Fuel cell power generation control system

Abstract

To provide a fuel cell power generation control system that can efficiently determine the target power generation amount of each fuel cell system with a small calculation load when an output limit occurs in any of a plurality of fuel cell systems.SOLUTION: A fuel cell power generation control system 1 includes: a plurality of fuel cell systems 4 each having a fuel cell 41 capable of generating power by the reaction of a fuel gas and an oxidant gas; a required power generation amount acquisition unit 21 that acquires the required power generation amount for the plurality of fuel cell systems 4; a limit value acquisition unit 22 that acquires the output limit value for each fuel cell 41 of the plurality of fuel cell systems 4; and a power generation amount determination unit 23 that determines the target power generation amount for each of the plurality of fuel cell systems 4, the power generation amount determination unit 23 determining the target power generation amount on the basis of the required power generation amount and the output limit value.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a fuel cell power generation control system that can efficiently determine the target power generation amount for each fuel cell system with a small calculation load even in the event of a failure for a plurality of fuel cell systems. [Background technology]

[0002] In recent years, research and development into fuel cells has been conducted to contribute to energy efficiency, ensuring that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] Some fuel cell vehicles, which use fuel cells as one of their power sources, are equipped with multiple fuel cell systems and can achieve high output by operating them simultaneously according to the required power. For such vehicles, technologies have been developed to improve power generation efficiency by adjusting the operation timing and output of each of the multiple fuel cell systems.

[0004] For example, Patent Document 1 discloses a technology that attempts to optimize the power generation efficiency of the entire system by varying the output of the fuel cell systems, such as by varying the number of fuel cell systems to be operated depending on the required power, and by operating multiple fuel cell systems simultaneously, for example by operating some fuel cell systems at an output close to the optimum efficiency while operating other fuel cell systems at a minimum output close to where stable power generation is possible. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-034394 Summary of the Invention [Problem to be solved by the invention]

[0006] In a system in which multiple fuel cell systems are operated at different outputs, as in the conventional technology described above, the degree of deterioration varies among the fuel cell systems, which can result in problems such as a shorter lifespan for the entire system and increased maintenance frequency. Therefore, efforts have been made to equalize the output of each fuel cell system as much as possible, with the aim of equalizing the deterioration among the fuel cell systems. In this case, for example, output equalization is achieved by setting the target power generation amount for each of the N fuel cell systems to P / N, where P is the required power generation amount for the entire fuel cell system.

[0007] Typically, fuel cell systems are set with upper and lower limits on output (power generation) during operation, and are controlled to operate within these limits. The lower limit of output (lower limit power value) is determined by factors such as degradation characteristics determined by the design of the fuel cell system, and typically does not change significantly throughout the system's lifespan. On the other hand, the upper limit of output (upper limit power value) can change depending on factors such as the temperature of the fuel cell even under normal conditions, and can also drop significantly due to fuel cell degradation or failure.

[0008] In the case of a power generation system that distributes the required power generation amount equally to each of multiple fuel cell systems, if the upper limit power value of a certain fuel cell system falls below the equally distributed target power generation amount due to, for example, a malfunction, control is required to redistribute the excess power generation amount to the other fuel cell systems.

[0009] FIG. 7 is a diagram illustrating an example of redistribution control in the event of a failure in a power generation system that equally distributes the required power generation. In this example, four fuel cell systems (FCS1 to FCS4) are used simultaneously. Since the required power generation is equally distributed among the four systems, 25% of the required power generation is assigned as the target power generation for each system. However, the upper limit power value of two of the four systems (FCS1 and FCS2) has decreased compared to normal and is below the target power generation. In this case, equal distribution is no longer possible, so redistribution control is executed, and the power generation exceeding the upper limit power value is equally distributed to the remaining two systems (FCS3 and FCS4). As a result, the target power generation assigned to FCS3 exceeds the upper limit power value, so redistribution control is executed again, and the excess power generation is distributed to FCS4.

[0010] In this way, in a power generation system that executes control to equally distribute the required power generation amount among multiple fuel cell systems, it may become impossible to equally distribute the required power generation amount when the upper limit power value of one of the multiple fuel cell systems drops due to a malfunction, deterioration, etc. Furthermore, in control to redistribute the power generation amount that exceeds the upper limit power value to other fuel cell systems, there is a problem that the redistribution control becomes complicated and the calculation load increases depending on the number of fuel cell systems used, the number of fuel cell systems with output restriction, the degree of output restriction, etc.

[0011] The present invention has been made to solve these problems, and aims to provide a fuel cell power generation control system that can efficiently determine the target power generation amount for each fuel cell system with a small calculation load when an output limit occurs in any of the fuel cell systems, thereby contributing to energy efficiency. [Means for solving the problem]

[0012] In order to achieve this object, the fuel cell power generation control system according to claim 1 of the present invention comprises a plurality of fuel cell systems each having a fuel cell capable of generating power by the reaction of a fuel gas and an oxidant gas, a required power generation amount acquisition unit that acquires the required power generation amount for the plurality of fuel cell systems, a limit value acquisition unit that acquires the output limit value for each fuel cell of the plurality of fuel cell systems, and a power generation amount determination unit that determines a target power generation amount for each of the plurality of fuel cell systems, wherein the power generation amount determination unit determines the target power generation amount based on the required power generation amount and the output limit value.

[0013] In this fuel cell power generation control system, a limit value acquisition unit acquires the output limit value for each fuel cell in a plurality of fuel cell systems, and a power generation amount determination unit determines a target power generation amount for each of the plurality of fuel cell systems based on the required power generation amount and the output limit value. Therefore, even if an output limit occurs in one of the multiple fuel cell systems due to a malfunction, deterioration, etc., the target power generation amount for each fuel cell system can be determined based on the required power generation amount and the output limit value, taking the output limit into consideration in advance. This makes it possible to determine the target power generation amount for each fuel cell system efficiently with a small calculation load, without having to repeat calculations for redistribution multiple times depending on the number of fuel cell systems that have experienced output restrictions and the degree of output restriction.

