Control systems and management systems

Abstract

The system accurately calculates the distribution of active power instructed to multiple energy storage devices. [Solution] The control system 40 is a control system for controlling an energy storage system that adjusts the active power at the point of combination with the power system by a plurality of energy storage units, each including an energy storage device that discharges and charges DC power. The system comprises a command calculation unit 51 that calculates a total DC power command value Cp, which is the sum of the power that the energy storage devices in the plurality of energy storage units should discharge or charge, by adding power losses, including conversion losses due to the conversion between DC power and AC power and conversion losses due to the conversion between AC power and the active power at the point of combination, to the basic command value C0 of the active power; a command distribution unit 52 that calculates an active power distribution value P[m] to be distributed from the total DC power command value Cp to each of the plurality of energy storage units; and an operation instruction unit 53 that instructs each of the plurality of energy storage units to set the active power distribution value P[m] for that energy storage unit.

Description

Technical Field

[0001] The present disclosure relates to a technique for controlling a plurality of power storage devices.

Background Art

[0002] For example, a technique for controlling a plurality of power storage devices according to a command value of power to be exchanged with a power system has been conventionally proposed. For example, Patent Document 1 discloses a configuration for controlling charging and discharging of each storage battery according to a command value based on a charging request or a discharging request in a storage battery system including a plurality of banks each composed of an AC-DC conversion device and a storage battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Various power losses can occur in the path from each power storage device to the synthesis point. Therefore, there is room for further improvement from the viewpoint of appropriately calculating the distribution of active power instructed to the plurality of power storage devices.

Means for Solving the Problems

[0005] To solve the above problems, a control system according to one aspect of the present disclosure is a control system for controlling an energy storage system that adjusts the active power at a point of combination with a power system by a plurality of energy storage units, each including an energy storage device that discharges and charges DC power, and comprises a command calculation unit that calculates a total DC power command value, which is the sum of the power that the energy storage devices in the plurality of energy storage units should discharge or charge, by adding power losses, including conversion losses due to the conversion between DC power and AC power and transformation losses due to the mutual transformation between the energy storage system and the substation equipment between the energy storage system and the point of combination, to the basic command value of the active power; a command distribution unit that calculates an active power distribution value to be distributed to each of the plurality of energy storage units from the total DC power command value; and an operation instruction unit that instructs each of the plurality of energy storage units on the active power distribution value of the energy storage unit.

[0006] A management system according to one aspect of the present disclosure comprises a power storage system that adjusts the active power at a point of integration with a power grid by a plurality of power storage units, each including a power storage device that discharges and charges DC power, and a control system that controls the power storage system, wherein the control system comprises a command calculation unit that calculates a total DC power command value, which is the sum of the power that the power storage devices in the plurality of power storage units should discharge or charge, by adding power losses, including conversion losses due to the conversion between DC power and AC power and transformation losses due to the mutual transformation between the power storage system and the substation equipment between the power storage system and the point of integration, to the basic command value of the active power; a command distribution unit that calculates an active power distribution value to be distributed to each of the plurality of power storage units from the total DC power command value; and an operation instruction unit that instructs each of the plurality of power storage units on the active power distribution value of the power storage unit. [Brief explanation of the drawing]

[0007] [Figure 1] This is a block diagram illustrating the configuration of the management system according to the first embodiment. [Figure 2] This is a block diagram illustrating the configuration of a control system. [Figure 3] This is a block diagram illustrating the functional configuration of a control system. [Figure 4] This is an equivalent circuit diagram that virtually integrates multiple energy storage units. [Figure 5] This is a diagram illustrating the operation of the command calculation unit. [Figure 6] This is a diagram illustrating the operation of the command calculation unit. [Figure 7] This is a block diagram illustrating the configuration of the command distribution unit. [Figure 8] This is a specific example of how the distribution processing unit operates when the total DC power command value indicates discharge. [Figure 9] This is an explanatory diagram illustrating the relationship between the active power distribution value and the combined point power. [Figure 10] This is a specific example of how the distribution processing unit operates when the total DC power command value indicates charging. [Figure 11] This is an explanatory diagram illustrating the relationship between the active power distribution value and the combined point power. [Figure 12] This is a flowchart of the control process. [Figure 13] This is a block diagram illustrating the configuration of the limit setting unit in the second embodiment. [Figure 14] This is an explanatory diagram illustrating the operation of the candidate value setting unit, which sets candidate values ​​according to the voltage. [Figure 15] This is an explanatory diagram illustrating the operation of the candidate value setting unit, which sets candidate values ​​according to the charge level. [Figure 16] This is an explanatory diagram illustrating the operation of the candidate value setting unit, which sets candidate values ​​according to the temperature. [Figure 17] This shows the relationship between temperature and candidate values ​​when an energy storage device absorbs heat due to discharge. [Figure 18] This is an explanatory diagram illustrating the operation of the candidate value setting unit, which sets candidate values ​​according to the voltage. [Figure 19] This is an explanatory diagram illustrating the operation of the candidate value setting unit, which sets candidate values ​​according to the charge level. [Figure 20] This is an explanatory diagram illustrating the operation of the candidate value setting unit, which sets candidate values ​​according to the temperature. [Figure 21]It is the relationship between the temperature and the candidate value when the power storage device generates heat due to charging. [Figure 22] It is an explanatory diagram of the operation of the coefficient setting unit in the third embodiment. [Figure 23] It is an explanatory diagram of the operation of the coefficient setting unit in the third embodiment. [Figure 24] It is an explanatory diagram of the operating watt-hour capacity. [Figure 25] It is an explanatory diagram of the first process in the fourth embodiment. [Figure 26] It is an explanatory diagram of the process of calculating the weighting value in the fourth embodiment. [Figure 27] It is an explanatory diagram of the weighting value when the total DC power command value indicates charging. [Figure 28] It is an explanatory diagram of the process of calculating the weighting value in the fourth embodiment. [Figure 29] It is an explanatory diagram of the process of calculating the weighting value in the fourth embodiment. [Figure 30] It is an explanatory diagram of the first process in the fifth embodiment. [Figure 31] It is an explanatory diagram of the process of calculating the weighting value in the fifth embodiment. [Figure 32] It is an explanatory diagram of the process of calculating the weighting value in the fifth embodiment. [Figure 33] It is an explanatory diagram of the process of calculating the weighting value α[m] in the fifth embodiment. [Figure 34] It is an explanatory diagram of the weighting value when the total DC power command value indicates charging. [Figure 35] It is an explanatory diagram of the first process in the sixth embodiment. [Figure 36] It is an explanatory diagram of the process of calculating the weighting value in the sixth embodiment. [Figure 37] It is an explanatory diagram of the process of calculating the weighting value in the sixth embodiment. [Figure 38] It is an explanatory diagram of the first process in the seventh embodiment. [Figure 39] It is an explanatory diagram of the operation of the coefficient setting unit in the eighth embodiment. [Figure 40] This is an explanatory diagram of the smoothing process. [Figure 41] This is a diagram illustrating the specific configuration for achieving smoothing. [Figure 42] This is an explanatory diagram illustrating the operation when an additional energy storage unit is activated while the energy storage system is discharging. [Figure 43] This is an explanatory diagram illustrating the temporal changes in the allocation coefficient and allocation value. [Figure 44] This is an explanatory diagram illustrating the operation when an additional energy storage unit is activated while charging is in progress by the energy storage system. [Figure 45] This is an explanatory diagram illustrating the temporal changes in the allocation coefficient and allocation value. [Figure 46] This is an explanatory diagram regarding the operation when one energy storage unit is stopped while the energy storage system is performing a discharge. [Figure 47] This is an explanatory diagram illustrating the temporal changes in the allocation coefficient and allocation value. [Figure 48] This is an explanatory diagram regarding the operation when one energy storage unit is stopped while charging is being performed by the energy storage system. [Figure 49] This is an explanatory diagram illustrating the temporal changes in the allocation coefficient and allocation value. [Figure 50] This is an explanatory diagram of the operation of the command calculation unit in the 11th embodiment. [Figure 51] This is an explanatory diagram of the operation of the management system in the 11th embodiment. [Figure 52] This is an explanatory diagram of the operation of the management system in operation case 1 of the first embodiment. [Figure 53] This is an explanatory diagram of the operation of the management system in operation case 1 of the first embodiment. [Figure 54] This is an explanatory diagram of the operation of the management system in operation case 2 of the first embodiment. [Figure 55] This is an explanatory diagram of the operation of the management system in operation case 2 of the first embodiment. [Figure 56] This is an explanatory diagram of the operation of the management system in operation case 3 of the first embodiment. [Figure 57] This is an explanatory diagram of the operation of the management system in operation case 3 of the first embodiment. [Figure 58] This is an explanatory diagram of the operation of the management system in operation case 4 of the first embodiment. [Figure 59] This is an explanatory diagram of the operation of the management system in operation case 4 of the first embodiment. [Figure 60] This is a block diagram illustrating the functional configuration of the control system in the 13th embodiment. [Figure 61] This is an explanatory diagram of the operation of the command calculation unit in the 13th embodiment. [Figure 62] This is an explanatory diagram illustrating the operation of the command distribution unit in calculating the reactive power distribution value for each energy storage unit. [Figure 63] This is a block diagram illustrating the configuration of the management system according to the 14th embodiment. [Figure 64] This is a block diagram illustrating the configuration of the management system according to the 15th embodiment. [Figure 65] This is a block diagram illustrating the configuration of the energy storage unit in the 16th embodiment. [Modes for carrying out the invention]

[0008] The embodiments for implementing this disclosure will be described with reference to the drawings. The embodiments described below are exemplary embodiments that may be envisioned when implementing this disclosure. Therefore, the scope of this disclosure is not limited to the embodiments described below.

[0009] 1. First Embodiment Figure 1 is a block diagram illustrating the configuration of the management system 100 according to the first embodiment. The management system 100 is a system that exchanges AC power with the power system 10. The power system 10 is a distribution system or transmission system that supplies AC power generated by power generation equipment 23 (not shown), such as a thermal power plant or a nuclear power plant, to business facilities or consumers such as general households. The management system 100 is connected to the power system 10 at the integration point 11. The integration point 11 is an interconnection point corresponding to the boundary between the power system 10 and the management system 100.

[0010] As illustrated in Figure 1, the management system 100 comprises a substation 21, load equipment 22, a power storage system 30, and a control system 40. The power storage system 30 is a power facility that exchanges AC power with the power grid 10.

[0011] The substation 21 is a power facility that aggregates the outputs of multiple energy storage units U[m] constituting the energy storage system 30 and the inputs of the load equipment 22, and transforms the voltage of the AC power exchanged between these and the combination point 11 using a transformer. Note that the transformer in the substation 21 may be omitted. The load equipment 22 consists of various loads (in-house loads) that operate by consuming power supplied from the energy storage system 30 or the power grid 10. For example, the load equipment 22 includes various equipment that supplies control power, operating power, or auxiliary power to each element of the management system 100 (substation 21, energy storage system 30, or control system 40). Specifically, examples of load equipment 22 include: an in-house transformer that transforms the voltage supplied from the substation 21; a DC power supply that supplies control power or operating power to the substation 21 or AC / DC converter 322; an uninterruptible power supply (UPS) that supplies power in the event of an abnormality; a power supply that supplies auxiliary power (e.g., driving power required for auxiliary equipment such as air conditioning equipment) or control power to the energy storage device 31; an oil pump or cooling fan used in the substation 21 or AC / DC converter 322; communication equipment used for security telephones with the power company, etc.; lighting equipment or air conditioning equipment installed on the premises or in buildings, etc.; a measurement system that measures environmental information such as temperature or humidity; or various fire-fighting equipment (smoke detectors, heat detectors, fire alarms, etc.). Note that load equipment 22 may be omitted.

[0012] The energy storage system 30 of the first embodiment is composed of a plurality of energy storage units U[m] (m=1 to 5). For convenience, in the following description, a configuration in which the energy storage system 30 includes five energy storage units U[1] to U[5] will be used as an example. However, the number of energy storage units U[m] constituting the energy storage system 30 can be arbitrarily changed.

[0013] Each of the multiple energy storage units U[m] is a power facility capable of charging and discharging electricity. As illustrated in Figure 1, each energy storage unit U[m] comprises an energy storage device 31 and a power adjustment device 32. The energy storage device 31 is a secondary battery that discharges and charges DC power. The type of energy storage device 31 is arbitrary, but examples include lithium-ion batteries and sodium-sulfur batteries.

[0014] The power conditioning device 32 is a PCS (Power Conditioning System) that controls the discharge and charging of the energy storage device 31. Specifically, the power conditioning device 32 comprises a transformer 321 and an AC / DC converter 322. The transformer 321 converts the voltage of the AC power. The AC / DC converter 322 converts between DC power and AC power. Specifically, the AC / DC converter 322 converts the DC power supplied by the discharge of the energy storage device 31 into AC power, and the transformer 321 converts the voltage of the AC power after conversion by the AC / DC converter 322 and supplies it to the combination point 11. The transformer 321 also converts the voltage of the AC power supplied from the power system 10, and converts the AC power after transformation by the transformer 321 into DC power and supplies it to the energy storage device 31. As described above, the energy storage system 30 adjusts the active power at the point of integration 11 with the power system 10 using multiple energy storage units U[m], including the energy storage device 31. The transformer 321 may be omitted. Alternatively, multiple energy storage units U[m] may share a single transformer 321.

[0015] The control system 40 is a computer system (PMS: ​​Power Management System) that controls the energy storage system 30. Specifically, the control system 40 instructs each energy storage unit U[m] of the energy storage system 30 to have an active power distribution value P[m]. Each energy storage unit U[m] causes the energy storage device 31 to discharge or charge DC power corresponding to the active power distribution value P[m]. The active power distribution value P[m] is the power value of AC power that the energy storage unit U[m] should discharge or charge. Specifically, a positive value of the active power distribution value P[m] corresponds to a command for discharge (i.e., power supply from the energy storage unit U[m] to the combination point 11), and a negative value of the active power distribution value P[m] corresponds to a command for charge (i.e., power reception from the combination point 11 by the energy storage unit U[m]). Alternatively, a negative value of the active power distribution value P[m] may correspond to a command for discharge, and a positive value of the active power distribution value P[m] may correspond to a command for charge.

[0016] Figure 2 is a block diagram illustrating the configuration of the control system 40. As illustrated in Figure 2, the control system 40 comprises a control device 41, a storage device 42, and a transmitting / receiving device 43. The control system 40 can be implemented as a single device or as a group of devices configured separately from each other.

[0017] The control device 41 consists of one or more processors that control each element of the control system 40. Specifically, the control device 41 is composed of one or more types of processors, such as a PLD (Programmable Logic Device), a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit).

[0018] The storage device 42 is one or more memories that store programs executed by the control device 41 and data used by the control device 41. The storage device 42 is composed of known recording media, such as magnetic recording media or semiconductor recording media. The storage device 42 may be composed of a combination of multiple types of recording media. A portable recording media that can be attached to and detached from the control system 40 may be used as the storage device 42.

[0019] The transceiver 43 transmits and receives signals to and from external devices via wired or wireless means. Specifically, the transceiver 43 communicates with each energy storage unit U[m] (specifically, the power adjustment device 32) via a communication network (not shown), such as a dedicated line. For example, the active power distribution value P[m] is transmitted from the transceiver 43 to each energy storage unit U[m]. The signals exchanged between the transceiver 43 and each energy storage unit U[m] (specifically, the power adjustment device 32) may be either digital or analog signals.

[0020] Figure 3 is a block diagram illustrating the functional configuration of the control system 40. The control device 41 executes a program stored in the memory device 42 to realize multiple functions (command calculation unit 51, command distribution unit 52, operation instruction unit 53) for controlling multiple energy storage units U[m].

[0021] As illustrated in Figure 3, the control system 40 receives a basic command value C0. The basic command value C0 is the command value for the active power (hereinafter referred to as "combination point power") at the combination point 11 with the power system 10. In other words, the basic command value C0 is the total value of the power to be discharged or charged by the entire management system 100. In addition to indicating the numerical value of the combination point power, the basic command value C0 also indicates the direction of power (discharge / charge) to the combination point 11 by sign. Specifically, the power supply from the energy storage system 30 to the combination point 11 (i.e., discharge by the energy storage unit U[m]) is indicated by a positive number, and the power reception from the combination point 11 by the energy storage system 30 (i.e., charging by the energy storage unit U[m]) is indicated by a negative number.

[0022] The basic command value C0 is transmitted to the control system 40 from an external system that manages the electricity market, such as the wholesale electricity market or the supply and demand adjustment market. In other words, the basic command value C0 is the total value of electricity that the management system 100 should trade in various electricity markets.

[0023] The command calculation unit 51 in Figure 3 calculates the total DC power command value Cp from the basic command value C0. The total DC power command value Cp is a command value obtained by adding the power loss from the energy storage device 31 of each energy storage unit U[m] to the combination point 11 to the basic command value C0. Specifically, the total DC power command value Cp specifies the total value of DC power that each energy storage device 31 should generate so that the power at the combination point is maintained at the basic command value C0 even if there is a power loss from each energy storage device 31 to the combination point 11. In other words, the total DC power command value Cp is the total value of DC power that the energy storage devices 31 in multiple energy storage units U[m] should discharge or charge in order to realize the basic command value C0.

[0024] Figure 4 is an equivalent circuit diagram that virtually integrates multiple energy storage units U[m]. As illustrated in Figure 4, the energy storage devices 31 in multiple energy storage units U[m] are equivalently replaced by a single energy storage device 31eq, and the power regulators 32 in multiple energy storage units U[m] are equivalently replaced by a single power regulator 32eq.

[0025] As illustrated in Figure 4, the total DC power command value Cp calculated by the command calculation unit 51 is the total value of DC power that the energy storage device 31eq should discharge or receive. As can be understood from the above explanation, the total DC power command value Cp can also be expressed as a value obtained by equivalently converting the AC power to be set at the combination point 11 (i.e., the combination point power specified by the basic command value C0) into DC power generated by the energy storage device 31.

[0026] As illustrated in Figure 4, in the path from the energy storage device 31 of each energy storage unit U[m] to the synthesis point 11, transformation losses X1, load losses X2, and conversion losses X3 occur.

[0027] The substation loss X1 is the power loss caused by the voltage transformation by the substation equipment 21. In other words, the substation loss X1 is the loss (e.g., load loss and no-load loss) that occurs due to the voltage transformation between the AC voltage between the energy storage system 30 and the substation equipment 21 and the voltage at the combination point 11.

[0028] The substation loss X1 is calculated by adding the calculated copper loss that occurs in the transformer of the substation equipment 21 when power equivalent to the basic command value C0 passes through the combination point 11, and the iron loss that occurs in the transformer of the substation equipment 21 when voltage is applied to the substation equipment 21. Stray load loss or dielectric loss of the transformer in the substation equipment 21 may also be added to the substation loss X1. The substation loss X1 may also be calculated by the absolute difference between the power at the combination point 11 equivalent to the basic command value C0 (or the value measured by a power meter installed at the combination point 11) and the value measured by a meter installed at the input of the substation equipment 21. In addition, line loss between the energy storage system 30 and the substation equipment 21 may be added to the substation loss X1.

[0029] The load loss X2 is the power loss caused by the power consumption of the load equipment 22. In other words, the load loss X2 corresponds to the active power consumed by the load equipment 22. The load loss X2 is calculated, for example, according to the measured value measured by a measuring instrument. Alternatively, the load loss X2 may be calculated according to a pre-set planned value for the load equipment 22. In addition, line losses between the energy storage system 30 and the load equipment 22 may be added to the load loss X2.

[0030] The conversion loss X3 is the total power loss obtained by summing the conversion losses x[m] caused by the power adjustment device 32 in each energy storage unit U[m] across multiple energy storage units U[m]. The conversion loss x[m] in each energy storage unit U[m] is the loss that occurs due to the conversion between the DC power between the energy storage device 31 and the power adjustment device 32 and the AC power between the control system 40 and the substation equipment 21.

[0031] The conversion loss x[m] is the sum of the losses of the transformer 321 (e.g., load loss and no-load loss) and the AC / DC converter 322 in the energy storage unit U[m]. Line losses between the transformer 321 and the AC / DC converter 322 may also be added to the conversion loss x[m].

[0032] The loss of transformer 321 is calculated by adding the calculated copper loss of transformer 321 that occurs when power equivalent to the active power distribution value P[m] passes through transformer 321 to the iron loss of transformer 321 that occurs when voltage is applied to transformer 321. Stray load loss or dielectric loss of transformer 321 may also be added to the conversion loss x[m]. Alternatively, the loss of transformer 321 may be calculated by the absolute difference between the power equivalent to the active power distribution value P[m] input to transformer 321 (or the value measured by a power meter installed at the input of transformer 321) and the value measured by a power meter installed at the output of transformer 321.

[0033] The loss of the AC / DC converter 322 is calculated, for example, by the absolute difference between the active power distribution value P[m] (or the value measured by a power meter installed on the AC side of the AC / DC converter 322) and the measured value of the DC power.

[0034] Figures 5 and 6 are explanatory diagrams of the operation of the command calculation unit 51. Figure 5 shows the operation of the command calculation unit 51 when discharge by the energy storage system 30 is instructed by the basic command value C0 (C0>0). As illustrated in Figure 5, the command calculation unit 51 calculates the total DC power command value Cp by adding the power loss (X1+X2+X3), which includes the substation loss X1, load loss X2, and conversion loss X3, to the basic command value C0. In Figure 5, the conversion loss x[m] of each energy storage unit U[m] is "1", so the conversion loss X3 is "5" is illustrated as an example.

[0035] Figure 6 shows the operation of the command calculation unit 51 when charging by the energy storage system 30 is instructed by the basic command value C0 (C0 < 0). The basic command value C0 is a negative number, while the substation loss X1, load loss X2, and conversion loss X3 are positive numbers. Even when charging by the energy storage system 30 is instructed by the basic command value C0, the command calculation unit 51 calculates the total DC power command value Cp by adding the power loss (X1 + X2 + X3), which includes the substation loss X1, load loss X2, and conversion loss X3, to the basic command value C0, similar to the case in Figure 5.

[0036] In other words, the command calculation unit 51 calculates the total DC power command value Cp by adding the substation loss X1, load loss X2, and conversion loss X3 to the basic command value C0, as expressed by the following formula (1).

