be determined based on various information.

[0045] An example of a power supply mode in the power supply system 1 will be described below with reference to FIG.

[0046] 2, the second mode is set for the storage batteries H40 of all the houses H (first house H1, second house H2, third house H3, and fourth house H4) indicated by the symbol C. That is, all the storage batteries H40 are in load following operation. Also, the storage battery H40 of the first house H1 is fully charged.

[0047] In this manner, when the second mode is set for all the storage batteries H40, the power output from the storage system H20 located downstream rather than upstream (the power generated by the solar power generation unit H30 and the discharged power of the storage battery H40) is given priority for supplying to the load H10 the power required to cover the power consumption of the load H10.

[0048] 2, the power generated by the solar power generation unit H30 of the fourth residence H4 and the power discharged by the storage battery H40 are all supplied to the load H10. Since the power from the fourth residence H4 alone is insufficient, the power generated by the solar power generation unit H30 of the third residence H3 is supplied to the load H10 to make up for the shortfall. This covers the power consumption of the load H10.

[0049] In addition, a portion of the power generated by the photovoltaic power generation unit H30 of the third residence H3 is surplus to the load H10, and is therefore charged to the storage battery H40 of the third residence H3. In addition, a portion of the power generated by the photovoltaic power generation unit H30 of the second residence H2 is surplus to the load H10, and is therefore charged to the storage battery H40 of the second residence H2, and the remainder is reverse-flowed to the power grid S. In addition, the power generated by the photovoltaic power generation unit H30 of the first residence H1 is surplus to the load H10, and is therefore entirely reverse-flowed to the power grid S.

[0050] Thus, by using the power supply mode described above, in the power supply system 1, power from the solar power generation unit H30 and the storage battery H40 of each residence H can be supplied (interchanged) not only to the load H10 of the residence H itself, but also to the load H10 of other residences H.

[0051] In addition, in this embodiment, when the storage battery H40 of each residence H is charged using power supplied from the system power source S, the resident of each residence H purchases power from the power retailer. In this way, the resident of each residence H can purchase and use power at a price relatively cheaper than the general price. Note that in this embodiment, the power supplied from the system power source S may be referred to as power purchased from the system power source S.

[0052] The electricity generated by the solar power generation unit H30 of each house H and the discharged electricity of the storage battery H40 are purchased by the electricity retailer from the residents of each house H. The electricity flowed back to the grid power source S (surplus electricity generated by the solar power generation unit H30) is purchased by the electric power company from the electricity retailer.

[0053] When the second mode is set for all the storage batteries H40, the power output from the storage system H20 located downstream rather than upstream (the power generated by the solar power generation unit H30 and the power discharged from the storage battery H40) is supplied to the load H10 with priority as the power to cover the power consumption of the load H10, so that the ease (or difficulty) of discharging each storage battery H40 differs from one another.

[0054] Here, if the ease (difficulty) of discharging the storage batteries H40 differs from one another, a bias is likely to occur in the charge / discharge amounts of the storage batteries H40. If a bias occurs in the charge / discharge amounts of the storage batteries H40 in this way, the degree of deterioration of the storage batteries H40 will differ, and the amount of electricity sold from each storage battery H40 (each residence H) to an electricity retailer will differ, which is undesirable.

[0055] In addition, in the power supply system 1, it may be desirable to supply the generated power of the solar power generation unit H30 to the load H10 as much as possible for self-consumption (improving the power self-sufficiency rate and the PV self-consumption rate). The self-consumption includes not only directly supplying the generated power of the solar power generation unit H30 to the load H10, but also discharging the generated power of the solar power generation unit H30 that has been charged in the storage battery H40 and indirectly supplying it to the load H10. From the viewpoint of improving the power self-sufficiency rate and the PV self-consumption rate, it is desirable to preferentially use the generated power of the solar power generation unit H30 over the power consumption of the load H10. It is also desirable to charge the generated power of the solar power generation unit H30 to the storage battery H40 without allowing it to flow backward to the system power source S.

[0056] 2, when all the storage batteries H40 discharge by load following operation, for example, the power output from the power storage systems H20 of the fourth house H4 and the third house H3 covers the power consumption of the load H10, and the power generated by the photovoltaic power generation units H30 of the second house H2 and the first house H1 flows back to the grid power supply. When all the storage batteries H40 discharge by load following operation in this way, it may be difficult to improve the power self-sufficiency rate and the PV self-consumption rate.

[0057] Therefore, in the power supply system 1, the EMS 60 can execute a process (hereinafter referred to as a "charge / discharge control process") to prevent the occurrence of the above-mentioned imbalance in the charge / discharge amount and to improve the power self-sufficiency rate and the PV self-consumption rate.

[0058] The charge / discharge control process executed by the EMS 60 will be described below with reference to the flowcharts of FIGS.

