Power supply system and control method for the same

Abstract

A power supply system (1a) includes a photovoltaic facility (10), a storage battery facility (30), and a fuel cell facility (20). A device to be operated is selected from among candidates to be operated based on an estimation result of degrees of degradation of the candidates to be operated. The candidates to be operated include at least one device in the storage battery facility (30) and / or at least one device in the fuel cell facility (20).

Description

POWER SUPPLY SYSTEM AND CONTROL METHOD FOR THE SAME

[0001] The present disclosure relates to a power supply system and a control method for the same.

[0002] Patent literature 1 discloses a power supply system that includes a photovoltaic device, a power storage device, and a fuel cell system. In the power supply system disclosed in Patent Literature 1, a ratio between power to be supplied from the power storage device to a load and power to be supplied from the fuel cell system to the load is controlled based on electricity expense.

[0003] JP2023-9101A

[0004] The present disclosure provides a technique suitable for extending a period over which power supply capability of a power supply system is maintained.

[0005] The present disclosure provides a control method for a power supply system that includes: a photovoltaic facility; a storage battery facility; and a fuel cell facility, the control method includes selecting a device to be operated from among candidates to be operated, based on an estimation result of degrees of degradation of the candidates to be operated, and the candidates to be operated include at least one device in the storage battery facility and / or at least one device in the fuel cell facility.

[0006] According to another aspect, the present disclosure provides a power supply system including: a photovoltaic facility; a storage battery facility; a fuel cell facility; and a control unit that controls the photovoltaic facility, the storage battery facility, and the fuel cell facility, the control unit selects a device to be operated from among candidates to be operated, based on an estimation result of degrees of degradation of the candidates to be operated, and the candidates to be operated include at least one device in the storage battery facility and / or at least one device in the fuel cell facility.

[0007] According to another aspect, the present disclosure provides a control method for a power supply system that includes: a photovoltaic facility; a storage battery facility; and a fuel cell facility, the control method includes selecting a device to be operated from among candidates to be operated, based on a record of previous use of the candidates to be operated, and the candidates to be operated include at least one device in the storage battery facility and / or at least one device in the fuel cell facility.

[0008] According to another aspect, the present disclosure provides a power supply system including: a photovoltaic facility; a storage battery facility; a fuel cell facility; and a control unit that controls the photovoltaic facility, the storage battery facility, and the fuel cell facility, the control unit selects a device to be operated from among candidates to be operated, based on a record of previous use of the candidates to be operated, and the candidates to be operated include at least one device in the storage battery facility and / or at least one device in the fuel cell facility.

[0009] The technique according to the present disclosure is suitable for extending a period over which power supply capability of a power supply system is maintained.

[0010] Fig. 1 is a configuration diagram of a power supply system according to an embodiment.Fig. 2 is a chart showing a normal mode according to one specific example.Fig. 3 is a sequence diagram illustrating a long lifespan mode according to one specific example.Fig. 4 is a chart showing a priority order database according to one specific example.

[0011] (Findings on which the present disclosure is based, and the like) Power is supplied to an electrical load from a power supply system that includes a photovoltaic facility, a storage battery facility, and a fuel cell facility. In the power supply system, the storage battery facility and the fuel cell facility may be operated according to power generated by the photovoltaic facility and power supplied to the electrical load.

[0012] If a degree of operation is unbalanced among a plurality of devices in the storage battery facility and / or the fuel cell facility, a degree of degradation may become uneven. In this case, the lifespan of a part of the devices may be exhausted in a short time period, and the level of the power supply capability as the entirety of the power supply system may be lowered from the initial level. Therefore, the inventors of the present invention have examined a technique suitable for extending a period over which the power supply capability of the power supply system is maintained.

[0013] Embodiments will be described below in detail with reference to the drawings. However, unnecessarily detailed description may be omitted. For example, detailed description of already well-known matters or repeated description of the substantially same configurations may be omitted.

[0014] The accompanying drawings and the following description are provided for allowing a person skilled in the art to sufficiently understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0015] (Embodiment) An embodiment will be described below with reference to Fig. 1 to Fig. 4.

[0016] [1-1. Configuration] Fig. 1 is a configuration diagram illustrating a power supply system 1a according to an embodiment. The power supply system 1a and a commercial power supply 2 are interconnected. The power supply system 1a supplies power to an electrical load 5. The power supply system 1a is connected to an EMS (energy management system) server 52 through a network 60.

[0017] The power supply system 1a is a distributed power supply system. The power supply system 1a includes a photovoltaic facility 10, a fuel cell facility 20, a storage battery facility 30, a control unit 50a, an electric path 70, a distribution board 4, a current sensor 3a, and a current sensor 3b.

[0018] The photovoltaic facility 10 includes a photovoltaic module 11, a DCDC converter 12, and a DCAC inverter 13. DC power generated by the photovoltaic module 11 is converted to DC power having a different voltage by the DCDC converter 12. The converted DC power is converted to AC power by the DCAC inverter 13. The AC power is supplied to the electric path 70. In the present embodiment, the photovoltaic module may be read as photovoltaic device.

[0019] The fuel cell facility 20 includes a fuel cell system 20a, a fuel cell system 20b, and a fuel cell system 20c. Each of the fuel cell system 20a, the fuel cell system 20b, and the fuel cell system 20c is, for example, a polymer electrolyte fuel cell (PEFC) system, a solid oxide fuel cell (SOFC) system, etc. In the present embodiment, the fuel cell system may be read as fuel cell device.

[0020] The fuel cell system 20a includes a fuel cell stack 21a, a DCDC converter 22a, and a DCAC inverter 23a. DC power generated by the fuel cell stack 21a is converted to DC power having a different voltage by the DCDC converter 22a. The converted DC power is converted to AC power by the DCAC inverter 23a. The AC power is supplied to the electric path 70.

[0021] The fuel cell system 20b includes a fuel cell stack 21b, a DCDC converter 22b, and a DCAC inverter 23b. DC power generated by the fuel cell stack 21b is converted to DC power having a different voltage by the DCDC converter 22b. The converted DC power is converted to AC power by the DCAC inverter 23b. The AC power is supplied to the electric path 70.