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[0037] The command distribution unit 52 in Figure 3 calculates the command value of active power (hereinafter referred to as "active power distribution value P[m]") that should be distributed to each of the multiple energy storage units U[m] from the total DC power command value Cp. The active power distribution value P[m] is the command value of AC power that each energy storage unit U[m] should discharge (P[m]>0) or charge (P[m]<0).

[0038] The operation instruction unit 53 instructs each of the multiple energy storage units U[m] to determine the active power distribution value P[m] for that energy storage unit U[m]. Specifically, the operation instruction unit 53 transmits the active power distribution value P[m] calculated by the command distribution unit 52 to the energy storage unit U[m] via the transceiver 43.

[0039] Figure 7 is a block diagram illustrating the specific configuration of the command distribution unit 52. As illustrated in Figure 7, the command distribution unit 52 comprises a coefficient setting unit 521, a limit value setting unit 522, and a distribution processing unit 523.

[0040] The coefficient setting unit 521 sets a distribution coefficient K[m] (K[1] to K[5]) for each of the multiple energy storage units U[m]. Each distribution coefficient K[m] is a positive number representing the ratio of the total DC power command value Cp that the energy storage unit U[m] should be responsible for. In the first embodiment, the coefficient setting unit 521 sets the distribution coefficient K[m] according to the specifications or state of each energy storage device 31, for example.

[0041] The limit value setting unit 522 sets limit values ​​L[m] (L[1] to L[5]) for each of the multiple energy storage units U[m]. Each limit value L[m] is a numerical value for limiting the active power distribution value P[m] to a predetermined range. The limit value L[m] includes a limit value L[m]_d (d:discharge) related to the discharge of the energy storage device 31 and a limit value L[m]_c (c:charge) related to the charging of the energy storage device 31. In the first embodiment, the limit value setting unit 522 sets the limit value L[m] according to the specifications or state of each energy storage device 31, for example.

[0042] The distribution processing unit 523 calculates the active power distribution value P[m] to be distributed to each energy storage unit U[m] from the total DC power command value Cp. In the first embodiment, the distribution processing unit 523 distributes the total DC power command value Cp to a plurality of active power distribution values ​​P[m] according to the distribution coefficient K[m] set by the coefficient setting unit 521 for each energy storage unit U[m] and the limit value L[m](L[m]_d, L[m]_c) set by the limit value setting unit 522 for each energy storage unit U[m].

[0043] Figures 8 to 11 are explanatory diagrams of the operation of the distribution processing unit 523. First, Figure 8 shows a specific example of the operation of the distribution processing unit 523 when the total DC power command value Cp indicates discharge (Cp > 0).

[0044] In step Sa1, the distribution processing unit 523 calculates the power distribution value Pa[m] to be distributed to each energy storage unit U[m] from the total DC power command value Cp, according to the distribution coefficient K[m] of each energy storage unit U[m]. Specifically, the distribution processing unit 523 calculates each power distribution value Pa[m] such that each power distribution value Pa[m] is a ratio corresponding to the distribution coefficient K[m]. Note that the power distribution value Pa[m] is an example of the "first power distribution value".

[0045] For example, the distribution processing unit 523 calculates each power distribution value Pa[m] by the following formula (2). That is, the distribution processing unit 523 calculates each power distribution value Pa[m] by multiplying the ratio of each distribution coefficient K[m] to the sum of multiple distribution coefficients K[m] (K[1]~K[5]) ΣK[m] by the total DC power command value Cp of the discharge exemplified in Figure 5. As can be understood from the above explanation, according to the first embodiment, the total DC power command value Cp can be distributed to each of the multiple energy storage units U[m] according to the distribution coefficient K[m] of each energy storage unit U[m].

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[0046] The power distribution value Pa[m] calculated in step Sa1 may exceed the discharge limit value L[m]_d. When the total DC power command value Cp indicates discharge, the power distribution value Pa[m] exceeds the limit value L[m]_d if the power distribution value Pa[m] is greater than the limit value L[m]_d (Pa[m]>L[m]_d). For example, Figure 8 illustrates a case where the power distribution value Pa[1] (=50) of energy storage unit U[1] exceeds the limit value L[1]_d (=40), and the power distribution value Pa[2] (=40) of energy storage unit U[2] exceeds the limit value L[2]_d (=30).

[0047] The distribution processing unit 523 distributes the total excess value E1, which is the sum of the excess values ​​(Pa[m]-L[m]_d) for one or more energy storage units U[m] whose power distribution value Pa[m] exceeds the limit value L[m]_d, to each of the one or more energy storage units U[m] whose power distribution value Pa[m] does not exceed the limit value L[m]_d (Sa2~Sa5).

[0048] Specifically, in step Sa2 of Figure 8, the distribution processing unit 523 calculates the total excess value E1 by summing the difference between the power distribution value Pa[m] and the limit value L[m]_d (i.e., the excess value) for one or more energy storage units U[m] whose power distribution value Pa[m] exceeds the limit value L[m]_d. In the situation shown in Figure 8, the total excess value E1 is calculated as "20", which is the sum of the excess value of energy storage unit U[1] (Pa[1]-L[1]_d), "10", and the excess value of energy storage unit U[2] (Pa[2]-L[2]_d), "10".

[0049] In step Sa3, the allocation processing unit 523 calculates the total available power E2 by summing the difference (i.e., margin) between the limit value L[m]_d and the power allocation value Pa[m] for one or more of the multiple energy storage units U[m] whose power allocation value Pa[m] does not exceed the limit value L[m]_d. In the situation shown in Figure 8, the total available power E2 is calculated as "30", which is the sum of the margin value (L[4]_d-Pa[4]) of energy storage unit U[4], "10", and the margin value (L[5]_d-Pa[5]) of energy storage unit U[5], "20".

[0050] In step Sa4, the allocation processing unit 523 calculates an additional allocation value ΔP[m] for one or more energy storage units U[m] whose power allocation value Pa[m] does not exceed the limit value L[m]_d. Specifically, the allocation processing unit 523 calculates each additional allocation value ΔP[m] by performing the following calculation using formula (3a). That is, the allocation processing unit 523 calculates the additional allocation value ΔP[m] by multiplying the total excess value E1 by the ratio of each margin value (L[m]_d-Pa[m]) to the total available power E2.

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[0051] In step Sa5, the allocation processing unit 523 calculates the power allocation value Pb[m] for each energy storage unit U[m]. That is, each power allocation value Pa[m] is updated to the power allocation value Pb[m]. Specifically, for one or more energy storage units U[m] whose power allocation value Pa[m] exceeds the limit value L[m]_d, the allocation processing unit 523 sets the limit value L[m]_d as the updated power allocation value Pb[m]. In addition, for one or more energy storage units U[m] whose power allocation value Pa[m] does not exceed the limit value L[m]_d, the allocation processing unit 523 calculates the updated power allocation value Pb[m] by adding an additional allocation value ΔP[m] to the power allocation value Pa[m]. For energy storage units U[m] among multiple energy storage units U[m] where the power distribution value Pa[m] and the limit value L[m]_d are equal, the power distribution value Pa[m] is adopted as the power distribution value Pb[m]. The power distribution value Pb[m] is the command value of the DC power that the energy storage device 31 of each energy storage unit U[m] should discharge.

[0052] In step Sa6, the distribution processing unit 523 calculates the active power distribution value P[m] by subtracting the conversion loss x[m] in each energy storage unit U[m] from the power distribution value Pb[m] calculated for each energy storage unit U[m] (P[m]=Pb[m]-x[m]). In other words, the active power distribution value P[m] is the command value of the active power that the energy storage unit U[m] should discharge, as described above. The operation by which the distribution processing unit 523 calculates the active power distribution value P[m] when the total DC power command value Cp indicates discharge (Cp>0) is as described above.

[0053] As described above, between each energy storage unit U[m] and the combination point 11, a substation loss X1 due to the substation equipment 21 and a load loss X2 due to the load equipment 22 occur. As illustrated in Figure 9, the substation loss X1 and load loss X2 are reduced from the sum of the active power distribution values ​​P[m] calculated by the above procedure ΣP[m], and as a result, AC power equivalent to the basic command value C0 (=130) is supplied from the management system 100 to the combination point 11.

[0054] Figure 10 shows a specific example of the operation of the allocation processing unit 523 when the total DC power command value Cp indicates charging (Cp < 0).

[0055] In step Sa1, the distribution processing unit 523 calculates the power distribution value Pa[m] to be distributed to each energy storage unit U[m] from the total DC power command value Cp, according to the distribution coefficient K[m] of each energy storage unit U[m]. Specifically, the distribution processing unit 523 calculates each power distribution value Pa[m] such that each power distribution value Pa[m] is a ratio corresponding to the distribution coefficient K[m]. That is, as shown in formula (2) above, the distribution processing unit 523 calculates each power distribution value Pa[m] by multiplying the ratio of each distribution coefficient K[m] to the sum of multiple distribution coefficients K[m] (K[1]~K[5]) ΣK[m] by the total DC power command value Cp of charging exemplified in Figure 6.

[0056] The power distribution value Pa[m] calculated in step Sa1 may exceed the charging limit value L[m]_c. When the total DC power command value Cp indicates charging, the case where the power distribution value Pa[m] exceeds the limit value L[m]_c means the case where the power distribution value Pa[m] is less than the limit value L[m]_c (Pa[m]<L[m]_c). For example, in FIG. 10, the power distribution value Pa[4](=-40) of the power storage unit U[4] exceeds the limit value L[4]_c(=-30), and the power distribution value Pa[5](=-50) of the power storage unit U[5] exceeds the limit value L[5]_c(=-40) are illustrated.

[0057] The distribution processing unit 523 distributes the total excess value E1, which is the sum of the excess values (Pa[m]-L[m]_c) for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] exceeds the limit value L[m]_c, to each of one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] does not exceed the limit value L[m]_c (Sa2~Sa5).

[0058] Specifically, in step Sa2 of FIG. 10, the distribution processing unit 523 calculates the total excess value E1 by summing the difference (i.e., the excess value) between the power distribution value Pa[m] and the limit value L[m]_c for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] exceeds the limit value L[m]_c. In the situation of FIG. 10, "-20", which is the sum of "-10", the excess value (Pa[4]-L[4]_c) of the power storage unit U[4], and "-10", the excess value (Pa[5]-L[5]_c) of the power storage unit U[5], is calculated as the total excess value E1.

[0059] In step Sa3, the allocation processing unit 523 calculates the total available power E2 by summing the difference (i.e., margin) between the limit value L[m]_c and the power allocation value Pa[m] for one or more energy storage units U[m] whose power allocation value Pa[m] does not exceed the limit value L[m]_c. In the situation shown in Figure 10, the total available power E2 is calculated as "-30", which is the sum of the margin value (L[1]_c-Pa[1]) of energy storage unit U[4], "-20", and the margin value (L[2]_c-Pa[2]) of energy storage unit U[2], "-10".

[0060] In step Sa4, the allocation processing unit 523 calculates an additional allocation value ΔP[m] for one or more energy storage units U[m] whose power allocation value Pa[m] does not exceed the limit value L[m]_c. Specifically, the allocation processing unit 523 calculates each additional allocation value ΔP[m] by performing the following calculation using formula (3b). That is, the allocation processing unit 523 calculates the additional allocation value ΔP[m] by multiplying the total excess value E1 by the ratio of each margin value (L[m]_c-Pa[m]) to the total available power E2.

number

[0061] In step Sa5, the allocation processing unit 523 calculates the power allocation value Pb[m] for each energy storage unit U[m]. That is, each power allocation value Pa[m] is updated to the power allocation value Pb[m]. Specifically, for one or more energy storage units U[m] whose power allocation value Pa[m] exceeds the limit value L[m]_c, the allocation processing unit 523 sets the limit value L[m]_c as the updated power allocation value Pb[m]. In addition, for one or more energy storage units U[m] whose power allocation value Pa[m] does not exceed the limit value L[m]_c, the allocation processing unit 523 calculates the updated power allocation value Pb[m] by adding an additional allocation value ΔP[m] to the power allocation value Pa[m]. For energy storage units U[m] among multiple energy storage units U[m] where the power distribution value Pa[m] and the limit value L[m]_c are equal, the power distribution value Pa[m] is adopted as the power distribution value Pb[m]. The power distribution value Pb[m] is the command value of the DC power that the energy storage device 31 of each energy storage unit U[m] should charge.

[0062] In step Sa6, the distribution processing unit 523 calculates the active power distribution value P[m] by subtracting the conversion loss x[m] in each energy storage unit U[m] from the power distribution value Pb[m] calculated for each energy storage unit U[m] (P[m]=Pb[m]-x[m]). In other words, the active power distribution value P[m] is the command value of the active power that the energy storage unit U[m] should charge, as described above. The operation by which the distribution processing unit 523 calculates the active power distribution value P[m] when the total DC power command value Cp indicates charging (Cp<0) is as described above.

[0063] As described above, between each energy storage unit U[m] and the combination point 11, a substation loss X1 due to the substation equipment 21 and a load loss X2 due to the load equipment 22 occur. As illustrated in Figure 11, the substation loss X1 and load loss X2 are reduced from the sum of the active power distribution values ​​P[m] calculated by the above procedure ΣP[m], and as a result, AC power equivalent to the basic command value C0 (=-170) is supplied from the combination point 11 to the management system 100.

[0064] Figure 12 is a flowchart of the overall operation of the control system 40 (hereinafter referred to as "control process"). For example, the control process in Figure 12 is repeated at a predetermined cycle.

[0065] When control processing begins, the control device 41 (command calculation unit 51) acquires the basic command value C0 (S1). The control device 41 (command calculation unit 51) calculates the total DC power command value Cp by adding power losses, including substation loss X1, load loss X2, and conversion loss X3, to the basic command value C0 (S2).

[0066] The control device 41 (command distribution unit 52) ​​calculates the active power distribution value P[m], which is the command value of the power to be distributed from the total DC power command value Cp to each of the multiple energy storage units U[m] (S3). A specific example of the process for calculating the active power distribution value P[m] is as described above with reference to Figures 8 and 10. The control device 41 (operation instruction unit 53) instructs each of the multiple energy storage units U[m] to have the active power distribution value P[m] for that energy storage unit U[m] (S4).

[0067] Furthermore, if the energy storage system 30 includes an energy storage unit U[m] that responds with DC power in response to a DC power command, the control device 41 (operation instruction unit 53) may instruct the energy storage unit U[m] to provide the power distribution value Pb[m] calculated for the energy storage unit U[m]. Also, if the energy storage system 30 includes an energy storage unit U[m] that responds with the active power at a point between the transformer 321 and the AC / DC converter 322 in response to an active power command at that point, the control device 41 (operation instruction unit 53) may instruct the energy storage unit U[m] to provide a value obtained by subtracting the loss of the transformer 321 in the energy storage unit U[m] from the power distribution value Pb[m] calculated for the energy storage unit U[m].

[0068] As explained above, in the first embodiment, the total DC power command value Cp is calculated by adding power losses, including the conversion loss X3 due to the conversion between DC power discharged or charged by the energy storage device 31 and AC power, and the transformation loss X1 due to the voltage transformation between the substation equipment 21 and the energy storage system 30, to the basic command value C0, and the total DC power command value Cp is allocated to each energy storage unit U[m]. Therefore, compared to an embodiment in which the basic command value C0 is allocated to each energy storage unit U[m] without considering the transformation loss X1 and the conversion loss X3, the effective power allocation value P[m] instructed to each energy storage unit U[m] can be calculated appropriately. When the basic command value C0 is small, the influence of the conversion losses (X1~X3) on the basic command value C0 increases relatively, so the configuration of the first embodiment in which the transformation loss X1 and the conversion loss X3 are taken into account in the basic command value C0 is particularly effective.

[0069] Furthermore, in the first embodiment, the total excess value E1, which is the sum of the excess values ​​of one or more energy storage units U[m] whose power distribution value Pa[m] exceeds the limit value L[m], is distributed to each of the one or more energy storage units U[m] whose power distribution value Pa[m] does not exceed the limit value L[m]. Therefore, while maintaining the combined point power at the basic command value C0, the power distributed to each energy storage unit U[m] can be suppressed to stay within the limit value L[m] range.

[0070] 2. Second Embodiment A second embodiment of this disclosure will now be described. For elements whose function is the same as in the first embodiment in each of the embodiments described below, the same reference numerals as in the first embodiment will be used, and detailed descriptions of each will be omitted as appropriate.

[0071] In the second embodiment, the configuration and operation of the limit value setting unit 522 differ from those in the first embodiment. The configuration and operation of elements other than the limit value setting unit 522 are the same as in the first embodiment. Therefore, the same effects as in the first embodiment are achieved in the second embodiment as well.

[0072] Figure 13 is a block diagram illustrating the configuration of the limit value setting unit 522 in the second embodiment. The transceiver 43 of the second embodiment receives state data D[m] from each energy storage unit U[m]. The state data D[m] is data representing the state of the energy storage unit U[m] (particularly the energy storage device 31). Specifically, the state data D[m] includes the voltage V[m], charge level S[m], and temperature T[m] of the energy storage device 31. The voltage V[m] is a measured value of the DC voltage used for discharging or charging the energy storage device 31 (for example, the voltage at the output terminal of the energy storage device 31). The charge level S[m] is the ratio of the current charge amount to the capacity (full charge capacity) of the energy storage device 31 (SOC: State of Charge). The temperature T[m] is a measured value of the temperature of the energy storage device 31.

[0073] As illustrated in Figure 13, the limit value setting unit 522 includes a first setting unit 61 and a second setting unit 62. The first setting unit 61 sets a discharge limit value L[m]_d for each energy storage unit U[m]. Specifically, the first setting unit 61 sets the limit value L[m]_d for each energy storage unit U[m] according to the state data D[m] acquired from the energy storage unit U[m]. Similarly, the second setting unit 62 sets a charge limit value L[m]_c for each energy storage unit U[m]. Specifically, the second setting unit 62 sets the limit value L[m]_c for each energy storage unit U[m] according to the state data D[m] acquired from the energy storage unit U[m].

[0074] [First setting section 61] The first setting unit 61 includes a candidate value setting unit 611, a candidate value setting unit 612, a candidate value setting unit 613, and a candidate value selection unit 614. The candidate value setting unit 611 sets a candidate value Z1[m]_d according to the voltage V[m] of the energy storage device 31. The candidate value setting unit 612 sets a candidate value Z2[m]_d according to the charge level S[m] of the energy storage device 31. The candidate value setting unit 613 sets a candidate value Z3[m]_d according to the temperature T[m] of the energy storage device 31. Note that candidate value Z1[m]_d is an example of a "first candidate value", candidate value Z2[m]_d is an example of a "second candidate value", and candidate value Z3[m]_d is an example of a "third candidate value".

[0075] The candidate value selection unit 614 selects a limit value L[m]_d from a plurality of candidate values ​​Z[m]_d. The plurality of candidate values ​​Z[m]_d include candidate values ​​Z1[m]_d, Z2[m]_d, and Z3[m]_d, as well as candidate values ​​Z4[m]_d and Z5[m]_d. Candidate value Z4[m]_d is the capacity on the discharge side at the DC end of the AC / DC converter 24 of the energy storage unit U[m]. Candidate value Z5[m]_d is the required value on the discharge side according to the specifications of the energy storage device 31 of the energy storage unit U[m]. Specifically, the candidate value selection unit 614 selects the minimum value among the plurality of candidate values ​​Z[m]_d as the limit value L[m]_d.

[0076] As can be understood from the above explanation, the limit value setting unit 522 selects a limit value L[m]_d from a plurality of candidate values ​​Z[m]_d relating to different states of each of the plurality of energy storage units U[m]. Therefore, the limit value L[m]_d can be appropriately set from multiple perspectives relating to the state of the energy storage unit U[m]. The setting of candidate values ​​Z1[m]_d, Z2[m]_d, and Z3[m]_d will be described in detail below.

[0077] [Setting of candidate value Z1[m]_d by candidate value setting unit 611] Figure 14 is an explanatory diagram illustrating the operation of the candidate value setting unit 611 in which candidate value Z1[m]_d is set according to the voltage V[m]. The relationship between voltage V[m] and candidate value Z1[m]_d is illustrated in Figure 14. Note that each element (R11[m]_d, R12[m]_d, R13[m]_d, V1[m]_d, V2[m]_d, z11[m]_d, z12[m]_d, z13[m]_d) relating to the relationship between voltage V[m] and candidate value Z1[m]_d may be set individually for each energy storage unit U[m], or it may be set to a common value across multiple energy storage units U[m].

[0078] As illustrated in Figure 14, the voltage range V[m] is divided into three ranges: the first range R11[m]_d, the second range R12[m]_d, and the third range R13[m]_d. The first range R11[m]_d is the range of positive numbers below a given voltage V1[m]_d. The second range R12[m]_d is the range above a given voltage V2[m]_d. Voltage V2[m]_d is above voltage V1[m]_d. The third range R13[m]_d is the range between the first range R11[m]_d and the second range R12[m]_d. That is, the third range R13[m]_d is the range between voltage V1[m]_d and voltage V2[m]_d.

[0079] If the voltage V[m] is a value within the first range R11[m]_d, the candidate value setting unit 611 sets the candidate value Z1[m]_d to the first value z11[m]_d. On the other hand, if the voltage V[m] is a value within the second range R12[m]_d, the candidate value setting unit 611 sets the candidate value Z1[m]_d to the second value z12[m]_d. The first value z11[m]_d is a fixed value less than the second value z12[m]_d. Specifically, the first value z11[m]_d is set to a negative number slightly below 0. On the other hand, the second value z12[m]_d is a variable positive value that changes according to the voltage V[m]. Specifically, the second value z12[m]_d increases monotonically with respect to the voltage V[m] at a predetermined gradient. Note that the second value z12[m]_d in Figure 14 is calculated, for example, by multiplying the voltage V[m] by the discharge current limit value of the energy storage unit U[m]. Therefore, if the voltage V[m] is a value within the second range R12[m]_d, the candidate value Z1[m]_d (and furthermore the limit value L[m]_d) can be set so as not to exceed the discharge current limit value of the energy storage unit U[m].

[0080] If the voltage V[m] is a value within the third range R13[m]_d, the candidate value setting unit 611 sets the candidate value Z1[m]_d to a third value z13[m]_d that changes according to the voltage V[m] between the first value z11[m]_d and the second value z12[m]_d. The third value z13[m]_d increases monotonically with respect to the voltage V[m] at a predetermined gradient. The gradient of the third value z13[m]_d with respect to the voltage V[m] is greater than the gradient of the second value z12[m]_d with respect to the voltage V[m].