[0059] In the charge / discharge control process, the second mode is not set for the storage batteries H40 of all the houses H, but the second mode is set for the storage battery H40 of the first house H1 provided at the most upstream, and the first mode is set for the storage batteries H40 of the remaining houses H. That is, as shown in FIG. 3, the first mode is set for the storage batteries H40 of the houses H (second house H2, third house H3, fourth house H4) indicated by D, and the second mode is set for the storage battery H40 of the house H (first house H1) indicated by E. Hereinafter, the storage batteries H40 of the houses H (second house H2, third house H3, fourth house H4) indicated by D may be referred to as the "interchange control storage battery H40a," and the storage battery H40 of the house H (first house H1) indicated by E may be referred to as the "load following storage battery H40b."

[0060] The charge / discharge control process is repeatedly executed at predetermined time intervals (for example, every minute) by the EMS 60. As shown in Fig. 4, in the charge / discharge control process, first, a preliminary control process is executed in step S1, and then, an interchange control process is executed in step S2.

[0061] First, the interchange control process executed by the EMS 60 will be described below with reference to the flowchart of FIG.

[0062] In step S10, the EMS 60 determines whether the total residential load is equal to or greater than the total PV power generation. If the EMS 60 determines that the total residential load is equal to or greater than the total PV power generation (step S10: YES), the EMS 60 proceeds to processing in step S11. On the other hand, if the EMS 60 determines that the total residential load is smaller than the total PV power generation (step S10: NO), the EMS 60 proceeds to processing in step S18.

[0063] Here, when the total residential load is equal to or greater than the total PV power generation, the total PV power generation is insufficient for the total residential load, so the discharged power of the interchange control battery H40a is given priority to be supplied to make up for the shortfall.

[0064] In step S11, the EMS 60 calculates the discharge power required from the interchange control battery H40a (hereinafter referred to as "discharge required power") to supply the shortfall with respect to the total residential load from the interchange control battery H40a. The discharge required power is calculated by subtracting the total PV power generation power from the total residential load. The EMS 60 then proceeds to the process of step S12.

[0065] In step S12, the EMS 60 calculates the number of interchange control batteries H40a to be discharged according to the required discharge power among all the interchange control batteries H40a (hereinafter referred to as the "required discharge number"). The required discharge number is calculated by dividing the required discharge power by the maximum discharge power of the battery H40 (2000 W in this embodiment). The EMS 60 then proceeds to the process of step S13.

[0066] Here, when the result of dividing the discharge required power by the maximum discharge power of the storage battery H40 includes a decimal, the number of units required to be discharged can be calculated by rounding up or down the decimal point. When the result is calculated by rounding up the decimal point, the total discharge power of the interchange control storage battery H40a in the number of units required to be discharged becomes larger than the discharge required power. When the above number of interchange control storage batteries H40a are discharged, the supply of power from the system power source S and the load following storage battery H40b can be suppressed.

[0067] Furthermore, when calculation is performed by rounding down the decimal point, the total discharge power of the interchange control batteries H40a in the number of units required to be discharged is smaller than the discharge request power. When the above number of interchange control batteries H40a are discharged, the discharge power of the interchange control batteries H40a alone is insufficient for the discharge request power, so that a supply of power from the system power source S and the load following battery H40b is required, but the supply of power from these batteries can be minimized. After calculating the number of units required to be discharged, the EMS 60 proceeds to the process of step S13.

[0068] In step S13, the EMS 60 calculates the number of interchange control batteries H40a that can be discharged (hereinafter referred to as the "dischargeable number") among all the interchange control batteries H40a. The dischargeable number is calculated as the total number of interchange control batteries H40a whose stored amount is equal to or greater than the dischargeable amount (in this embodiment, 30% or more) among all the interchange control batteries H40a. The EMS 60 then proceeds to the process of step S14.

[0069] In step S14, EMS 60 determines whether the number of units that can be discharged is equal to or greater than the number of units that can be discharged. If EMS 60 determines that the number of units that can be discharged is equal to or greater than the number of units that can be discharged (step S14: YES), it proceeds to step S15. On the other hand, if EMS 60 determines that the number of units that can be discharged is less than the number of units that can be discharged (step S14: NO), it proceeds to step S16.

[0070] In step S15, the EMS 60 calculates the number of interchange control batteries H40a for which a discharge instruction is to be given (hereinafter referred to as the "discharge instruction number"). In step S15, the discharge request number is set as the discharge instruction number. The EMS 60 then proceeds to the process of step S17.

[0071] In step S16, the EMS 60 calculates the number of units to be discharged. In step S16, the number of units capable of being discharged is set as the number of units to be discharged. The EMS 60 then proceeds to the process of step S17.

[0072] In step S17, the EMS 60 issues a discharge instruction to the interchange control batteries H40a in the number of batteries for which a discharge instruction has been issued, in descending order of discharge priority. The EMS 60 also issues a standby instruction to the interchange control batteries H40a for which a discharge instruction has not been issued. After the process of step S17, the EMS 60 temporarily ends the interchange control process.

[0073] Here, as described above, when the total residential load is smaller than the total PV power generation power (step S10: NO), the total PV power generation power is surplus to the total residential load, and the surplus is preferentially charged to the interchange control battery H40a.