[0022] The fuel cell system 20c includes a fuel cell stack 21c, a DCDC converter 22c, and a DCAC inverter 23c. DC power generated by the fuel cell stack 21c is converted to DC power having a different voltage by the DCDC converter 22c. The converted DC power is converted to AC power by the DCAC inverter 23c. The AC power is supplied to the electric path 70.

[0023] The storage battery facility 30 incudes a storage battery module 31a, a storage battery module 31b, a storage battery module 31c, a bidirectional DCDC converter 32a, a bidirectional DCDC converter 32b, a bidirectional DCDC converter 32c, and a DCAC inverter 33. Each of the storage battery module 31a, the storage battery module 31b, and the storage battery module 31c is, for example, a lithium-ion storage battery module, a nickel-hydrogen storage battery module, or a lead storage battery module. In the present embodiment, the storage battery module may be read as storage battery device.

[0024] Power discharged from the storage battery module 31a is converted to DC power having a different voltage by the bidirectional DCDC converter 32a. The converted DC power is converted to AC power by the DCAC inverter 33. The AC power is supplied to the electric path 70.

[0025] AC power supplied from the electric path 70 to the DCAC inverter 33 is converted to DC power. The DC power is converted to DC power having a different voltage by the bidirectional DCDC converter 32a. The storage battery module 31a is charged with the converted DC power.

[0026] Power discharged from the storage battery module 31b is converted to DC power having a different voltage by the bidirectional DCDC converter 32b. The converted DC power is converted to AC power by the DCAC inverter 33. The AC power is supplied to the electric path 70.

[0027] AC power supplied from the electric path 70 to the DCAC inverter 33 is converted to DC power. The DC power is converted to DC power having a different voltage by the bidirectional DCDC converter 32b. The storage battery module 31b is charged with the converted DC power.

[0028] Power discharged from the storage battery module 31c is converted to DC power having a different voltage by the bidirectional DCDC converter 32c. The converted DC power is converted to AC power by the DCAC inverter 33. The AC power is supplied to the electric path 70.

[0029] AC power supplied from the electric path 70 to the DCAC inverter 33 is converted to DC power. The DC power is converted to DC power having a different voltage by the bidirectional DCDC converter 32c. The storage battery module 31c is charged with the converted DC power.

[0030] In the present embodiment, a plurality of the fuel cell systems 20a, 20b, and 20c have the same specifications. Therefore, in a case where the plurality of the fuel cell systems 20a, 20b, and 20c are used in the same manner, the fuel cell systems 20a, 20b, and 20c may be degraded at the same rate. A plurality of the fuel cell stacks 21a, 21b, and 21c have the same specifications. Therefore, in a case where the plurality of the fuel cell stacks 21a, 21b, and 21c are used in the same manner, the fuel cell stacks 21a, 21b, and 21c may be degraded at the same rate. A plurality of the storage battery modules 31a, 31b, and 31c have the same specifications. Therefore, in a case where the plurality of the storage battery modules 31a, 31b, and 31c are used in the same manner, the storage battery modules 31a, 31b, and 31c may be degraded at the same rate.

[0031] Power may flow from the electric path 70 to the commercial power supply 2. Power may flow from the commercial power supply 2 to the electric path 70. The current sensor 3a detects current flowing between the electric path 70 and the commercial power supply 2. The control unit 50a can cause power flowing from the commercial power supply 2 to the power supply system 1a or power flowing from the power supply system 1a to the commercial power supply 2 to track target power (for example, 0 W) by monitoring a current value detected by the current sensor 3a.

[0032] Power may flow from the electric path 70 through the distribution board 4 to the electrical load 5. The current sensor 3b detects current flowing to the electrical load 5.

[0033] The storage battery facility 30 includes a control unit 50b. The photovoltaic facility 10 includes a control unit 50c. Each of the fuel cell system 20a, the fuel cell system 20b, and the fuel cell system 20c includes a control unit 50d. Hereinafter, the control unit 50d of the fuel cell system 20a may be referred to as first control unit 50d. The control unit 50d of the fuel cell system 20b may be referred to as second control unit 50d. The control unit 50d of the fuel cell system 20c may be referred to as third control unit 50d.

[0034] The EMS server 52 may be a cloud server or an on-premises server. The network 60 may be a wired network or a wireless network. The network 60 is typically the Internet. The EMS server 52 includes a priority order database 53. The priority order database 53 indicates the priority order for operations of the devices. The priority order database 53 will be described below in detail with reference to Fig. 4.

[0035] [1-2. Operation] The control unit 50a communicates with the current sensor 3a, the current sensor 3b, the control unit 50b, the control unit 50c, the first control unit 50d, the second control unit 50d, and the third control unit 50d. Furthermore, the control unit 50a communicates with the EMS server 52 through the network 60. Through these communications, the control unit 50a generates control signals for controlling the control unit 50b, the control unit 50c, the first control unit 50d, the second control unit 50d, and the third control unit 50d.

[0036] The control unit 50b receives the control signal from the control unit 50a. The control unit 50b controls the bidirectional DCDC converter 32a, the bidirectional DCDC converter 32b, the bidirectional DCDC converter 32c, and the DCAC inverter 33, according to the control signal. By controlling the bidirectional DCDC converter 32a, the storage battery module 31a is controlled so as to be charged, be in a stand-by state, or be discharged. By controlling the bidirectional DCDC converter 32b, the storage battery module 31b is controlled so as to be charged, be in a stand-by state, or be discharged. By controlling the bidirectional DCDC converter 32c, the storage battery module 31c is controlled so as to be charged, be in a stand-by state, or be discharged. By controlling the DCAC inverter 33, power conversion between DC and AC is performed. Through these controls, power flowing between the storage battery facility 30 and the electric path 70 is controlled.

[0037] Specifically, by controlling the bidirectional DCDC converter 32a, charge / discharge power of the storage battery module 31a is controlled. By controlling the bidirectional DCDC converter 32b, charge / discharge power of the storage battery module 31b is controlled. By controlling the bidirectional DCDC converter 32c, charge / discharge power of the storage battery module 31c is controlled.