[0081] As described above, in the second embodiment, the candidate value Z1[m]_d is set according to the voltage V[m] of the energy storage device 31. Therefore, the limit value L[m]_d can be appropriately set from the perspective of the voltage V[m] of the energy storage device 31. Furthermore, when the voltage V[m] is a value within the third range R13[m]_d, the candidate value Z1[m]_d changes between the first value z11[m]_d and the second value z12[m]_d according to the voltage V[m]. Therefore, compared to the form in which the candidate value Z1[m]_d is selectively set to either the first value z11[m]_d or the second value z12[m]_d, the steep and frequent fluctuations of the limit value L[m]_d according to the voltage V[m] of the energy storage device 31 can be suppressed. Furthermore, in a configuration where the candidate value Z1[m]_d (second value z12[m]_d) when the voltage V[m] is a value within the second range R12[m]_d is calculated by multiplying the voltage V[m] by the discharge-side current limit value of the energy storage unit U[m], the candidate value Z1[m]_d (and thus the limit value L[m]_d) can be set so as not to exceed the discharge-side current limit value of the energy storage unit U[m].

[0082] Furthermore, the first value z11[m]_d, which is the minimum value of the candidate value Z1[m]_d, is set to a negative number that instructs the energy storage device 31 to charge. Therefore, when the voltage V[m] of the energy storage device 31 falls within the first range R11[m]_d, a small amount of charging is performed on the energy storage device 31, and as a result, it is possible to raise the voltage V[m] to a specific range.

[0083] [Setting of candidate value Z2[m]_d by candidate value setting unit 612] Figure 15 is an explanatory diagram illustrating the operation of the candidate value setting unit 612 in which candidate value Z2[m]_d is set according to the charge level S[m]. The relationship between the charge level S[m] and candidate value Z2[m]_d is illustrated in Figure 15. Note that each element (R21[m]_d, R22[m]_d, R23[m]_d, S1[m]_d, S2[m]_d, z21[m]_d, z22[m]_d, z23[m]_d) relating to the relationship between voltage V[m] and candidate value Z2[m]_d may be set individually for each energy storage unit U[m], or a common value may be set across multiple energy storage units U[m].

[0084] As illustrated in Figure 15, the range of charge rate S[m] is divided into a first range R21[m]_d, a second range R22[m]_d, and a third range R23[m]_d. The first range R21[m]_d is the range below a predetermined charge rate S1[m]_d. The second range R22[m]_d is the range above a predetermined charge rate S2[m]_d. Charge rate S2[m]_d is above charge rate S1[m]_d. The third range R23[m]_d is the range between the first range R21[m]_d and the second range R22[m]_d. That is, the third range R23[m]_d is the range between charge rate S1[m]_d and charge rate S2[m]_d.

[0085] If the charge level S[m] is a value within the first range R21[m]_d, the candidate value setting unit 612 sets the candidate value Z2[m]_d to the first value z21[m]_d. On the other hand, if the charge level S[m] is a value within the second range R22[m]_d, the candidate value setting unit 612 sets the candidate value Z2[m]_d to the second value z22[m]_d. The first value z21[m]_d is a fixed value slightly below 0. The second value z22[m]_d is a fixed value greater than the first value z21[m]_d.

[0086] If the charge rate S[m] is a value within the third range R23[m]_d, the candidate value setting unit 612 sets the candidate value Z2[m]_d to a third value z23[m]_d that changes according to the charge rate S[m] between the first value z21[m]_d and the second value z22[m]_d. The third value z23[m]_d increases monotonically with respect to the charge rate S[m] at a predetermined gradient.

[0087] As described above, in the second embodiment, the candidate value Z2[m]_d is set according to the charge rate S[m] of the energy storage device 31. Therefore, the limit value L[m]_d can be appropriately set from the viewpoint of the charge rate S[m] of the energy storage device 31. Furthermore, when the charge rate S[m] is a value within the third range R23[m]_d, the candidate value Z2[m]_d changes between the first value z21[m]_d and the second value z22[m]_d according to the charge rate S[m]. Therefore, compared to the form in which the candidate value Z2[m]_d is selectively set to either the first value z21[m]_d or the second value z22[m]_d, the steep and frequent fluctuations of the limit value L[m]_d according to the charge rate S[m] of the energy storage device 31 can be suppressed.

[0088] Furthermore, the first value z21[m]_d, which is the minimum value of the candidate value Z2[m]_d, is set to a negative number that instructs the energy storage device 31 to charge. Therefore, when the charge rate S[m] of the energy storage device 31 falls within the first range R21[m]_d, a small amount of charging is performed on the energy storage device 31, and as a result, it is possible to raise the charge rate S[m] to a specific range.

[0089] [Setting of candidate value Z3[m]_d by candidate value setting unit 613] Figure 16 is an explanatory diagram illustrating the operation of the candidate value setting unit 613 in which the candidate value Z3[m]_d is set according to the temperature T[m]. The relationship between temperature T[m] and candidate value Z3[m]_d is illustrated in Figure 16. In Figure 16, an energy storage device 31 with the characteristic of generating heat due to discharge is assumed. Note that each element (R31[m]_d, R32[m]_d, R33[m]_d, T1[m]_d, T2[m]_d, z31[m]_d, z32[m]_d, z33[m]_d) relating to the relationship between voltage V[m] and candidate value Z3[m]_d may be set individually for each energy storage unit U[m], or it may be set to a common value across multiple energy storage units U[m].

[0090] As illustrated in Figure 16, the temperature range T[m] is divided into a first range R31[m]_d, a second range R32[m]_d, and a third range R33[m]_d. The first range R31[m]_d is the range above a predetermined temperature T1[m]_d. The second range R32[m]_d is the range below a predetermined temperature T2[m]_d. Temperature T2[m]_d is below temperature T1[m]_d. The third range R33[m]_d is the range between the first range R31[m]_d and the second range R32[m]_d. That is, the third range R33[m]_d is the range between temperature T1[m]_d and temperature T2[m]_d.

[0091] If the temperature T[m] is a value within the first range R31[m]_d, the candidate value setting unit 613 sets the candidate value Z3[m]_d to the first value z31[m]_d. On the other hand, if the temperature T[m] is a value within the second range R32[m]_d, the candidate value setting unit 613 sets the candidate value Z3[m]_d to the second value z32[m]_d. The first value z31[m]_d is a fixed value slightly below 0. The second value z32[m]_d is a fixed value greater than the first value z31[m]_d.

[0092] If the temperature T[m] is a value within the third range R33[m]_d, the candidate value setting unit 613 sets the candidate value Z3[m]_d to a third value z33[m]_d that changes according to the temperature T[m] between the first value z31[m]_d and the second value z32[m]_d. The third value z33[m]_d decreases monotonically with respect to the temperature T[m] at a predetermined gradient.

[0093] On the other hand, Figure 17 shows the relationship between temperature T[m] and candidate value Z3[m]_d when the energy storage device 31 absorbs heat by discharge. As illustrated in Figure 17, the range of temperature T[m] is divided into a first range R31[m]_d, a second range R32[m]_d, and a third range R33[m]_d. The first range R31[m]_d is the range below a predetermined temperature T1[m]_d. The second range R32[m]_d is the range above a predetermined temperature T2[m]_d. Temperature T2[m]_d is above temperature T1[m]_d. The third range R33[m]_d is the range between the first range R31[m]_d and the second range R32[m]_d. That is, the third range R33[m]_d is the range between temperature T1[m]_d and temperature T2[m]_d.

[0094] If the temperature T[m] is a value within the first range R31[m]_d, the candidate value setting unit 613 sets the candidate value Z3[m]_d to the first value z31[m]_d. On the other hand, if the temperature T[m] is a value within the second range R32[m]_d, the candidate value setting unit 613 sets the candidate value Z3[m]_d to the second value z32[m]_d. The first value z31[m]_d is a fixed value slightly below 0. The second value z32[m]_d is a fixed value greater than the first value z31[m]_d.

[0095] If the temperature T[m] is a value within the third range R33[m]_d, the candidate value setting unit 613 sets the candidate value Z3[m]_d to a third value z33[m]_d that changes according to the temperature T[m] between the first value z31[m]_d and the second value z32[m]_d. The third value z33[m]_d increases monotonically with respect to the temperature T[m] at a predetermined gradient.

[0096] As described above, in the second embodiment, the candidate value Z3[m]_d is set according to the temperature T[m] of the energy storage device 31. Therefore, the limit value L[m]_d can be appropriately set from the perspective of the temperature T[m] of the energy storage device 31. Furthermore, when the temperature T[m] is a value within the third range R33[m]_d, the candidate value Z3[m]_d changes between the first value z31[m]_d and the second value z32[m]_d according to the temperature T[m]. Therefore, compared to the form in which the candidate value Z3[m]_d is selectively set to either the first value z31[m]_d or the second value z32[m]_d, the steep and frequent fluctuations of the limit value L[m]_d according to the temperature T[m] of the energy storage device 31 can be suppressed.

[0097] Furthermore, the first value z31[m]_d, which is the minimum value of the candidate value Z3[m]_d, is set to a negative number that instructs the energy storage device 31 to charge. Therefore, when the temperature T[m] of the energy storage device 31 is within the first range R31[m]_d, a small amount of charging is performed on the energy storage device 31, and as a result, it is possible to return the temperature T[m] to a specific range.

[0098] [Second setting section 62] The second setting unit 62 in Figure 13 includes a candidate value setting unit 621, a candidate value setting unit 622, a candidate value setting unit 623, and a candidate value selection unit 624. The candidate value setting unit 621 sets a candidate value Z1[m]_c according to the voltage V[m] of the energy storage device 31. The candidate value setting unit 622 sets a candidate value Z2[m]_c according to the charge level S[m] of the energy storage device 31. The candidate value setting unit 623 sets a candidate value Z3[m]_c according to the temperature T[m] of the energy storage device 31. Note that candidate value Z1[m]_c is an example of a "first candidate value", candidate value Z2[m]_c is an example of a "second candidate value", and candidate value Z3[m]_c is an example of a "third candidate value".

[0099] The candidate value selection unit 624 selects a limit value L[m]_c from a plurality of candidate values ​​Z[m]_c. The plurality of candidate values ​​Z[m]_c include candidate values ​​Z1[m]_c, Z2[m]_c, and Z3[m]_c, as well as candidate values ​​Z4[m]_c and Z5[m]_c. Candidate value Z4[m]_c is the capacity on the charging side at the DC end of the AC / DC converter 24 of the energy storage unit U[m]. Candidate value Z5[m]_c is the required value on the charging side according to the specifications of the energy storage device 31 of the energy storage unit U[m]. Specifically, the candidate value selection unit 624 selects the maximum value among the plurality of candidate values ​​Z[m]_c as the limit value L[m]_c.

[0100] As can be understood from the above explanation, the limit value setting unit 522 selects a limit value L[m]_c from a plurality of candidate values ​​Z[m]_c relating to different states of each of the plurality of energy storage units U[m]. Therefore, the limit value L[m]_c can be appropriately set from multiple perspectives regarding the state of the energy storage unit U[m]. The setting of candidate values ​​Z1[m]_c, Z2[m]_c, and Z3[m]_c will be described in detail below.

[0101] [Setting of candidate value Z1[m]_c by candidate value setting unit 621] Figure 18 is an explanatory diagram illustrating the operation of the candidate value setting unit 621, which sets the candidate value Z1[m]_c according to the voltage V[m]. The relationship between the voltage V[m] and the candidate value Z1[m]_c is illustrated in Figure 18. Note that each element (R11[m]_c, R12[m]_c, R13[m]_c, V1[m]_c, V2[m]_c, z11[m]_c, z12[m]_c, z13[m]_c) relating to the relationship between the voltage V[m] and the candidate value Z1[m]_c may be set individually for each energy storage unit U[m], or it may be set to a common value across multiple energy storage units U[m].

[0102] As illustrated in Figure 18, the voltage range V[m] is divided into three ranges: the first range R11[m]_c, the second range R12[m]_c, and the third range R13[m]_c. The first range R11[m]_c is the range above a predetermined voltage V1[m]_c. The second range R12[m]_c is the range below a predetermined voltage V2[m]_c. Voltage V2[m]_c is below voltage V1[m]_c. The third range R13[m]_c is the range between the first range R11[m]_c and the second range R12[m]_c. That is, the third range R13[m]_c is the range between voltage V1[m]_c and voltage V2[m]_c.

[0103] If the voltage V[m] is a value within the first range R11[m]_c, the candidate value setting unit 621 sets the candidate value Z1[m]_c to the first value z11[m]_c. On the other hand, if the voltage V[m] is a value within the second range R12[m]_c, the candidate value setting unit 621 sets the candidate value Z1[m]_c to the second value z12[m]_c. The first value z11[m]_c is a fixed value that is greater than the second value z12[m]_c. Specifically, the first value z11[m]_c is set to a positive number slightly above 0. On the other hand, the second value z12[m]_c is a variable negative value that changes according to the voltage V[m]. Specifically, the second value z12[m]_c decreases monotonically with respect to the voltage V[m] at a predetermined gradient. Note that the second value z12[m]_c in Figure 18 is calculated, for example, by multiplying the voltage V[m] by the current limit value on the charging side of the energy storage unit U[m]. Therefore, if the voltage V[m] is a value within the second range R12[m]_c, a candidate value Z1[m]_c (and furthermore, the limit value L[m]_c) can be set so as not to exceed the current limit value on the charging side of the energy storage unit U[m].

[0104] If the voltage V[m] is a value within the third range R13[m]_c, the candidate value setting unit 621 sets the candidate value Z1[m]_c to a third value z13[m]_c that changes according to the voltage V[m] between the first value z11[m]_c and the second value z12[m]_c. The third value z13[m]_c increases monotonically with respect to the voltage V[m] at a predetermined gradient. The gradient of the third value z13[m]_c with respect to the voltage V[m] is greater than the gradient of the second value z12[m]_c with respect to the voltage V[m].

[0105] As described above, in the second embodiment, the candidate value Z1[m]_c is set according to the voltage V[m] of the energy storage device 31. Therefore, the limit value L[m]_c can be appropriately set from the viewpoint of the voltage V[m] of the energy storage device 31. Furthermore, when the voltage V[m] is a value within the third range R13[m]_c, the candidate value Z1[m]_c changes between the first value z11[m]_c and the second value z12[m]_c according to the voltage V[m]. Therefore, compared to the form in which the candidate value Z1[m]_c is selectively set to either the first value z11[m]_c or the second value z12[m]_c, the steep and frequent fluctuations of the limit value L[m]_c according to the voltage V[m] of the energy storage device 31 can be suppressed. Furthermore, in a configuration where the candidate value Z1[m]_c (second value z12[m]_c) when the voltage V[m] is a value within the second range R12[m]_c is calculated by multiplying the voltage V[m] by the current limit value on the charging side of the energy storage unit U[m], the candidate value Z1[m]_c (and consequently the limit value L[m]_c) can be set so as not to exceed the current limit value on the charging side of the energy storage unit U[m].

[0106] The first value z11[m]_c, which is the maximum value of the candidate value Z1[m]_c, is set to a positive number that instructs the energy storage device 31 to discharge. Therefore, when the voltage V[m] of the energy storage device 31 rises within the first range R11[m]_c, a small discharge is performed by the energy storage device 31, which in turn makes it possible to reduce the voltage V[m] to a specific range.

[0107] [Setting of candidate value Z2[m]_c by candidate value setting unit 622] Figure 19 is an explanatory diagram illustrating the operation of the candidate value setting unit 622 in which candidate value Z2[m]_c is set according to the charge level S[m]. The relationship between the charge level S[m] and the candidate value Z2[m]_c is illustrated in Figure 19. Note that each element (R21[m]_c, R22[m]_c, R23[m]_c, S1[m]_c, S2[m]_c, z21[m]_c, z22[m]_c, z23[m]_c) relating to the relationship between voltage V[m] and candidate value Z2[m]_c may be set individually for each energy storage unit U[m], or a common value may be set across multiple energy storage units U[m].

[0108] As illustrated in Figure 19, the range of charge rate S[m] is divided into a first range R21[m]_c, a second range R22[m]_c, and a third range R23[m]_c. The first range R21[m]_c is the range above a predetermined charge rate S1[m]_c. The second range R22[m]_c is the range below a predetermined charge rate S2[m]_c. Charge rate S2[m]_c is below charge rate S1[m]_c. The third range R23[m]_c is the range between the first range R21[m]_c and the second range R22[m]_c. That is, the third range R23[m]_c is the range between charge rate S1[m]_c and charge rate S2[m]_c.

[0109] If the charge level S[m] is a value within the first range R21[m]_c, the candidate value setting unit 622 sets the candidate value Z2[m]_c to the first value z21[m]_c. On the other hand, if the charge level S[m] is a value within the second range R22[m]_c, the candidate value setting unit 622 sets the candidate value Z2[m]_c to the second value z22[m]_c. The first value z21[m]_c is a fixed value slightly above 0. The second value z22[m]_c is a fixed value below the first value z21[m]_c.

[0110] If the charge rate S[m] is a value within the third range R23[m]_c, the candidate value setting unit 622 sets the candidate value Z2[m]_c to a third value z23[m]_c that changes according to the charge rate S[m] between the first value z21[m]_c and the second value z22[m]_c. The third value z23[m]_c increases monotonically with respect to the charge rate S[m] at a predetermined gradient.

[0111] As described above, in the second embodiment, the candidate value Z2[m]_c is set according to the charge rate S[m] of the energy storage device 31. Therefore, the limit value L[m]_c can be appropriately set from the viewpoint of the charge rate S[m] of the energy storage device 31. Furthermore, when the charge rate S[m] is a value within the third range R23[m]_c, the candidate value Z2[m]_c changes between the first value z21[m]_c and the second value z22[m]_c according to the charge rate S[m]. Therefore, compared to the form in which the candidate value Z2[m]_c is selectively set to either the first value z21[m]_c or the second value z22[m]_c, the steep and frequent fluctuations of the limit value L[m]_c according to the charge rate S[m] of the energy storage device 31 can be suppressed.

[0112] The first value z21[m]_c, which is the maximum value of the candidate value Z2[m]_c, is set to a positive number that instructs the energy storage device 31 to discharge. Therefore, when the voltage V[m] of the energy storage device 31 rises within the first range R21[m]_c, a small discharge is performed by the energy storage device 31, which in turn makes it possible to reduce the voltage V[m] to a specific range.

[0113] [Setting of candidate value Z3[m]_c by candidate value setting unit 623] Figure 20 is an explanatory diagram illustrating the operation of the candidate value setting unit 623 in which candidate value Z3[m]_c is set according to the temperature T[m]. The relationship between temperature T[m] and candidate value Z3[m]_c is illustrated in Figure 20. Note that each element (R31[m]_c, R32[m]_c, R33[m]_c, T1[m]_c, T2[m]_c, z31[m]_c, z32[m]_c, z33[m]_c) relating to the relationship between voltage V[m] and candidate value Z3[m]_c may be set individually for each energy storage unit U[m], or may be set to a common value across multiple energy storage units U[m]. Furthermore, Figure 20 assumes an energy storage device 31 that absorbs heat during charging.

[0114] As illustrated in Figure 20, the temperature range T[m] is divided into three ranges: the first range R31[m]_c, the second range R32[m]_c, and the third range R33[m]_c. The first range R31[m]_c is the range below a predetermined temperature T1[m]_c. The second range R32[m]_c is the range above a predetermined temperature T2[m]_c. Temperature T2[m]_c is above temperature T1[m]_c. The third range R33[m]_c is the range between the first range R31[m]_c and the second range R32[m]_c. That is, the third range R33[m]_c is the range between temperature T1[m]_c and temperature T2[m]_c.

[0115] If the temperature T[m] is a value within the first range R31[m]_c, the candidate value setting unit 623 sets the candidate value Z3[m]_c to the first value z31[m]_c. On the other hand, if the temperature T[m] is a value within the second range R32[m]_c, the candidate value setting unit 623 sets the candidate value Z3[m]_c to the second value z32[m]_c. The first value z31[m]_c is a fixed value slightly above 0. The second value z32[m]_c is a fixed value below the first value z31[m]_c.

[0116] If the temperature T[m] is a value within the third range R33[m]_c, the candidate value setting unit 623 sets the candidate value Z3[m]_c to a third value z33[m]_c that changes according to the temperature T[m] between the first value z31[m]_c and the second value z32[m]_c. The third value z33[m]_c decreases monotonically with respect to the temperature T[m] at a predetermined gradient.

[0117] Figure 21 shows the relationship between temperature T[m] and candidate value Z3[m]_c when the energy storage device 31 generates heat due to charging. As illustrated in Figure 21, the range of temperature T[m] is divided into a first range R31[m]_c, a second range R32[m]_c, and a third range R33[m]_c. The first range R31[m]_c is the range above a predetermined temperature T1[m]_c. The second range R32[m]_c is the range below a predetermined temperature T2[m]_c. Temperature T2[m]_c is below temperature T1[m]_c. The third range R33[m]_c is the range between the first range R31[m]_c and the second range R32[m]_c. That is, the third range R33[m]_c is the range between temperature T1[m]_c and temperature T2[m]_c.

[0118] If the temperature T[m] is a value within the first range R31[m]_c, the candidate value setting unit 623 sets the candidate value Z3[m]_c to the first value z31[m]_c. On the other hand, if the temperature T[m] is a value within the second range R32[m]_c, the candidate value setting unit 623 sets the candidate value Z3[m]_c to the second value z32[m]_c. The first value z31[m]_c is a fixed value slightly above 0. The second value z32[m]_c is a fixed value below the first value z31[m]_c.

[0119] If the temperature T[m] is a value within the third range R33[m]_c, the candidate value setting unit 623 sets the candidate value Z3[m]_c to a third value z33[m]_c that changes according to the temperature T[m] between the first value z31[m]_c and the second value z32[m]_c. The third value z33[m]c increases monotonically with respect to the temperature T[m] at a predetermined gradient.