[0014] The invention according to claim 2 of the present invention is characterized in that, in the fuel cell power generation control system according to claim 1, the limit value acquisition unit acquires an upper limit power value, which is the upper limit value of the output of each fuel cell, and a lower limit power value, which is the lower limit value of the output, as output limit values, and the power generation amount determination unit calculates the difference between the upper limit power value and the lower limit power value of each fuel cell as the power generation possible range, and then calculates the proportion of the power generation possible range of each fuel cell to the total power generation possible range of all the fuel cells as the power generation possible ratio of each fuel cell, and determines the target power generation amount for each of the multiple fuel cell systems based on the required power generation amount and the power generation possible ratio.

[0015] According to this configuration, the power generation amount determination unit calculates the difference between the upper and lower limit power values ​​of each fuel cell in the multiple fuel cell systems as the power generation capacity of that fuel cell. Furthermore, the unit calculates the percentage of the power generation capacity of each fuel cell to the total power generation capacity of all fuel cells as the power generation capacity ratio of that fuel cell. Then, the unit determines the target power generation amount for each of the multiple fuel cell systems based on the calculated power generation capacity ratio of each fuel cell and the required power generation amount. In this way, the power generation capacity of each fuel cell is acquired in advance as a percentage of the total power generation capacity of all fuel cells, and the target power generation amount is determined based on the percentage of the total power generation capacity and the required power generation amount. Therefore, for example, when all fuel cells are operating normally and the percentages of the total power generation capacity of each fuel cell are approximately equal, the required power generation amount can be distributed approximately equally to each fuel cell. Furthermore, even if an output limit is imposed on one of the fuel cells due to a malfunction or deterioration, for example, the percentage of the total power generation capacity according to the degree of the output limit can be calculated and the target power generation amount can be determined accordingly. Therefore, the target power generation amount can be determined efficiently with a small calculation load so as not to exceed the upper power limit value of each fuel cell.

[0016] The invention according to claim 3 of the present invention is characterized in that in the fuel cell power generation control system according to claim 2, the power generation amount determination unit calculates the distributed power generation amount for each fuel cell by multiplying the value obtained by subtracting the total value of the lower limit power values ​​of all fuel cells from the required power generation amount by the power generation potential rate of each fuel cell, and sets the value obtained by adding the lower limit power value of each fuel cell and the distributed power generation amount as the target power generation amount for each of the multiple fuel cell systems.

[0017] According to this configuration, the power generation amount determination unit calculates the amount of power generation to be distributed to each fuel cell by subtracting the total of the minimum power limits of all fuel cells from the required power generation amount (i.e., multiplying the amount of power generation that can be freely distributed to each fuel cell out of the required power generation amount by the power generation potential rate of each fuel cell).Then, the sum of the minimum power limit and the distributed power generation amount for each fuel cell is determined as the target power generation amount for the fuel cell system that includes that fuel cell. In this way, the distributed power generation for each fuel cell is calculated by subtracting the total of the lower limit power values ​​of all fuel cells from the required power generation amount and multiplying this value by the power generation potential ratio, and the total of the distributed power generation amount and the lower limit power value is set as the target power generation for that fuel cell system. This makes it possible to determine a target power generation amount that more accurately reflects the power generation potential ratio of each fuel cell, making it possible to determine the target power generation for each fuel cell system efficiently with a small calculation load.

[0018] The control method for a fuel cell power generation control system according to claim 4 of the present invention is a control method for a fuel cell power generation control system having a plurality of fuel cell systems, each of which has a fuel cell capable of generating electricity by the reaction of a fuel gas and an oxidant gas, a required power generation amount acquisition means for acquiring the required power generation amount for the plurality of fuel cell systems, a limit value acquisition means for acquiring the output limit value for each fuel cell in the plurality of fuel cell systems, and a power generation amount determination means for determining a target power generation amount for each of the plurality of fuel cell systems, wherein the power generation amount determination means executes control to determine the target power generation amount based on the required power generation amount and the output limit value.

[0019] According to this control method for a fuel cell power generation control system, the power generation amount determination means executes control to determine the target power generation amount for each of the plurality of fuel cell systems based on the required power generation amount and the output limit value. Therefore, even if an output limit occurs in one of the multiple fuel cell systems due to a malfunction, deterioration, etc., the target power generation amount for each fuel cell system can be determined based on the required power generation amount and the output limit value, taking the output limit into consideration in advance. This makes it possible to determine the target power generation amount for each fuel cell system efficiently with a small calculation load, without having to repeat calculations for redistribution multiple times depending on the number of fuel cell systems that have experienced output restrictions and the degree of output restriction. [Brief explanation of the drawings]

[0020] [Figure 1]1 is a diagram showing an example of a schematic configuration of a fuel cell vehicle equipped with a power generation control system according to an embodiment; [Figure 2] 1 is a diagram illustrating an example of a schematic configuration of an FC system according to a first embodiment. [Figure 3] 4 is a flowchart showing a control process for determining a target power generation amount in the power generation control system according to the embodiment. [Figure 4] 10 is a diagram for explaining the determination of the target power generation amount by the target power generation amount determination control in a normal state. FIG. [Figure 5] 10A and 10B are diagrams for explaining the determination of a target power generation amount by the target power generation amount determination control during output restriction. [Figure 6] 10 is a table comparing procedures for determining a target power generation amount in the embodiment and the prior art. [Figure 7] FIG. 1 is a diagram for explaining a procedure for determining a target power generation amount in a conventional technique for equally distributing a required power generation amount. [Figure 8] FIG. 10 is a diagram illustrating an example of a schematic configuration of an FC system according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Preferred embodiments of the fuel cell power generation control system of the present invention will be described in detail below with reference to the drawings. The fuel cell power generation control system according to the first embodiment is mounted on a fuel cell vehicle, and the electric power generated by the fuel cell is used as one of the power sources of the fuel cell vehicle. The fuel cell vehicle may be a two-wheeled, three-wheeled, four-wheeled, or other vehicle, or may be a large vehicle capable of mounting multiple fuel cell systems, as described below. Note that the configuration described below is an example of the present invention, and the present invention is not limited thereto.