[0038] In the illustrated example, an inter-terminal voltage V1 of the bidirectional DCDC converter 32a is controlled relative to an inter-terminal voltage V2 of the DCAC inverter 33, whereby charge and discharge of the storage battery module 31a is controlled. An inter-terminal voltage V1 of the bidirectional DCDC converter 32b is controlled relative to the inter-terminal voltage V2 of the DCAC inverter 33, whereby charge and discharge of the storage battery module 31b is controlled. An inter-terminal voltage V1 of the bidirectional DCDC converter 32c is controlled relative to the inter-terminal voltage V2 of DCAC inverter 33, whereby charge and discharge of the storage battery module 31c is controlled.

[0039] The control unit 50c receives the control signal from the control unit 50a. The control unit 50c controls the DCDC converter 12 and the DCAC inverter 13 according to the control signal. By controlling the DCDC converter 12, the output voltage of the photovoltaic module 11 is adjusted. By controlling the DCAC inverter 13, power conversion between DC and AC is performed. Through these controls, power is extracted from the photovoltaic facility 10 to the electric path 70.

[0040] The first control unit 50d receives the control signal from the control unit 50a. The first control unit 50d controls the DCDC converter 22a and the DCAC inverter 23a according to the control signal. By controlling the DCDC converter 22a, the output voltage of the fuel cell stack 21a is adjusted. By controlling the DCAC inverter 23a, power conversion between DC and AC is performed. Through these controls, power is extracted from the fuel cell system 20a to the electric path 70.

[0041] The second control unit 50d receives the control signal from the control unit 50a. The second control unit 50d controls the DCDC converter 22b and the DCAC inverter 23b according to the control signal. By controlling the DCDC converter 22b, the output voltage of the fuel cell stack 21b is adjusted. By controlling the DCAC inverter 23b, power conversion between DC and AC is performed. Through these controls, power is extracted from the fuel cell system 20b to the electric path 70.

[0042] The third control unit 50d receives the control signal from the control unit 50a. The third control unit 50d controls the DCDC converter 22c and the DCAC inverter 23c according to the control signal. By controlling the DCDC converter 22c, the output voltage of the fuel cell stack 21c is adjusted. By controlling the DCAC inverter 23c, power conversion between DC and AC is performed. Through these controls, power is extracted from the fuel cell system 20c to the electric path 70.

[0043] An operation mode of the power supply system 1a includes a normal mode and a long lifespan mode.

[0044] Fig. 2 is a chart showing the normal mode of one specific example.

[0045] (1) of Fig. 2 indicates a case where power PLflowing from the electric path 70 to the electrical load 5 is less than power PPVgenerated by the photovoltaic facility 10 in the normal mode. In this case, the storage battery facility 30 is charged, and power flows from the electric path 70 to the storage battery facility 30. The fuel cell facility 20 is in a stand-by state, and power does not flow between the fuel cell facility 20 and the electric path 70. Power does not flow from the commercial power supply 2 to the electric path 70.

[0046] Even in the case of (1), when the storage battery facility 30 is in a fully charged state, the storage battery facility 30 is in a stand-by state, and power does not flow between the storage battery facility 30 and the electric path 70. A part or the entirety of power exceeding the power PLin power supplied from the photovoltaic facility 10 to the electric path 70 may be caused to flow to the commercial power supply 2.

[0047] (2) of Fig. 2 indicates a case where the power PLflowing from the electric path 70 to the electrical load 5 is larger than the power PPVgenerated by the photovoltaic facility 10 and less than the total of the power PPVgenerated by the photovoltaic facility 10 and the maximum generated power PFCMAXgenerated by the fuel cell facility 20, in the normal mode. In this case, the storage battery facility 30 is discharged, and power flows from the storage battery facility 30 to the electric path 70. The fuel cell facility 20 is in a power generating state, and power flows from the fuel cell facility 20 to the electric path 70. Power does not flow from the commercial power supply 2 to the electric path 70. The maximum generated power PFCMAXis the maximum power that can be generated by the fuel cell facility 20.

[0048] Specifically, in the case of (2), the photovoltaic facility 10 cannot compensate for the power PLby itself. The stable component of the insufficient power that cannot be compensated for is compensated for mainly by the fuel cell facility 20. The fluctuating component of the insufficient power is compensated for by the storage battery facility 30. Typically, most (for example, 80% or more) of the insufficient power is compensated for by the fuel cell facility 20.

[0049] (3) of Fig. 2 indicates a case where the power PLflowing from the electric path 70 to the electrical load 5 is larger than the total of the power PPVgenerated by the photovoltaic facility 10 and the maximum generated power PFCMAXgenerated by the fuel cell facility 20, in the normal mode. In this case, the storage battery facility 30 is discharged, and power flows from the storage battery facility 30 to the electric path 70. The fuel cell facility 20 is in a power generating state, and power flows from the fuel cell facility 20 to the electric path 70. Power does not flow from the commercial power supply 2 to the electric path 70.

[0050] Specifically, in the case of (3), the fuel cell facility 20 exhibits its power generation capability to the maximum extent, and power flows from the fuel cell facility 20 to the electric path 70. Even in this state, in the case of (3), the power PLcannot be compensated for. The insufficient power that cannot be compensated for is compensated for by the storage battery facility 30. Even in the case of (3), when a charge amount of the storage battery facility 30 is zero, power does not flow between the storage battery facility 30 and the electric path 70, and power flows from the commercial power supply 2 to the electric path 70.

[0051] Fig. 3 is a sequence diagram illustrating the long lifespan mode according to one specific example. In Fig. 3, the “control unit 50d” represents at least one selected from the group consisting of the first control unit 50d, the second control unit 50d, and the third control unit 50d.

[0052] In step S1, the EMS server 52 receives an instruction for changing to the long lifespan mode. In one example, an administrator inputs the change instruction through a user interface to the EMS server 52. The user interface can include a dashboard. In another embodiment, the change instruction is transmitted from a higher-order control unit to the EMS server 52.

