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

[0006] , ,

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

Background Art

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

[0003] In a fuel cell vehicle using a fuel cell as one of the power sources, there are some that mount a plurality of fuel cell systems and obtain high output by operating the plurality of fuel cell systems simultaneously according to the required power. In such vehicles, technologies have been developed to improve power generation efficiency by adjusting the operation timing and output of each of the plurality of fuel cell systems.

[0004] For example, in Patent Document 1, while changing the number of fuel cell systems to be operated according to the required power, when operating a plurality of fuel cell systems simultaneously, for example, while operating some fuel cell systems at an output near the optimum efficiency, other fuel cell systems are operated near the minimum output at which stable power generation is possible. Technologies have been disclosed that attempt to optimize the power generation efficiency of the entire system by varying the outputs between fuel cell systems.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] As with the conventional technology described above, in systems where multiple fuel cell systems are operated at different outputs, differences in the degree of degradation occur among the fuel cell systems, which can result in problems such as a shorter overall system lifespan and increased maintenance frequency. Therefore, in order to equalize the degradation among fuel cell systems, attempts are being made to equalize the output of each fuel cell system as much as possible. In this case, for example, output equalization is achieved by setting the target power generation of each of the N operating fuel cell systems to P / N relative to the required power generation P for the entire fuel cell system.

[0007] Typically, fuel cell systems have lower and upper limits on their operating output (power generation), and control is implemented to keep them within these limits. The lower limit of output (lower power limit) is determined by degradation characteristics and other factors specified in the fuel cell system design, and usually does not change significantly throughout the system's lifespan. On the other hand, the upper limit of output (upper power limit) can change depending on the fuel cell temperature and other factors even under normal conditions, and can also decrease significantly due to fuel cell degradation or failure.

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

[0009] Figure 7 illustrates 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 (FCS1-4) are used simultaneously. Since the required power generation is equally distributed among the four units, 25% of the required power generation is allocated to each unit as the target power generation. However, in two of the four units (FCS1 and FCS2), the upper limit power value falls below the normal level, resulting in power generation below the target. In this case, equal distribution becomes impossible, so redistribution control is executed, and the power generation exceeding the upper limit power value is equally distributed to the remaining two units (FCS3 and FCS4). As a result, the target power generation allocated to FCS3 exceeds the upper limit power value, so redistribution control is executed again, and the excess power generation is distributed to FCS4.

[0010] Thus, in power generation systems that perform control to equally distribute the required power generation among multiple fuel cell systems, if the upper limit power value decreases due to failure or deterioration in any of the fuel cell systems, it may become impossible to equally distribute the required power generation. Furthermore, in the control of redistributing the amount of power generated that exceeds the upper limit power value to other fuel cell systems, there is a problem in that the redistribution control becomes complicated and the computational load increases depending on the number of fuel cell systems used, the number of fuel cell systems with output restrictions, and the degree of output restriction.

[0011] This invention was 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 computational load when an output limitation occurs in any of multiple fuel cell systems. This will ultimately contribute to energy efficiency. [Means for solving the problem]

[0012] To achieve this objective, the fuel cell power generation control system according to claim 1 of the present invention comprises: a plurality of fuel cell systems each equipped with a fuel cell capable of generating electricity through the reaction of a fuel gas and an oxidizer gas; a requested power generation amount acquisition unit for acquiring the requested power generation amount for the plurality of fuel cell systems; a limit value acquisition unit for acquiring the output limit value for each fuel cell in the plurality of fuel cell systems; and a power generation amount determination unit for determining the 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 requested power generation amount and the output limit value. In a fuel cell power generation control system, the limit value acquisition unit acquires the upper limit power value, which is the upper limit of the output, and the lower limit power value, which is the lower limit of the output, for each fuel cell as output limit values. The power generation amount determination unit calculates the difference between the upper limit power value and the lower limit power value for each fuel cell as the power generation range, and then calculates the ratio of the power generation range for each fuel cell to the total power generation range for all fuel cells as the power generation range for each fuel cell. The power generation amount determination unit calculates the distributed power generation amount for each fuel cell by subtracting the sum of the lower limit power values ​​for all fuel cells from the requested power generation amount and multiplying the value by the power generation range for each fuel cell. The value obtained by adding the lower limit power value and the distributed power generation amount for each fuel cell is set as the target power generation amount for each of the multiple fuel cell systems.