[0022] <General Configuration of Fuel Cell Vehicle 100> 1 is a schematic diagram of a fuel cell vehicle 100 equipped with a fuel cell power generation control system 1 according to a first embodiment. The fuel cell vehicle 100 is, for example, a fuel cell electric vehicle, and as shown in the figure, the fuel cell vehicle 100 includes a vehicle control device 101, a current controller 102, a motor 103, a battery 104, a management ECU (Electronic Control Unit) 2, a memory unit 3, and an FC (Fuel Cell) system 4.

[0023] In the example of FIG. 1, four FC systems 4A, 4B, 4C, and 4D are shown, but the number of FC systems 4 installed is not limited to this. When the individual FC systems are not to be distinguished from one another, they may be simply referred to as "FC systems 4." The FC systems 4 and the management ECU 2 constitute the power generation control system 1 in this embodiment. It is also possible to configure the vehicle control device 101 to be included as part of the power generation control system.

[0024] The motor 103 is, for example, a three-phase AC motor, and is driven by power supplied from the FC system 4 or the battery 104 via a current controller 102. The rotor of the motor 103 is connected to drive wheels (not shown), and the motor 103 outputs to the drive wheels a driving force used to run the fuel cell vehicle 100 under the control of the vehicle control device 101. The motor 103 also performs regenerative power generation using the kinetic energy of the vehicle when the vehicle is decelerating.

[0025] The battery 104 is a secondary battery such as a lithium-ion battery. The battery 104 stores the power generated by the FC system 4 or the motor 103, and supplies the power to the motor 103 for running the fuel cell vehicle 100 under the control of the vehicle control device 101. When the FC system 4 is started up, the battery 104 also supplies power to drive the accessories of the FC system 4. After the FC system 4 starts up, the battery 104 also supplies the power that is insufficient until the power generated by the FC system 4 reaches the required power. The battery 104 is provided with sensors such as a current sensor, a voltage sensor, and a temperature sensor (not shown), and outputs the current value, voltage value, temperature, etc. detected by these sensors to the vehicle control device 101.

[0026] The vehicle control device 101 is an ECU configured with a microcomputer including, for example, a CPU, RAM, ROM, and an I / O interface (none of which are shown), and comprehensively controls the running of the fuel cell vehicle 100 and the operation of on-board equipment not shown. The vehicle control device 101 controls the supply of power stored in the battery 104 and power generated by the FC system 4 in accordance with the power required by the fuel cell vehicle 100. The power required by the fuel cell vehicle 100 is the total load power required to drive and operate the motor 103, as well as brake devices and various sensors (not shown), and other on-board equipment and auxiliary machinery. Furthermore, the vehicle control device 101 may control the running of the fuel cell vehicle 100 , or may control the power running / regenerative drive of the motor 103 , or control the charging / discharging of the battery 104 .

[0027] The management ECU 2 is an ECU configured with a microcomputer including, for example, a CPU, RAM, ROM, and an I / O interface (none of which are shown), and performs overall control of the multiple FC systems 4 (FC systems 4A, 4B, 4C, 4D). The management ECU 2 is provided with multiple communication interfaces corresponding to the number of the multiple FC systems 4, and each communication interface communicates with the FC system 4 to which it is connected. As will be described later, the management ECU 2 acquires information on power supply instructions and required power generation amounts for the FC systems 4 from the vehicle control device 101, and determines the power generation amount for each FC system based on this information. The management ECU 2 includes functional units such as a required power generation amount acquisition unit 21, a limit value acquisition unit 22, and a power generation amount determination unit 23. Details of each functional unit will be described later.

[0028] The memory unit 3 is implemented by hardware such as, for example, a HDD (Hard Disk Drive), a flash memory, an EEPROM (Electrically Erasable Programmable Read Only Memory), a ROM (Read Only Memory), or a RAM (Random Access Memory). The memory unit 3 stores, for example, state information indicating the states of each FC system described later.

[0029] The plurality of FC systems 4 each have a fuel cell. A fuel cell is a battery that generates electricity through an electrochemical reaction between a fuel gas supplied to the anode and an oxidant gas supplied to the cathode. In this embodiment, hydrogen gas is used as the fuel gas and air containing oxygen is used as the oxidant gas. As will be described later, the FC system 4 generates electricity according to a target power generation amount determined by the control of the management ECU 2, and supplies the generated power to the motor 103 or the battery 104 via the current controller 102 under the control of the vehicle control device 100.

[0030] <Configuration of FC System 4> The specific configuration of the FC system 4 will be described with reference to FIG. 2. FIG. 2 is a diagram showing an example of a schematic configuration of the FC system according to the embodiment. The configuration shown in FIG. 2 is applicable to each of the plurality of FC systems 4 mounted on the fuel cell vehicle 100. Note that the configuration described below is merely an example, and any configuration may be used as long as it is a system configuration that generates electricity using an anode and a cathode. The FC system 4 shown in FIG. 2 includes an FC stack (fuel cell) 41, an oxidant gas supply device 42, a hydrogen gas supply device 43, an FC control device 44, a contactor 45, an FCVCU (Fuel Cell Voltage Control Unit) 46, an FC cooling system 47, and a diluter 48.

[0031] The FC stack 41 is a structure in which multiple power generation cells 411 are stacked. The FC stack 41 is provided with an oxidant gas inlet 41a, an oxidant gas outlet 41b, a hydrogen gas inlet 41c, a hydrogen gas outlet 41d, and electrodes 41e, 41e.

[0032] Each power generation cell 411 of the FC stack 41 has a configuration in which a solid polymer electrolyte membrane (hereinafter simply referred to as the electrolyte membrane) 412 made of a cation exchange membrane such as a thin film of water-containing perfluorosulfonic acid is sandwiched between an anode electrode 413 and a cathode electrode 414. As the electrolyte membrane 412, a fluorine-based electrolyte or a hydrocarbon-based electrolyte can be used.