[0053] In step S2, the EMS server 52 extracts an SB operation priority order of the plurality of the storage battery modules 31a, 31b, and 31c, and an FC operation priority order of the plurality of the fuel cell systems 20a, 20b, and 20c, from the priority order database 53. The SB operation priority order represents any of the plurality of the storage battery modules 31a, 31b, and 31c, which is to be preferentially operated. The FC operation priority order represents any of the plurality of the fuel cell systems 20a, 20b, and 20c, which is to be preferentially operated. In one illustrative example (hereinafter, referred to as this example) of the present embodiment, in the SB operation priority order, the SB operation priority of the storage battery module 31b is highest, the SB operation priority of the storage battery module 31a is second-highest, and the SB operation priority of the storage battery module 31c is third-highest. In the FC operation priority order, the FC operation priority of the fuel cell system 20a is highest, the FC operation priority of the fuel cell system 20c is second-highest, and the FC operation priority of the fuel cell system 20b is third-highest.

[0054] In step S3, the EMS server 52 transmits the change instruction, the SB operation priority order, and the FC operation priority order through the network 60 to the control unit 50a.

[0055] In step S4, the control unit 50a receives a current value detected by the current sensor 3b from the current sensor 3b. The detected current value represents the latest current flowing to the electrical load 5.

[0056] In step S5, the control unit 50a receives a PV operation record from the control unit 50c. The PV operation record includes information representing the latest power PPVgenerated by the photovoltaic facility 10.

[0057] In step S6, the control unit 50a calculates SB target power and FC target power based on the detected current value and the PV operation record which have been received. The SB target power represents a target value of the charge / discharge power of the storage battery facility 30. The charge / discharge power represents charge power or discharge power. A positive value of the charge / discharge power represents discharge power, and the absolute value of a negative value of the charge / discharge power represents charge power. The FC target power represents a target value of power generated by the fuel cell facility 20.

[0058] In the present embodiment, the voltage of the electrical load 5 is known. Therefore, the power PLflowing from the electric path 70 to the electrical load 5 can be calculated from the voltage and the detected current value. The SB target power and the FC target power are calculated such that the total of the generated power PPV, the SB target power, and the FC target power is equal to the power PL. A ratio between the SB target power and the FC target power is, for example, defined by a predetermined algorithm.

[0059] In step S7, the control unit 50a determines an SB operation target and an FC operation target. The SB operation target is determined so as to supply the SB target power. The FC operation target is determined so as to supply the FC target power.

[0060] Specifically, the number of the storage battery modules to be operated, among the plurality of the storage battery modules 31a, 31b, and 31c, is determined when the SB operation target is determined. Hereinafter, the determined number of the storage battery modules is represented as X. X represents a natural number larger than or equal to 1. Subsequently, X storage battery modules that have high priorities in the SB operation priority order are selected from among the plurality of the storage battery modules 31a, 31b, and 31c as the storage battery modules to be operated. In this example, X=2 is satisfied. The storage battery modules 31b and 31a are selected as two storage battery modules to be operated.

[0061] The number of the fuel cell systems to be operated, among the plurality of the fuel cell systems 20a, 20b, and 20c, is determined when the FC operation target is determined. Hereinafter, the determined number of the fuel cell systems is represented as Y. Y represents a natural number larger than or equal to 1. Subsequently, Y fuel cell systems that have high priorities in the FC operation priority order are selected from among the plurality of the fuel cell systems 20a, 20b, and 20c as the fuel cell systems to be operated. In this example, Y=2 is satisfied. The fuel cell systems 20a and 20c are selected as two fuel cell systems to be operated.

[0062] In step S8, the control unit 50a transmits a charge / discharge instruction to the control unit 50b. The charge / discharge instruction includes the SB operation target. The charge / discharge instruction may include the SB target power. In a case where the SB operation target includes two or more storage battery modules, the charge / discharge instruction may include a target value of the charge / discharge power of each storage battery module which is included in the SB operation target.

[0063] In step S9, the control unit 50b controls charging / discharging of the storage battery facility 30 according to the charge / discharge instruction. Specifically, the control unit 50b controls the DCDC converter connected to the storage battery module included in the SB operation target according to the charge / discharge instruction, thereby controlling charging / discharging of the storage battery module. Thus, charging / discharging of the storage battery facility 30 is controlled. As described above, in this example, the storage battery modules included in the SB operation target are the storage battery modules 31b and 31a. The DCDC converters connected thereto are the bidirectional DCDC converters 32b and 32a.

[0064] In step S10, the control unit 50a transmits a PV power generation instruction to the control unit 50c. The PV power generation instruction includes a content of control for the DCDC converter 12 for extracting power from the photovoltaic module 11.

[0065] In step S11, the control unit 50c controls the DCDC converter 12 according to the PV power generation instruction. Thus, power generation of the photovoltaic module 11 is controlled, and power generation (hereinafter, referred to as PV power generation) of the photovoltaic facility 10 is controlled.

[0066] In step S12, the control unit 50a transmits an FC power generation instruction to the control unit 50d of the fuel cell system included in the FC operation target. The FC power generation instruction may include a target value of power generated by the fuel cell system included in the FC operation target. In a case where the FC operation target includes two or more fuel cell systems, the FC power generation instructions to be transmitted to the control units included in the two or more fuel cell systems may be different from each other. As described above, in this example, the fuel cell systems included in the FC operation target are the fuel cell systems 20a and 20c. The control units 50d included therein are the first control unit 50d and the third control unit 50d.

[0067] In step S13, in the fuel cell systems included in the FC operation target, the control units 50d control powers generated by the fuel cell systems according to the FC power generation instructions. Specifically, the control units 50d control powers generated by the fuel cell stacks in the fuel cell systems according to the FC power generation instructions. Thus, power generation (hereinafter, referred to as FC power generation) of the fuel cell systems is controlled, and power generation of the fuel cell facility 20 is controlled. As described above, in this example, the fuel cell systems included in the FC operation target are the fuel cell systems 20a and 20c. The first control unit 50d controls power generated by the fuel cell stack 21a according to the FC power generation instruction. The third control unit 50d controls power generated by the fuel cell stack 21c according to the FC power generation instruction.