[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 the target power generation amount for each of the plurality of fuel cell systems based on the requested power generation amount and the output limit value. Therefore, even if output limitations occur in any of the multiple fuel cell systems due to failure, 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 limitation value, taking that output limitation into consideration in advance. This allows for the efficient determination of the target power generation amount for each fuel cell system with minimal computational load, without having to repeatedly perform redistribution calculations depending on the number of fuel cell systems affected by output limitations and the degree of those limitations.

[0015] Also The power generation determination unit calculates the difference between the upper and lower power limits for each fuel cell in the multiple fuel cell systems as the power generation range for that fuel cell. Furthermore, it calculates the ratio of each fuel cell's power generation range to the total power generation range of all fuel cells as the power generation ratio for that fuel cell. Based on the calculated power generation ratio for each fuel cell and the required power generation amount, it then determines the target power generation amount for each of the multiple fuel cell systems. In this way, the power generation capacity of each fuel cell is obtained in advance as a percentage of the total number of fuel cells that can generate power, and the target power generation amount is determined based on the percentage of power generation that can generate power and the required power generation amount. For example, if all fuel cells are operating normally and the percentage of power generation that can generate power that each fuel cell can generate power is approximately equal to the others, the required power generation amount can be distributed almost equally to each fuel cell. Furthermore, even if, for example, one of the fuel cells experiences output limitations due to failure or deterioration, the percentage of power generation that can generate power can be calculated according to the degree of output limitation, and the target power generation amount can be determined accordingly. This allows for efficient determination of the target power generation amount without exceeding the upper limit power value of each fuel cell, with a small computational load.

[0017] Also The power generation determination unit calculates the distributed power generation amount for each fuel cell by subtracting the sum of the minimum power values ​​for all fuel cells from the required power generation amount, that is, the amount of power generation that can be freely distributed to each fuel cell out of the required power generation amount, and multiplying this by the power generation rate of each fuel cell. The sum of the minimum power value for each fuel cell and the distributed power generation amount is then determined as the target power generation amount for the fuel cell system having that fuel cell. In this way, the amount of power distributed to each fuel cell is calculated by subtracting the sum of the minimum power values ​​of all fuel cells from the required power generation amount and multiplying the result by the power generation potential ratio. The sum of the distributed power generation amount and the minimum power values ​​is then set as the target power generation amount for that fuel cell system. This allows for the determination of a target power generation amount that more accurately reflects the power generation potential ratio of each fuel cell, thus enabling the efficient determination of the target power generation amount for each fuel cell system with a small computational load.

[0018] Claims of the present invention 2The control method of the power generation control system of a fuel cell according to claim 1 comprises: a plurality of fuel cell systems each including a fuel cell capable of generating power by the reaction between 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 the target power generation amount for each of the plurality of fuel cell systems. The power generation amount determination means executes control for determining the target power generation amount based on the required power generation amount and the output limit value. The limit value acquisition means acquires the upper limit power value, which is the upper limit of the output, and the lower limit power value, which is the lower limit of the output, for each fuel cell as output limit values. The power generation amount determination means calculates the difference between the upper limit power value and the lower limit power value for each fuel cell as the power generation range, and then calculates the ratio of the power generation range for each fuel cell to the total power generation range for all fuel cells as the power generation range for each fuel cell. The power generation amount determination means calculates the distributed power generation amount for each fuel cell by subtracting the sum of the lower limit power values ​​for all fuel cells from the requested power generation amount and multiplying the value by the power generation range for each fuel cell. The value obtained by adding the lower limit power value and the distributed power generation amount for each fuel cell is then used as the target power generation amount for each of the multiple fuel cell systems, and control is performed accordingly.

[0019] According to this control method of the power generation control system of a fuel cell, the power generation amount determination means executes control for determining 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 when output limitation occurs due to failure, deterioration, etc. in any of the plurality of fuel cell systems, 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 limitation into consideration in advance. As a result, the target power generation amount for each fuel cell system can be efficiently determined with a small computational load without repeatedly performing calculations for redistribution according to the number of fuel cell systems with output limitation and the degree of output limitation.