[0033] Hydrogen gas, a fuel gas containing hydrogen, is supplied to the anode electrode 413 from a hydrogen gas supply device 43. Air, an oxidizing gas containing oxygen, is supplied to the cathode electrode 414 from an oxidizing gas supply device 42. The hydrogen supplied to the anode electrode 413 is ionized by a catalytic reaction on an anode catalyst (not shown), and the generated hydrogen ions permeate the electrolyte membrane 412 and move to the cathode electrode 414. Electrons released as the hydrogen is ionized move to an external circuit via electrode 41e, generating a current, which then generates electricity. The hydrogen ions that move from the anode electrode 413 to the cathode electrode 414 react with the oxygen supplied to the cathode electrode 414 to produce water.

[0034] The oxidizing gas supply device 42 includes an air pump 421 that compresses air from the atmosphere and supplies it to the FC stack 41, and the air pump 421 is disposed in an air supply flow path 425. The air pump 421 is controlled by the FC control device 44. A humidifier 423 is provided in the air supply flow path 425. The air supply flow path 425 communicates with an oxidizing gas inlet 41a of the FC stack 41.

[0035] The oxidant gas outlet 41b is connected to an air discharge flow path 426 that passes through a humidifier 423. The humidifier 423 recovers moisture from the post-reaction air (including post-reaction gas and off-gas) that is discharged from the oxidant gas outlet 41b and passes through the air discharge flow path 426, and uses this moisture to humidify the air that passes through the air supply flow path 425. This makes it possible to maintain the electrolyte membrane 412 in each power generation cell 411 of the FC stack 41 at a humidity suitable for power generation.

[0036] A supply-side seal valve 422 is provided downstream of the air pump 421 in the air supply flow path 425. The supply-side seal valve 422 is opened and closed under the control of the FC control device 44, thereby switching the air supply flow path 425 between open and closed states. In addition, a discharge-side seal valve 424 is provided in the air discharge flow path 426. The discharge-side seal valve 424 is opened and closed under the control of the FC control device 44, thereby switching between opening and closing of the air discharge flow path 426. A diluter 48, which will be described later, is connected downstream of the discharge-side seal valve 424.

[0037] The hydrogen gas supply device 43 has a hydrogen tank 431 that stores high-pressure hydrogen gas. The hydrogen tank 431 communicates with a hydrogen gas inlet 41c of the FC stack 41 via a hydrogen supply flow path 437. An injector 432 and an ejector 433 are provided in series in the hydrogen supply flow path 437. The opening of the injector 432 is controlled by the FC control device 44, and determines the flow rate and supply timing of the hydrogen gas supplied to the FC stack 41. The ejector 433 creates a negative pressure inside, and sucks in the off-gas discharged from the hydrogen gas outlet 41d to the off-gas flow path 438, and circulates it to the hydrogen supply flow path 437.

[0038] An off-gas passage 438 communicates with the hydrogen gas outlet 41d of the FC stack 41, and a gas-liquid separator 434 is connected to the off-gas passage 438. The gas-liquid separator 434 separates the off-gas discharged from the hydrogen gas outlet 41d of the FC stack 41 into a gas component and a liquid component. The liquid component separated from the off-gas is discharged to a purge flow path 439 via a drain valve 435 whose opening and closing is controlled by the FC control device 44. In addition, part of the gas component separated from the off-gas is recirculated via the ejector 433, and the other part is discharged to the purge flow path 439 via a purge valve 436 whose opening and closing is controlled by the FC control device 44. The purge flow path is connected to a diluter 48.

[0039] The diluter 48 mixes the post-reaction air (including post-reaction gas and off-gas) discharged from the oxidant gas outlet 41b of the FC stack 41 with the off-gas discharged from the hydrogen gas outlet 41d of the FC stack 41, diluting the hydrogen concentration to below a specified value, and then discharging it to the outside.

[0040] The contactor 45 is provided between the anode electrode 413 and cathode electrode 414 of the FC stack 41 and the FCVCU 46, and switches the electrical connection between the FC stack 41 and the FCVCU 46 on and off based on the control of the FC control device 44.

[0041] The FCVCU 46 is a step-up DC-DC converter. The FCVCU 46 is disposed between the anode electrode 413 and the cathode electrode 414 of the FC stack 41 via the contactor 45 and an electrical load external to the FC system 4. The FCVCU 46 boosts the voltage at the output terminal 49 connected to the electrical load side to a target voltage determined by the FC control device 44. The FCVCU 46 boosts the voltage output from the FC stack 41 to the target voltage and outputs it to the output terminal 49.

[0042] The FC control device 44 is an ECU configured with a microcomputer including a CPU, RAM, ROM, and an I / O interface (none of which are shown), and is provided in each FC system 4. Each FC control device 44 is configured to be able to acquire information regarding the state of the FC system 4 to which it belongs based on the detection values of various sensors (not shown). Each FC control device 44 continuously acquires information regarding the state of the FC system 4 or in response to an instruction from the management ECU 2, and transmits the acquired information to the management ECU 2. The states of the FC system to be acquired include, for example, the current power generation status, power generation amount, power generation time, number of start-ups (or number of stops), etc., and particularly include information on output limitation in the FC stack 41. This output limitation information includes the lower power value and the upper power value described later.

[0043] In addition, the FC control device 44 controls the start and end of power generation, the power generation amount, etc. in the FC system 4 according to the control of the management ECU 2. Further, the FC control device 44 performs control such as opening and closing control of various valves in the FC system 4 and driving control of various auxiliary machines (such as the air pump 421). Also, the FC control device 44 performs control regarding temperature adjustment of the FC stack 41 using the FC cooling system 47. Furthermore, the FC control device 44 may perform power supply control of the fuel cell vehicle 100 in cooperation with the management ECU 2 and the vehicle control device 101.