[0074] In step S18 following step S10, the EMS 60 calculates the amount of power surplus to the total residential load out of the total PV power generation (hereinafter referred to as "total surplus power") in order to charge the surplus to the interchange control storage battery H40a. The total surplus power is calculated by subtracting the total residential load from the total PV power generation. The EMS 60 then proceeds to processing in step S19.

[0075] In step S19, the EMS 60 calculates the number of interchange control batteries H40a to be charged according to the total surplus power among all the interchange control batteries H40a (hereinafter referred to as the "number of batteries requested to be charged"). The number of batteries requested to be charged is calculated by dividing the total surplus power by the maximum charging power of the batteries H40 (2000 W in this embodiment).

[0076] If the result of dividing the total surplus power by the maximum charging power (2000 W) of the storage battery H40 includes a decimal, whether the value rounded up or down to the nearest integer should be used as the number of units requesting charging is determined based on whether the surplus exceeds a predetermined charging condition value (whether the charging condition is satisfied or not). The charging condition value will be described later. After calculating the number of units requesting charging, the EMS 60 proceeds to the process of step S20.

[0077] In step S20, the EMS 60 calculates the number of interchange control batteries H40a that can be charged (hereinafter referred to as the "chargeable number") among all interchange control batteries H40a. The chargeable number is calculated as the total number of interchange control batteries H40a whose stored electricity amount is less than a predetermined value (in this embodiment, less than 100%) relative to the capacity among all interchange control batteries H40a. The EMS 60 then proceeds to the process of step S21.

[0078] In step S21, the EMS 60 determines whether the number of chargeable vehicles is equal to or greater than the number of requested charging vehicles. If the EMS 60 determines that the number of chargeable vehicles is equal to or greater than the number of requested charging vehicles (step S21: YES), the EMS 60 proceeds to processing in step S22. On the other hand, if the EMS 60 determines that the number of chargeable vehicles is less than the number of requested charging vehicles (step S21: NO), the EMS 60 proceeds to processing in step S23.

[0079] In step S22, the EMS 60 calculates the number of interchange control storage batteries H40a for which charging instructions are to be given (hereinafter referred to as the "number of instructed charging units"). In step S22, the number of units requesting charging is set as the instructed charging number. The EMS 60 then proceeds to the process of step S24.

[0080] In step S23, the EMS 60 calculates the number of vehicles to be instructed to be charged. In step S22, the EMS 60 sets the number of vehicles that can be charged as the number of vehicles to be instructed to be charged. The EMS 60 then proceeds to the process of step S24.

[0081] In step S24, the EMS 60 issues a charge instruction to the interchange control storage batteries H40a for the number of batteries for which charging is instructed, in descending order of charging priority. The EMS 60 also issues a standby instruction to the interchange control storage batteries H40a for which charging instructions are not issued. After the process of step S24, the EMS 60 temporarily ends the interchange control process.

[0082] In this way, by executing the interchange control process, the power generated by the photovoltaic power generation unit H30 of each house H can be supplied to the load H10 in priority to the power purchased from the power grid S and the discharged power of the storage battery H40, substantially regardless of the arrangement order of the power storage systems H20 in the power path L. In this way, the power self-sufficiency rate and the PV self-consumption rate can be improved.

[0083] In addition, the storage battery H40 provided at the most upstream side is set to the second mode (load following storage battery H40b), and all the storage batteries H40 downstream of it are set to the first mode (interchange control storage battery H40a). This allows the load following storage battery H40b to respond to sudden changes in the total residential load and the total PV power generation, and suppresses the purchase of power from the grid power source S.

[0084] Specifically, if there is no load following battery H40b (i.e., if the batteries H40 of all the storage systems H20 are in the first mode), depending on the execution interval of the interchange control process by the EMS 60, if the total residential load suddenly increases or the total PV power generation suddenly decreases, the power output from each storage system H20 may not be enough to cover the power consumption of the load H10. In such a case, power purchase from the grid power source S will occur.

[0085] However, since the storage battery H40 provided at the most upstream is in the second mode (load following storage battery H40b), when the power consumption of the load H10 cannot be covered due to a sudden change in the total residential load or the total PV power generation, the discharged power of the load following storage battery H40b can be supplied to the load H10 according to the power flowing through the power path L. In this way, the load following storage battery H40b can quickly respond to the change in power consumption of the load H10 that cannot be handled by the interchange control storage battery H40a. In other words, the purchase of power from the system power source S can be suppressed.

[0086] Furthermore, by issuing a discharge command for the requested discharge power starting from the interchange control battery H40a with the highest discharge priority, it is possible to suppress bias in the discharge amount of the interchange control battery H40a of each residence H. That is, as in this embodiment, by determining that the interchange control battery H40a with the smaller discharge amount on the previous day has a higher priority, it is possible to equalize the discharge amounts of the interchange control batteries H40a.