Brief Description of the Drawings

[0020] [Figure 1] It is a diagram showing an example of the schematic configuration of a fuel cell vehicle equipped with the power generation control system according to the embodiment. [Figure 2] It is a diagram showing an example of the schematic configuration of the FC system according to the first embodiment. [Figure 3] It is a flowchart showing the control process of target power generation amount determination in the power generation control system according to the embodiment. [Figure 4] It is a diagram for explaining the determination of the target power generation amount by the target power generation amount determination control in normal times. [Figure 5]This is a diagram for explaining the determination of the target power generation amount by the target power generation amount determination control during output limitation. [Figure 6] This is a table comparing the procedures for determining the target power generation amount in the embodiment and the prior art. [Figure 7] This is a diagram for explaining the procedure for determining the target power generation amount in the prior art that evenly distributes the required power generation amount. [Figure 8] This is a diagram showing an example of the schematic configuration of the FC system according to the second embodiment.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, referring to the drawings, preferred embodiments of the power generation control system of the fuel cell of the present invention will be described in detail. The power generation control system of the fuel cell according to the first embodiment to be illustrated is mounted on a fuel cell vehicle, and the 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 an automobile such as a two-wheeled, three-wheeled, or four-wheeled vehicle, or may be a large vehicle capable of mounting a plurality of fuel cell systems to be described later. Note that the configurations described below are examples of the present invention, and the present invention is not limited thereto.

[0022] <Schematic Configuration of Fuel Cell Vehicle 100> FIG. 1 is a schematic configuration diagram of a fuel cell vehicle 100 on which a power generation control system 1 of a fuel cell according to the first embodiment is mounted. The fuel cell vehicle 100 is, for example, a fuel cell electric vehicle. 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 storage unit 3, and an FC (Fuel Cell) system 4.

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

[0024] Motor 103 is, for example, a three-phase AC motor and is driven by power supplied from the FC system 4 or battery 104 via the current controller 102. The rotor of motor 103 is connected to a drive wheel (not shown), and motor 103 outputs the driving force used to propel the fuel cell vehicle 100 to the drive wheel under the control of the vehicle control device 101. In addition, motor 103 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 electricity generated by the FC system 4 or the motor 103, and, under the control of the vehicle control device 101, supplies electricity to the motor 103 for the fuel cell vehicle 100 to run. It also supplies electricity to drive the auxiliary equipment of the FC system 4 when the FC system 4 is started up. Furthermore, after the FC system 4 starts up, it supplies the insufficient electricity until the power generated by the FC system 4 reaches the required power. The battery 104 is equipped 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 composed of a microcomputer consisting of, for example, a CPU, RAM, ROM, and I / O interfaces (none of which are shown), and comprehensively controls the driving 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 response to the power demanded by the fuel cell vehicle 100. The power demanded by the fuel cell vehicle 100 is the total load power required for driving and operating the motor 103, as well as brake devices (not shown), various sensors, and other on-board equipment and auxiliary devices. Furthermore, the vehicle control device 101 may also perform driving control of the fuel cell vehicle 100, and may perform power and regenerative drive control for the motor 103, or charge and discharge control for the battery 104.

[0027] The management ECU2 is an ECU composed of a microcomputer consisting of components such as a CPU, RAM, ROM, and I / O interfaces (none of which are shown), and it comprehensively controls multiple FC systems 4 (FC systems 4A, 4B, 4C, 4D). The management ECU2 has multiple communication interfaces corresponding to the number of FC systems 4, and each communication interface communicates with the connected FC system 4. As will be described later, the management ECU2 acquires information regarding power supply instructions and requested power generation amounts from the vehicle control device 101 to the FC system 4, and determines the power generation amount for each FC system based on this information. The management ECU2 includes functional units such as a requested 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 storage unit 3 is implemented by hardware such as an HDD (Hard Disk Drive), flash memory, EEPROM (Electrically Erasable Programmable Read Only Memory, ROM (Read Only Memory), or RAM (Random Access Memory). The storage unit 3 stores, for example, status information indicating the status of each FC system, which will be described later.