[0044] The FC cooling system 47 cools the FC stack 41 according to the control of the FC control device 44. For example, the FC cooling system 47 cools the FC stack 41 by circulating a refrigerant such as pure water or ethylene glycol through a refrigerant flow path (not shown) provided in the FC stack 41.

[0045] <Power generation operation of the FC system 4> The power generation operation of the FC system 4 configured as described above (power generation operation in the fuel cell stack 2) will be described below.

[0046] The oxidant gas supply device 42 supplies air as an oxidant gas to the air supply flow path 425 via the air pump 421. This air is humidified through the humidifier 423 and then supplied to the fuel cell stack 41 from the oxidant gas inlet 41a.

[0047] Meanwhile, the hydrogen gas supply device 43 supplies hydrogen gas from the hydrogen tank 431 to the hydrogen supply flow path 437 based on the opening control of the injector 432 by the FC control device 44. After passing through the ejector 433, this hydrogen gas is supplied to the FC stack 41 from the hydrogen gas inlet 41c.

[0048] Air supplied to the FC stack 41 from the oxidant gas inlet 41a is supplied to the cathode electrode 414 of each power generation cell 411, and hydrogen gas supplied to the FC stack 41 from the hydrogen gas inlet 41c is supplied to the anode electrode 413 of each power generation cell 411. As a result, in each power generation cell 411, hydrogen and oxygen in the air are consumed by an electrochemical reaction, generating electricity. The generated electric power is supplied to a battery 104 or a motor 103 through a current controller 102 under the control of the FC control device 44 .

[0049] The air (including the post-reaction gas and the off-gas) after the reaction at the cathode electrode 414 of each power generation cell 411 is discharged from the oxidant gas outlet 41b to the air discharge passage 426. The discharged air has moisture recovered when it passes through the humidifier 423, and then is introduced into the diluter 48. As described above, the moisture recovered by the humidifier 423 is used to humidify the air passing through the air supply passage 425, thereby adjusting the humidity of the electrolyte membrane 412.

[0050] Furthermore, hydrogen gas after the reaction at the anode electrode 413 of each power generation cell 411 is discharged as off-gas (partially consumed fuel gas) from the hydrogen gas outlet 41d to an off-gas flow path 438. The discharged off-gas is introduced from the off-gas flow path 438 into a gas-liquid separator 434 where liquid water is separated, and then the off-gas is recirculated via the ejector 433 or discharged to the outside via a purge flow path 439.

[0051] Furthermore, during the execution of the series of power generation operations described above, the FC cooling system 47 is driven in accordance with the temperature of the FC stack 41 under the control of the FC control device 44, and the FC stack 41 is cooled.

[0052] <Configuration of management ECU2> Next, the configuration of the control system of the management ECU 2 will be described. As shown in Fig. 1, the management ECU 2 includes a required power generation amount obtaining unit 21, a limit value obtaining unit 22, and a power generation amount determining unit 23. These functional units 21 to 23 are realized, for example, by a hardware processor such as a CPU of the management ECU 2 reading and executing a program (software). Such a program may be stored in a ROM or RAM included in the management ECU 2, or may be stored in a storage device (a storage device including a non-transitory storage medium such as an HDD or flash memory) that constitutes the storage unit 3.

[0053] The required power generation amount obtaining unit 21 includes, for example, a communication interface unit that communicates with the vehicle control device 101. The required power generation amount obtaining unit 21 obtains commands from the vehicle control device 100 via the communication interface unit regarding the required power generation amounts for the multiple FC systems 4 (for example, the amount of power required by the entire fuel cell vehicle 100 excluding the amount of power supplied by the battery 104).

[0054] The limit value acquisition unit 22 includes, for example, a plurality of communication interface units corresponding to the number of the plurality of FC systems 4. The limit value acquisition unit 22 acquires, at a predetermined timing or period, information on the limit value of the amount of power generation from among the information on various states output from each FC system 4 via these communication interface units. The limit values ​​related to the amount of power generation include, for example, an upper limit power value that is the upper limit of the output (amount of power generation) of each FC system 4, and a lower limit power value that is the lower limit of the output (amount of power generation) of each FC system 4. The limit value acquisition unit 22 stores the acquired information on the limit value of the amount of power generation of each FC system 4 in the storage unit 3.

[0055] The power generation amount determination unit 23 determines the target power generation amount, which is the power that each FC system 4 should generate, by executing the target power generation amount determination control described below based on the required power generation amount for the FC system 4 acquired by the required power generation amount acquisition unit 21 and the information on the power generation amount limit value acquired by the limit value acquisition unit 22.

[0056] <Target power generation amount determination control> Next, the target power generation amount determination control in the power generation control system 1 of this embodiment will be described with reference to Fig. 3 to Fig. 6. Fig. 3 is a flowchart showing the control process for determining the target power generation amount in this embodiment. This process is executed repeatedly at a predetermined timing or at a predetermined cycle, for example, during the power generation operation of the FC system 4.

[0057] In this control process, first, the required power generation amount acquisition unit 21 of the management ECU 2 acquires the required power generation amount for the entire FC system 4 (step 301 (shown as "S301"; the same applies below)). This required power generation amount may be for driving the fuel cell vehicle 100, or for driving and operating on-board equipment and auxiliary machinery. After the required power generation amount is acquired, the limit value acquisition unit 22 acquires an upper limit power value and a lower limit power value as limit values ​​for the output of each FC system 4 (step 302). In the processing of step 302, the limit value acquisition unit 22 may store the acquired upper limit power value and lower limit power value of each FC system 4 as limit value information in the storage unit 3. Furthermore, the processing of step 302 may be repeatedly executed at a predetermined timing or period before step 301 is executed.

[0058] Next, in the subsequent steps 303 to 306, the power generation amount determination unit 23 determines the target power generation amount of each FC system 4 based on the acquired required power generation amount and the limit value information of each FC system 4. First, the power generation amount determination unit 23 calculates the possible power generation range for each FC system 4 from the upper limit power value and lower limit power value of each FC system 4 (step 303). This possible power generation range means the range of power values ​​(output range) that can be generated by each FC system 4, and in this embodiment is calculated as the difference between the upper limit power value and the lower limit power value of each FC system 4.