[0087] Furthermore, by issuing a charge instruction for the requested charge amount starting from the interchange control battery H40a with a higher charge priority, it is possible to suppress bias in the stored amount of the interchange control battery H40a of each residence H. That is, as in this embodiment, by determining that the interchange control battery H40a with a smaller stored amount has a higher priority, it is possible to equalize the stored amounts of the interchange control batteries H40a.

[0088] In this embodiment, when a charging instruction is issued, the storage battery H40 operates to charge 2000 W of power even if the surplus power is less than 2000 W, which may result in power being purchased from the grid power source S. Therefore, if the number of storage batteries H40 requesting charging (see step S19) is reduced so as to prevent power purchases from occurring, the surplus power may flow upstream, resulting in more opportunities for charging the load following storage battery H40b than the interchange control storage battery H40a.

[0089] In this way, when the load following battery H40b has more opportunities to be charged, the amount of electricity stored in the load following battery H40b increases, and the amount of electricity discharged from the load following battery H40b increases. In such a case, the amount of electricity discharged from the load following battery H40b becomes greater than the amount of electricity discharged from the interchange control battery H40a, which may cause variations in the amount of electricity discharged among all the batteries H40.

[0090] When the discharge amount of the load following battery H40b increases, the storage amount of the load following battery H40b often reaches 100%. When the storage amount reaches 100%, the load following battery H40b cannot be charged any more, and the power flowing back to the grid power source S may increase. When the power flowing back increases, the power self-sufficiency rate and the PV self-consumption rate may decrease.

[0091] Therefore, in the power supply system 1 according to this embodiment, a process (pre-control process) is executed to suppress the purchase of power from the system power source S while suppressing the occurrence of variations in the discharge amounts in the multiple (all) storage batteries H40.

[0092] The pre-control process executed by the EMS 60 will be described below with reference to the flowcharts of FIGS.

[0093] In the advance control process, a predetermined charging condition value used in the process of calculating the number of vehicles requesting charging (step S19) in the interchange control process (S2) as described above is set. First, the setting of the charging condition value will be described below.

[0094] Here, the charging condition value is a reference value for changing the charging condition (whether to encourage or not encourage charging) of the interchange control storage battery H40a. Specifically, the charging condition value is a reference value for determining whether to adopt a value obtained by rounding up or rounding down the decimal point as the number of units requesting charging when a result of dividing the total surplus power by the maximum charging power (2000 W) of the storage battery H40 includes a decimal in the process of calculating the number of units requesting charging (step S19). The charging condition value is stored in the EMS 60 and managed by the EMS 60. The charging condition value is configured to be changeable (to three levels including an initial value) by the EMS 60.

[0095] In this embodiment, the initial value of the charging condition value is set to 1500 W. Thus, for example, when the charging condition value is the initial value and the surplus is 1500 W or more, a value obtained by rounding up the decimal point is adopted as the number of units requested to be charged. Also, for example, when the charging condition value is the initial value and the surplus is smaller than 1500 W, a value obtained by rounding down the decimal point is adopted as the number of units requested to be charged.

[0096] In this embodiment, the charging condition value can be reduced from an initial value of 1500 W to 1000 W. Thus, for example, when the charging condition value is reduced, if the surplus is 1000 W or more, a value obtained by rounding up the decimal point is adopted as the number of units requested to be charged. Also, for example, when the charging condition value is reduced, if the surplus is less than 1000 W, a value obtained by rounding down the decimal point is adopted as the number of units requested to be charged.

[0097] In this way, when the charging condition value is lowered from the initial value, the number of units that request discharging is more likely to increase than when the initial value is used. In other words, the number of interchange control batteries H40a for which a charging instruction is issued is more likely to increase, and conversely, charging becomes more difficult for the load following batteries H40b. Note that, hereinafter, lowering the charging condition value from the initial value may be referred to as easing the charging condition for the interchange control batteries H40a.

[0098] In this embodiment, the charging condition value can be increased from an initial value of 1500 W to 1800 W. Thus, for example, when the charging condition value is increased, if the surplus is 1800 W or more, a value obtained by rounding up the decimal point is adopted as the number of units requested to be charged. Also, for example, when the charging condition value is increased, if the surplus is less than 1800 W, a value obtained by rounding down the decimal point is adopted as the number of units requested to be charged.

[0099] In this way, when the charging condition value is raised from the initial value, the number of units requesting discharge is less likely to increase compared to when the charging condition value is the initial value. In other words, since the number of interchange control batteries H40a for which a charging instruction is issued is less likely to increase, conversely, charging becomes easier for the load following batteries H40b. Note that hereinafter, raising the charging condition value from the initial value may be referred to as strengthening the charging condition for the interchange control batteries H40a.

[0100] As shown in the flowchart of FIG. 6, when the pre-control process is started, the EMS 60 executes the process of step S50.

[0101] In step S50, the EMS 60 determines whether or not the charge relaxation is ON. Here, the charge relaxation being ON means that the charging condition of the interchange control storage battery H40a is relaxed (i.e., the charging condition value is lowered from the initial value of 1500 W to 1000 W).