[0120] As described above, in the second embodiment, the candidate value Z3[m]_c is set according to the temperature T[m] of the energy storage device 31. Therefore, the limit value L[m]_c can be appropriately set from the perspective of the temperature T[m] of the energy storage device 31. Furthermore, when the temperature T[m] is a value within the third range R33[m]_c, the candidate value Z3[m]_c changes between the first value z31[m]_c and the second value z32[m]_c according to the temperature T[m]. Therefore, compared to the form in which the candidate value Z3[m]_c is selectively set to either the first value z31[m]_c or the second value z32[m]_c, the steep and frequent fluctuations of the limit value L[m]_c according to the temperature T[m] of the energy storage device 31 can be suppressed.

[0121] The first value z31[m]_c, which is the maximum value of the candidate value Z3[m]_c, is set to a positive number that instructs the energy storage device 31 to discharge. Therefore, when the temperature T[m] of the energy storage device 31 is within the first range R31[m]_c, a small discharge is performed by the energy storage device 31, which in turn makes it possible to return the temperature T[m] to a specific range.

[0122] Note that the relationship between each element of the state data D[m] (voltage V[m], charge level S[m], or temperature T[m]) and the candidate value Z[m] is not limited to the relationships exemplified in Figures 14 to 21. For example, a relationship in which the candidate value Z[m] changes curvilinearly may hold for each element of the state data D[m].

[0123] 3. Third Embodiment In the third embodiment, the operation of the coefficient setting unit 521, which sets the distribution coefficient K[m], differs from that of the first embodiment. The configuration and operation of elements other than the coefficient setting unit 521 are the same as in the first embodiment. Therefore, the same effects as in the first embodiment are achieved in the third embodiment as well.

[0124] Figures 22 and 23 are explanatory diagrams illustrating the operation of the coefficient setting unit 521 in the third embodiment. The coefficient setting unit 521 in the third embodiment sets the distribution coefficient K[m] for each energy storage unit U[m] by executing the first process Sb1, the second process Sb2, and the third process Sb3.

[0125] The first process Sb1 is the process of setting a weight value α[m] for each of the multiple energy storage units U[m]. The weight value α[m] is the reference value that forms the basis of the distribution coefficient K[m]. In the third embodiment, it is assumed that each weight value α[m] is set to a common positive number. However, each weight value α[m] may be different.

[0126] The second process Sb2 is a process that sets a correction value β[m] for each of the multiple energy storage units U[m], according to the operating watt-hour capacity B[m] of the energy storage unit U[m]. Specifically, the second process Sb2 includes processes Sb21 and Sb22.

[0127] Process Sb21 is a process for calculating the operating watt-hour capacity B[m] of each energy storage unit U[m]. The operating watt-hour capacity B[m] is the amount of energy (Wh) corresponding to the capacity of the energy storage device 31 in the energy storage unit U[m]. As illustrated in Figure 23, the operating watt-hour capacity B[m] may differ for each energy storage unit U[m].

[0128] Figure 24 is an explanatory diagram of the operating watt-hour capacity B[m]. Figure 24 illustrates the total watt-hour capacity B_all[m] of the energy storage unit U[m]. The total watt-hour capacity B_all[m] is the total usable capacity in the energy storage unit U[m]. Specifically, the total watt-hour capacity B_all[m] is calculated from the initial watt-hour capacity B0[m] and health H[m] of the energy storage device 31 in the energy storage unit U[m].

[0129] The initial watt-hour capacity B0[m] is the initial watt-hour capacity of the energy storage device 31 (i.e., the maximum watt-hour capacity expected for an undegraded energy storage device 31). Health H[m] is the ratio of the current watt-hour capacity to the initial watt-hour capacity B0[m] (SOH: State of Health). The coefficient setting unit 521 calculates the total watt-hour capacity B_all[m] by multiplying, for example, health H[m] and the initial watt-hour capacity B0[m] (B_all[m] = H[m] × B0[m]).

[0130] Furthermore, the energy storage device 31 is operated at a charge rate S[m] within a predetermined range (hereinafter referred to as the "operational charge rate range Rs[m]"). That is, the operational charge rate range Rs[m] is the specified range of charge rates S[m] in which the energy storage device 31 can be used. Specifically, the operational charge rate range Rs[m] is the range between the minimum value Smin[m] and the maximum value Smax[m] of the charge rate S[m]. As illustrated in Figure 24, the operating watt-hour capacity B[m] corresponds to the operational charge rate range Rs[m] of the charge rate S[m]. In the second process Sb2, the coefficient setting unit 521 calculates the operating watt-hour capacity B[m] by the calculation of the following formula (4) in process Sb21 of the second process Sb2.

number

[0131] The second process Sb2 in Figures 22 and 23 is a process that calculates a correction value β[m] for each of the multiple energy storage units U[m] according to the operating watt-hour capacity B[m] of the energy storage unit U[m]. Specifically, the coefficient setting unit 521 calculates the correction value β[m] as the ratio of the operating watt-hour capacity B[m] to the total value ΣB[m] of the operating watt-hour capacity B[m] across the multiple energy storage units U[m] (β[m] = B[m] / ΣB[m]). However, the method for calculating the correction value β[m] is not limited to the above examples.

[0132] The third process Sb3 is a process that calculates the allocation coefficient K[m] for each of the multiple energy storage units U[m] according to the weighted value α[m] and the correction value β[m]. Specifically, the product of the weighted value α[m] and the correction value β[m] is calculated as the allocation coefficient K[m] (K[m] = α[m] × β[m]). However, the method for calculating the allocation coefficient K[m] is not limited to the above examples. For example, a configuration in which the weighted sum of the weighted value α[m] and the correction value β[m] is calculated as the allocation coefficient K[m], or a configuration in which the allocation coefficient K[m] is calculated by a predetermined calculation including the weighted value α[m] and the correction value β[m] is also conceivable. Furthermore, the use of the correction value β[m] may be omitted. For example, the allocation coefficient K[m] may be calculated by a predetermined calculation applying only the weighted value α[m].

[0133] As described above, the coefficient setting unit 521 of the third embodiment sets the distribution coefficient K[m] according to the operating watt-hour capacity B[m] of each energy storage unit U[m]. For example, the larger the operating watt-hour capacity B[m], the larger the value of the distribution coefficient K[m] is set to. As can be understood from the description of the first embodiment, generally speaking, the larger the distribution coefficient K[m], the larger the active power distribution value P[m] of each energy storage unit U[m] becomes.

[0134] In a configuration where the allocation coefficient K[m] does not depend on the operating watt-hour capacity B[m] of each energy storage unit U[m] (hereinafter referred to as "proportional"), for example, the allocation coefficient K[m] of an energy storage device 31 with a small operating watt-hour capacity B[m] may be set to a large value. Therefore, in the proportional configuration, the time required for discharge or charge according to the active power allocation value P[m], or the charge rate of the energy storage device 31, may differ significantly for each energy storage unit U[m]. As described above, if the discharge or charge conditions of the energy storage device 31 differ significantly among each energy storage unit U[m], there is a problem that the rate of characteristic degradation of the energy storage device 31 will differ for each energy storage unit U[m].

[0135] In the third embodiment, as described above, the distribution coefficient K[m] is set according to the operating watt-hour capacity B[m] of each energy storage unit U[m]. Therefore, variations in the discharge or charge time or the charge rate of the energy storage device 31 among the energy storage units U[m] are suppressed. Thus, according to the third embodiment, it is possible to suppress variations in the rate of characteristic degradation of the energy storage device 31 among the energy storage units U[m] compared to proportionality.

[0136] 4. Fourth Embodiment In the third embodiment, a case in which each weighting value α[m] is set to a common positive number is conveniently illustrated. The fourth embodiment is a specific example of the first process Sb1 in which the coefficient setting unit 521 sets the weighting value α[m] in the third embodiment.

[0137] Figure 25 is an explanatory diagram of the first process Sb1 in the fourth embodiment. Figure 25 also illustrates the aforementioned operational charge range Rs[m]. As described above, the operational charge range Rs[m] is the range between the minimum value Smin[m] and the maximum value Smax[m] of the charge rate S[m]. As illustrated in Figure 25, the first process Sb1 in the fourth embodiment includes a normalization process Sb11, a deviation calculation process Sb12, and a weighted value setting process Sb13.

[0138] The operational charge rate range Rs[m] of the energy storage device 31 may differ for each energy storage unit U[m]. Specifically, one or both of the minimum value Smin[m] and the maximum value Smax[m] may differ for each energy storage unit U[m]. The normalization process Sb11 is a process that normalizes the charge rate S[m] of the energy storage device 31 for each energy storage unit U[m] to a charge rate Sn[m] within a predetermined numerical range (hereinafter referred to as the "standard range Rs_n").

[0139] The standard range Rs_n is a common numerical range across multiple energy storage units U[m]. Specifically, the standard range Rs_n is from a minimum value of 0 to a maximum value of 1. That is, the normalized charge rate Sn[m] will be a value within the standard range Rs_n, from a minimum value of 0 to a maximum value of 1, regardless of the operational charge rate range Rs[m] of each energy storage unit U[m].

[0140] Specifically, in the normalization process Sb11, the coefficient setting unit 521 calculates the normalized charge rate Sn[m] by performing the following calculation using formula (5).

number

[0141] The deviation calculation process Sb12 calculates the deviation ΔS[m] between the normalized charge rate Sn[m] obtained by the normalization process Sb11 and the reference value Sref (ΔS[m] = Sn[m] - Sref). The reference value Sref is, for example, a representative value of the charge rate Sn[m] across multiple energy storage units U[m]. Specifically, the average value of the charge rate Sn[m] (for example, a simple average) is used as the reference value Sref to calculate the deviation ΔS[m]. Note that the deviation ΔS[m] is an example of the "first deviation".

[0142] The weighting value setting process Sb13 is a process that sets the weighting value α[m] according to the deviation ΔS[m] calculated by the deviation calculation process Sb12.

[0143] The larger the deviation ΔS[m] of a storage unit U[m], the higher its charge rate Sn[m] is compared to other storage units U[m]. Therefore, when the total DC power command value Cp indicates discharge (Cp>0), storage units U[m] with a larger deviation ΔS[m] should be given priority for discharge. On the other hand, the larger the allocation coefficient K[m] (the larger the weighting value α[m]), the larger the effective power allocation value P[m] for each storage unit U[m]. Taking these circumstances into consideration, the coefficient setting unit 521 of the fourth embodiment sets the weighting value α[m] to a larger value as the deviation ΔS[m] increases.

[0144] On the other hand, when the total DC power command value Cp indicates charging (Cp < 0), energy storage units U [m] with smaller deviations ΔS [m] should be given priority for charging. On the other hand, the larger the allocation coefficient K [m] (the larger the weighting value α [m]), the larger the active power allocation value P [m] for each energy storage unit U [m] becomes. Taking these circumstances into consideration, the coefficient setting unit 521 of the fourth embodiment sets the weighting value α [m] to a larger value the smaller the deviation ΔS [m].

[0145] As described above, in the fourth embodiment, the weighted value α[m] (and thus the distribution coefficient K[m]) is set according to the charge rate S[m] of the energy storage device 31 in each energy storage unit U[m]. Therefore, each distribution coefficient K[m] can be set so that the charge rates S[m] of each energy storage device 31 approach each other. Consequently, the possibility that the output of each energy storage unit U[m] is limited due to the charge rate S[m] of the energy storage device 31 can be reduced. In other words, the total energy storage capacity of the energy storage system 30 can be effectively utilized.

[0146] In the fourth embodiment, the following embodiments 4A and 4B may be adopted as methods for the coefficient setting unit 521 to calculate the weighted value α[m] according to the deviation ΔS[m].

[0147] [Aspect 4A] Figures 26 and 27 are explanatory diagrams illustrating the process by which the coefficient setting unit 521 calculates the weighted value α[m] in embodiment 4A of the fourth embodiment. Specifically, the relationship between the deviation ΔS[m] of the charge rate S[m] and the weighted value α[m] is illustrated in Figures 26 and 27.

[0148] Figure 26 is an explanatory diagram of the weighted value α[m] when the total DC power command value Cp indicates discharge (Cp>0). As illustrated in Figure 26, when the total DC power command value Cp indicates discharge, the coefficient setting unit 521 generally sets the weighted value α[m] to the function value Fa(ΔS). The function value Fa(ΔS) is a variable value corresponding to the deviation ΔS[m]. The larger the deviation ΔS[m], the larger the function value Fa(ΔS) is set to. Note that the function value Fa(ΔS) is an example of a "second value".

[0149] In FIG. 26, threshold values Y1 and Y2 are illustrated. The threshold values Y1 and Y2 are positive numbers. The threshold value Y1 is greater than the threshold value Y2 (Y1>Y2). When the deviation ΔS[m] increases from a value below the threshold value Y1 to a value above the threshold value Y1, the coefficient setting unit 521 sets the weighting value α[m] from the function value Fa(ΔS) to the maximum value 1 (the first value). With the above configuration, each effective power distribution value P[m] is set so that the power storage unit U[m] with a large deviation ΔS[m] among the plurality of power storage units U[m] preferentially executes discharging. On the other hand, when the deviation ΔS[m] decreases from a value above the threshold value Y2 to a value below the numerical value Y2, the coefficient setting unit 521 sets the weighting value α[m] to the function value Fa(ΔS).

[0150] Also, in FIG. 26, threshold values Y3 and Y4 are illustrated. The threshold values Y3 and Y4 are negative numbers. The threshold value Y3 is less than the threshold value Y4 (Y3<Y4). When the deviation ΔS[m] decreases from a value above the threshold value Y3 to a value below the threshold value Y3, the coefficient setting unit 521 sets the weighting value α[m] from the function value Fa(ΔS) to the minimum value 0 (the second value). With the above configuration, each effective power distribution value P[m] is set so that discharging of the power storage unit U[m] with a small deviation ΔS[m] among the plurality of power storage units U[m] is preferentially avoided. Also, when the deviation ΔS[m] increases from a value below the threshold value Y4 to a value above the numerical value Y4, the coefficient setting unit 521 sets the weighting value α[m] to the function value Fa(ΔS).

[0151] FIG. 27 is an explanatory diagram of the weighting value α[m] when the total DC power command value Cp indicates charging (Cp<0). As illustrated in FIG. 27, when the total DC power command value Cp indicates charging, the coefficient setting unit 521 generally sets the weighting value α[m] to the function value Fa(ΔS). The function value Fa(ΔS) is a variable value corresponding to the deviation ΔS[m]. The larger the deviation ΔS[m], the smaller the function value Fa(ΔS) is set.

[0152] The coefficient setting unit 521 sets the weighting value α[m] from the function value Fa(ΔS) to the minimum value 0 (first value) when the deviation ΔS[m] increases from a value below the threshold Y1 to a value above the threshold Y1. With this configuration, each active power distribution value P[m] is set so that charging of the energy storage unit U[m] with a large deviation ΔS[m] among the multiple energy storage units U[m] is preferentially avoided. In addition, the coefficient setting unit 521 sets the weighting value α[m] to the function value Fa(ΔS) when the deviation ΔS[m] decreases from a value above the threshold Y2 to a value below the value Y2.

[0153] The coefficient setting unit 521 sets the weighting value α[m] from the function value Fa(ΔS) to the maximum value 1 (second value) when the deviation ΔS[m] decreases from a value above the threshold Y3 to a value below the threshold Y3. With this configuration, each active power distribution value P[m] is set so that the energy storage unit U[m] with the smallest deviation ΔS[m] among the multiple energy storage units U[m] is given priority in charging. In addition, the coefficient setting unit 521 sets the weighting value α[m] to the function value Fa(ΔS) when the deviation ΔS[m] increases from a value below the threshold Y4 to a value above the threshold Y4.

[0154] As described above, in embodiment 4A, the relationship between the deviation ΔS[m] and the weighted value α[m] exhibits hysteresis characteristics. Therefore, even when the deviation ΔS[m] fluctuates near each threshold (Y1, Y2, Y3, Y4), excessively frequent fluctuations in the weighted value α[m] can be suppressed. Note that each threshold (Y1, Y2, Y3, Y4) related to the deviation ΔS[m] may be set individually for each energy storage unit U[m], or it may be set to a common value across multiple energy storage units U[m].

[0155] [Aspect 4B] Figures 28 and 29 are explanatory diagrams illustrating the process by which the coefficient setting unit 521 calculates the weighted value α[m] in embodiment 4B of the fourth embodiment. Specifically, the relationship Fb(ΔS) between the deviation ΔS[m] of the charge rate S[m] and the weighted value α[m] is illustrated in Figures 28 and 29.

[0156] Figure 28 is an explanatory diagram of the weighted value α[m] when the total DC power command value Cp indicates discharge (Cp>0). As illustrated in Figure 28, the relationship Fb(ΔS) is represented by a straight line passing through a point corresponding to a predetermined positive number s1 of the deviation ΔS[m] and the maximum value 1 of the weighted value α[m]. The coefficient setting unit 521 sets the numerical value in the relationship Fb(ΔS) with respect to the deviation ΔS[m] as the weighted value α[m].

[0157] Furthermore, the coefficient setting unit 521 determines the relationship Fb(ΔS) according to the total DC power command value Cp. Specifically, the coefficient setting unit 521 changes the slope of the relationship Fb(ΔS) according to the absolute value |Cp| of the total DC power command value Cp. For example, the larger the absolute value |Cp|, the smaller the slope of the relationship Fb(ΔS). Specifically, the relationship Fb(ΔS) changes between relationship F1 and relationship F2 according to the absolute value |Cp|.

[0158] When relation Fb(ΔS) is set to relation F1, the weighting value α[m] is set to a positive number for energy storage units U[m] whose deviation ΔS[m] is within a wide range from negative s2 to positive s1. Because the weighting value α[m] is set to a positive number, the distribution coefficient K[m] is also set to a positive number, so that each active power distribution value P[m] is set so that a large number of energy storage units U[m] perform discharge. The positive number s1 and the negative number s2 are arbitrary values.

[0159] When relation Fb(ΔS) is set to relation F2, the weighting value α[m] is set to a positive number for energy storage units U[m] whose deviation ΔS[m] is within the range of positive numbers. On the other hand, for energy storage units U[m] whose deviation ΔS[m] is within the range of negative numbers, the weighting value α[m] is set to 0, and therefore the distribution coefficient K[m] is also set to 0. In other words, each active power distribution value P[m] is set so that some energy storage units U[m] whose deviation ΔS[m] is within the range of positive numbers preferentially perform discharge.

[0160] Figure 29 is an explanatory diagram of the weighted value α[m] when the total DC power command value Cp indicates charging (Cp<0). As illustrated in Figure 29, the relationship Fb(ΔS) is represented by a straight line passing through a point corresponding to a predetermined negative number s2 of the deviation ΔS[m] and the maximum value 1 of the weighted value α[m]. The coefficient setting unit 521 sets the numerical value in the relationship Fb(ΔS) with respect to the deviation ΔS[m] as the weighted value α[m].

[0161] The coefficient setting unit 521 determines the relationship Fb(ΔS) according to the total DC power command value Cp. Specifically, the coefficient setting unit 521 changes the slope of the relationship Fb(ΔS) according to the absolute value |Cp| of the total DC power command value Cp. For example, the larger the absolute value |Cp|, the smaller the slope of the relationship Fb(ΔS). Specifically, the relationship Fb(ΔS) changes between relationship F1 and relationship F2 according to the absolute value |Cp|.

[0162] When relation Fb(ΔS) is set to relation F1, the weighting value α[m] is set to a positive number for energy storage units U[m] whose deviation ΔS[m] is within a wide range from negative s2 to positive s1. As the weighting value α[m] is set to a positive number, the distribution coefficient K[m] is also set to a positive number, so that each active power distribution value P[m] is set so that a large number of energy storage units U[m] perform charging.

[0163] When relation Fb(ΔS) is set to relation F2, the weighting value α[m] is set to a positive number for energy storage units U[m] whose deviation ΔS[m] is within the negative range. On the other hand, for energy storage units U[m] whose deviation ΔS[m] is within the positive range, the weighting value α[m] is set to 0, and therefore the allocation coefficient K[m] is also set to 0. In other words, each active power allocation value P[m] is set so that some energy storage units U[m] whose deviation ΔS[m] is within the negative range are given preferential treatment in charging.

[0164] As described above, according to embodiment 4B, the relationship Fb(ΔS) between the deviation ΔS[m] and the weighted value α[m] is determined according to the total DC power command value Cp. Therefore, compared to the form in which the relationship between the deviation ΔS[m] and the weighted value α[m] is fixed, the total DC power command value Cp can be appropriately distributed to multiple energy storage units U[m]. Note that the configuration in which the relationship Fb(ΔS) changes according to the total DC power command value Cp may be omitted. That is, the relationship Fb(ΔS) may be a fixed relationship between, for example, relationship F1 and relationship F2.

[0165] 5. Fifth Embodiment In the third embodiment, a case in which each weighting value α[m] is set to a common positive number is conveniently illustrated. The fifth embodiment is a specific example of the first process Sb1 in which the coefficient setting unit 521 sets the weighting value α[m] in the third embodiment, similar to the fourth embodiment.

[0166] Figure 30 is an explanatory diagram of the first process Sb1 in the fifth embodiment. As illustrated in Figure 30, the first process Sb1 in the fifth embodiment includes a normalization process Sb11, a deviation calculation process Sb12, and a weighted value setting process Sb13, similar to the fourth embodiment.

[0167] Figure 30 illustrates the operating temperature range Rt[m] of the energy storage device 31. The operating temperature range Rt[m] is the specified range of temperatures T[m] in which the energy storage device 31 can be used. Specifically, the operating temperature range Rt[m] is the range between the minimum value Tmin[m] and the maximum value Tmax[m] of the temperature T[m].

[0168] The operating temperature range Rt[m] of the energy storage device 31 may differ for each energy storage unit U[m]. Specifically, one or both of the minimum value Tmin[m] and the maximum value Tmax[m] may differ for each energy storage unit U[m]. The normalization process Sb11 is a process that normalizes the temperature T[m] of the energy storage device 31 for each energy storage unit U[m] to a temperature Tn[m] within a predetermined numerical range (hereinafter referred to as the "standard range Rt_n").

[0169] The standard range Rt_n, like the standard range Rs_n in the fourth embodiment, is a numerical range common to multiple energy storage units U[m]. In the normalization process Sb11, the coefficient setting unit 521 calculates the normalized temperature Tn[m] by the following formula (6).

number

[0170] The deviation calculation process Sb12 calculates the deviation ΔT[m] between the temperature Tn[m] normalized by the normalization process Sb11 and the reference value Tref (ΔT[m]=Tn[m]-Tref). The reference value Tref is, for example, a representative value (e.g., the average value) of the temperature Tn[m] across multiple energy storage units U[m]. Note that the deviation ΔT[m] is an example of a "second deviation".