[0059] Next, based on the calculated power generation capacity width of each FC system 4, the ratio of the power generation capacity width of each FC system 4 to the total power generation capacity width of all FC systems 4 is calculated as the power generation capacity ratio of that FC system 4 (step 304). The calculated power generation capacity ratio serves as an index showing the proportion of the amount of power generation that can be handled by that FC system 4. Next, the power generation amount determination unit 23 calculates the value obtained by subtracting the total value of the lower limit power values ​​of all FC systems 4 from the required power generation amount obtained, i.e., the value of the power generation amount that can be freely distributed to each FC system 4 from the required power generation amount, and multiplies this value by the power generation capacity ratio of each FC system 4 to calculate the distributed power generation amount for each FC system 4 (step 305). Then, the total value of the lower limit power value and the distributed power generation amount for each FC system 4 is determined as the target power generation amount for that FC system 4 (step 306), and then this process ends.

[0060] Figures 4 and 5 are diagrams for explaining the determination of the target power generation amount by the target power generation amount determination control of this embodiment, where Figure 4 shows the determination of the target power generation amount under normal conditions, and Figure 5 shows the determination of the target power generation amount when output restrictions are imposed on some of the FC systems 4.

[0061] First, the flow of determining the target power generation amount in normal times will be described with reference to Figure 4. First, the possible power generation range is calculated based on the upper and lower limit power values ​​of each of the four FC systems 4 (FCS1 to 4). Next, the possible power generation ranges of all FC systems 4 are added together to calculate the overall possible power generation range, and then the possible power generation rate of each FC system 4 is calculated. In this example, since each FC system 4 is operating normally (the upper limit power value is not limited), the possible power generation range of each FC system 4 is approximately equal, and therefore the possible power generation rate of each FC system 4 is also equal. Here, since four FC systems 4 are used, the possible power generation rate of each FC system 4 is 25%.

[0062] Next, the lower limit power value of each FC system 4 is subtracted from the required power generation amount, and the distributed power generation amount is calculated based on the calculated possible power generation ratio.Then, the value obtained by adding the lower limit power value to the calculated distributed power generation amount is determined as the target power generation amount of each FC system 4. In this way, when the upper limit power value of each FC system 4 is not limited and the power generation capacity is approximately equal, the target power generation amount of each FC system 4 will be the same as when the required power generation amount is distributed equally according to the number of FC systems 4. Furthermore, since the target power generation amount for each FC system 4 is determined based on the power generation capacity ratio, it will not exceed the upper limit power value.

[0063] Next, referring to Figure 5, we will explain the flow of determining the target power generation amount when an output restriction occurs in one of the four FC systems 4 (FCS1). First, as in the example of Figure 4, the possible power generation range is calculated based on the upper and lower limit power values ​​of each of the four FC systems 4 (FCS1-4), and then the possible power generation range is calculated. In this example, the upper limit power value of FCS1 has decreased due to factors such as a failure or deterioration, and the possible power generation range has decreased to about one-third of its normal state. Therefore, the possible power generation rate of each FC system 4 is 10% for FCS1 and 30% for each of FCS2-4.

[0064] Next, similarly to the example of FIG. 4, the amount of power generation to be distributed to each FC system 4 is calculated based on the possible power generation ratio, and the target amount of power generation is determined by adding the lower limit power value to the distributed amount of power generation. In this way, even if an output restriction occurs in one of the multiple FC systems 4 and the upper limit power value decreases, the target power generation amount can be determined according to the power generation capacity ratio of the FC system 4 that has experienced the output restriction, so the target power generation amount will not exceed the upper limit power value, and each FC system 4 can be operated efficiently at an appropriate output.

[0065] Furthermore, in this target power generation amount determination control, the power generation potential ratio of each FC system 4 is first calculated, and the target power generation amount of each FC system 4 is determined by distributing the required power generation amount accordingly. Therefore, even if the number of FC systems 4 used, the number of FC systems 4 with output restriction, the degree of output restriction, etc. changes, the target power generation amount can be determined with a small calculation load using the same control flow, without the need for recalculation, etc.

[0066] Fig. 6 is a table comparing the target power generation amount determination control of this embodiment with the procedure for determining the target power generation amount in the prior art, which equally distributes the required power generation amount. In the example of Fig. 6, the required power generation amount for the entire FC system 4 is 100 kW, four FC systems 4 (FCS1 to 4) are used, and the upper limit power of each FC system 4 under normal conditions is 60 kW. Also, to avoid complexity, the lower limit power value of each FC system 4 is conveniently set to 0 kW.

[0067] FIG. 6(a) shows the procedure for determining the target power generation amount in normal times (when no output restriction is imposed on each FC system 4).

[0068] First, in the prior art, the target power generation amount is the value obtained by equally dividing the required power generation amount by the number of FC systems 4, so the target power generation amount for each FC system 4 is 100 kW / 4 = 25 kW.

[0069] On the other hand, in the case of this embodiment, as explained above, the possible power generation ratio is calculated based on the possible power generation range (upper limit power value - lower limit power value) of each FC system 4. Since the possible power generation range of each FC system 4 is all 60 kW, the possible power generation ratio is equal, 25% for each. Therefore, the target power generation amount of each FC system 4 is the required power generation amount 100 kW x 0.25 = 25 kW.

[0070] In this way, the target power generation amount during normal operation is determined in the same manner in this embodiment as in the prior art.

[0071] Next, with reference to FIG. 6(b), a case where output restriction occurs in one of the four FC systems 4 (FCS1) will be considered.