[0029] The plurality of FC systems 4 each have a fuel cell. A fuel cell is a cell 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 a plurality of 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, respectively.

[0032] Each power generation cell 411 of the FC stack 41 has a configuration in which a solid polymer electrolyte membrane (hereinafter also simply referred to as an electrolyte membrane) 412 made of, for example, a cation exchange membrane such as a perfluorosulfonic acid thin film containing moisture is sandwiched between an anode electrode 413 and a cathode electrode 414. As the electrolyte membrane 412, in addition to a fluorine-based electrolyte, a hydrocarbon-based electrolyte or the like 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 a result of hydrogen ionization move to an external circuit via electrode 41e, generating an electric current, thereby producing electricity. The hydrogen ions that have moved from the anode electrode 413 to the cathode electrode 414 react with oxygen supplied to the cathode electrode 414 to produce water.

[0034] The oxidizer 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 located in the air supply passage 425. The air pump 421 is driven and controlled by the FC control device 44. A humidifier 423 is provided in the air supply channel 425. The air supply channel 425 is connected to the oxidizer gas inlet 41a of the FC stack 41.

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

[0036] A supply-side sealing valve 422 is provided downstream of the air pump 421 in the air supply passage 425. The supply-side sealing valve 422 is opened and closed by the control of the FC control device 44, thereby switching the air supply passage 425 between open and closed. Furthermore, an exhaust-side sealing valve 424 is provided in the air discharge passage 426. The exhaust-side sealing valve 424 is opened and closed by the control of the FC control device 44, thereby switching the air discharge passage 426 between open and closed. A diluent 48, which will be described later, is connected downstream of the exhaust-side sealing valve 424.

[0037] The hydrogen gas supply device 43 has a hydrogen tank 431 for storing high-pressure hydrogen gas. The hydrogen tank 431 communicates with the hydrogen gas inlet 41c of the FC stack 41 via a hydrogen supply channel 437. An injector 432 and an ejector 433 are provided in series in the hydrogen supply channel 437. The injector 432's opening is controlled by the FC control device 44, which defines the flow rate and timing of hydrogen gas supplied to the FC stack 41. The ejector 433, by creating negative pressure inside, draws in the off-gas discharged from the hydrogen gas outlet 41d to the off-gas passage 438 and circulates it to the hydrogen supply passage 437.

[0038] An off-gas channel 438 is connected to the hydrogen gas outlet 41d of the FC stack 41, and a gas-liquid separator 434 is connected to the off-gas channel 438. The gas-liquid separator 434 separates the off-gas discharged from the hydrogen gas outlet 41d of the FC stack 41 into gaseous and liquid components. The liquid component separated from the off-gas is discharged into the purge channel 439 via a drain valve 435, which is controlled to open and close by the FC control device 44. The gaseous component separated from the off-gas is partially recirculated via an ejector 433, and the remaining portion is discharged into the purge channel 439 via a purge valve 436, which is also controlled to open and close by the FC control device 44. The purge channel is connected to a diluent 48.

[0039] The diluent 48 mixes the reaction air (including 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 to dilute the hydrogen concentration to below a specified value before 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 FCVCU46 is a boost DC-DC converter. The FCVCU46 is positioned between the anode electrode 413 and cathode electrode 414 of the FC stack 41 via a contactor 45 and an external electrical load of the FC system 4. The FCVCU46 boosts the voltage at the output terminal 49 connected to the electrical load to a target voltage determined by the FC control device 44. The FCVCU46 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 composed of a microcomputer consisting of a CPU, RAM, ROM, and I / O interface (none of which are shown), and is installed in each FC system 4. Each FC control device 44 is configured to acquire information regarding the status of the FC system 4 to which it belongs, based on detection values ​​from various sensors (not shown). Each FC control device 44 continuously acquires information regarding the status of the FC system 4, or in response to instructions from the management ECU 2, and transmits the acquired information to the management ECU 2. The acquired FC system status includes, for example, the current power generation status, power generation amount, power generation time, and the number of starts (or stops), and in particular, information on the output limit in the FC stack 41. This output limit information includes the lower power limit and upper power limit values, which will be described later.