[0068] In step S14, the control unit 50b transmits an SB operation record to the control unit 50a. The SB operation record includes the number of times of charging / discharging of each of the plurality of the storage battery modules 31a, 31b, and 31c. The number of times of charging / discharging represents the total of the number of times of charging and the number of times of discharging. The number of times of charging represents the number of times the storage battery switches from a stand-by state or a discharge state to a charge state. The number of times of discharging represents the number of times the storage battery switches from a stand-by state or a charge state to a discharge state.

[0069] In step S15, the control unit 50c transmits the PV operation record to the control unit 50a. The PV operation record includes information representing the latest power PPVgenerated by the photovoltaic facility 10.

[0070] In step S16, each of the first control unit 50d, the second control unit 50d, and the third control unit 50d transmits an FC operation record to the control unit 50a. The FC operation record (hereinafter, referred to as first FC operation record) transmitted by the first control unit 50d includes the number of times the fuel cell stack 21a has been activated, and an operation time thereof. The FC operation record (hereinafter, referred to as second FC operation record) transmitted by the second control unit 50d includes the number of times the fuel cell stack 21b has been activated, and an operation time thereof. The FC operation record (hereinafter, referred to as third FC operation record) transmitted by the third control unit 50d includes the number of times the fuel cell stack 21c has been activated, and an operation time thereof. The number of times the fuel cell stack has been activated represents the number of times the fuel cell stack has switched from an off state to an on state. In the off state, the fuel cell stack does not generate power. In the on state, the fuel cell stack generates power. The number of times the fuel cell stack has been activated specifically represents the cumulative number of times the fuel cell stack has been activated, and more specifically represents the cumulative number of times the fuel cell stack has been activated as counted from a time when the fuel cell stack was new. The operation time is obtained by counting times during which the fuel cell stack is in the on state. The operation time of the fuel cell stack specifically represents a cumulative operation time during which the fuel cell stack has been operated, and more specifically represents a cumulative operation time of the fuel cell stack from a time when the fuel cell stack was new.

[0071] In step S17, the control unit 50a transmits the SB operation record, the PV operation record, the first FC operation record, the second FC operation record, and the third FC operation record through the network 60 to the EMS server 52.

[0072] In step S18, the EMS server 52 updates the priority order database 53 based on the SB operation record, the PV operation record, the first FC operation record, the second FC operation record, and the third FC operation record.

[0073] Steps S2 to S18 are repeated until the operation mode is changed from the long lifespan mode to another mode. Typically, a control cycle including steps S2 to S18 is repeated at a predetermined control cycle period.

[0074] Fig. 4 is a chart showing the priority order database 53 according to one specific example.

[0075] In the specific example illustrated in Fig. 4, each of the plurality of the storage battery modules 31a, 31b, and 31c has an SB evaluation point representing a degree of degradation. The larger the number of times of charging / discharging of the storage battery module is, the higher the SB evaluation point is. The higher SB evaluation point indicates that degradation of the storage battery module has progressed. The SB evaluation point represents an estimated result of a degree of degradation of the storage battery module. Specifically, the SB evaluation point is calculated according to the following mathematical expression 1. Mathematical expression 1: SB evaluation point=Σ(coefficient A1×the number of times of charging / discharging)

[0076] For example, in the specific example illustrated in Fig. 4, on June 1, 2023, the SB evaluation point of the storage battery module 31a is 1165, the SB evaluation point of the storage battery module 31b is 1132, and the SB evaluation point of the storage battery module 31c is 1465. These SB evaluation points indicate that degradation of the storage battery module 31a has progressed more as compared with the storage battery module 31b, and degradation of the storage battery module 31c has progressed more as compared with the storage battery module 31a. Therefore, in the SB operation priority order, the SB operation priority of the storage battery module 31b is highest, the SB operation priority of the storage battery module 31a is second-highest, and the SB operation priority of the storage battery module 31c is third-highest. In this specific example, X=2 is satisfied, and the two storage battery modules 31b and 31a having high priorities in the SB operation priority order are operated. In Fig. 4, the storage battery modules to be operated are underlined.

[0077] In the specific example illustrated in Fig. 4, on June 2, 2023, in the SB operation priority order, the SB operation priority of the storage battery module 31a is highest, the SB operation priority of the storage battery module 31b is second-highest, and the SB operation priority of the storage battery module 31c is third-highest. In this specific example, X=1 is satisfied, and the one storage battery module 31a having a high priority in the SB operation priority order is operated.

[0078] In the specific example illustrated in Fig. 4, on June 3, 2023, in the SB operation priority order, the SB operation priority of the storage battery module 31b is highest, the SB operation priority of the storage battery module 31a is second-highest, and the SB operation priority of the storage battery module 31c is third-highest. In this specific example, X=2 is satisfied, and the two storage battery modules 31b and 31a having high priorities in the SB operation priority order are operated.

[0079] In the specific example illustrated in Fig. 4, each of the plurality of the fuel cell stacks 21a, 21b, and 21c has an FC evaluation point representing a degree of degradation. The larger the number of times the fuel cell stack has been activated is, the higher the FC evaluation point is. The longer the operation time of the fuel cell stack is, the higher the FC evaluation point is. The higher FC evaluation point indicates that degradation of the fuel cell stack has progressed. The FC evaluation point represents an estimated result of a degree of degradation of the fuel cell stack. Specifically, the FC evaluation point is calculated according to the following mathematical expression 2. Mathematical expression 2: FC evaluation point=Σ(coefficient B1×the number of times of activation+coefficient B2×operation time)

[0080] For example, in the specific example illustrated in Fig. 4, on June 1, 2023, the FC evaluation point of the fuel cell stack 21a is 756, the FC evaluation point of the fuel cell stack 21b is 847, and the FC evaluation point of the fuel cell stack 21c is 832. These FC evaluation points indicate that degradation of the fuel cell stack 21c has progressed more as compared with the fuel cell stack 21a, and degradation of the fuel cell stack 21b has progressed more as compared with the fuel cell stack 21c. Therefore, in the FC operation priority order, the FC operation priority of the fuel cell system 20a including the fuel cell stack 21a is highest, the FC operation priority of the fuel cell system 20c including the fuel cell stack 21c is second-highest, and the FC operation priority of the fuel cell system 20b including the fuel cell stack 21b is third-highest. In this specific example, Y=2 is satisfied, and the two fuel cell systems 20a and 20c having high priorities in the FC operation priority order are operated. In Fig. 4, the fuel cell stacks included in the fuel cell systems to be operated are underlined.