[0102] Thus, when the EMS 60 determines that the charge relaxation is ON (step S50: YES), the EMS 60 proceeds to the process of step S51. On the other hand, when the EMS 60 determines that the charge relaxation is not ON (step S50: NO), the EMS 60 proceeds to the process of step S55.

[0103] In step S51, the EMS 60 determines whether the amount of stored power in the load following battery H40b is less than a set value for mitigation OFF (second value). Here, the set value for mitigation OFF is a reference value for whether or not to turn off charge mitigation when charge mitigation is ON. In this embodiment, a value equivalent to 90% of the capacity of the storage battery H40 is adopted as the set value for mitigation OFF (second value). When the EMS 60 determines that the amount of stored power in the load following battery H40b is less than the set value for mitigation OFF (step S51: YES), the EMS 60 proceeds to processing in step S52. On the other hand, when the EMS 60 determines that the amount of stored power in the load following battery H40b is not less than the set value for mitigation OFF (step S51: NO), the EMS 60 proceeds to processing in step S60.

[0104] In step S52, the EMS 60 cancels the relaxation of the charging condition for the interchange control storage battery H40a. That is, the EMS 60 raises (returns) the charging condition value from 1000 W to the initial value of 1500 W. The EMS 60 then proceeds to the process of step S53.

[0105] In step S53, the EMS 60 turns off the charge relaxation. Here, the charge relaxation being OFF means that the charging condition of the interchange control storage battery H40a is not relaxed (the charging condition value is the initial value (1500 W) or 1800 W). The EMS 60 then proceeds to the process of step S60.

[0106] In step S55 following step S50, the EMS 60 determines whether or not the charging enhancement is ON. Here, the charging enhancement being ON means that the charging condition of the interchange control storage battery H40a has been enhanced (i.e., the charging condition value has been increased from the initial value of 1500 W to 1800 W).

[0107] Thus, when the EMS 60 determines that the charging enhancement is ON (step S55: YES), the EMS 60 proceeds to the process of step S56. On the other hand, when the EMS 60 determines that the charging enhancement is not ON (step S55: NO), the EMS 60 proceeds to the process of step S60.

[0108] In step S56, the EMS 60 determines whether the amount of stored power in the load following battery H40b is greater than a set value for enhanced OFF (fourth value). Here, the set value for enhanced OFF is a reference value for determining whether or not to turn off the enhanced charging when the enhanced charging is ON. In this embodiment, a value equivalent to 40% of the capacity of the battery H40 is adopted as the set value for enhanced OFF (fourth value). When the EMS 60 determines that the amount of stored power in the load following battery H40b is greater than the set value for enhanced OFF (step S56: YES), the EMS 60 proceeds to processing in step S57. On the other hand, when the EMS 60 determines that the amount of stored power in the load following battery H40b is not greater than the set value for enhanced OFF (step S56: NO), the EMS 60 proceeds to processing in step S60.

[0109] In step S57, the EMS 60 cancels the strengthening of the charging condition for the interchange control storage battery H40a. That is, the EMS 60 lowers (returns) the charging condition value from 1800 W to the initial value of 1500 W. The EMS 60 then proceeds to the process of step S58.

[0110] In step S58, the EMS 60 turns off the charging enhancement. Here, the charging enhancement being OFF means that the charging condition of the interchange control storage battery H40a has not been enhanced (the charging condition value is the initial value (1500 W) or 1000 W). The EMS 60 then proceeds to the process of step S60.

[0111] In step S60, the EMS 60 determines whether the amount of stored power in the load following battery H40b is less than a set value for mitigation ON (first value). Here, the set value for mitigation ON is a reference value for whether or not to turn on charge mitigation when charge mitigation is OFF. In this embodiment, a value equivalent to 95% of the capacity of the storage battery H40 is adopted as the set value for mitigation ON (first value). When the EMS 60 determines that the amount of stored power in the load following battery H40b is equal to or greater than the set value for mitigation ON (step S60: YES), the EMS 60 proceeds to processing in step S61. On the other hand, when the EMS 60 determines that the amount of stored power in the load following battery H40b is not equal to or greater than the set value for mitigation ON (step S60: NO), the EMS 60 proceeds to processing in step S61.

[0112] In step S61, the EMS 60 relaxes the charging condition of the interchange control storage battery H40a. That is, the EMS 60 lowers the charging condition value from 1800 W or the initial value of 1500 W to 1000 W. The EMS 60 then proceeds to the process of step S64.

[0113] In step S62, the EMS 60 turns on the charge relaxation. Here, the charge relaxation being on means that the charging condition of the interchange control storage battery H40a is relaxed. After the process of step S62, the EMS 60 temporarily ends the pre-control process.