[0171] The weighting value setting process Sb13 is a process that sets the weighting value α[m] according to the deviation ΔT[m] calculated by the deviation calculation process Sb12. In the following explanation, it is assumed that the energy storage device 31 of each energy storage unit U[m] absorbs heat when discharging and releases heat when charging. That is, the temperature T[m] of the energy storage device 31 decreases when discharging and increases when charging.

[0172] The larger the deviation ΔT[m] of a storage unit U[m], the higher its temperature Tn[m] is compared to other storage units U[m]. Therefore, when the total DC power command value Cp indicates discharge (Cp>0), the storage unit U[m] with a larger deviation ΔT[m] should be given priority for discharge to lower its temperature T[m]. Taking these circumstances into consideration, the coefficient setting unit 521 of the fifth embodiment sets the weighting value α[m] to a larger value as the deviation ΔT[m] increases.

[0173] On the other hand, when the total DC power command value Cp indicates charging (Cp < 0), the energy storage unit U [m] with a smaller deviation ΔT [m] should be given priority for charging in order to raise the temperature T [m]. Taking these circumstances into consideration, the coefficient setting unit 521 of the fifth embodiment sets the weighting value α [m] to a larger value as the deviation ΔT [m] decreases.

[0174] As described above, in the fifth embodiment, the weighted value α[m] (and thus the distribution coefficient K[m]) is set according to the temperature T[m] of the energy storage device 31 in each energy storage unit U[m]. Therefore, each distribution coefficient K[m] can be set so that the temperatures T[m] of each energy storage device 31 are close to each other. Consequently, the possibility that the output of each energy storage unit U[m] will be limited due to variations in the temperature T[m] of the energy storage device 31 can be reduced. In other words, the total energy storage capacity of the energy storage system 30 can be effectively utilized.

[0175] In the fifth embodiment, the following embodiments 5A and 5B can be adopted as methods for the coefficient setting unit 521 to calculate the weighted value α[m] according to the deviation ΔT[m].

[0176] [Aspect 5A] Figures 31 and 32 are explanatory diagrams illustrating the process by which the coefficient setting unit 521 calculates the weighted value α[m] in embodiment 5A of the fifth embodiment. Specifically, the relationship between the temperature T[m] deviation ΔT[m] and the weighted value α[m] is illustrated in Figures 31 and 32.

[0177] Figure 31 is an explanatory diagram of the weighted value α[m] when the total DC power command value Cp indicates discharge (Cp>0). As illustrated in Figure 31, when the total DC power command value Cp indicates discharge, the coefficient setting unit 521 generally sets the weighted value α[m] to the function value Fa(ΔT). The function value Fa(ΔT) is a variable value corresponding to the deviation ΔT[m]. The larger the deviation ΔT[m], the larger the function value Fa(ΔT) is set to. Note that the function value Fa(ΔT) is an example of a "second value".

[0178] The coefficient setting unit 521 sets the weighting value α[m] from the function value Fa(ΔT) to the maximum value 1 (first value) when the deviation ΔT[m] increases from a value below the threshold Y1 to a value above the threshold Y1. With this configuration, each active power distribution value P[m] is set so that the energy storage unit U[m] with the largest deviation ΔT[m] among the multiple energy storage units U[m] is given priority in discharge. On the other hand, the coefficient setting unit 521 sets the weighting value α[m] to the function value Fa(ΔT) when the deviation ΔT[m] decreases from a value above the threshold Y2 to a value below the value Y2.

[0179] The coefficient setting unit 521 sets the weighting value α[m] from the function value Fa(ΔT) to the minimum value 0 (second value) when the deviation ΔT[m] decreases from a value above the threshold Y3 to a value below the threshold Y3. With this configuration, the active power distribution value P[m] is set so that the discharge of the energy storage unit U[m] with the smallest deviation ΔT[m] among the multiple energy storage units U[m] is preferentially avoided. In addition, the coefficient setting unit 521 sets the weighting value α[m] to the function value Fa(ΔT) when the deviation ΔT[m] increases from a value below the threshold Y4 to a value above the threshold Y4.

[0180] Figure 32 is an explanatory diagram of the weighted value α[m] when the total DC power command value Cp indicates charging (Cp<0). As illustrated in Figure 32, when the total DC power command value Cp indicates charging, the coefficient setting unit 521 generally sets the weighted value α[m] to the function value Fa(ΔT). The function value Fa(ΔT) is a variable value corresponding to the deviation ΔT[m]. The larger the deviation ΔT[m], the smaller the value of the function value Fa(ΔT) is set to.

[0181] The coefficient setting unit 521 sets the weighting value α[m] from the function value Fa(ΔT) to the minimum value 0 (first value) when the deviation ΔT[m] increases from a value below the threshold Y1 to a value above the threshold Y1. With this configuration, each active power distribution value P[m] is set so that charging of the energy storage unit U[m] with a large deviation ΔT[m] among the multiple energy storage units U[m] is preferentially avoided. On the other hand, the coefficient setting unit 521 sets the weighting value α[m] to the function value Fa(ΔT) when the deviation ΔT[m] decreases from a value above the threshold Y2 to a value below the value Y2.

[0182] Furthermore, the coefficient setting unit 521 sets the weighting value α[m] from the function value Fa(ΔT) to the maximum value 1 (second value) when the deviation ΔT[m] decreases from a value above the threshold Y3 to a value below the threshold Y3. With the above configuration, each active power distribution value P[m] is set so that the energy storage unit U[m] with the smallest deviation ΔT[m] among the multiple energy storage units U[m] is given priority in charging. On the other hand, the coefficient setting unit 521 sets the weighting value α[m] to the function value Fa(ΔT) when the deviation ΔT[m] increases from a value below the threshold Y4 to a value above the value Y4.

[0183] As described above, in embodiment 5A, the relationship between the deviation ΔT[m] and the weighted value α[m] exhibits hysteresis characteristics. Therefore, even when the deviation ΔT[m] fluctuates near each threshold (Y1, Y2, Y3, Y4), excessively frequent fluctuations in the weighted value α[m] can be suppressed. Note that each threshold (Y1, Y2, Y3, Y4) related to the deviation ΔT[m] may be set individually for each energy storage unit U[m], or it may be set to a common value across multiple energy storage units U[m].

[0184] [Aspect 5B] Figures 33 and 34 are explanatory diagrams illustrating the process by which the coefficient setting unit 521 calculates the weighted value α[m] in embodiment 5B of the fifth embodiment. Specifically, the relationship Fb(ΔT) between the temperature T[m] deviation ΔT[m] and the weighted value α[m] is illustrated in Figures 33 and 34.

[0185] Figure 33 is an explanatory diagram of the weighted value α[m] when the total DC power command value Cp indicates discharge (Cp>0). As illustrated in Figure 33, the relationship Fb(ΔT) is represented by a straight line passing through a point corresponding to a predetermined positive number s1 of the deviation ΔT[m] and the maximum value 1 of the weighted value α[m]. The coefficient setting unit 521 sets the numerical value in the relationship Fb(ΔT) with respect to the deviation ΔT[m] as the weighted value α[m].

[0186] Furthermore, the coefficient setting unit 521 determines the relationship Fb(ΔT) according to the total DC power command value Cp. Specifically, the coefficient setting unit 521 decreases the slope of the relationship Fb(ΔT) as the absolute value |Cp| increases. In other words, the relationship Fb(ΔT) changes between relationship F1 and relationship F2 according to the absolute value |Cp|.

[0187] When relation Fb(ΔT) is set to relation F1, the weighting value α[m] is set to a positive number for energy storage units U[m] whose deviation ΔT[m] is within a wide range from negative s2 to positive s1. Therefore, each active power distribution value P[m] is set so that a large number of energy storage units U[m] perform discharge. On the other hand, when relation Fb(ΔT) is set to relation F2, the weighting value α[m] is set to a positive number for energy storage units U[m] whose deviation ΔT[m] is within a positive range, while the weighting value α[m] is set to 0 for energy storage units U[m] whose deviation ΔT[m] is within a negative range. Therefore, each active power distribution value P[m] is set so that some energy storage units U[m] whose deviation ΔT[m] is within a positive range perform discharge preferentially.

[0188] Figure 34 is an explanatory diagram of the weighted value α[m] when the total DC power command value Cp indicates charging (Cp<0). As illustrated in Figure 34, the relationship Fb(ΔT) is represented by a straight line passing through the point corresponding to the negative number s2 of the deviation ΔT[m] and the maximum value 1 of the weighted value α[m]. The coefficient setting unit 521 sets the numerical value in the relationship Fb(ΔT) with respect to the deviation ΔT[m] as the weighted value α[m].

[0189] Furthermore, the coefficient setting unit 521 determines the relationship Fb(ΔT) according to the total DC power command value Cp. Specifically, the coefficient setting unit 521 decreases the slope of the relationship Fb(ΔT) as the absolute value |Cp| increases. In other words, the relationship Fb(ΔT) changes between relationship F1 and relationship F2 according to the absolute value |Cp|.

[0190] When relation Fb(ΔT) is set to relation F1, the weighted value α[m] is set to a positive number for energy storage units U[m] whose deviation ΔT[m] is within a wide range from negative s2 to positive s1. Therefore, each active power distribution value P[m] is set so that a large number of energy storage units U[m] perform charging. On the other hand, when relation Fb(ΔT) is set to relation F2, the weighted value α[m] is set to a positive number for energy storage units U[m] whose deviation ΔT[m] is within a negative range, while the weighted value α[m] is set to 0 for energy storage units U[m] whose deviation ΔT[m] is within a positive range. Therefore, each active power distribution value P[m] is set so that some energy storage units U[m] whose deviation ΔT[m] is within a negative range perform charging preferentially.

[0191] As described above, according to embodiment 5B, the relationship Fb(ΔT) between the deviation ΔT[m] and the weighted value α[m] is determined according to the total DC power command value Cp. Therefore, compared to the form in which the relationship between the deviation ΔT[m] and the weighted value α[m] is fixed, the total DC power command value Cp can be appropriately distributed to multiple energy storage units U[m]. Note that the configuration in which the relationship Fb(ΔT) changes according to the total DC power command value Cp may be omitted. That is, the relationship Fb(ΔT) may be a fixed relationship between, for example, relationship F1 and relationship F2.

[0192] In the above explanation, it was assumed that the energy storage device 31 of each energy storage unit U[m] absorbs heat through discharge and releases heat through charging. However, depending on the type of energy storage device 31, it is also possible that the energy storage device 31 releases heat through discharge and absorbs heat through charging. In a configuration in which an energy storage device 31 with the characteristic of releasing heat through discharge and absorbing heat through charging is installed in each energy storage unit U[m], the relationship between the deviation ΔT[m] and the weighted value α[m] in the above-described embodiments 5A and 5B becomes an inverted relationship with respect to the vertical axis. Furthermore, in a configuration in which an energy storage device 31 with the characteristic of releasing heat through both discharge and charging is installed in each energy storage unit U[m], in embodiment 5A the characteristics of Figure 32 apply regardless of the polarity of the total DC power command value Cp, and in embodiment 5B the characteristics of Figure 34 apply regardless of the polarity of the total DC power command value Cp.

[0193] 6. Sixth Embodiment In the third embodiment, a case in which each weighting value α[m] is set to a common positive number is conveniently illustrated. The sixth embodiment is a specific example of the first process Sb1 in which the coefficient setting unit 521 sets the weighting value α[m] in the third embodiment, similar to the fourth embodiment.

[0194] Figure 35 is an explanatory diagram of the first process Sb1 in the sixth embodiment. As illustrated in Figure 35, the first process Sb1 in the sixth embodiment includes a normalization process Sb11, a deviation calculation process Sb12, and a weighted value setting process Sb13, similar to the fourth embodiment.

[0195] In the sixth embodiment, we focus on the number of charge-discharge cycles N[m] of the energy storage device 31 in each energy storage unit U[m]. The number of charge-discharge cycles N[m] is the number of times the charge-discharge pair is repeated (number of cycles). Specifically, the number of charge-discharge cycles N[m] is the number of repetitions of a pair of charging from the minimum value Smin[m] to the maximum value Smax[m] of the charge rate S[m] and discharging from the maximum value Smax[m] to the minimum value Smin[m]. The number of charge-discharge cycles N[m] is included in the state data D[m] transmitted from each energy storage unit U[m] to the control system 40.

[0196] The number of charge / discharge cycles N[m] may be measured by the control system 40. Alternatively, the sum of the accumulated power obtained by integrating the DC power in the charging direction between the energy storage device 31 and the power adjustment device 32, and the accumulated power obtained by integrating the DC power in the discharging direction (integrated charge / discharge power) may be applied as the number of charge / discharge cycles N[m].

[0197] The maximum number of cycles Nmax[m] in Figure 35 is the maximum value of the number of charge / discharge cycles N[m] in operation of the energy storage unit U[m] (i.e., the lifespan of the energy storage device 31). In the form in which the aforementioned cumulative charge / discharge energy is applied as the number of charge / discharge cycles N[m], the maximum number of cycles Nmax[m] is the maximum value of the cumulative charge / discharge energy in operation of the energy storage unit U[m]. The normalization process Sb11 is a process that normalizes the number of charge / discharge cycles N[m] of the energy storage device 31 of each energy storage unit U[m] to a number of charge / discharge cycles Nn[m] within a predetermined numerical range (hereinafter referred to as the "standard range Rn_n").

[0198] The standard range Rn_n, like the standard range Rs_n in the fourth embodiment, is a numerical range common to multiple energy storage units U[m]. In the normalization process Sb11, the coefficient setting unit 521 calculates the normalized charge / discharge cycle Nn[m] by the following formula (7).

number

[0199] The deviation calculation process Sb12 calculates the deviation ΔN[m] between the normalized charge / discharge cycle count Nn[m] (normalized by the normalization process Sb11) and the reference value Nref (ΔN[m] = Nn[m] - Nref). The reference value Nref is, for example, a representative value (e.g., the average value) of the charge / discharge cycle count Nn[m] across multiple energy storage units U[m]. Note that the deviation ΔN[m] is an example of a "third deviation".

[0200] The weighting value setting process Sb13 is a process that sets the weighting value α[m] according to the deviation ΔN[m] calculated by the deviation calculation process Sb12. Energy storage units U[m] with a larger deviation ΔN[m] have a relatively higher number of charge / discharge cycles Nn[m] compared to other energy storage units U[m]. Therefore, the coefficient setting unit 521 should preferentially allocate energy storage units U[m] with a smaller deviation ΔN[m] to discharge or charge. Taking these circumstances into consideration, the coefficient setting unit 521 of the sixth embodiment sets the weighting value α[m] to a larger value as the deviation ΔN[m] decreases.

[0201] As described above, in the sixth embodiment, the weighted value α[m] (and thus the distribution coefficient K[m]) is set according to the number of charge / discharge cycles N[m] of the energy storage device 31 in each energy storage unit U[m]. Therefore, each distribution coefficient K[m] can be set so that the number of charge / discharge cycles N[m] of each energy storage device 31 approaches each other. Consequently, the possibility that the output of each energy storage unit U[m] will be limited due to variations in the number of charge / discharge cycles N[m] of the energy storage device 31 can be reduced. In other words, the total energy storage capacity of the energy storage system 30 can be effectively utilized.

[0202] In the sixth embodiment, the coefficient setting unit 521 may employ the following embodiments 6A and 6B as methods for calculating the weighted value α[m] according to the deviation ΔN[m].

[0203] [Aspect 6A] Figure 36 is an explanatory diagram of the process by which the coefficient setting unit 521 calculates the weighted value α[m] in embodiment 6A of the sixth embodiment. Specifically, Figure 36 illustrates the relationship between the deviation ΔN[m] of the number of charge / discharge cycles N[m] and the weighted value α[m]. The relationship between the deviation ΔN[m] and the weighted value α[m] is the same regardless of whether the total DC power command value Cp represents discharge or charge.

[0204] As illustrated in Figure 36, the coefficient setting unit 521 generally sets the weighted value α[m] to the function value Fa(ΔN). The function value Fa(ΔN) is a variable value corresponding to the deviation ΔN[m]. The larger the deviation ΔN[m], the smaller the value of the function value Fa(ΔN) is set to. Note that the function value Fa(ΔN) is an example of a "second value".

[0205] The coefficient setting unit 521 sets the weighting value α[m] from the function value Fa(ΔN) to the minimum value 0 (first value) when the deviation ΔN[m] increases from a value below the threshold Y1 to a value above the threshold Y1. With this configuration, each active power distribution value P[m] is set so that the discharge and charging of the energy storage unit U[m] with a large deviation ΔN[m] among the multiple energy storage units U[m] are preferentially avoided. On the other hand, the coefficient setting unit 521 sets the weighting value α[m] to the function value Fa(ΔN) when the deviation ΔN[m] decreases from a value above the threshold Y2 to a value below the value Y2.

[0206] Furthermore, the coefficient setting unit 521 sets the weighting value α[m] from the function value Fa(ΔN) to the maximum value 1 (second value) when the deviation ΔN[m] decreases from a value above the threshold Y3 to a value below the threshold Y3. With the above configuration, each active power distribution value P[m] is set so that the energy storage unit U[m] with the smallest deviation ΔN[m] among the multiple energy storage units U[m] preferentially performs discharge and charging. On the other hand, the coefficient setting unit 521 sets the weighting value α[m] to the function value Fa(ΔN) when the deviation ΔN[m] increases from a value below the threshold Y4 to a value above the value Y4.

[0207] As described above, in embodiment 6A, the relationship between the deviation ΔN[m] and the weighted value α[m] exhibits hysteresis characteristics. Therefore, even when the deviation ΔN[m] fluctuates near each threshold (Y1, Y2, Y3, Y4), excessively frequent fluctuations in the weighted value α[m] can be suppressed. Note that each threshold (Y1, Y2, Y3, Y4) related to the deviation ΔN[m] may be set individually for each energy storage unit U[m], or it may be set to a common value across multiple energy storage units U[m].

[0208] [Aspect 6B] Figure 37 is an explanatory diagram of the process by which the coefficient setting unit 521 calculates the weighted value α[m] in embodiment 6B of the sixth embodiment. Specifically, Figure 37 shows the relationship Fb(ΔN) between the deviation ΔN[m] of the number of charge / discharge cycles N[m] and the weighted value α[m].

[0209] As illustrated in Figure 37, the relationship Fb(ΔN) is represented by a straight line passing through a point corresponding to a predetermined negative number s2 of the deviation ΔN[m] and the maximum value 1 of the weighting value α[m]. The coefficient setting unit 521 sets the numerical value in the relationship Fb(ΔN) for the deviation ΔN[m] as the weighting value α[m].

[0210] Furthermore, the coefficient setting unit 521 determines the relationship Fb(ΔN) according to the total DC power command value Cp. Specifically, the coefficient setting unit 521 decreases the slope of the relationship Fb(ΔN) as the absolute value |Cp| increases. In other words, the relationship Fb(ΔN) changes between relationship F1 and relationship F2 according to the absolute value |Cp|.

[0211] When relation Fb(ΔN) is set to relation F1, the weighted value α[m] is set to a positive number for energy storage units U[m] whose deviation ΔN[m] is within a wide range from negative s2 to positive s1. Therefore, each active power distribution value P[m] is set so that a large number of energy storage units U[m] perform discharge or charge. On the other hand, when relation Fb(ΔN) is set to relation F2, the weighted value α[m] is set to a positive number for energy storage units U[m] whose deviation ΔN[m] is within a negative range, while the weighted value α[m] is set to 0 for energy storage units U[m] whose deviation ΔN[m] is within a positive range. Therefore, each active power distribution value P[m] is set so that some energy storage units U[m] whose deviation ΔN[m] is within a positive range preferentially perform discharge or charge.

[0212] As described above, according to embodiment 6B, the relationship Fb(ΔN) between the deviation ΔN[m] and the weighted value α[m] is determined according to the total DC power command value Cp. Therefore, compared to the form in which the relationship between the deviation ΔN[m] and the weighted value α[m] is fixed, the total DC power command value Cp can be appropriately distributed to multiple energy storage units U[m]. Note that the configuration in which the relationship Fb(ΔN) changes according to the total DC power command value Cp may be omitted. That is, the relationship Fb(ΔN) may be a fixed relationship between, for example, relationship F1 and relationship F2.

[0213] 7. Seventh Embodiment Figure 38 is an explanatory diagram of the first process Sb1 in the seventh embodiment. As illustrated in Figure 38, the first process Sb1 in the seventh embodiment includes setting process Sc11, setting process Sc12, setting process Sc13, adjustment process Sc21, adjustment process Sc22, adjustment process Sc23, and addition process Sc3.

[0214] The setting process Sc11 is a process that sets a weighted value α1[m] according to the charge rate S[m] of the energy storage device 31 in each energy storage unit U[m]. The weighted value α1[m] corresponds to the weighted value α[m] in the fourth embodiment. That is, the setting process Sc11 includes, for example, the normalization process Sb11, the deviation calculation process Sb12, and the weighted value setting process Sb13 in the fourth embodiment. The adjustment process Sc21 is a process that adjusts the weighted value α1[m] by multiplying it by an adjustment value γ1[m]. The adjustment value γ1[m] is set to a predetermined value. Note that the weighted value α1[m] is an example of a "first weighted value".

[0215] The setting process Sc12 is a process that sets a weighted value α2[m] corresponding to the temperature T[m] of the energy storage device 31 in each energy storage unit U[m]. The weighted value α2[m] corresponds to the weighted value α[m] in the fifth embodiment. That is, the setting process Sc12 includes, for example, the normalization process Sb11, the deviation calculation process Sb12, and the weighted value setting process Sb13 in the fifth embodiment. The adjustment process Sc22 is a process that adjusts the weighted value α2[m] by multiplying it by an adjustment value γ2[m]. The adjustment value γ2[m] is set to a predetermined value. Note that the weighted value α2[m] is an example of a "second weighted value".