[0081] In the specific example illustrated in Fig. 4, on June 2, 2023, in the FC operation priority order, the FC operation priority of the fuel cell system 20a including the fuel cell stack 21a is highest, the FC operation priority of the fuel cell system 20b including the fuel cell stack 21b is second-highest, and the FC operation priority of the fuel cell system 20c including the fuel cell stack 21c is third-highest. In this specific example, Y=1 is satisfied, and the one fuel cell system 20a having a high priority in the FC operation priority order is operated.

[0082] In the specific example illustrated in Fig. 4, on June 3, 2023, in the FC operation priority order, the FC operation priority of the fuel cell system 20b including the fuel cell stack 21b is highest, the FC operation priority of the fuel cell system 20c including the fuel cell stack 21c is second-highest, and the FC operation priority of the fuel cell system 20a including the fuel cell stack 21a is third-highest. In this specific example, Y=1 is satisfied, and the one fuel cell system 20b having a high priority in the FC operation priority order is operated.

[0083] Various modifications can be applied to the above-described embodiment.

[0084] In the above-described embodiment, the fuel cell system to be operated is selected based on the FC operation priority order. The storage battery module to be operated is selected based on the SB operation priority order. That is, both of selection of the fuel cell system to be operated and selection of the storage battery module to be operated are performed. However, one of selection of the fuel cell system to be operated and selection of the storage battery module to be operated may be merely performed.

[0085] For example, in the example described with reference to Fig. 3, a cycle period at which the plurality of the storage battery modules 31a, 31b, and 31c are controlled, and a cycle period at which the plurality of the fuel cell systems 20a, 20b, and 20c are controlled may be the same. However, a cycle period at which the plurality of the storage battery modules 31a, 31b, and 31c are controlled may be shorter than a cycle period at which the plurality of the fuel cell systems 20a, 20b, and 20c are controlled. In this case, a fluctuating component of power of the electrical load 5 may be easily compensated for by the plurality of the storage battery modules 31a, 31b, and 31c controlled at a relatively short control cycle period. In one example, among the plurality of steps including steps S2 to S18 in Fig. 3, steps concerning the operations of the plurality of the storage battery modules 31a, 31b, and 31c are performed more frequently than steps concerning the operations of the plurality of the fuel cell systems 20a, 20b, and 20c.

[0086] In the above-described embodiment, the FC operation priority order is provided for the plurality of fuel cell systems. The fuel cell system to be operated is selected, based on the FC operation priority order, from among the plurality of fuel cell systems. The SB operation priority order is provided for the plurality of storage battery modules. The storage battery module to be operated is selected, based on the SB operation priority order, from among the plurality of storage battery modules. The FC operation priority order and the SB operation priority order are independent of each other. However, for a plurality of devices as a combination of the plurality of fuel cell systems and the plurality of storage battery modules, a priority order (hereinafter, referred to as common priority order) common to them may be provided, and a device to be operated may be selected from among the plurality of devices based on the common priority order.

[0087] For example, in the example described with reference to Fig. 4, by appropriately setting the coefficient A1, the coefficient B1, and the coefficient B2, the SB evaluation point and the FC evaluation point can be handled so as to be compared. Hereinafter, the SB evaluation point and the FC evaluation point in this example are referred to as common evaluation point. In the plurality of devices as a combination of the plurality of fuel cell systems and the plurality of storage battery modules, the lower the common evaluation point is, the higher the common priority to be set can be.

[0088] In the mode in which the above-described common evaluation point and common priority are used, in the plurality of devices as a combination of the plurality of fuel cell systems and the plurality of storage battery modules, a degree of degradation can be inhibited from becoming uneven.

[0089] In the above-described embodiment, when the SB operation target is determined, at least one storage battery module in the plurality of storage battery modules is selected as a storage battery module to be operated. That is, X≧1 is satisfied. When the FC operation target is determined, at least one fuel cell system in the plurality of fuel cell systems is selected as a fuel cell system to be operated. That is, Y≧1 is satisfied. However, the number of the storage battery modules to be operated may be 0, or the number of the fuel cell systems to be operated may be 0. Specifically, at least one device in the plurality of devices as a combination of the plurality of fuel cell systems and the plurality of storage battery modules may be selected as a device to be operated.

[0090] The order in which the steps are performed in the above-described sequence diagram in Fig. 3 may be changed as appropriate. For example, the order in which steps S8, S10, and S12 are performed can be particularly discretionarily set. For example, the order in which steps S14, S15, and S16 are performed can be particularly discretionarily set.

[0091] In the above-described specific example illustrated in Fig. 4, the FC evaluation point is calculated based on both the number of times of activation and the operation time. However, the FC evaluation point may be calculated merely based on one of the number of times of activation and the operation time. More generally, a degree of degradation of the fuel cell stack may be estimated based on both the number of times of activation and the operation time, or may be estimated merely based on one of them.

[0092] In the above-described embodiment, the number of the photovoltaic modules in the photovoltaic facility 10 is one. However, the number of the photovoltaic modules may be two, three, or four or more.

[0093] In the above-described embodiment, the number of the fuel cell systems in the fuel cell facility 20 is three. However, the number of the fuel cell systems may be one, two, or four or more.

[0094] In the above-described embodiment, the number of the storage battery modules in the storage battery facility 30 is three. However, the number of the storage battery modules may be one, two, or four or more.

[0095] In the above description of the embodiment, power loss such as conversion loss of the DCDC converter and conversion loss of the DCAC inverter is ignored. The control can be performed in consideration of the power loss.