[0114] In step S64 following step S60, EMS 60 determines whether the contract (power purchase contract) for the residents of each residence H to purchase electricity is for time-of-day lighting. EMS 60 has acquired information regarding the power purchase contract of each residence H in advance. If EMS 60 determines that the power purchase contract of each residence H is for time-of-day lighting (step S64: YES), it proceeds to processing of step S65. On the other hand, if EMS 60 determines that the power purchase contract of each residence H is not for time-of-day lighting (step S64: NO), it temporarily terminates the advance control processing.

[0115] In step S65, EMS 60 determines whether the current time is a time period when the price would be high if electricity were purchased or the time period before that (X hours ago). In this embodiment, taking into account the time required to change the operation of storage battery H40, EMS 60 determines not only whether the current time is a time period when the price would be high if electricity were purchased, but also whether the current time is the time period before that (X hours ago). If EMS 60 determines that the current time is a time period when the price would be high if electricity were purchased or the time period before that (step S65: YES), it proceeds to processing in step S66. On the other hand, if EMS 60 determines that the current time is not a time period when the price would be high if electricity were purchased or the time period before that (step S65: NO), it temporarily ends the pre-control processing.

[0116] In step S66, the EMS 60 determines whether the amount of stored power in the load following battery H40b is less than a set value for enhanced ON (third value). Here, the set value for enhanced ON is a reference value for whether or not to turn on enhanced charging when enhanced charging is OFF. In this embodiment, a value equivalent to 35% of the capacity of the storage battery H40 is adopted as the set value for enhanced ON (third value). When the EMS 60 determines that the amount of stored power in the load following battery H40b is equal to or less than the set value for enhanced ON (step S66: YES), the EMS 60 proceeds to the process of step S67. On the other hand, when the EMS 60 determines that the amount of stored power in the load following battery H40b is not equal to or less than the set value for enhanced ON (step S66: NO), the EMS 60 temporarily ends the pre-control process.

[0117] In step S67, the EMS 60 strengthens the charging condition of the interchange control storage battery H40a. That is, the EMS 60 raises the charging condition value from the initial value of 1500 W or 1000 W to 1800 W. The EMS 60 then proceeds to the process of step S68.

[0118] In step S68, the EMS 60 turns on the charging enhancement. Here, the charging enhancement being on means that the charging condition of the interchange control storage battery H40a is enhanced. After the process of step S68, the EMS 60 temporarily ends the pre-control process.

[0119] By executing the advance control process in this manner, for example, when the amount of stored power in the load following battery H40b has excessively increased (approaching 100%), the charging conditions for the interchange control battery H40a are relaxed, thereby making it possible to encourage charging of the interchange control battery H40a (steps S60 to S62). That is, for example, it is possible to prevent the amount of stored power in the load following battery H40b from reaching 100% (i.e., the load following battery H40b cannot be charged any more), and to prevent an increase in the power flowing backward to the system power source S.

[0120] Furthermore, after the charging condition of the interchange control battery H40a is relaxed as described above, when the amount of charge of the load following battery H40b becomes appropriate, the state in which charging of the interchange control battery H40a is encouraged can be eliminated by canceling the relaxation of the charging condition of the interchange control battery H40a (steps S51 to S53). In other words, the amount of charge of the load following battery H40b can be prevented from decreasing excessively.

[0121] Also, for example, when the amount of stored electricity in the load following battery H40b has decreased excessively (for example, to a level that is set in advance in preparation for a power outage and cannot be discharged), the charging condition of the interchange control battery H40a is strengthened, thereby urging charging of the load following battery H40b (steps S66 to S68). That is, it is possible to prevent the amount of stored electricity in the load following battery H40b from decreasing excessively and becoming unable to discharge. Also, it is possible to prevent an increase in the opportunity to charge the load following battery H40b due to an excessive decrease in the amount of stored electricity in the load following battery H40b, and thus an increase in the amount of discharge of the load following battery H40b.

[0122] Furthermore, after the charging condition of the interchange control battery H40a is strengthened as described above, when the amount of stored electricity in the load following battery H40b becomes appropriate, the strengthening of the charging condition of the interchange control battery H40a is cancelled, thereby eliminating the state in which charging of the load following battery H40b is encouraged (steps S56 to S58). In other words, an excessive increase in the amount of stored electricity in the load following battery H40b can be suppressed.

[0123] Furthermore, when strengthening the charging condition of the interchange control battery H40a, it is determined whether the current time is a time period when the price is high if purchasing electricity or the time period immediately preceding that (steps S64 and S65). In this way, when charging of the load following battery H40b can be promoted (steps S66 to S68), even if electricity is supplied from the system power source S, a large increase in costs can be suppressed.

[0124] In this way, by executing the advance control process, it is possible to suppress the occurrence of power purchase from the system power source S while suppressing the occurrence of variations in the discharge amounts in the plurality (all) of the storage batteries H40.