[0043] Furthermore, the FC control device 44 controls the start and end of power generation in the FC system 4, the amount of power generated, etc., according to the control of the management ECU 2. The FC control device 44 also controls the opening and closing of various valves in the FC system 4, and the drive control of various auxiliary equipment (such as the air pump 421). In addition, the FC control device 44 controls the 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] On the other hand, 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. This hydrogen gas is supplied to the FC stack 41 from the hydrogen gas inlet 41c after passing through the ejector 433.

[0048] The 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 the 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, and power generation is performed. The power generated by power generation is supplied to the battery 104 or the motor 103 through the current controller 102 based on the control of the FC control device 44.

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

[0050] Furthermore, the hydrogen gas produced 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 into the off-gas channel 438. The discharged off-gas is then introduced from the off-gas channel 438 into the gas-liquid separator 434 to separate the liquid water, and then either recirculated via the ejector 433 or discharged to the outside through the purge channel 439.

[0051] Furthermore, during the execution of the series of power generation operations described above, the FC cooling system 47 is driven according to the temperature of the FC stack 41 based on 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 ECU2 will be described. As shown in Figure 1, the management ECU2 includes a requested power generation amount acquisition unit 21, a limit value acquisition unit 22, and a power generation amount determination unit 23. Each of these functional units 21 to 23 is realized, for example, by a hardware processor such as the CPU of the management ECU2 reading and executing a program (software). Such a program may be stored in the ROM or RAM of the management ECU2, or it may be stored in a storage device (a storage device equipped with a non-transient storage medium such as an HDD or flash memory) that constitutes the storage unit 3.

[0053] The requested power generation acquisition unit 21 includes, for example, a communication interface unit that communicates with the vehicle control device 101. The requested power generation acquisition unit 21 acquires commands from the vehicle control device 100 via the communication interface unit regarding the requested power generation for the multiple FC systems 4 (for example, the amount of power required for 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, multiple communication interface units corresponding to the number of FC systems 4. The limit value acquisition unit 22 acquires information on the power generation limit value from among the various status information output from each FC system 4 via these communication interface units at predetermined timings or periods. This power generation limit value includes, for example, the upper limit power value, which is the upper limit of the output (power generation amount) of each FC system 4, and the lower limit power value, which is the lower limit of the output (power generation amount) of each FC system 4. The limit value acquisition unit 22 stores the acquired information on the power generation limit value 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 amount of power that each FC system 4 should generate, by executing the target power generation amount determination control described later, based on the requested power generation amount for the FC system 4 acquired by the requested power generation amount acquisition unit 21 and the information on the power generation limit value acquired by the limit value acquisition unit 22.

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

[0057] In this control process, first, the power generation acquisition unit 21 of the management ECU 2 acquires the power generation amount required for the entire FC system 4 (step 301 (illustrated as "S301"; the same applies hereinafter)). This power generation amount may be for driving the fuel cell vehicle 100, or it may be for driving and operating on-board equipment and auxiliary machinery. After the requested power generation amount is obtained, 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 process 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 process of step 302 may be repeatedly executed at a predetermined timing or period before step 301 is executed.

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

[0059] Next, based on the calculated power generation capacity of each FC system 4, the ratio of the power generation capacity of each individual FC system 4 to the total power generation capacity of all FC systems 4 is calculated as the power generation capacity of that FC system 4 (step 304). The calculated power generation capacity serves as an indicator of the proportion of power generation that that FC system 4 can handle. Next, the power generation amount determination unit 23 calculates a value by subtracting the sum of the lower limit power values ​​in all FC systems 4 from the acquired requested power generation amount, that is, the amount of power generation that can be freely distributed to each FC system 4 out of the requested power generation amount, and calculates a value by multiplying that value by the power generation capacity of each FC system 4 as the distributed power generation amount for each FC system 4 (step 305). Then, the sum of the minimum power value and the distributed power generation amount for each FC system 4 is determined to be the target power generation amount for that FC system 4 (step 306), and after that, this process is terminated.

[0060] Figures 4 and 5 illustrate the determination of the target power generation amount by the target power generation amount determination control of this embodiment. 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 limitations occur in some of the FC systems 4.