[0096] [1-3. Effects and the like] As is understood from the above description, in the technique according to one example of the present disclosure, the power supply system 1a includes the photovoltaic facility 10, the storage battery facility 30, and the fuel cell facility 20. The control unit 50a selects a device to be operated from among candidates to be operated, based on estimation results of degrees of degradation of the candidates to be operated. The candidates to be operated include at least one device in the storage battery facility 30 and / or at least one device in the fuel cell facility 20. The selected “device to be operated” is operated. In this configuration, in a plurality of devices which the storage battery facility 30 and / or the fuel cell facility 20 have as a whole, a degree of operation can be inhibited from becoming uneven. Therefore, a degree of degradation can be inhibited from becoming uneven in a plurality of devices. This is advantageous from the viewpoint of avoiding a situation in which lifespans of a part of devices are exhausted in a short time period, and the power supply capability of the power supply system 1a as a whole is lowered from the initial level. Thus, this configuration is suitable for extending a period over which the power supply capability of the power supply system 1a is maintained. The number of devices that are selected from among candidates to be operated and are to be operated may be one or plural. Specifically, the candidates to be operated are a plurality of candidate devices to be operated.

[0097] Various advantages are obtained by extending a period over which the power supply capability of the power supply system 1a is maintained. For example, this reduces frequency of maintenance of the power supply system 1a and / or frequency of replacing components, and can reduce running cost of the power supply system 1a.

[0098] In the above-described configuration, the lifespans of the plurality of devices can be made the same. Furthermore, in the above-described configuration, times at which maintenances of the plurality of devices are performed can be made the same.

[0099] In the technique according to one example of the present disclosure, the fuel cell facility 20 includes the plurality of the fuel cell systems 20a, 20b, and 20c. The candidates to be operated include the plurality of the fuel cell systems 20a, 20b, and 20c. This configuration is suitable for extending a period over which the power supply capability of the fuel cell facility 20 is maintained.

[0100] In the technique according to one example of the present disclosure, the storage battery facility 30 includes the plurality of the storage battery modules 31a, 31b, and 31c. The candidates to be operated include the plurality of the storage battery modules 31a, 31b, and 31c. This configuration is suitable for extending a period over which the power supply capability of the storage battery facility 30 is maintained.

[0101] In the technique according to one example of the present disclosure, the fuel cell facility 20 includes the plurality of the fuel cell systems 20a, 20b, and 20c. The storage battery facility 30 includes the plurality of the storage battery modules 31a, 31b, and 31c. A cycle period at which the plurality of the storage battery modules 31a, 31b, and 31c are controlled is shorter than a cycle period at which the plurality of the fuel cell systems 20a, 20b, and 20c are controlled. The candidates to be operated include the plurality of the fuel cell systems 20a, 20b, and 20c and the plurality of the storage battery modules 31a, 31b, and 31c. The control unit 50a selects a device to be operated from among the plurality of the fuel cell systems 20a, 20b, and 20c based on a first type priority order provided for the plurality of the fuel cell systems 20a, 20b, and 20c. The control unit 50a selects a device to be operated from among the plurality of the storage battery modules 31a, 31b, and 31c based on a second type priority order provided for the plurality of the storage battery modules 31a, 31b, and 31c. The first type priority order and the second type priority order are independent of each other. In this configuration, a fluctuating component of power of the electrical load 5 may be easily compensated for by the plurality of the storage battery modules 31a, 31b, and 31c controlled at a relatively short control cycle period. Furthermore, a degree of degradation can be inhibited from becoming uneven separately in the plurality of the fuel cell systems 20a, 20b, and 20c and the plurality of the storage battery modules 31a, 31b, and 31c which are controlled at different control cycle periods, respectively. The first type priority order is, for example, the FC operation priority order. The second type priority order is, for example, the SB operation priority order.

[0102] In the technique according to one example of the present disclosure, the fuel cell facility 20 includes the plurality of the fuel cell systems 20a, 20b, and 20c. The storage battery facility 30 includes the plurality of the storage battery modules 31a, 31b, and 31c. The candidates to be operated include the plurality of the fuel cell systems 20a, 20b, and 20c, and the plurality of the storage battery modules 31a, 31b, and 31c. The control unit 50a selects a device to be operated from among a group of devices based on a common priority order provided for the group of devices formed of the plurality of the fuel cell systems 20a, 20b, and 20c and the plurality of the storage battery modules 31a, 31b, and 31c. In this configuration, a degree of degradation can be inhibited from becoming uneven in the group of devices as a combination of the plurality of the fuel cell systems 20a, 20b, and 20c and the plurality of the storage battery modules 31a, 31b, and 31c.

[0103] In the technique according to one example of the present disclosure, an estimation result is obtained by estimating a degree of degradation of a candidate to be operated. This estimation is performed by, for example, the EMS server 52. However, this estimation may be performed by another component such as the control unit 50a.

[0104] In the technique according to one example of the present disclosure, a degree of degradation of a candidate to be operated is estimated based on a record of previous use of the candidate to be operated. This configuration is advantageous from the viewpoint of estimating a degree of degradation of a candidate to be operated at low cost. However, a degree of degradation of a candidate to be operated may be estimated based on a factor other than the record of previous use of the candidate to be operated. For example, sensing of a candidate to be operated is performed by a sensor, whereby a degree of degradation of the candidate to be operated may be estimated. Specifically, a voltage of the fuel cell stack is detected by a voltage sensor, whereby a degree of degradation of the fuel cell stack can be estimated. Furthermore, a voltage of the storage battery module is detected by a voltage sensor, whereby a degree of degradation of the storage battery module can be estimated.

[0105] In the technique according to one example of the present disclosure, the control unit 50a transmits, to a server, a record of previous use of a candidate to be operated. The control unit 50a receives the estimation result from the server. In this case, a device to be operated can be selected from among candidates to be operated based on the records of previous use of the candidates to be operated. The selection based on the records of previous use of devices to be operated can contribute to extension of a period over which the power supply capability of the power supply system 1a is maintained because the records of previous use of candidate devices to be operated include information about unevenness in a degree of degradation among a plurality of the candidate devices to be operated, and, thus, the selection can be performed so as to reduce the unevenness. The server is, for example, the EMS server 52.

[0106] In the technique according to one example of the present disclosure, the fuel cell facility 20 includes the plurality of the fuel cell systems 20a, 20b, and 20c. The candidates to be operated include the plurality of the fuel cell systems 20a, 20b, and 20c. The record of previous use incudes the number of times the fuel cell stack of the fuel cell system has been activated and / or the operation time thereof. In this configuration, a degree of degradation of the fuel cell stack can be estimated at low cost.