[0216] The setting process Sc13 is a process that sets a weighted value α3[m] corresponding to the number of charge / discharge cycles N[m] of the energy storage device 31 in each energy storage unit U[m]. The weighted value α3[m] corresponds to the weighted value α[m] in the sixth embodiment. That is, the setting process Sc13 includes, for example, the normalization process Sb11, the deviation calculation process Sb12, and the weighted value setting process Sb13 in the sixth embodiment. The adjustment process Sc23 is a process that adjusts the weighted value α3[m] by multiplying it by an adjustment value γ3[m]. The adjustment value γ3[m] is set to a predetermined value. Note that the weighted value α3[m] is an example of a "third weighted value".

[0217] The addition process Sc3 calculates the final weighted value α[m] by adding the adjusted values ​​γ1[m]·α1[m] from the adjustment process Sc21, the adjusted values ​​γ2[m]·α2[m] from the adjustment process Sc22, and the adjusted values ​​γ3[m]·α3[m] from the adjustment process Sc23. In other words, the coefficient setting unit 521 of the seventh embodiment sets the weighted value α[m] by the weighted sum of the weighted value α1[m] corresponding to the charge rate S[m], the weighted value α2[m] corresponding to the temperature T[m], and the weighted value α3[m] corresponding to the number of charge / discharge cycles N[m]. The adjusted values ​​γ1[m], γ2[m], and γ3[m] may be set to different values ​​or to a common value.

[0218] Note that some or all of adjustment processes Sc21, Sc22, and Sc23 may be omitted. For example, the coefficient setting unit 521 may set the weighted value α[m] by adding weighted values ​​α1[m], α2[m], and α3[m]. As can be understood from the above examples, the coefficient setting unit 521 of the seventh embodiment sets the weighted value α[m] according to weighted values ​​α1[m], α2[m], and α3[m]. Note that the third process Sb3, which calculates the distribution coefficient K[m] according to the weighted value α[m] and the correction value β[m] corresponding to the operating watt-hour capacity B[m] described above, is the same as in the third embodiment (Figure 22).

[0219] In the seventh embodiment, the weighted value α[m] is set according to the charge level S[m], temperature T[m], and charge / discharge cycle N[m] of each energy storage unit U[m]. Therefore, compared to an embodiment in which the weighted value α[m] is set according to only a specific state of the energy storage unit U[m], an appropriate weighted value α[m] (and thus the distribution coefficient K[m]) can be set from various perspectives (S[m], T[m], N[m]) regarding the state of the energy storage device 31.

[0220] 8. Eighth Embodiment Figure 39 is an explanatory diagram of the operation of the coefficient setting unit 521 in the eighth embodiment. The coefficient setting unit 521 of the eighth embodiment includes a smoothing process Sd in addition to the same processes (Sb1, Sb2, Sb3) as in the third embodiment. The smoothing process Sd is a process that reduces the rate of temporal variation of the distribution coefficient K[m] calculated by the third process Sb3.

[0221] Figure 40 is an explanatory diagram of the smoothing process Sd. As illustrated in Figure 40, the allocation coefficient K[m] immediately after the third process Sb3 may fluctuate discontinuously on the time axis. On the other hand, the allocation coefficient K[m] after the smoothing process Sd fluctuates continuously on the time axis. As explained above, the smoothing process Sd is a low-pass filter process that suppresses high-frequency components in the time series of the allocation coefficient K[m].

[0222] For example, if the allocation coefficient K[1] of energy storage unit U[1] changes sharply, the active power allocation value P[1] of energy storage unit U[1] will change in conjunction, and the active power allocation values ​​P[m] of the other energy storage units U[2] to U[5] will also change sharply in conjunction. However, there may be variations in the time it takes for each energy storage unit U[m] to receive the active power allocation value P[m]. Therefore, there is a possibility that the combined point power will change during the period from the time the allocation coefficient K[1] changes until the change in the allocation coefficient K[1] is reflected in the active power of all energy storage units U[m]. According to the eighth embodiment, the rate of temporal change of the allocation coefficient K[m] is reduced, so the possibility of sudden changes in the combined point power due to sharp changes in the allocated power of each energy storage unit U[m] can be reduced.

[0223] Figure 41 is an explanatory diagram of the specific configuration for realizing the smoothing process Sd. As illustrated in Figure 41, the coefficient setting unit 521 is supplied with an allocation target flag f[m] for each energy storage unit U[m]. The allocation target flag f[m] is a flag that indicates whether the total DC power command value Cp is to be allocated or not. Specifically, the allocation target flag f[m] for energy storage units U[m] that are to be allocated is set to a valid value (e.g., 1), and the allocation target flag f[m] for energy storage units U[m] that are not to be allocated is set to a invalid value (e.g., 0). For example, for each energy storage unit U[m] in a normal operating state, the allocation target flag f[m] is set to a valid value. On the other hand, for example, for energy storage units U[m] that are unable to respond to instructions from the control system 40 (e.g., stopped), or for each energy storage unit U[m] that is undergoing maintenance work such as repair or inspection, the allocation target flag f[m] is set to a invalid value.

[0224] As illustrated in Figure 41, the coefficient setting unit 521 includes a switching unit 5212 and a smoothing unit 5213. The allocation target flag f[m] is supplied to the switching unit 5212.

[0225] The smoothing unit 5213 smooths out the temporal fluctuations of the allocation coefficient K[m]. For example, a low-pass filter consisting of three first-order lag filters connected in series is exemplified as the smoothing unit 5213. The switching unit 5212 is a switch that switches whether or not to supply the allocation coefficient K[m] calculated by the third process Sb3 to the smoothing unit 5213, according to the allocation target flag f[m].

[0226] In the above configuration, for example, for a storage unit U[m] that starts operation upon completion of maintenance work, the allocation target flag f[m] is changed from an invalid value to an enabled value. When the allocation target flag f[m] is changed to an enabled value, the supply of the allocation coefficient K[m] to the smoothing unit 5213 begins. Therefore, it is possible to stably start (soft start) the setting and fluctuation of the allocation coefficient K[m] for a storage unit U[m] that starts operation.

[0227] On the other hand, for example, in the case of a storage unit U[m] that is shut down for maintenance work, the distribution target flag f[m] is changed from an active value to an inactive value, thereby stopping the supply of the distribution coefficient K[m] to the smoothing unit 5213. Therefore, it is possible to stably stop (soft stop) the setting and fluctuation of the distribution coefficient K[m] for a storage unit U[m] that is shut down.

[0228] 9. Ninth Embodiment The ninth embodiment is a configuration for additionally activating one or more energy storage units U[m] during the operation of the energy storage system 30.

[0229] FIG. 42 is an explanatory diagram regarding the operation when one power storage unit U[1] is additionally activated during the discharge by the four power storage units U[2] to U[5] of the power storage system 30. The conversion loss X3 before the activation of the power storage unit U[1] is a numerical value (for example, 4) obtained by summing the conversion losses x[m] for the four power storage units U[2] to U[5] during discharge. As a result of the activation of the power storage unit U[1], the conversion loss X3 is changed to a numerical value (for example, 5) obtained by summing the conversion losses x[m] for the five power storage units U[1] to U[5]. Therefore, as illustrated in FIG. 42, the total DC power command value Cp calculated by the command calculation unit 51 is changed by the activation of the power storage unit U[1].

[0230] As illustrated in FIG. 42, when the power storage unit U[1] is activated, the coefficient setting unit 521 increases the distribution coefficient K[1] from the minimum value 0 to the target value, and the limit value setting unit 522 increases the limit value L[1]_d from the reference value 0 to the target value. The target value of the distribution coefficient K[1] is, for example, a numerical value calculated according to the third to eighth embodiments, and the target value of the limit value L[1]_d is, for example, a numerical value calculated according to the second embodiment.

[0231] As described above, each power distribution value Pa[m] is calculated by multiplying the ratio of each distribution coefficient K[m] to the total value ΣK[m] of the distribution coefficients K[m] by the total DC power command value Cp. Therefore, when the distribution coefficient K[1] increases, as illustrated in FIG. 42, the power distribution value Pa[m] of the power storage unit U[1] to be added increases, while the power distribution values Pa[m] of the existing power storage units U[2] to U[5] decrease.

[0232] Figure 43 is an explanatory diagram illustrating the temporal changes in the distribution coefficient K[1] and the power distribution value Pa[1]. As illustrated in Figure 43, the coefficient setting unit 521 increases the distribution coefficient K[1] over time from a minimum value of 0 to a target value of 5 from the start to the end of period Ta. Consequently, the power distribution value Pa[1] increases over time from a minimum value of 0 to a target value of 40 from the start to the end of period Ta. The start of period Ta is, for example, the point at which the administrator of the management system 100 instructs the energy storage unit U[1] to start up, and when the energy storage unit U[1] becomes ready to respond to instructions from the control system 40.

[0233] Figure 43 also shows the temporal change in the active power distribution value P[1] limited by the limit value L[1]_d. The limit value setting unit 522 increases the limit value L[1]_d over time from the reference value 0 to the target value 40 from the start to the end of period Tb, thereby increasing the active power distribution value P[1] over time from the reference value 0 to the target value 39. The start of period Tb is the same time as the start of period Ta.

[0234] As described above, as the allocation coefficient K[1] and the limit value L[1]_d change over time, the active power allocation value P[1] of the energy storage unit U[1] increases over time from the initial value of 0 to the target value of 39 from the beginning to the end of period Tb. In the above explanation, the case in which the length of period Tb exceeds the length of period Ta was used as an example, but there are also cases in which the length of period Tb is less than the length of period Ta.

[0235] Figure 44 is an explanatory diagram of the operation when an additional energy storage unit U[5] is activated while charging is being performed by the four energy storage units U[1] to U[4] of the energy storage system 30. Similar to the case in Figure 42, the addition of energy storage unit U[5] changes the conversion loss X3, and as a result, the total DC power command value Cp calculated by the command calculation unit 51 is also changed.

[0236] As illustrated in Figure 44, when the energy storage unit U[5] is activated, the coefficient setting unit 521 increases the distribution coefficient K[5] from a minimum value of 0 to a target value, and the limit value setting unit 522 decreases the limit value L[5]_c from a reference value of 0 to a target value. As a result of the changes in the distribution coefficient K[5] and the limit value L[5]_c, the power distribution value Pa[5] of the additional energy storage unit U[5] decreases within the negative range, while the power distribution values ​​Pa[m] of the existing energy storage units U[1] to U[4] increase.

[0237] Figure 45 is an explanatory diagram illustrating the temporal changes in the distribution coefficient K[5] and the power distribution value Pa[5]. As illustrated in Figure 45, the coefficient setting unit 521 increases the distribution coefficient K[5] over time from a minimum value of 0 to a target value of 5 from the start to the end of period Ta. Consequently, the power distribution value Pa[5] decreases over time from an initial value of 0 to a target value of -40 from the start to the end of period Ta. The start of period Ta is, for example, the time when the administrator of the management system 100 instructs the start of the energy storage unit U[5].

[0238] Figure 45 also shows the temporal change in the active power distribution value P[5] limited by the limit value L[5]_c. The limit value setting unit 522 decreases the limit value L[5]_c over time from the reference value 0 to the target value -40 from the start to the end of period Tb, thereby decreasing the active power distribution value P[5] over time from the reference value 0 to the target value -41. The start of period Tb is the same time as the start of period Ta.

[0239] As described above, as the allocation coefficient K[5] and the limit value L[5]_c change over time, the active power allocation value P[5] of the energy storage unit U[5] decreases over time from the initial value of 0 to the target value of -41 from the beginning to the end of period Tb. In the above explanation, the case in which the length of period Tb exceeds the length of period Ta was used as an example, but there are also cases in which the length of period Tb is less than the length of period Ta.

[0240] As described above, in the ninth embodiment, the distribution coefficient K[m] and the limit value L[m] change continuously over the period Ta when the energy storage unit U[m] is started up. That is, discontinuous fluctuations in the distribution coefficient K[m] and the limit value L[m] caused by the start up of the energy storage unit U[m] are suppressed. Therefore, the possibility of sudden fluctuations in the combined point power due to sharp fluctuations in the distribution coefficient K[m] or the limit value L[m] in each energy storage unit U[m] can be reduced.

[0241] 10. Tenth Embodiment The ninth embodiment focuses on the additional activation of the energy storage unit U[m]. The tenth embodiment is a configuration for stopping one or more energy storage units U[m] during the operation of the energy storage system 30.

[0242] Figure 46 is an explanatory diagram of the operation when one energy storage unit U[1] is stopped while five energy storage units U[1] to U[5] of the energy storage system 30 are performing discharge. As illustrated in Figure 46, when energy storage unit U[1] is stopped, the coefficient setting unit 521 reduces the distribution coefficient K[1] to a minimum value of 0, and the limit value setting unit 522 reduces the limit value L[1]_d to a minimum value of 1. As a result of the changes in the distribution coefficient K[1] and the limit value L[1]_d, the power distribution value Pa[m] of the energy storage unit U[1] that is stopped decreases, while the power distribution value Pa[m] of the energy storage units U[2] to U[5] that continue to operate increases.

[0243] Figure 47 is an explanatory diagram illustrating the temporal changes in the allocation coefficient K[1] and the power allocation value Pa[1]. As illustrated in Figure 47, the coefficient setting unit 521 decreases the allocation coefficient K[1] from its current value of 5 to its minimum value of 0 over time, from the start to the end of period Ta. Consequently, the power allocation value Pa[1] decreases from its current value of 40 to its minimum value of 1 over time, from the start to the end of period Ta. The start of period Ta is, for example, the point in time when the administrator of the management system 100 instructs the power storage unit U[1] to be stopped.

[0244] Figure 47 also shows the temporal change in the active power distribution value P[1] limited by the limit value L[1]_d. The limit value setting unit 522 decreases the limit value L[1]_d over time from the start to the end of period Tb from the current value 40 to the minimum value 1, thereby decreasing the active power distribution value P[1] over time from the current value 39 to the reference value 0. The start of period Tb is the same time as the start of period Ta.

[0245] As described above, as the allocation coefficient K[1] and the limit value L[1]_d change over time, the active power allocation value P[1] of the energy storage unit U[1] decreases over time from the current value of 39 to the minimum value of 0 from the beginning to the end of period Tb. In the above explanation, the case in which the length of period Tb exceeds the length of period Ta was used as an example, but there are also cases in which the length of period Tb is less than the length of period Ta.

[0246] Figure 48 assumes a scenario where one of the five energy storage units U[1] to U[5] of the energy storage system 30 stops charging. As illustrated in Figure 48, when energy storage unit U[5] stops, the coefficient setting unit 521 decreases the allocation coefficient K[5] from its current value of 5 to its minimum value of 0, and the limit value setting unit 522 increases the limit value L[5]_c from its current value of -40 to its reference value of 0. As a result of the changes in the allocation coefficient K[5] and the limit value L[5]_c, the power allocation value Pa[5] of the additional energy storage unit U[5] increases, while the power allocation value Pa[m] of the energy storage units U[1] to U[4] decreases.

[0247] Figure 49 is an explanatory diagram illustrating the temporal changes in the allocation coefficient K[5] and the power allocation value Pa[5]. As illustrated in Figure 49, the coefficient setting unit 521 increases the allocation coefficient K[5] over time from the current value of 5 to the minimum value of 0 from the start to the end of period Ta. Consequently, the power allocation value Pa[5] increases over time from the current value of -40 to the reference value of 0 from the start to the end of period Ta.

[0248] FIG. 49 also shows the temporal change of the active power distribution value P[5] restricted by the limit value L[5]_c. The limit value setting unit 522 increases the limit value L[5]_c from the current value of -40 to the reference value of 0 over time from the start point to the end point of the period Tb, thereby increasing the active power distribution value P[5] from the current value of -41 to the reference value of 0 over time. Note that the start point of the period Tb is the same time point as the start point of the period Ta.

[0249] As described above, as a result of the distribution coefficient K[5] and the limit value L[5]_c changing over time, the active power distribution value P[5] of the power storage unit U[5] increases over time from the current value of -41 to the reference value of 0 from the start point to the end point of the period Tb. Note that in the above description, the case where the time length of the period Tb exceeds the time length of the period Ta is exemplified, but the time length of the period Tb may be shorter than the time length of the period Ta.

[0250] In the tenth embodiment, as in the ninth embodiment, when the power storage unit U[m] stops, the distribution coefficient K[m] and the limit value L[m] continuously change over the period Ta. That is, discontinuous fluctuations in the distribution coefficient K[m] and the limit value L[m] caused by the stop of the power storage unit U[m] are suppressed. Therefore, as in the ninth embodiment, it is possible to reduce the possibility that the combined point power suddenly fluctuates due to a sharp change in the distribution coefficient K[m] or the limit value L[m] in each power storage unit U[m].

[0251] 11. Eleventh Embodiment In the eleventh embodiment, it is assumed that some of the plurality of power storage units U[m] of the power storage system 30 (hereinafter referred to as "maintenance target units U[m]") are in a maintenance state such as repair or inspection. The maintenance target unit U[m] is excluded from the target of the distribution of the total DC power command value Cp. That is, the active power distribution value P[m] is not calculated for the maintenance target unit U[m].

[0252] Figure 50 is an explanatory diagram of the operation of the command calculation unit 51 in the 11th embodiment. The maintenance power Ga exemplified in Figure 50 is the active power (i.e., power for maintenance) used for maintenance work in the unit U [m] under maintenance. The maintenance power Ga is set to a predetermined value, for example, according to the content of the maintenance work. Note that the maintenance power Ga may also be the measured value of the active power of the unit U [m] under maintenance. Note that if the maintenance power Ga is a positive number, it means that charging is performed in the unit U [m] under maintenance, and if the maintenance power Ga is a negative number, it means that discharging is performed in the unit U [m] under maintenance.

[0253] The command calculation unit 51 of the 11th embodiment calculates the total DC power command value Cp by adding the maintenance power Ga to the basic command value C0 in addition to the substation loss X1, load loss X2, and conversion loss X3. Specifically, the total DC power command value Cp is calculated by adding the substation loss X1, load loss X2, conversion loss X3, and maintenance power Ga to the basic command value C0, as shown in the following formula (8).

number

[0254] The total DC power command value Cp calculated by formula (8) is distributed to each of the multiple energy storage units U[m] of the energy storage system 30, excluding the unit U[m] under maintenance. As can be understood from the above explanation, in the 11th embodiment, the extra operation of each energy storage unit U[m] other than the unit U[m] under maintenance secures maintenance power Ga for the unit U[m] under maintenance. In other words, the power discharged by each energy storage unit U[m] other than the unit U[m] under maintenance is used for maintenance work on the unit U[m] under maintenance.

[0255] Figure 51 is an explanatory diagram of the operation of the management system 100 in the 11th embodiment. In Figure 51, it is assumed that among the multiple energy storage units U[m], energy storage unit U[4] is the unit to be maintained U[4]. The total DC power command value Cp is a value indicating discharge (Cp>0).

[0256] As illustrated in Figure 51, the active power distribution value P[m] is calculated for the four energy storage units U[m] (U[1], U[2], U[3], U[5]) other than the unit U[4] under maintenance. In other words, for the unit U[4] under maintenance, the setting of the distribution coefficient K[m] and limit value L[m], the calculation of the power distribution value Pa[m] (Sa1), the calculation of the power distribution value Pb[m] (Sa2~Sa5), and the calculation of the active power distribution value P[m] are not performed.

[0257] A portion of the active power distribution value P[m] generated by each energy storage unit U[m] other than the unit U[4] under maintenance (maintenance power Ga) is supplied to the unit U[4] under maintenance and used for maintenance work. As described above, according to the 11th embodiment, the power required for the maintenance of the unit U[m] under maintenance can be shared by other operational energy storage units U[m] while maintaining the combined point power at the basic command value C0.

[0258] 12. Twelfth Embodiment In some cases, it may be necessary to prioritize the discharge or charging of a specific energy storage unit U[m] among the multiple energy storage units U[m] of the energy storage system 30. For example, if the energy storage unit U[m] to be maintained is sufficiently charged, it may be necessary to sufficiently reduce the charge rate S[m] by preferential discharge before starting maintenance work. If the energy storage unit U[m] to be maintained is not sufficiently charged, it may be necessary to sufficiently increase the charge rate S[m] of the energy storage unit U[m] by preferential charging before starting maintenance work.

[0259] Furthermore, if a newly added energy storage unit U[m] to the energy storage system 30 or an energy storage unit U[m] that has returned from maintenance work has a charge rate S[m] significantly lower than that of other energy storage units U[m], it may be necessary to increase the charge rate S[m] by preferential charging. On the other hand, if a newly added energy storage unit U[m] to the energy storage system 30 or an energy storage unit U[m] that has returned from maintenance work has a charge rate S[m] significantly higher than that of other energy storage units U[m], it may be necessary to decrease the charge rate S[m] by preferential discharge.

[0260] Taking the above circumstances into consideration, the 12th embodiment is a configuration in which a specific energy storage unit U[m] (hereinafter referred to as the "priority unit U[m]") among the multiple energy storage units U[m] of the energy storage system 30 is given priority in discharge or charging.

[0261] In the following explanation, the power discharged or charged by the priority unit U[m] is referred to as "correction power Gb". The correction power Gb indicates the discharge / charge of the priority unit U[m] by its sign. Specifically, a positive correction power Gb means the power value that the priority unit U[m] should discharge. On the other hand, a negative correction power Gb means the power value that the priority unit U[m] should charge.

[0262] Specifically, the command calculation unit 51 of the 12th embodiment calculates the total DC power command value Cp by adding power losses (X1, X2, X3) to the basic command value C0, as in the above-described embodiments, and by subtracting the corrected power Gb from the basic command value C0. That is, the command calculation unit 51 calculates the total DC power command value Cp by performing the calculation using the following formula (9).

number

[0263] Furthermore, the allocation processing unit 523 of the 12th embodiment calculates the active power allocation value P[m] from the total DC power command value Cp for each of the multiple energy storage units U[m] of the energy storage system 30 other than the priority unit U[m] (hereinafter referred to as "normal units") U[m], and sets the corrected power Gb as the active power allocation value P[m] for the priority unit U[m].

[0264] The operation of the 12th embodiment is described in detail below. In the following description, the cases in which the priority unit U[m] is discharged and received power are explained for each case in which the total DC power command value Cp indicates discharge (Cp>0) and charge (Cp<0).

[0265] [Operation Case 1] Figures 52 and 53 are explanatory diagrams of the operation of the management system 100 in operation case 1. Operation case 1 is when the total DC power command value Cp indicates discharge (Cp>0) and the priority unit U[m] is discharged (Gb>0). In the following explanation, it is assumed that the energy storage unit U[1] is the priority unit U[1] and the energy storage units U[2] to U[5] are the normal units U[m].