[0061] First, referring to Figure 4, we will explain the process for determining the target power generation amount under normal conditions. First, the power generation range is calculated based on the upper and lower power limits of each of the four FC systems 4 (FCS1-4). Then, the total power generation range is calculated by summing the power generation ranges of all FC systems 4, and then the power generation rate of each FC system 4 is calculated. In this example, since each FC system 4 is operating normally (the upper power limit is not restricted), the power generation range of each FC system 4 is approximately equal, and therefore, the power generation rate of each FC system 4 is also equal. Since four FC systems 4 are used here, the power generation rate of each FC system 4 is 25%.

[0062] Next, the minimum power value for each FC system 4 is subtracted from the required power generation amount, and then the distributed power generation amount is calculated based on the calculated power generation rate. Finally, the value obtained by adding the minimum power value to the calculated distributed power generation amount is determined as the target power generation amount for each FC system 4. Thus, if the upper limit power value of each FC system 4 is not restricted and the power generation range is approximately equal, the target power generation amount for each FC system 4 will be the same as if the required power generation amount were equally distributed 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 ratio, it will not exceed the upper limit power value.

[0063] Next, referring to Figure 5, we will explain the process for determining the target power generation amount when output limitations occur in one of the four FC systems 4 (FCS1). First, similar to the example in Figure 4, the power generation range is calculated based on the upper and lower power limits of each of the four FC systems 4 (FCS1-4). In this example, the upper power limit of FCS1 has decreased due to factors such as failure or deterioration, and the power generation range has decreased to about one-third of the normal range. Therefore, the power generation rate of each FC system 4 is 10% for FCS1 and 30% each for FCS2-4.

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

[0065] Furthermore, in this target power generation determination control, the power generation rate of each FC system 4 is calculated first, and the target power generation rate of each FC system 4 is determined by distributing the required power generation rate accordingly. Therefore, even if the number of FC systems 4 used, the number of FC systems 4 with output restrictions, or the degree of output restrictions change, the target power generation rate can be determined with a small computational load using the same control flow, without the need for recalculations.

[0066] Figure 6 is a table comparing the target power generation determination procedure in this embodiment with that of the conventional technology that equally distributes the required power generation. In the example in Figure 6, the required power generation for the entire FC system 4 is 100 kW, four FC systems 4 (FCS1-4) are used, and the normal upper limit power of each FC system 4 is 60 kW. Also, to avoid complexity, the lower limit power value of each FC system 4 is conveniently assumed to be 0 kW.

[0067] Figure 6(a) shows the procedure for determining the target power generation amount under normal conditions (when no output limitations are imposed on each FC system 4).

[0068] First, in conventional technology, the target power generation is calculated by equally distributing the required power generation amount among the number of FC systems 4. Therefore, 100kW / 4 = 25kW is the target power generation amount for each FC system 4.

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

[0070] Thus, in determining the target power generation amount under normal conditions, the results are the same for both this embodiment and the conventional technology.

[0071] Next, referring to Figure 6(b), we will consider the case where output limitations occur in one of the four FC systems 4 (FCS1).

[0072] In conventional technology, the required power generation of 100kW is first evenly distributed, with 25kW allocated to each of the FC systems 4. However, since the upper power limit of FCS1 has been reduced to 20kW, the target power generation exceeds the upper power limit. Therefore, the excess power of 5kW in FCS1 is re-evenly distributed among FCS2-4, and 25kW + (5kW / 3) ≈ 27kW is set as the target power generation for FCS2-4. The target power generation for FCS1 is then set to the upper power limit of 20kW.

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

[0074] Thus, in a system that determines the target power generation amount by equally distributing the required power generation amount, as in conventional technology, if an output limitation occurs in any of the FC systems 4, redistribution control processing may be required, which increases the computational load. On the other hand, in this embodiment, even if output limitations occur in any of the FC systems 4, the target power generation amount can be efficiently determined by the same control processing as under normal conditions.

[0075] Finally, referring to Figure 6(c), we consider the case where output limitations occur in multiple of the four FC systems 4 (FCS1-3).