[0125] As described above, in the power supply system 1 according to one embodiment of the present invention, a plurality of storage batteries H40 connected in series between the system power source S and a load H10, capable of charging power and discharging the charged power to supply power to the load H10; A plurality of photovoltaic power generation units H30 (power generation units) connected to the storage battery H40 and distributing generated power between a system power source S and the load H10; An EMS 60 (control unit) capable of controlling charging and discharging of the plurality of storage batteries H40; A power supply system comprising: Among the plurality of storage batteries H40, at least two or more interchange control storage batteries H40a (first storage batteries) are A first mode is set in which charging and discharging are controlled based on an instruction from the EMS 60 (control unit), Charging and discharging are controlled based on a result of comparing a total PV power generation (total power generation) obtained by adding up the amounts of power generated by the plurality of photovoltaic power generation units H30 (power generation units) with a total residential load (power consumption) consumed by the load H10, Among the plurality of storage batteries H40, a load following storage battery H40b (second storage battery) provided closer to the system power source S than the plurality of interchange control storage batteries H40a (first storage batteries) is A second mode is set in which charging and discharging are controlled based on the power flowing between the system power source S and the load H10, The EMS 60 (control unit) The charging conditions of the plurality of interchange control batteries H40a (first batteries) can be changed based on predetermined conditions including the charge state of the load following battery H40b (second battery).

[0126] With this configuration, it is possible to suppress the supply of power from the system power source S while suppressing the variation in the discharge amount among the multiple storage batteries H40.

[0127] In the power supply system 1, The charge state of the load following battery H40b (second battery) includes the charge amount of the load following battery H40b (second battery).

[0128] With this configuration, it is possible to appropriately suppress the variation in the discharge amount among the multiple storage batteries H40 based on the amount of electricity stored in the load following storage battery H40b (second storage battery), while suppressing the supply of power from the system power source S.

[0129] In the power supply system 1, The EMS 60 (control unit) When the amount of stored electricity in the load following battery H40b (second battery) is equal to or greater than a predetermined setting value (first value) for easing ON, the charging conditions of the multiple interchange control batteries H40a (first batteries) can be relaxed (steps S60 to S62).

[0130] With this configuration, when it is determined that the amount of stored electricity in the load following battery H40b is sufficient, the interchange control battery H40a is placed in a state in which it is easy to charge, and charging of the interchange control battery H40a can be promoted.

[0131] In the power supply system 1, The EMS 60 (control unit) When the amount of stored electricity in the load following battery H40b (second battery) is smaller than a predetermined setting value (second value) for mitigation OFF which is smaller than the setting value (predetermined first value) for mitigation ON, the relaxation of the charging conditions for the multiple interchange control batteries H40a (first batteries) can be released (steps S51 to S53).

[0132] With this configuration, when it is determined that the amount of stored electricity in the load following battery H40b is insufficient, the state in which the interchange control battery H40a is easily charged can be cancelled.

[0133] In the power supply system 1, The EMS 60 (control unit) When the amount of electricity stored in the load following battery H40b (second battery) is less than or equal to a predetermined setting value (third value) for reinforcement ON, the charging conditions for the multiple interchange control batteries H40a (first batteries) can be reinforced (steps S66 to S68).

[0134] With this configuration, when it is determined that the amount of stored electricity in the load following battery H40b is insufficient, the interchange control battery H40a is put into a state in which it is difficult to charge, and charging of the load following battery H40b can be promoted.

[0135] In the power supply system 1, The predetermined conditions include a cost of electricity supplied from the power grid S, When the cost is relatively high during the time period, the charging conditions of the multiple interchange control batteries H40a (first batteries) are not strengthened regardless of the amount of electricity stored in the load following battery H40b (second battery) (steps S64 and S65).

[0136] With this configuration, costs can be reduced when encouraging charging of the load following storage battery H40b.

[0137] In the power supply system 1, The EMS 60 (control unit) When the amount of stored electricity in the load following battery H40b (second battery) is greater than a predetermined enhanced OFF setting value (fourth value) that is greater than the enhanced ON setting value (third value), the enhanced charging conditions for the multiple interchange control batteries H40a (first batteries) can be released (steps S56 to S58).

[0138] With this configuration, when it is determined that the amount of stored electricity in the load following battery H40b is sufficient, the state in which it is difficult to charge the interchange control battery H40a can be lifted.

[0139] The solar power generation unit H30 according to this embodiment is one embodiment of a power generation unit. The EMS 60 according to this embodiment is one embodiment of a control unit. The interchange control battery H40a according to this embodiment is an embodiment of the first battery. The load following storage battery H40b according to this embodiment is an embodiment of a second storage battery. The setting value for mitigation ON according to this embodiment is an embodiment of the first value. The setting value for mitigation OFF according to this embodiment is an embodiment of the second value. The enhanced ON setting value according to this embodiment is an embodiment of the third value. The setting value for enhanced OFF according to this embodiment is an embodiment of the fourth value.

[0140] Although the embodiment of the present invention has been described above, the present invention is not limited to the above configuration, and various modifications are possible within the scope of the invention described in the claims.

[0141] For example, in this embodiment, the electricity retailer purchases electricity in bulk from the electric power company and supplies (shares) it between multiple homes H as appropriate, but the electricity retailer does not have to purchase electricity in bulk from the electric power company.