[0266] As illustrated in Figure 52, the command calculation unit 51 calculates the total DC power command value Cp by adding the power losses (X1, X2, X3) to the basic command value C0 and subtracting the corrected power Gb.

[0267] As illustrated in Figure 53, the allocation processing unit 523 excludes the priority unit U[1] from the allocation of the total DC power command value Cp by setting the limit value L[1]_d of the priority unit U[1] to 0. The allocation processing unit 523 calculates the power allocation value Pa[m] (Sa1), the power allocation value Pb[m] (Sa2~Sa5), and the active power allocation value P[m] (Sa6) for each normal unit U[m]. That is, the active power allocation value P[m] for each normal unit U[m] is calculated by the same processing (Sa1~Sa6) as described above. The allocation processing unit 523 also sets the active power allocation value P[m] of the priority unit U[1] to a value corresponding to the corrected power Gb. Specifically, the power distribution value Pb[1] of the priority unit U[1] is set to the corrected power Gb (=60), and the active power distribution value P[1] is set to the value obtained by subtracting the conversion loss x[1] from the power distribution value Pb[1] (=59).

[0268] The active power distribution value P[m] calculated using the above procedure is transmitted to each energy storage unit U[m]. Therefore, each normal unit U[m] (U[2] to U[5]) discharges power equal to the active power distribution value P[m], which is the total DC power command value Cp, while the priority unit U[1] discharges the corrected power Gb. As a result of the above operation, it is possible to preferentially discharge the priority unit U[1] while maintaining the combined point power at the basic command value C0.

[0269] [Operation Case 2] Figures 54 and 55 are explanatory diagrams of the operation of the management system 100 in operation case 2. Operation case 2 is when the total DC power command value Cp indicates discharge (Cp>0) and the priority unit U[m] is being charged (Gb<0). In the following explanation, it is assumed that the energy storage unit U[5] is the priority unit U[5] and the energy storage units U[1] to U[4] are the normal units U[m].

[0270] As illustrated in Figure 54, the command calculation unit 51 calculates the total DC power command value Cp by adding the power losses (X1, X2, X3) to the basic command value C0 and subtracting the corrected power Gb.

[0271] As illustrated in Figure 55, the allocation processing unit 523 excludes the priority unit U[5] from the allocation of the total DC power command value Cp by setting the limit value L[1]_d of the priority unit U[5] to 0. The allocation processing unit 523 calculates the active power allocation value P[m] for each normal unit U[m] by the same processing (Sa1~Sa6) as in the first embodiment. The allocation processing unit 523 also sets the active power allocation value P[5] of the priority unit U[5] to a value corresponding to the correction power Gb. Specifically, the power allocation value Pb[5] of the priority unit U[5] is set to the correction power Gb (-60), and the active power allocation value P[5] is set to a value (-61) obtained by subtracting the conversion loss x[5] from the power allocation value Pb[5].

[0272] The active power distribution value P[m] calculated using the above procedure is transmitted to each energy storage unit U[m]. Therefore, each normal unit U[m] (U[1] to U[4]) discharges power equal to the active power distribution value P[m], which is the total DC power command value Cp, while the priority unit U[5] charges with the corrected power Gb. As a result of the above operation, it is possible to prioritize charging the priority unit U[5] while maintaining the combined point power at the basic command value C0.

[0273] [Operation Case 3] Figures 56 and 57 are explanatory diagrams of the operation of the management system 100 in operation case 3. Operation case 3 is when the total DC power command value Cp indicates charging (Cp < 0) and the priority unit U[m] is discharged (Gb > 0). In the following explanation, it is assumed that the energy storage unit U[1] is the priority unit U[1] and the energy storage units U[2] to U[5] are the normal units U[m].

[0274] As illustrated in Figure 56, the command calculation unit 51 calculates the total DC power command value Cp by adding the power losses (X1, X2, X3) to the basic command value C0 and subtracting the corrected power Gb.

[0275] As illustrated in Figure 57, the allocation processing unit 523 excludes the priority unit U[1] from the allocation of the total DC power command value Cp by setting the limit value L[1]_c of the priority unit U[1] to 0. The allocation processing unit 523 calculates the active power allocation value P[m] for each normal unit U[m] by the same processing (Sa1~Sa6) as described above. The allocation processing unit 523 also sets the active power allocation value P[m] of the priority unit U[1] to a value corresponding to the correction power Gb. Specifically, the power allocation value Pb[1] of the priority unit U[1] is set to the correction power Gb (=60), and the active power allocation value P[1] is set to a value obtained by subtracting the conversion loss x[1] from the power allocation value Pb[1] (=59).

[0276] The active power distribution value P[m] calculated using the above procedure is transmitted to each energy storage unit U[m]. Therefore, each normal unit U[m] (U[2] to U[5]) charges with power equal to the active power distribution value P[m], which is the total DC power command value Cp, while the priority unit U[1] discharges the corrected power Gb. As a result of the above operation, it is possible to preferentially discharge the priority unit U[1] while maintaining the combined point power at the basic command value C0.

[0277] [Operation Case 4] Figures 58 and 59 are explanatory diagrams of the operation of the management system 100 in operation case 4. Operation case 4 is when the total DC power command value Cp indicates charging (Cp < 0) and the priority unit U[m] is being charged (Gb < 0). In the following explanation, it is assumed that the energy storage unit U[5] is the priority unit U[5] and the energy storage units U[1] to U[4] are the normal units U[m].

[0278] As illustrated in Figure 58, the command calculation unit 51 calculates the total DC power command value Cp by adding the power losses (X1, X2, X3) to the basic command value C0 and subtracting the corrected power Gb.

[0279] As illustrated in Figure 59, the allocation processing unit 523 excludes the priority unit U[5] from the allocation of the total DC power command value Cp by setting the limit value L[1]_c of the priority unit U[5] to 0. The allocation processing unit 523 calculates the active power allocation value P[m] for each normal unit U[m] by the same processing (Sa1~Sa6) as described above. The allocation processing unit 523 also sets the active power allocation value P[5] of the priority unit U[5] to the corrected power Gb. Specifically, the power allocation value Pb[5] of the priority unit U[5] is set to the corrected power Gb (=-60), and the active power allocation value P[5] is set to the value obtained by subtracting the conversion loss x[5] from the power allocation value Pb[5] (=-61).

[0280] The active power distribution value P[m] calculated using the above procedure is transmitted to each energy storage unit U[m]. Therefore, each normal unit U[m] (U[1] to U[4]) is charged with power equal to the active power distribution value P[m], which is the total DC power command value Cp, while the priority unit U[5] is charged with the corrected power Gb. As a result of the above operation, it is possible to prioritize the charging of the priority unit U[5] while maintaining the combined point power at the basic command value C0.

[0281] 13. The 13th Embodiment In each of the above embodiments, the focus was on the active power exchanged between the power system 10 and the management system 100. The 13th embodiment is an embodiment that focuses on the reactive power exchanged between the power system 10 and the management system 100. In the 13th embodiment, the configuration and method for calculating the active power distribution value P[m] for each energy storage unit U[m] from the basic command value C0 is the same as in the embodiments described above.

[0282] Figure 60 is a block diagram illustrating the functional configuration of the control system 40 in the 13th embodiment. The control device 41 in the 13th embodiment functions with the same elements as in the first embodiment (command calculation unit 51, command distribution unit 52, operation instruction unit 53).

[0283] The command calculation unit 51 of the 13th embodiment calculates the total DC power command value Cp, as in the above-described embodiments, and also calculates the total reactive power command value Cq. The total reactive power command value Cq is the sum of the reactive power that the multiple energy storage units U[m] should generate. For reactive power, the direction in which lagging reactive power is generated in the power system 10 (i.e., the direction in which the energy storage unit U[m] is capacitive) is expressed as a positive number, and the direction in which leading reactive power is absorbed from the power system 10 (i.e., the direction in which the energy storage unit U[m] is inductive) is expressed as a negative number.

[0284] Generally, when supplying active power to the power system 10, the voltage of the power system 10 rises, so the voltage rise is suppressed by operations that absorb leading reactive power from the power system 10. On the other hand, when consuming active power from the power system 10, the voltage of the power system 10 falls, so the voltage fall is suppressed by operations that generate lagging reactive power in the power system 10.

[0285] Figure 61 is an explanatory diagram of the operation of the command calculation unit 51 in the 13th embodiment. As illustrated in Figure 61, the command calculation unit 51 calculates the reactive power command value Cq0 according to the basic command value C0. For example, the command calculation unit 51 calculates the reactive power command value Cq0 by multiplying the basic command value C0 by a predetermined power factor.

[0286] The command calculation unit 51 calculates the total reactive power command value Cq by correcting the reactive power command value Cq0 with a correction value Xq. The correction value Xq is the sum of the reactive power generated within the management system 100 due to factors other than the normal operation of each energy storage unit U[m]. Specifically, the correction value Xq is calculated by subtracting the lagging reactive power (positive number) generated by an energy storage unit U[m] that has been excluded from the allocation of active power for maintenance work, for example, from the lagging reactive power (positive number) generated by the energy storage unit U[m] among the multiple energy storage units U[m], for example, by a load equipment 22 that is inductive or has been led by a load equipment 22, and

[0287] The command distribution unit 52 in Figure 60 calculates the active power distribution value P[m] for each energy storage unit U[m] from the total DC power command value Cp, similar to the configurations described above. In addition, it calculates the command value of the reactive power to be distributed to each of the multiple energy storage units U[m] from the total reactive power command value Cq (hereinafter referred to as "reactive power distribution value Q[m]"). The reactive power distribution value Q[m] is the command value of the reactive power that each energy storage unit U[m] should generate. In other words, the command distribution unit 52 distributes the total reactive power command value Cq to the multiple energy storage units U[m].

[0288] The operation instruction unit 53 instructs each energy storage unit U[m] to set an active power distribution value P[m] and a reactive power distribution value Q[m]. Specifically, the operation instruction unit 53 transmits the active power distribution value P[m] and the reactive power distribution value Q[m] calculated by the command distribution unit 52 to the energy storage unit U[m] via the transceiver 43. Each energy storage unit U[m] (power adjustment device 32) causes the energy storage device 31 to discharge or charge DC power corresponding to the active power distribution value P[m], and also generates reactive power corresponding to the reactive power distribution value Q[m].

[0289] Figure 62 is an explanatory diagram of the operation by which the command distribution unit 52 calculates the reactive power distribution value Q[m] for each energy storage unit U[m]. Figure 62 shows the active power distribution value P[m] calculated for each energy storage unit U[m] by the configuration and operation exemplified in each of the above-described forms.

[0290] In step Se1, the command distribution unit 52 acquires the capacity characteristic A[m] for each of the multiple energy storage units U[m]. The capacity characteristic A[m] is the relationship between the active power and reactive power that the energy storage unit U[m] can process (for example, the apparent power condition). The capacity characteristic A[m] may differ for each energy storage unit U[m]. The capacity characteristic A[m] is determined in advance, for example, according to the specifications of each energy storage unit U[m]. For example, the capacity characteristic A[m] may be included in the state data D[m] that the transceiver 43 receives from each energy storage unit U[m].

[0291] In step Se2, the command distribution unit 52 calculates the available reactive power q[m] for each energy storage unit U[m] according to the active power distribution value P[m] and the capacity characteristic A[m]. The available reactive power q[m] is the maximum amount of reactive power that the energy storage unit U[m] can generate. Specifically, the command distribution unit 52 calculates the available reactive power q[m] as the reactive power corresponding to the active power distribution value P[m] under the capacity characteristic A[m].

[0292] For example, when the basic command value C0 indicates discharge (C0>0), the discharge by each energy storage unit U[m] acts to increase the voltage at the combination point 11. To suppress the increase in voltage at the combination point 11, the command distribution unit 52 calculates the leading reactive power as idle reactive power q[m]. On the other hand, when the basic command value C0 indicates charging (C0<0), the charging by each energy storage unit U[m] acts to decrease the voltage at the combination point 11. To suppress the decrease in voltage at the combination point 11, the command distribution unit 52 calculates the lagging reactive power as idle reactive power q[m].

[0293] In step Se3, the command distribution unit 52 calculates the reactive power distribution value Q[m] for each energy storage unit U[m] according to the total reactive power command value Cq and each available reactive power q[m]. Specifically, the command distribution unit 52 calculates each reactive power distribution value Q[m] by the following formula (10).

number

[0294] As can be understood from equation (10), the command distribution unit 52 calculates the reactive power distribution value Q[m] for each energy storage unit U[m] by multiplying the total reactive power command value Cq by the ratio of each available reactive power q[m] to the sum of the multiple available reactive powers Σq[m]. In other words, the total reactive power command value Cq is distributed to each energy storage unit U[m] in proportion to each available reactive power q[m].

[0295] As described above, in the 13th embodiment, in addition to the generation of active power by each energy storage unit U[m], the generation of reactive power can also be controlled. Therefore, in principle, a reactive power compensation device (SVC (Static Var Compensator), SVG (Static Var Generator), STATCOM (Static synchronous Compensator)) dedicated to controlling the reactive power of each energy storage unit U[m] can be eliminated. However, in the 13th embodiment, a reactive power compensation device may be used in combination.

[0296] 14. Fourteenth Embodiment Figure 63 is a block diagram illustrating the configuration of the management system 100 according to the 14th embodiment. As illustrated in Figure 63, the management system 100 of the 14th embodiment includes a power generation facility 23 in addition to the same elements as the first embodiment (Figure 1) (substation equipment 21, load equipment 22, energy storage system 30, control system 40).

[0297] The power generation facility 23 is a distributed power source that generates electricity using renewable energy, for example. For example, any type of power generation system that utilizes renewable energy can be used as the power generation facility 23, such as a solar power generation system that converts solar energy into electricity, a wind power generation system that converts wind energy into electricity, a geothermal power generation system that converts geothermal energy into electricity, a hydroelectric power generation system that converts hydroelectric energy into electricity, or a biomass power generation system that converts biomass energy into electricity. The power generation facility 23 may also be composed of multiple power generation systems with different power generation methods.

[0298] In each of the above-described embodiments, the command calculation unit 51 calculates the total DC power command value Cp by adding the power loss (X1+X2+X3), which includes the substation loss X1, load loss X2, and conversion loss X3, to the basic command value C0, as shown in formula (1) above. In the 14th embodiment, the command calculation unit 51 calculates the total DC power command value Cp by adding the active power generated by the power generation equipment 23 (hereinafter referred to as "generated active power value Gc") to the power loss (X1+X2+X3) in addition to the basic command value C0. Specifically, the command calculation unit 51 calculates the total DC power command value Cp by performing a calculation that includes adding the power loss (X1+X2+X3) to the basic command value C0 and subtracting the generated active power value Gc, as shown in formula (11) below.

number

[0299] The configuration and operation for calculating the active power distribution value P[m] for each energy storage unit U[m] from the total DC power command value Cp are the same as in the embodiments described above. According to the 14th embodiment, even in an environment where power generation equipment 23 is installed in parallel with multiple energy storage units U[m], the combined point power can be maintained at the basic command value C0 with high accuracy.

[0300] 15. 15th Embodiment Figure 64 is a block diagram illustrating the configuration of the management system 100 according to the 15th embodiment. As illustrated in Figure 64, the power adjustment device 32 in each energy storage unit U[m] of the 15th embodiment is a DC / DC converter that converts DC power to DC power of a different voltage value. That is, each energy storage unit U[m] of the 15th embodiment supplies or receives DC power. In the 15th embodiment, the conversion loss X3 applied to the calculation of the total DC power command value Cp includes a value that is the sum of the power loss caused by power conversion by the power adjustment device 32 across multiple energy storage units U[m].

[0301] As illustrated in Figure 64, an AC / DC converter 24 is installed between the substation 21 and the energy storage system 30. The AC / DC converter 24 is an AC / DC converter that converts DC power and AC power to each other. AC power is exchanged between the AC / DC converter 24 and the substation 21, and DC power is exchanged between the AC / DC converter 24 and each energy storage unit U[m]. In the above configuration, the substation loss X1 is the power loss caused by the substation 21's substation, and the conversion loss x[m] is the sum of the loss of the AC / DC converter 24 and the loss of the power adjustment device 32 (DC / DC converter) of each energy storage unit U[m].

[0302] The management system 100 of the 15th embodiment includes load equipment 22a and load equipment 22b. Load equipment 22a is installed in parallel with a plurality of energy storage units U[m], similar to load equipment 22 of the first embodiment. Load equipment 22b is connected between the AC / DC converter 24 and the substation 21. The load loss X2 of the 15th embodiment is the sum of the power loss in load equipment 22a and the power loss in load equipment 22b.

[0303] In the 15th embodiment, as in the first embodiment, the command calculation unit 51 calculates the total DC power command value Cp by adding the power loss (X1+X2+X3), which includes the substation loss X1, load loss X2, and conversion loss X3, to the basic command value C0. The power generation equipment 23 of the 14th embodiment may also be added to the 15th embodiment.

[0304] 16. Sixteenth Embodiment Figure 65 is a block diagram illustrating the configuration of each energy storage unit U[m] in the 16th embodiment. As illustrated in Figure 65, the energy storage unit U[m] of the 16th embodiment includes load equipment 33 in addition to the same elements as in the aforementioned embodiments (energy storage device 31, power adjustment device 32). The load equipment 33 consists of various loads that operate by consuming the power supplied from the power adjustment device 32. For example, the load equipment 33 is a power supply device that generates auxiliary power or control power used within the energy storage unit U[m].

[0305] In the 16th embodiment, the conversion loss x[m] of each energy storage unit U[m] includes the losses of the transformer 321 and the AC / DC converter 322 (and also line losses), plus the active power X31 of the load equipment 33 in the energy storage unit U[m]. That is, the conversion loss X3 in the 16th embodiment includes the sum of the active power X31 of the load equipment 33 in multiple energy storage units U[m]. The active power X31 of the load equipment 33 is measured, for example, by a measuring instrument (not shown) installed in each energy storage unit U[m].

[0306] In the sixteenth embodiment described above, we assume that one or more energy storage units U[m] are stopped during the operation of the energy storage system 30, as in the tenth embodiment. Similar to the example in Figure 47 above, the limit value setting unit 522 decreases the limit value L[1]_d from the current value 40 to the numerical value -X31 over time from the start to the end of period Tb. Therefore, the active power distribution value P[1] decreases from the current value 39 to the numerical value -X31 over time from the start to the end of period Tb.

[0307] 17. Variations The following are examples of specific modifications that may be added to each of the embodiments exemplified above. Two or more embodiments may be arbitrarily selected from the following examples and merged as appropriate, provided they do not contradict each other.

[0308] (1) Two or more embodiments selected from the multiple embodiments exemplified above may be arbitrarily combined. The configurations exemplified in each of the above embodiments may be implemented without presupposing the configurations of the other embodiments.

[0309] (2) The functions of the control system 40 in the above-described form are realized through the cooperation of one or more processors constituting the control device 41 and the program stored in the storage device 42, as described above. The programs exemplified above can be provided in a form stored on a computer-readable recording medium and installed on a computer. The recording medium is, for example, a non-transitory recording medium, such as an optical recording medium (optical disc) like a CD-ROM, but also includes any known form of recording medium such as a semiconductor recording medium or a magnetic recording medium. Note that a non-transitory recording medium includes any recording medium except for transient propagation signals (transitory, propagating signals), and volatile recording media are not excluded. Furthermore, in a configuration in which a distribution device distributes a program via a communication network, the recording medium in which the distribution device stores the program corresponds to the non-transitory recording medium described above.

[0310] (3) The notation "the nth" (where n is a natural number) in this application is used solely as a formal and convenient label to distinguish each element in notation, and has no substantive meaning whatsoever. Therefore, there is no room for restrictive interpretation of the position or order of each element based on the notation "the nth".

[0311] 18. Addendum From the forms exemplified above, the following configuration can be understood, for example.

[0312] A control system according to one aspect of the present disclosure (Aspect 1) is a control system for controlling an energy storage system that adjusts the active power at a point of combination with a power system by a plurality of energy storage units, each including an energy storage device that discharges and charges DC power, comprising: a command calculation unit that calculates a total DC power command value, which is the sum of the power that the energy storage devices in the plurality of energy storage units should discharge or charge, by adding power losses, including conversion losses due to conversion between DC power and AC power and transformation losses due to voltage transformation between the energy storage system and the substation equipment between the energy storage system and the point of combination and the energy storage system, to the basic command value of the active power; a command distribution unit that calculates an active power distribution value to be distributed to each of the plurality of energy storage units from the total DC power command value; and an operation instruction unit that instructs each of the plurality of energy storage units on the active power distribution value of the energy storage unit.

[0313] In the above embodiment, the total DC power command value is calculated by adding power losses, including conversion losses due to the conversion between DC power discharged or charged by the energy storage device and AC power, and substation losses due to the voltage transformation between the substation and the energy storage system (i.e., losses caused by the voltage transformation between the AC voltage between the energy storage system and the substation and the voltage at the point of combination), to the basic command value, and the total DC power command value is allocated to each energy storage unit. Therefore, compared to an embodiment in which the basic command value is allocated to each energy storage unit without considering the conversion loss between DC power and AC power, and the substation loss between the energy storage system and the substation, the effective power allocation value instructed to each energy storage unit can be calculated appropriately. When the basic command value is small, the influence of conversion loss and substation loss on the basic command value increases relatively, so the configuration of this disclosure in which conversion loss and substation loss are added to the basic command value is particularly effective.

[0314] In a specific example of Embodiment 1 (Embodiment 2), the command distribution unit includes a coefficient setting unit that sets a distribution coefficient for each of the plurality of energy storage units, and a distribution processing unit that calculates a first power distribution value to be distributed to each of the plurality of energy storage units from the total DC power command value, according to the distribution coefficient of each energy storage unit. According to the above embodiment, the total DC power command value can be distributed to each of the plurality of energy storage units according to the distribution coefficient of each energy storage unit.

[0315] In a specific example of Embodiment 2 (Embodiment 3), the command distribution unit further includes a limit value setting unit that sets a limit value for each of the plurality of energy storage units, and the distribution processing unit distributes a total excess value, obtained by summing the excess values ​​of one or more energy storage units among the plurality of energy storage units whose first power distribution value exceeds the limit value, to each of the one or more energy storage units among the plurality of energy storage units whose first power distribution value does not exceed the limit value. In the above embodiment, the power distributed to each energy storage unit can be kept within the range of the limit value while maintaining the active power at the composite point at the basic command value.