[0072] In the conventional technology, first, the required power generation amount of 100 kW is evenly distributed, and 25 kW is allocated to each FC system 4. However, because the upper limit power value of FCS1 has been reduced to 20 kW, the target power generation amount exceeds the upper limit power value. Therefore, the excess power of 5 kW in FCS1 is evenly distributed again among FCS2 to 4, and 25 kW + (5 kW / 3) ≒ 27 kW is set as the target power generation amount for FCS2 to 4. The target power generation amount of FCS1 is set to 20 kW, which is the upper limit power value.

[0073] On the other hand, in this embodiment, as in normal times, the power generation capacity ratio is calculated based on the power generation capacity width (upper limit power value - lower limit power value) of each FC system 4. In this example, the power generation capacity width of FCS1 has decreased to 20 kW, so the power generation capacity ratio is 10% (20 kW / 200 kW) for FCS1 and 30% (60 kW / 200 kW) for each of FCS2 to 4. Therefore, the target power generation amount for each FC system 4 is the required power generation amount 100 kW x 0.1 = 10 kW for FCS1, and the required power generation amount 100 kW x 0.3 = 30 kW for each of FCS2 to 4.

[0074] In this way, in a system that determines the target power generation amount by evenly distributing the required power generation amount as in the conventional technology, if an output restriction occurs in one of the FC systems 4, a control process for redistribution may be required, resulting in a large computational load. On the other hand, in this embodiment, even if an output restriction occurs in any of the FC systems 4, the target power generation amount can be determined efficiently by the same control processing as in normal times.

[0075] Finally, with reference to FIG. 6(c), a case where output restrictions occur in more than one of the four FC systems 4 (FCS1 to 3) will be considered.

[0076] In the conventional technology, first, the required power generation amount of 100 kW is evenly distributed, and 25 kW is allocated to each FC system 4. Because the upper limit power value of FCS1 and FCS2 is 10 kW, the target power generation amount exceeds the upper limit power value. Therefore, the total value of 30 kW, which is the excess power of 15 kW in FCS1 and the excess power of 15 kW in FCS2, is equally distributed again among FCS3-4. As a result, FCS1-2 are allocated the upper limit power value of 10 kW, and FCS3-4 are allocated 25 kW + (30 kW / 2) = 40 kW each. However, because the upper limit power value of FCS3 is 30 kW, there is an excess of 10 kW, and this excess amount must be allocated again to FCS4. As a result, the final target power generation amount is set to 10 kW for FCS1-2, 30 kW for FCS3, and 50 kW for FCS4.

[0077] On the other hand, in this embodiment, as in normal times, the power generation capacity ratio is calculated based on the power generation capacity range (upper limit power value - lower limit power value) of each FC system 4. In this example, the power generation capacity range of FCS1 and FCS2 has decreased to 10 kW, and the power generation capacity range of FCS3 has decreased to 30 kW. Therefore, the power generation capacity ratios are 9% (10 kW / 110 kW) for FCS1-2, 27% (30 kW / 110 kW) for FCS3, and 55% (60 kW / 110 kW) for FCS4. Therefore, the target power generation amount of each FC system 4 is 100 kW × 0.09 = 9 kW for FCS1-2, 100 kW × 0.27 = 27 kW for FCS3, and 100 kW × 0.55 = 55 kW for FCS4.

[0078] As described above, in the case of conventional technology, depending on the number of FC systems 4 that have experienced output restrictions and the degree of output restrictions, it may be necessary to perform redistribution control processing multiple times, which results in a very large computational load. On the other hand, in the target power generation amount determination control of this embodiment, even if output restrictions occur in multiple FC systems 4 or the degree of output restrictions varies, an appropriate target power generation amount can be determined efficiently and with a small calculation load using the same control processing as under normal circumstances.

[0079] <Effects of this embodiment> The effects of this embodiment will be described below. According to this embodiment, in the target power generation amount determination control of the fuel cell power generation control system 1, the limit value acquisition unit 22 of the management ECU 2 acquires the output limit value of each FC system 4, and the power generation amount determination unit 23 determines the target power generation amount of each FC system 4 based on the required power generation amount and the output limit value. Therefore, even if an output limit occurs in any of the multiple FC systems 4 due to a failure, deterioration, etc., the target power generation amount of each FC system 4 can be determined based on the required power generation amount and the output limit value, taking the output limit into consideration in advance. This makes it possible to determine the target power generation amount for each FC system 4 efficiently with a small computational load, without the need to change the control flow depending on the number of FC systems 4 that have experienced output restrictions or the degree of output restriction, or to repeat calculations for redistribution.

[0080] The power generation amount determination unit 23 also calculates the difference between the upper limit power value and the lower limit power value for each of the multiple FC systems 4 (of the FC stack 41) as the possible power generation range for that FC system 4. Furthermore, it calculates the proportion of the possible power generation range of each FC system 4 to the total possible power generation range of all FC systems 4 as the possible power generation ratio for that FC system 4. Then, it determines the target power generation amount for each FC system 4 based on the calculated possible power generation ratio and the required power generation amount. In this way, the power generation capacity of each FC system 4 is acquired in advance as a possible power generation ratio relative to all FC systems 4, and the target power generation amount is determined based on the possible power generation ratio and the required power generation amount, so that, for example, when all FC systems 4 are operating normally and the possible power generation ratios of each FC system 4 are approximately equal, the required power generation amount can be distributed approximately equally to each FC system 4. Furthermore, even if an output restriction occurs in any of the FC systems 4 due to a failure, deterioration, or the like, the possible power generation ratio can be calculated according to the degree of the output restriction, and the target power generation amount can be determined accordingly, so that the target power generation amount can be determined efficiently with a small calculation load so as not to exceed the upper power limit value of each FC system 4.