[0142] Furthermore, the EMS 60 may be configured by, for example, a home server (not shown), a control unit of a storage battery, or a HEMS provided in a house (when the power supply system 1 is applied to a house).

[0143] Furthermore, the power generating unit uses solar light as natural energy in the above embodiment, but may also use hydraulic power, wind power, tidal power, etc., or may not use natural energy.

[0144] In addition, in this embodiment, when the charge / discharge control process is executed, the first mode is set for three storage batteries H40, but this is not limited to the above, and the first mode may be set for an appropriate number of batteries.

[0145] Furthermore, in the present embodiment, when the charge / discharge control process is executed, an example has been shown in which the second mode is set in the most upstream storage battery H40 installed in the house H (first house H1) in the residential block T, but the storage battery H40 (the most upstream storage battery H40) to which the second mode is set is not limited to the one installed in the house H. For example, the most upstream storage battery H40 may be installed in a shared facility such as a meeting hall in the residential block T.

[0146] In addition, in the present embodiment, when the charge / discharge control process is executed, the second mode is set to one storage battery H40, but the second mode is not limited to one storage battery H40, and a plurality of storage batteries H40 may be set to the second mode. In this case, among the plurality of storage batteries H40, an appropriate number of storage batteries H40 may be set to the second mode in order from the storage battery H40 arranged on the upstream side.

[0147] In addition, in the present embodiment, when the charging condition value is changed to ease the charging condition, for example, the initial value is reduced to 1000 W at once, but the present invention is not limited to this. That is, the charging condition value can be made variable depending on the amount of stored electricity in the load following storage battery H40b. Specifically, for example, when the remaining amount of stored electricity in the load following storage battery H40b exceeds 90% of the capacity, the charging condition value can be reduced from 1500 W to 1200 W until it decreases to 85%, and when the remaining amount of stored electricity in the load following storage battery H40b exceeds 95% of the capacity, the charging condition value can be reduced from 1200 W to 1000 W until it decreases to 90%.

[0148] In addition, in this embodiment, when the amount of stored power in the load following battery H40b is less than the set value for reinforcement ON (third value), the charging condition of the interchange control battery H40a is reinforced, but instead of (or in addition to) this, the dischargeable amount of the load following battery H40b may be adjusted. Specifically, in this embodiment, the dischargeable amount of the load following battery H40b is 30% of the capacity, but this can be temporarily reduced to, for example, 20%.

[0149] In addition, the setting value for relaxed ON (first value), the setting value for relaxed OFF (second value), the setting value for strengthened ON (third value), and the setting value for strengthened OFF (fourth value) are not limited to the values ​​in this embodiment, and any value can be adopted. [Explanation of symbols]

[0150] 1. Power supply system 60 EMS H10 load H30 Solar Power Generation Department H40 Battery H40a Battery for interchange control H40b Load following battery S grid power supply

Claims

1. a plurality of storage batteries connected in series between a system power supply and a load, capable of charging power and discharging the charged power to supply power to the load; a plurality of power generation units connected to the storage battery and configured to distribute generated power between a system power supply and the load; A control unit capable of controlling charging and discharging of the plurality of storage batteries; A power supply system comprising: Among the plurality of storage batteries, at least two or more first storage batteries are A first mode in which charging and discharging are controlled based on an instruction from the control unit is set, Charging and discharging are controlled based on a result of comparing a total generated power obtained by adding up the amounts of power generated by the plurality of power generation units with the power consumption consumed by the load; Among the plurality of storage batteries, a second storage battery provided closer to a system power supply than the plurality of first storage batteries, a second mode is set in which charging and discharging are controlled based on the power flowing between the system power supply and the load; The control unit is The charging condition of the first storage batteries is changeable based on a predetermined condition including a charge state of the second storage battery. Power supply system.

2. The power storage status of the second storage battery includes a power storage amount of the second storage battery. The power supply system according to claim 1 .

3. The control unit is When the amount of stored electricity in the second storage battery is equal to or greater than a predetermined first value, a charging condition for the first storage batteries can be relaxed. The power supply system according to claim 2 .

4. The control unit is When the amount of charge stored in the second storage battery is smaller than a predetermined second value smaller than the first value, relaxation of the charging condition for the first storage batteries can be lifted. The power supply system according to claim 3 .

5. The control unit is When the amount of charge of the second storage battery is equal to or less than a predetermined third value, a charging condition of the first storage batteries can be strengthened. The power supply system according to claim 2 .

6. The predetermined conditions include a cost of electricity supplied from a grid power source, When the cost is relatively high during the time period, the charging conditions of the first storage batteries are not strengthened regardless of the amount of charge stored in the second storage battery. The power supply system according to claim 5 .

7. The control unit is When the amount of charge stored in the second storage battery is greater than a predetermined fourth value that is greater than the third value, the strengthening of the charging condition for the first storage batteries can be lifted. The power supply system according to claim 5 or 6.

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