[0316] In a specific example of Embodiment 3 (Embodiment 4), the limit value setting unit selects the limit value for each of the plurality of energy storage units from a plurality of candidate values ​​relating to different states of the energy storage unit. In the above embodiment, the limit value is selected from a plurality of candidate values ​​relating to different states of the energy storage unit. Therefore, the limit value can be appropriately set from multiple perspectives relating to the state of the energy storage unit.

[0317] In a specific example of Embodiment 4 (Embodiment 5), the plurality of candidate values ​​include a first candidate value corresponding to the voltage of the energy storage device. The first candidate value is set to a first value when the voltage is within a first range, to a second value different from the first value when the voltage is within a second range different from the first range, and to a value that changes between the first and second values ​​depending on the voltage when the voltage is within a third range between the first and second ranges. In the above embodiment, the first candidate value is set according to the voltage of the energy storage device. Therefore, the limit value can be appropriately set from the viewpoint of the voltage of the energy storage device. Furthermore, when the voltage is within a third range, the first candidate value changes between the first and second values ​​depending on the voltage. Therefore, compared to an embodiment in which the first candidate value is selectively set to either the first or second value, it is possible to suppress steep and frequent fluctuations of the limit value according to the voltage of the energy storage device.

[0318] In a specific example of Embodiment 4 (Embodiment 6), the plurality of candidate values ​​include a second candidate value corresponding to the charge level of the energy storage device. The second candidate value is set to a first value when the charge level is within a first range, to a second value different from the first value when the charge level is within a second range different from the first range, and to a value that changes between the first and second values ​​depending on the charge level when the charge level is within a third range between the first and second ranges. In the above embodiment, the second candidate value is set according to the charge level of the energy storage device. Therefore, the limit value can be appropriately set from the viewpoint of the charge level of the energy storage device. Furthermore, when the charge level is within a third range, the second candidate value changes between the first and second values ​​depending on the charge level. Therefore, compared to an embodiment in which the second candidate value is selectively set to either the first or second value, it is possible to suppress steep and frequent fluctuations of the limit value according to the charge level of the energy storage device.

[0319] In a specific example of Embodiment 4 (Embodiment 7), the plurality of candidate values ​​include a third candidate value corresponding to the temperature of the energy storage device. The third candidate value is set to a first value if the temperature is within a first range, to a second value different from the first value if the temperature is within a second range different from the first range, and to a value that changes between the first and second values ​​depending on the temperature if the temperature is within a third range between the first and second ranges. In the above embodiment, the third candidate value is set according to the temperature of the energy storage device. Therefore, the limit value can be appropriately set from the standpoint of the temperature of the energy storage device. Furthermore, when the temperature is within the third range, the third candidate value changes between the first and second values ​​depending on the temperature. Therefore, compared to an embodiment in which the third candidate value is selectively set to either the first or second value, it is possible to suppress steep and frequent fluctuations of the limit value according to the temperature of the energy storage device.

[0320] In any specific example of Embodiments 2 to 7 (Embodiment 8), the coefficient setting unit performs the following: a first process of setting a weighted value for each of the plurality of energy storage units; a second process of setting a correction value for each of the plurality of energy storage units according to the operating watt-hour capacity of the energy storage unit; and a third process of calculating the distribution coefficient for each of the plurality of energy storage units according to the weighted value and the correction value. In the above embodiment, the distribution coefficient is set according to the operating watt-hour (Wh) capacity of the energy storage unit. For example, the larger the operating watt-hour capacity, the larger the value of the distribution coefficient is set to. Therefore, variations in charge / discharge time or charge rate among each energy storage unit can be suppressed.

[0321] In a specific example of Embodiment 8 (Embodiment 9), the first process includes a normalization process that normalizes the charge rate of the energy storage device in the energy storage unit to a value within a predetermined standard range, a deviation calculation process that calculates a first deviation between the normalized charge rate and a reference value, and a weighting value setting process that sets the weighting value according to the first deviation. In the above embodiment, the weighting value is set according to the charge rate of the energy storage device in each energy storage unit. Therefore, the possibility that the output of each energy storage unit will be limited due to the charge rate of the energy storage device can be reduced. In other words, the energy storage capacity of the entire energy storage system can be effectively utilized.

[0322] In a specific example of Embodiment 9 (Embodiment 10), in the weighting value setting process, when the first deviation changes from a value below a first threshold to a value above the first threshold, the weighting value is set to a predetermined first value, and when the first deviation changes from a value above a second threshold smaller than the first threshold to a value below the second threshold, the weighting value is set to a second value corresponding to the first deviation. In the above embodiment, the relationship between the first deviation and the weighting value exhibits hysteresis characteristics. Therefore, even when the first deviation fluctuates near the first or second threshold, excessively frequent fluctuations in the weighting value can be suppressed.

[0323] In a specific example of Embodiment 9 (Embodiment 11), the weighting value setting process determines the relationship between the first deviation and the weighting value according to the total DC power command value, and sets the numerical value that has the relationship described above with respect to the first deviation calculated by the deviation calculation process as the weighting value. In the above embodiment, the relationship between the first deviation and the weighting value is determined according to the total DC power command value. Therefore, compared to an embodiment in which the relationship between the first deviation and the weighting value is fixed, the total DC power command value can be appropriately allocated to multiple energy storage units.

[0324] In any specific example of embodiments 8 to 11 (embodiment 12), the first process includes a normalization process that normalizes the temperature of the energy storage device in the energy storage unit to a value within a predetermined standard range, a deviation calculation process that calculates a second deviation between the normalized temperature and a reference value, and a weighting value setting process that sets the weighting value according to the second deviation. In the above embodiments, the weighting value is set according to the temperature of the energy storage device in each energy storage unit. Therefore, the possibility that the output of each energy storage unit will be limited due to the temperature of the energy storage device can be reduced. In other words, the energy storage capacity of the entire energy storage system can be effectively utilized.

[0325] In a specific example of Embodiment 12 (Embodiment 13), in the weighting value setting process, when the second deviation changes from a value below the first threshold to a value above the first threshold, the weighting value is set to a predetermined first value, and when the second deviation changes from a value above a second threshold smaller than the first threshold to a value below the second threshold, the weighting value is set to a second value corresponding to the temperature deviation. In the above embodiment, the relationship between the second deviation and the weighting value exhibits hysteresis characteristics. Therefore, even when the second deviation fluctuates near the first or second threshold, excessively frequent fluctuations in the weighting value can be suppressed.

[0326] In a specific example of Embodiment 12 (Embodiment 14), in the weighting value setting process, the relationship between the second deviation and the weighting value is determined according to the total DC power command value, and a numerical value relating to the second deviation calculated by the deviation calculation process is set as the weighting value. In the above embodiment, the relationship between the second deviation and the weighting value is determined according to the total DC power command value. Therefore, compared to an embodiment in which the relationship between the second deviation and the weighting value is fixed, the total DC power command value can be appropriately allocated to multiple energy storage units.

[0327] In any specific example of embodiments 8 to 14 (embodiment 15), the first process includes a normalization process that normalizes the number of charge-discharge cycles of the energy storage device in the energy storage unit to a value within a predetermined standard range, a deviation calculation process that calculates a third deviation between the normalized number of charge-discharge cycles and a reference value, and a weighting value setting process that sets the weighting value according to the third deviation. In the above embodiments, the weighting value is set according to the number of charge-discharge cycles of the energy storage device in each energy storage unit. Therefore, the possibility that the output of each energy storage unit will be limited due to the number of charge-discharge cycles of the energy storage device can be reduced. In other words, the energy storage capacity of the entire energy storage system can be effectively utilized.

[0328] In a specific example of Embodiment 15 (Embodiment 16), in the weighting value setting process, when the third deviation changes from a value below the first threshold to a value above the first threshold, the weighting value is set to a predetermined first value, and when the third deviation changes from a value above a second threshold smaller than the first threshold to a value below the second threshold, the weighting value is set to a second value corresponding to the third deviation. In the above embodiments, the relationship between the third deviation and the weighting value exhibits hysteresis characteristics. Therefore, even when the third deviation fluctuates near the first or second threshold, excessively frequent fluctuations in the weighting value can be suppressed.

[0329] In a specific example of Embodiment 15 (Embodiment 17), the weighting value setting process determines the relationship between the third deviation and the weighting value according to the total DC power command value, and sets the numerical value that has the above relationship to the third deviation calculated by the deviation calculation process as the weighting value. In the above embodiment, the relationship between the third deviation and the weighting value is determined according to the total DC power command value. Therefore, compared to an embodiment in which the relationship between the third deviation and the weighting value is fixed, the total DC power command value can be appropriately allocated to multiple energy storage units.

[0330] In any specific example of embodiments 8 to 17 (embodiment 18), the first process sets the weight value according to a first weight value corresponding to the charge rate of the energy storage device in the energy storage unit, a second weight value corresponding to the temperature of the energy storage device, and a third weight value corresponding to the number of charge-discharge cycles of the energy storage device. In the above embodiments, the weight value is set according to the charge rate, temperature, and number of charge-discharge cycles of the energy storage unit. Therefore, compared to embodiments in which the weight value is set according to only a specific state of the energy storage unit, it is possible to set an appropriate weight value (and thus a distribution coefficient) from various perspectives regarding the state of the energy storage device. The weight value is calculated, for example, by the weighted sum of the first weight value, the second weight value, and the third weight value.

[0331] In any specific example of embodiments 8 to 18 (embodiment 19), the first process includes a process to reduce the rate of temporal variation of the distribution coefficient. In the above embodiments, since the rate of temporal variation of the distribution coefficient is reduced, abrupt fluctuations in the distribution value to each energy storage unit are suppressed. Therefore, the possibility of sudden fluctuations in the active power at the composite point due to abrupt fluctuations in the distribution coefficient in each energy storage unit can be reduced.

[0332] In any specific example of Embodiments 3 to 19 (Embodiment 20), when one of the plurality of energy storage units is started or stopped, the coefficient setting unit changes the distribution coefficient over time over a predetermined period of time, and the limit value setting unit changes the limit value over time over a predetermined period of time. In the above embodiments, discontinuous fluctuations of the distribution coefficient and limit value caused by the starting or stopping of the energy storage unit are suppressed. Therefore, the possibility of sudden fluctuations in the active power at the composite point due to sharp fluctuations in the distribution coefficient in each energy storage unit can be reduced.

[0333] In any specific example of Embodiments 1 to 20 (Embodiment 21), the energy storage system includes an energy storage unit in a maintenance state, and the command calculation unit adds the power for maintenance related to the energy storage unit in the maintenance state to the basic command value. According to the above embodiments, the power required for the maintenance of the energy storage unit can be supplied by other operational energy storage units while maintaining the active power of the composite point at the basic command value.

[0334] In any specific example of Embodiments 1 to 21 (Embodiment 22), the command calculation unit calculates the total DC power command value by subtracting the correction power from the basic command value, and the allocation processing unit calculates the active power allocation value from the total DC power command value for each normal unit among the plurality of energy storage units other than the priority unit, and sets the correction power as the active power allocation value for the priority unit. In the above embodiment, the correction power subtracted from the basic power is set as the active power allocation value for the priority unit. Therefore, it is possible to preferentially (or forcibly) have the priority unit discharge or charge the correction power.

[0335] In any specific example of Embodiments 1 to 22 (Embodiment 23), the command calculation unit calculates a total reactive power command value, which is the sum of the reactive power that the plurality of energy storage units should generate; the command distribution unit calculates a reactive power distribution value to be distributed to each of the plurality of energy storage units from the total reactive power command value; and the operation instruction unit instructs each of the plurality of energy storage units to use its respective reactive power distribution value. According to the above embodiments, it is possible to control not only the generation of active power but also the generation of reactive power in each energy storage unit.

[0336] In any specific example of Embodiments 1 to 23 (Embodiment 24), the command calculation unit subtracts the active power generated by the power generation system from the basic command value. According to the above embodiments, even in an environment where power generation equipment is installed in parallel with multiple energy storage systems, the active power at the composite point can be maintained at the basic command value with high accuracy.

[0337] In any specific example of Embodiments 1 to 24 (Embodiment 25), the command calculation unit adds the active power consumed by the load equipment to the basic command value. According to the above embodiments, even in an environment where the load equipment consumes the power generated by the energy storage system, the active power at the composite point can be maintained at the basic command value with high accuracy.

[0338] A management system according to one aspect of the present disclosure (Aspect 26) comprises a power storage system that adjusts the active power at a point of integration with a power grid by a plurality of power storage units, each including a power storage device that discharges and charges DC power, and a control system that controls the power storage system, wherein the control system comprises a command calculation unit that calculates a total DC power command value, which is the sum of the power that the power storage devices in the plurality of power storage units should discharge or charge, by adding power losses, including conversion losses due to the conversion between DC power and AC power and transformation losses due to the mutual transformation between the power storage system and the substation equipment between the power storage system and the point of integration, to the basic command value of the active power; a command distribution unit that calculates an active power distribution value to be distributed to each of the plurality of power storage units from the total DC power command value; and an operation instruction unit that instructs each of the plurality of power storage units on the active power distribution value of the power storage unit. [Explanation of Symbols]

[0339] 100...Management system, 10, 10a, 10b...Power system, 11, 11a, 11b...Combination point, 21, 21a, 21b...Substation equipment, 22, 22a, 22b...Load equipment, 23...Power generation equipment, 24...AC / DC converter, 30...Energy storage system, 31...Energy storage device, 32...Control device, 321...Transformer, 322...AC / DC converter, 33...Load equipment, 40...Control system, 41...Control device, 42...Memory device, 43...Transceiver, 5 1...Command calculation unit, 52...Command distribution unit, 521...Coefficient setting unit, 522...Limit value setting unit, 523...Distribution processing unit, 53...Operation instruction unit, 61...First setting unit, 611...Candidate value setting unit, 612...Candidate value setting unit, 613...Candidate value setting unit, 614...Candidate value selection unit, 62...Second setting unit, 621...Candidate value setting unit, 622...Candidate value setting unit, 623...Candidate value setting unit, 614...Candidate value selection unit, 5212...Switching unit, 5213...Smoothing unit.

Claims

1. A control system for controlling an energy storage system that adjusts the active power at the point of integration with the power grid by using multiple energy storage units, including energy storage devices that discharge and charge DC power, A command calculation unit calculates a total DC power command value, which is the sum of the power that the energy storage devices in the plurality of energy storage units should discharge or charge, by adding power losses, including conversion losses due to the conversion between DC power and AC power, and transformation losses due to the voltage transformation between the energy storage system and the substation equipment between the energy storage system and the point of convergence and the energy storage system, to the basic command value of the active power. A command distribution unit that calculates the active power distribution value to be distributed to each of the plurality of energy storage units from the total DC power command value, An operation instruction unit that instructs each of the plurality of energy storage units on the effective power distribution value of the energy storage unit. A control system equipped with the following features.

2. The command distribution unit, A coefficient setting unit that sets a distribution coefficient for each of the plurality of energy storage units, Includes a distribution processing unit that calculates a first power distribution value to be distributed to each of the plurality of energy storage units from the total DC power command value, according to the distribution coefficient of each energy storage unit. The control system according to claim 1.

3. The command distribution unit, The system further includes a limit value setting unit that sets a limit value for each of the plurality of energy storage units, The aforementioned allocation processing unit, For one or more of the plurality of energy storage units whose first power distribution value exceeds the limit value, the total excess value obtained by summing the excess values ​​of those units is distributed to each of the one or more of the plurality of energy storage units whose first power distribution value does not exceed the limit value. The control system of claim 2.

4. The limit value setting unit is, For each of the plurality of energy storage units, the limit value is selected from a plurality of candidate values ​​relating to different states of the energy storage unit. The control system according to claim 3.

5. The plurality of candidate values ​​include a first candidate value corresponding to the voltage of the energy storage device, The first candidate value is, If the voltage is a value within the first range, it is set to a first value. If the voltage is a value within a second range that differs from the first range, it is set to a second value that differs from the first value. If the voltage is a value within a third range between the first range and the second range, the value is set to change between the first value and the second value according to the voltage. The control system according to claim 4.

6. The aforementioned plurality of candidate values ​​include a second candidate value corresponding to the charge level of the energy storage device, The second candidate value is, If the charge level is a value within the first range, it is set to a first value. If the charge level is a value within a second range that differs from the first range, it is set to a second value that differs from the first value. If the charge rate is a value within a third range between the first range and the second range, the charge rate is set to a value that changes between the first value and the second value according to the charge rate. The control system according to claim 4.

7. The aforementioned plurality of candidate values ​​include a third candidate value corresponding to the temperature of the energy storage device, The third candidate value is, If the temperature is a value within the first range, it is set to the first value. If the temperature is a value within a second range that differs from the first range, it is set to a second value that differs from the first value. If the temperature is a value within a third range between the first range and the second range, the value is set to change between the first and second values ​​depending on the temperature. The control system according to claim 4.

8. The coefficient setting unit is, A first process of setting a weight value for each of the aforementioned plurality of energy storage units, A second process for setting a correction value for each of the aforementioned plurality of energy storage units according to the operating watt-hour capacity of the energy storage unit, For each of the plurality of energy storage units, a third process is performed to calculate the distribution coefficient according to the weighting value and the correction value. The control system of claim 2.

9. The first process is, A normalization process that normalizes the charge level of the energy storage device in the energy storage unit to a value within a predetermined standard range, A deviation calculation process for calculating the first deviation between the normalized charge rate and the reference value, Includes a weighting value setting process that sets the weighting value according to the first deviation. The control system of claim 8.

10. In the aforementioned weight value setting process, When the first deviation changes from a value below a first threshold to a value above the first threshold, the weighted value is set to a predetermined first value. When the first deviation changes from a value that is greater than a second threshold (which is smaller than the first threshold) to a value that is less than the second threshold, the weighted value is set to the second value corresponding to the first deviation. The control system of claim 9.

11. In the aforementioned weight value setting process, The relationship between the first deviation and the weighted value is determined according to the total DC power command value. The numerical values ​​relating to the first deviation calculated by the aforementioned deviation calculation process are set as the weighted values. The control system of claim 9.

12. The first process is, A normalization process that normalizes the temperature of the energy storage device in the energy storage unit to a value within a predetermined standard range, A deviation calculation process for calculating the second deviation between the normalized temperature and the reference value, Includes a weighting value setting process that sets the weighting value according to the second deviation. The control system of claim 8.

13. In the aforementioned weight value setting process, When the second deviation changes from a value below the first threshold to a value above the first threshold, the weighted value is set to a predetermined first value. When the second deviation changes from a value above a second threshold that is smaller than the first threshold to a value below the second threshold, the weighted value is set to a second value corresponding to the temperature deviation. The control system of claim 12.

14. In the aforementioned weight value setting process, The relationship between the second deviation and the weighted value is determined according to the total DC power command value. The numerical values ​​relating to the second deviation calculated by the aforementioned deviation calculation process are set as the weighted values. The control system of claim 12.

15. The first process is, A normalization process that normalizes the number of charge and discharge cycles of the energy storage device in the energy storage unit to a value within a predetermined standard range, A deviation calculation process is performed to calculate the third deviation between the normalized number of charge / discharge cycles and the reference value, Includes a weighting value setting process that sets the weighting value according to the third deviation. The control system of claim 8.

16. In the aforementioned weight value setting process, When the third deviation changes from a value below the first threshold to a value above the first threshold, the weighted value is set to a predetermined first value. When the third deviation changes from a value above a second threshold that is smaller than the first threshold to a value below the second threshold, the weighted value is set to the second value corresponding to the third deviation. The control system of claim 15.

17. In the aforementioned weight value setting process, The relationship between the third deviation and the weighted value is determined according to the total DC power command value. The numerical values ​​relating to the third deviation calculated by the aforementioned deviation calculation process are set as the weighted values. The control system of claim 15.

18. In the first process, A first weighted value corresponding to the charge level of the energy storage device in the energy storage unit, A second weighting value corresponding to the temperature of the energy storage device, A third weighted value corresponding to the number of charge and discharge cycles of the aforementioned energy storage device and The weight value is set accordingly. The control system of claim 8.

19. The first process includes a process to reduce the rate of temporal variation of the distribution coefficient. The control system of claim 8.

20. When starting or stopping one of the aforementioned multiple energy storage units, The coefficient setting unit changes the distribution coefficient over time over a predetermined period of time. The limit value setting unit changes the limit value over time over a predetermined period of time. The control system according to claim 3.

21. The aforementioned energy storage system includes energy storage units in a maintenance state. The command calculation unit adds the maintenance power for the energy storage unit in maintenance state to the basic command value. The control system according to claim 1.

22. The command calculation unit calculates the total DC power command value by subtracting the correction power from the basic command value. The aforementioned allocation processing unit, For each of the above-mentioned multiple energy storage units, excluding the priority unit, the active power distribution value is calculated from the total DC power command value. For the priority unit, the correction power is set as the active power distribution value. The control system of claim 2.

23. The command calculation unit calculates a total reactive power command value, which is the sum of the reactive power that the plurality of energy storage units should generate. The command distribution unit calculates the reactive power distribution value to be distributed to each of the plurality of energy storage units from the total reactive power command value, The operation instruction unit instructs each of the plurality of energy storage units on the reactive power distribution value of that energy storage unit. The control system according to claim 1.

24. The command calculation unit subtracts the active power generated by the power generation system from the basic command value. The control system according to claim 1.

25. The command calculation unit adds the active power consumed by the load equipment to the basic command value. The control system according to claim 1.

26. A power storage system that adjusts the active power at the point of integration with the power grid by using multiple power storage units, including power storage devices that discharge and charge DC power, The system comprises a control system for controlling the aforementioned energy storage system, The control system is A command calculation unit calculates a total DC power command value, which is the sum of the power that the energy storage devices in the plurality of energy storage units should discharge or charge, by adding power losses, including conversion losses due to the conversion between DC power and AC power, and transformation losses due to the voltage transformation between the energy storage system and the substation equipment between the energy storage system and the point of convergence and the energy storage system, to the basic command value of the active power. A command distribution unit that calculates the active power distribution value to be distributed to each of the plurality of energy storage units from the total DC power command value, An operation instruction unit that instructs each of the plurality of energy storage units on the effective power distribution value of the energy storage unit. A management system equipped with the following features.

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