[0076] In conventional technology, the required power generation of 100kW is first evenly distributed, with 25kW allocated to each FC system 4. Since the upper power limits for FCS1 and FCS2 are 10kW, the target power generation exceeds these limits. Therefore, the excess power of 15kW from FCS1 and 15kW from FCS2, totaling 30kW, is re-distributed equally among FCS3 and FCS4. As a result, 10kW, the upper power limit, is allocated to FCS1 and FCS2, and 25kW + (30kW / 2) = 40kW is allocated to FCS3 and FCS4, respectively. However, since the upper power limit for FCS3 is 30kW, an excess of 10kW occurs, requiring this excess to be re-allocated to FCS4. Consequently, the final target power generation is set at 10kW for FCS1 and FCS2, 30kW for FCS3, and 50kW for FCS4.

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

[0078] Thus, with conventional technology, depending on the number of FC systems 4 that experience output limitations and the degree of those limitations, multiple redistribution control processes may be required, resulting in a very large computational load. On the other hand, in the target power generation determination control of this embodiment, even if output limitations occur in multiple FC systems 4, or if there are variations in the degree of output limitations, an appropriate target power generation amount can be determined efficiently and with a small computational load using the same control processing as under normal conditions.

[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 requested power generation amount and the output limit value. Therefore, even if an output limitation occurs in any of the multiple FC systems 4 due to failure, deterioration, etc., the target power generation amount of each FC system 4 can be determined based on the requested power generation amount and the output limit value, taking that output limitation into consideration in advance. This allows for the efficient determination of the target power generation amount for each FC system 4 with a small computational load, without the need to change the control flow or repeat calculations for redistribution depending on the number of FC systems 4 experiencing output limitations or the degree of output limitations.

[0080] Furthermore, the power generation determination unit 23 calculates the difference between the upper and lower power limits for each of the multiple FC systems 4 (specifically, its FC stack 41) as the power generation range for that FC system 4. It then calculates the ratio of the power generation range of each FC system 4 to the total power generation range of all FC systems 4 as the power generation range for that FC system 4. Finally, based on the calculated power generation range and the required power generation amount, the unit determines the target power generation amount for each FC system 4. In this way, the power generation capacity of each FC system 4 is obtained in advance as a power generation ratio to the total number of FC systems 4, and the target power generation amount is determined based on the power generation ratio and the required power generation amount. For example, if all FC systems 4 are operating normally and the power generation ratios of each FC system 4 are approximately equal, the required power generation amount can be distributed to each FC system 4 almost equally. Furthermore, even if, for example, one of the FC systems 4 experiences output limitations due to failure or deterioration, the power generation ratio can be calculated according to the degree of output limitation, and the target power generation amount can be determined accordingly. This allows for efficient determination of the target power generation amount with a small computational load, ensuring that the upper power limit of each FC system 4 is not exceeded.

[0081] Furthermore, the power generation determination unit 23 calculates the amount of power to be distributed to each FC system 4 by multiplying the value obtained by subtracting the sum of the lower limit power values ​​for all FC systems 4 from the requested power generation amount, that is, the amount of power that can be freely distributed to each FC system 4 out of the requested power generation amount, by the power generation rate of each FC system 4. Then, the sum 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 amount of power generated for each FC system 4 is calculated by subtracting the sum of the lower limit power values ​​of all FC systems 4 from the required power generation amount and multiplying the result by the power generation capability ratio. The sum of the distributed power generation amount and the lower limit power value is then set as the target power generation amount for that FC system 4. This allows for the determination of a target power generation amount that more accurately reflects the power generation capability ratio of each FC system 4, enabling the efficient determination of the target power generation amount for each FC system 4 with a small computational load.

[0082] Next, a second embodiment of the fuel cell power generation control system of the present invention, applied to stationary facilities such as houses and factories, will be described with reference to Figure 8. In the following description, the same reference numerals are used for components that are the same as those in the fuel cell power generation control system 1 of the first embodiment, and their descriptions are omitted.

[0083] As shown in Figure 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 factory, and functions as an auxiliary power supply that supplies the insufficient power when the power required by the stationary facility 200 exceeds the power supplied by the main power supply equipment.

[0084] The stationary power control device 201 is an ECU composed of a microcomputer consisting of, for example, a CPU, RAM, ROM, and I / O interfaces (none of which are shown). In the first embodiment of the power generation control system 1, the vehicle control device 101 controlled the supply of generated power in response to the power request from the fuel cell vehicle 100. However, in the second embodiment of the power generation control system 10, the stationary power control device 201 controls the supply of power stored in the battery 104 or power generated by the FC system 4 in response to the power request from a higher-level power management device (not shown).