[0081] Furthermore, the power generation amount determination unit 23 calculates the distributed power generation amount for each FC system 4 as the value obtained by subtracting the total value of the lower limit power values ​​of all FC systems 4 from the requested power generation amount, i.e., the value obtained by multiplying the value of the power generation amount that can be freely distributed to each FC system 4 out of the requested power generation amount by the power generation possible ratio of each FC system 4. Then, the total value of the lower limit power value and the distributed power generation amount for each FC system 4 is determined as the target power generation amount for that FC system 4. In this way, the distributed power generation amount for each FC system 4 is calculated by first subtracting the total of the lower limit power values ​​of all FC systems 4 from the requested power generation amount and multiplying this value by the power generation capacity ratio, and the sum of the distributed power generation amount and the lower limit power value is set as the target power generation amount for that FC system 4. This makes it possible to determine a target power generation amount that more accurately reflects the power generation capacity ratio of each FC system 4, so that the target power generation amount for each FC system 4 can be determined efficiently with a small calculation load.

[0082] Next, a second embodiment in which the fuel cell power generation control system of the present invention is applied to a stationary facility such as a house or a factory will be described with reference to Fig. 8. In the following description, the same components as those in the fuel cell power generation control system 1 of the first embodiment will be assigned the same reference numerals, and their description will be omitted.

[0083] As shown in FIG. 8, the fuel cell power generation control system 10 according to the second embodiment is installed in a stationary facility 200 such as a house or a factory, and functions as an auxiliary power supply facility that supplies the shortfall in power when, for example, the power required by the stationary facility 200 exceeds the power supplied by the main power supply facility.

[0084] The stationary power supply control device 201 is an ECU configured with a microcomputer including, for example, a CPU, RAM, ROM, and an I / O interface (none of which are shown). In the power generation control system 1 of the first embodiment, the vehicle control device 101 controls the supply of generated power in accordance with the power requested from the fuel cell vehicle 100, but in the power generation control system 10 of the second embodiment, the stationary power supply control device 201 controls the supply of power stored in the battery 104 and power generated by the FC system 4 in accordance with the power requested from a higher-level power supply management device (not shown).

[0085] The configuration and functions of the management ECU 2 in the power generation control system 10 are the same as those in the power generation control system 1. The management ECU 2 acquires information on the power supply instructions and required power generation amounts for the FC systems 4 from the stationary power supply control device 201, and executes the above-mentioned target power generation amount determination control based on the information to determine the target power generation amount for each FC system 4. The required power generation amount acquisition unit 21 of the management ECU 2 includes, for example, a communication interface unit that communicates with the stationary power supply control device 201, and acquires instructions on the required power generation amounts for the multiple FC systems 4 from the stationary power supply control device 201 via this communication interface.

[0086] The configuration and functions of the FC system 4 in the power generation control system 10 are similar to those in the power generation control system 1. The FC system 4 generates power in accordance with the target power generation amount determined by the target power generation amount determination control of the management ECU 2, and supplies the generated power to the battery 104 or the inverter 202 via the current controller 102 under the control of the stationary power supply control device 201. The inverter 202 converts the supplied DC power into AC power and supplies it to the stationary equipment 200.

[0087] In this way, the fuel cell power generation control system of the present invention can also be applied to stationary facilities such as homes and factories, and just as when installed in a mobile object such as a vehicle, the target power generation amount of each FC system 4 can be determined efficiently with a small computational load without the need to change the control flow depending on the number of FC systems 4 that have experienced output restrictions or the degree of output restriction, or to repeat calculations for redistribution.

[0088] The present invention is not limited to the embodiments described above, and can be implemented in various forms. In addition, the detailed configuration can be appropriately changed within the scope of the spirit of the present invention. [Explanation of symbols]

[0089] 1...Fuel cell power generation control system 2…Management ECU 21... Required power generation amount acquisition unit (required power generation amount acquisition means) 22...Limit value acquisition unit (limit value acquisition means) 23...Power generation amount determination unit (power generation amount determination means) 3...Storage section 4...FC system (fuel cell system) 41...FC stack (fuel cell) 42...Oxidant gas supply device 43...Hydrogen gas supply device 44...FC control device 100...Fuel cell vehicle 101...Vehicle control device 103...Motor 104...Battery

Claims

1. a plurality of fuel cell systems each including a fuel cell capable of generating electricity by a reaction between a fuel gas and an oxidant gas; a required power generation amount acquisition unit that acquires required power generation amounts for the plurality of fuel cell systems; a limit value acquisition unit that acquires an output limit value of the fuel cell in each of the plurality of fuel cell systems; a power generation amount determination unit that determines a target power generation amount for each of the plurality of fuel cell systems, the power generation amount determination unit determines the target power generation amount based on the required power generation amount and the output limit value. Fuel cell power generation control system.

2. the limit value acquisition unit acquires, as the output limit values, an upper limit power value that is an upper limit value of output in each of the fuel cells and a lower limit power value that is a lower limit value of output; The power generation amount determination unit calculates the difference between the upper limit power value and the lower limit power value of each of the fuel cells as a power generation capacity range, and then calculates the ratio of the power generation capacity range of each of the fuel cells to the total power generation capacity range of all of the fuel cells as a power generation capacity ratio of each of the fuel cells, and determines the target power generation amount for each of the plurality of fuel cell systems based on the required power generation amount and the power generation capacity ratio.

2. The fuel cell power generation control system according to claim 1.

3. The power generation amount determination unit calculates a value obtained by subtracting the total value of the lower limit power values ​​of all of the fuel cells from the required power generation amount, and multiplying the result by the power generation possible ratio of each of the fuel cells to obtain a power generation amount to be distributed to each of the fuel cells, and determines a value obtained by adding the lower limit power value of each of the fuel cells and the distributed power generation amount as a target power generation amount for each of the plurality of fuel cell systems.

3. The fuel cell power generation control system according to claim 2.

4. a plurality of fuel cell systems each including a fuel cell capable of generating electricity by a reaction between a fuel gas and an oxidant gas; a required power generation amount obtaining means for obtaining a required power generation amount for each of the plurality of fuel cell systems; a limit value acquisition means for acquiring an output limit value of the fuel cell of each of the plurality of fuel cell systems; a power generation amount determination means for determining a target power generation amount for each of the plurality of fuel cell systems, the power generation amount determination means executes control to determine the target power generation amount based on the required power generation amount and the output limit value. A control method for a fuel cell power generation control system.

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