[0107] In the technique according to one example of the present disclosure, in each of the plurality of the fuel cell systems 20a, 20b, and 20c, the less the number of times the fuel cell stack has been activated and / or the shorter the operation time thereof is, the higher the FC operation priority set to the fuel cell system including the fuel cell stack is. The control unit 50a preferentially selects a fuel cell system having a higher FC operation priority in the FC operation priority order from among the plurality of the fuel cell systems 20a, 20b, and 20c as a device to be operated. In this configuration, the fuel cell system including the fuel cell stack having a lower degree of degradation can be preferentially operated. The FC operation priority order is, for example, set by the EMS server 52. However, the FC operation priority order may be set by another component such as the control unit 50a.

[0108] In the technique according to one example of the present disclosure, the storage battery facility 30 includes the plurality of the storage battery modules 31a, 31b, and 31c. The candidates to be operated include the plurality of the storage battery modules 31a, 31b, and 31c. The record of previous use includes the number of times of charging / discharging of the storage battery module. In this configuration, a degree of degradation of the storage battery module can be estimated at low cost.

[0109] In the technique according to one example of the present disclosure, in each of the plurality of the storage battery modules 31a, 31b, and 31c, the less the number of times of charging / discharging of the storage battery module is, the higher the SB operation priority set to the storage battery module is. The control unit 50a preferentially selects the storage battery module having a higher SB operation priority in the SB operation priority order from among the plurality of the storage battery modules 31a, 31b, and 31c as a device to be operated. In this configuration, the storage battery module having a lower degree of degradation can be preferentially operated. The SB operation priority order is, for example, set by the EMS server 52. However, the SB operation priority order may be set by another component such as the control unit 50a.

[0110] The configuration for the control method can be applied to the power supply system, and the configuration for the power supply system can be applied to the control method as long as there is no contradiction in particular.

[0111] The control method according to the present disclosure can be performed in factories and the like. The power supply system according to the present disclosure can be provided in factories and the like.

Claims

1. A control method for a power supply system comprising: a photovoltaic facility; a storage battery facility; and a fuel cell facility, the control method comprising selecting a device to be operated from among candidates to be operated, based on an estimation result of degrees of degradation of the candidates to be operated, wherein the candidates to be operated include at least one device in the storage battery facility and / or at least one device in the fuel cell facility.

2. The control method according to claim 1, wherein the fuel cell facility includes a plurality of fuel cell devices, and the candidates to be operated include the plurality of fuel cell devices.

3. The control method according to claim 1 or 2, wherein the storage battery facility includes a plurality of storage battery devices, and the candidates to be operated include the plurality of storage battery devices.

4. The control method according to any one of claims 1 to 3, wherein the fuel cell facility includes a plurality of fuel cell devices, the storage battery facility includes a plurality of storage battery devices, a cycle period at which the plurality of storage battery devices are controlled is shorter than a cycle period at which the plurality of fuel cell devices are controlled, the candidates to be operated include the plurality of fuel cell devices and the plurality of storage battery devices, the control method comprises selecting the device to be operated from among the plurality of fuel cell devices based on a first type priority order provided for the plurality of fuel cell devices, and selecting the device to be operated from among the plurality of storage battery devices based on a second type priority order provided for the plurality of storage battery devices, and the first type priority order and the second type priority order are independent of each other.

5. The control method according to any one of claims 1 to 4, comprising obtaining the estimation result by estimating the degrees of degradation of the candidates to be operated.

6. The control method according to claim 5, comprising estimating the degrees of degradation of the candidates to be operated, based on a record of previous use of the candidates to be operated.

7. The control method according to claim 6, wherein the fuel cell facility includes a plurality of fuel cell devices, the candidates to be operated include the plurality of fuel cell devices, and the record of previous use includes the number of times a fuel cell stack of each of the plurality of fuel cell devices has been activated and / or an operation time of the fuel cell stack.

8. The control method according to claim 7, comprising: setting the plurality of fuel cell devices such that the less the number of times the fuel cell stack has been activated is and / or the shorter the operation time thereof is, the higher a priority set to the fuel cell device including the fuel cell stack is; and preferentially selecting the fuel cell device having the higher priority from among the plurality of fuel cell devices, as the device to be operated.

9. The control method according to any one of claims 6 to 8, wherein the storage battery facility includes a plurality of storage battery devices, the candidates to be operated include the plurality of storage battery devices, and the record of previous use includes the number of times of charging / discharging of each of the plurality of storage battery devices.

10. The control method according to claim 9, comprising: setting the plurality of storage battery devices such that the less the number of times of charging / discharging of the storage battery device is, the higher a priority set to the storage battery device is; and preferentially selecting the storage battery device having the higher priority from among the plurality of storage battery devices, as the device to be operated.

11. A power supply system comprising: a photovoltaic facility; a storage battery facility; a fuel cell facility; and a control unit that controls the photovoltaic facility, the storage battery facility, and the fuel cell facility, wherein the control unit selects a device to be operated from among candidates to be operated, based on an estimation result of degrees of degradation of the candidates to be operated, and the candidates to be operated include at least one device in the storage battery facility and / or at least one device in the fuel cell facility.

12. The power supply system according to claim 11, wherein the control unit transmits, to a server, a record of previous use of the candidates to be operated, and receives the estimation result from the server.

13. A control method for a power supply system comprising: a photovoltaic facility; a storage battery facility; and a fuel cell facility, the control method comprising selecting a device to be operated from among candidates to be operated, based on a record of previous use of the candidates to be operated, wherein the candidates to be operated include at least one device in the storage battery facility and / or at least one device in the fuel cell facility.

14. A power supply system comprising: a photovoltaic facility; a storage battery facility; a fuel cell facility; and a control unit that controls the photovoltaic facility, the storage battery facility, and the fuel cell facility, wherein the control unit selects a device to be operated from among candidates to be operated, based on a record of previous use of the candidates to be operated, and the candidates to be operated include at least one device in the storage battery facility and / or at least one device in the fuel cell facility.

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