[0085] The configuration and functions of the management ECU2 in the power generation control system 10 are the same as those in the power generation control system 1. The management ECU2 acquires information regarding power supply instructions and requested power generation amounts for the FC systems 4 from the stationary power control device 201, and based on this, executes the target power generation amount determination control described above to determine the target power generation amount for each FC system 4. The requested power generation amount acquisition unit 21 of the management ECU2 includes, for example, a communication interface unit that communicates with the stationary power control device 201, and acquires commands regarding the requested power generation amounts for the multiple FC systems 4 from the stationary power 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 the same as those in the power generation control system 1. The FC system 4 generates power according to 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 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] Thus, the fuel cell power generation control system of the present invention is applicable to stationary facilities such as houses and factories, and, as with the case when mounted on a mobile body such as a vehicle, it can efficiently determine the target power generation amount of each FC system 4 with a small computational load, without having to change the control flow or repeat calculations for redistribution depending on the number of FC systems 4 that have experienced output limitations or the degree of output limitations.

[0088] Furthermore, the present invention is not limited to the embodiments described and can be implemented in various forms. In addition, the details of the configuration can be appropriately modified 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... Requested power generation amount acquisition unit (requested power generation amount acquisition means) 22... Limit value acquisition unit (means for acquiring limit values) 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… Oxidizer gas supply device 43…Hydrogen gas supply device 44...FC control unit 100…Fuel cell vehicles 101... Vehicle control device 103...motor 104... Battery

Claims

1. Multiple fuel cell systems, each equipped with a fuel cell capable of generating electricity through the reaction of a fuel gas and an oxidizer gas, A 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 an output limit value for each of the fuel cells in the plurality of fuel cell systems, The system includes a power generation determination unit that determines the 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 requested power generation amount and the output limit value. A power generation control system for fuel cells, The limit value acquisition unit acquires, as output limit values, an upper limit power value which is the upper limit of the output in each of the fuel cells and a lower limit power value which is the lower limit of the output. The power generation amount determination unit calculates the difference between the upper limit power value and the lower limit power value for each of the fuel cells as the power generation range, and then calculates the ratio of the power generation range for each of the fuel cells to the total power generation range for all of the fuel cells as the power generation rate for each of the fuel cells. The power generation amount determination unit calculates the distributed power generation amount for each fuel cell by multiplying the value obtained by subtracting the sum of the lower limit power values ​​for all the fuel cells from the requested power generation amount by the power generation possible ratio for each of the fuel cells, and sets the target power generation amount for each of the plurality of fuel cell systems as the value obtained by adding the lower limit power value for each of the fuel cells and the distributed power generation amount. A power generation control system for fuel cells.

2. Multiple fuel cell systems, each equipped with a fuel cell capable of generating electricity through the reaction of a fuel gas and an oxidizer gas, A 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 an output limit value in each of the fuel cells of the plurality of fuel cell systems, A control method for a fuel cell power generation control system, comprising power generation amount determination means for determining a target power generation amount in each of the plurality of fuel cell systems, The power generation amount determination means performs control to determine the target power generation amount based on the requested power generation amount and the output limit value. The limit value acquisition means acquires, as the output limit values, an upper limit power value which is the upper limit of the output in each of the fuel cells and a lower limit power value which is the lower limit of the output. The power generation amount determination means calculates the difference between the upper limit power value and the lower limit power value in each of the fuel cells as the power generation range, and then calculates the ratio of the power generation range in each of the fuel cells to the total power generation range of all the fuel cells as the power generation rate of each of the fuel cells. The power generation amount determination means calculates the distributed power generation amount for each fuel cell by subtracting the sum of the lower limit power values ​​for all the fuel cells from the requested power generation amount and multiplying the power generation rate for each fuel cell by the power generation rate for each fuel cell, and then performs control to set the target power generation amount for each of the plurality of fuel cell systems as the sum of the lower limit power value for each fuel cell and the distributed power generation amount. A control method for a fuel cell power generation control system.

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