Fuel battery module

Abstract

To provide a fuel battery module in which power actually supplied to an external load follows a request power value with high accuracy.SOLUTION: A fuel battery module comprises a control part that controls a power generation operation of a fuel battery on the basis of a request power value provided from a fuel battery and an external load, and is electrically connected so that power can be supplied to the external load. The control part calculates a module power setting value expressing a setting value of the power supplied to the external load from the fuel battery module on the basis of a first power value expressing a measurement value of the power generated by the fuel battery, a second power value expressing the measurement value of the power supplied to the external load from the fuel battery module, and a power generation amount limit value determined in accordance with the state of the fuel battery module. The control part performs a PI calculation for an error between a smaller value of the request power value or the module power setting value and the second power value, and controls a power generation operation of the fuel battery by using their calculation result.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a fuel cell module for supplying power to an external load. [Background technology]

[0002] Fuel cell systems generate power by electrochemically reacting fuel gas and oxidizing gas via an electrolyte. For example, the amount of fuel gas and / or oxidizing gas supplied to the fuel cell is adjusted in response to a request from an external load to generate the power required by the external load. Furthermore, fuel cell systems often have a function for limiting output. For example, the fuel cell system described in Patent Document 1 has a function for limiting the output of the fuel cell in response to the cell voltage, and a function for lifting the output limit when the amount of power that the fuel cell can output during the output limit exceeds the amount of power required for the fuel cell. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-202695 A Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional fuel cell systems, the output of the fuel cell is controlled by monitoring the power actually supplied to an external load and providing feedback, so that the power required by the external load is supplied to the external load.

[0005] However, with this method, the power actually supplied to the external load may not be able to keep up with the power value required by the external load. In particular, immediately after the operation mode of the fuel cell system returns from a limited power generation mode, which limits the output of the fuel cell, to a normal power generation mode, the power actually supplied to the external load may deviate significantly from the required value.

[0006] An object according to one aspect of the present invention is to provide a fuel cell module in which the power actually supplied to an external load accurately tracks the required power value. [Means for solving the problem]

[0007] A fuel cell module according to one aspect of the present invention is electrically connected to an external load so as to be able to supply power to the external load. The fuel cell module includes a fuel cell and a control unit that controls the power generation operation of the fuel cell based on a required power value notified by the external load. The control unit controls the power generation operation in a normal power generation mode or a limited power generation mode executed due to detection of an abnormal state of the fuel cell module, calculates a module power setting value that represents a set value of the power supplied from the fuel cell module to the external load based on a first power value that represents a measured value of the power generated by the fuel cell, a second power value that represents a measured value of the power supplied from the fuel cell module to the external load, and a power generation limit value that represents an upper limit of the power generation amount of the fuel cell determined according to the state of the fuel cell module, performs a PI calculation on the error between the smaller of the required power value or the module power setting value and the second power value, and controls the power generation operation of the fuel cell using the calculation result of the PI calculation.

[0008] According to the above-mentioned configuration, when the amount of power generation of the fuel cell is limited in the limited power generation mode, the module power setting value is reduced, and power generation control is performed using the module power setting value instead of the required power value. In this case, the error between the two input values ​​in the PI calculation is reduced, so that the integral term of the PI calculation is reduced immediately after returning from the limited power generation mode to the normal power generation mode, and the power supplied from the fuel cell module to the external load converges to the required power value in a short time. In other words, the power actually supplied to the external load accurately tracks the required power value.

[0009] The control unit may calculate the module power setting value by subtracting the difference between the first power value and the second power value from the power generation limit value.

[0010] The first power value is calculated, for example, by multiplying a measurement value from a first current sensor that measures the output current of the fuel cell by a measurement value from a first voltage sensor that measures the output voltage of the fuel cell.

[0011] The second power value is calculated, for example, by multiplying a measurement by a second current sensor that measures the current supplied from the fuel cell module to the external load and a measurement by a second voltage sensor that measures the output voltage from the fuel cell module to the external load.

[0012] The fuel cell module may further include a DC / DC converter that converts the output voltage of the fuel cell into a predetermined DC voltage, in which case the second current sensor measures the output current of the DC / DC converter and the second voltage sensor measures the output voltage of the DC / DC converter.

[0013] The power generation limit value is preset, for example, for the temperature of the cooling water of the fuel cell, or the power generation limit value is preset for the minimum value of the output voltage of each of the fuel cell units that make up the fuel cell. Effect of the Invention

[0014] According to the above-described aspect, in a fuel cell module that supplies power to an external load, the power actually supplied to the external load accurately tracks the required power value. [Brief description of the drawings]

[0015] [Figure 1] 1 is a diagram showing an example of a fuel cell module according to an embodiment of the present invention; [Diagram 2] FIG. 4 is a diagram illustrating an example of power generation control. [Diagram 3] FIG. 13 is a diagram showing an example of an operation map showing an operation when an abnormal state is detected. [Figure 4] 10A and 10B are diagrams illustrating problems that arise when returning from a limited power generation mode to a normal power generation mode. [Diagram 5]FIG. 4 is a diagram illustrating an example of power generation control according to an embodiment of the present invention. [Figure 6] 5A to 5C are diagrams illustrating the effect of power generation control according to the embodiment of the present invention. [Figure 7] 10 is a flowchart illustrating an example of a process of a control unit. [Figure 8] 5A to 5C are diagrams illustrating variations of power generation control according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] FIG. 1 shows an example of a fuel cell module according to an embodiment of the present invention. The fuel cell module 100 according to the embodiment of the present invention includes a fuel cell stack 1, a fuel gas supply device 2, an oxidizing gas supply device 3, a DC / DC converter 4, a DC / DC converter 5, and a control unit 6. The fuel cell module 100 also includes various sensors (V1, A1, V2, A2, T, etc.). The fuel cell module 100 may also include other devices, circuits, and functions not shown in FIG. 1. The fuel cell module 100 is electrically connected to an external load 200 so as to be able to supply power to the external load 200. The external load 200 is not particularly limited, and may be, for example, an industrial machine, an industrial vehicle, or a stationary power generator.

[0017] The fuel cell stack 1 is composed of multiple fuel cell units. Each fuel cell generates electricity by electrochemically reacting fuel gas and oxidizing gas via an electrolyte. However, since the output voltage of each fuel cell is small, the fuel cell stack 1 is composed of multiple fuel cell units stacked together. In other words, the fuel cell stack 1 has the required number of fuel cell units stacked together to output the desired voltage.

[0018] The fuel gas supplying device 2 includes, for example, a hydrogen injector and a hydrogen pump, and supplies a required amount of hydrogen from a hydrogen tank to the fuel cell stack 1 in response to instructions from the control unit 6. The oxidizing gas supplying device 3 includes an air compressor, and supplies a required amount of oxidizing gas (for example, air) to the fuel cell stack 1 in response to instructions from the control unit 6.

[0019] The DC / DC converter 4 converts the output voltage of the fuel cell stack 1 into a specified DC voltage. The DC / DC converter 4 is designed to output a DC voltage required by the external load 200, for example. The DC / DC converter 5 converts the output voltage of the DC / DC converter 4 into a specified DC voltage. The power output from the DC / DC converter 5 is used to operate the auxiliary equipment in the fuel cell module 100. The auxiliary equipment in the fuel cell module 100 corresponds to devices and circuits for operating the fuel cell module 100, and includes the above-mentioned hydrogen pump, air compressor, etc. The power output from the DC / DC converter 5 may be stored in a battery or a capacitor before being supplied to the auxiliary equipment in the fuel cell module 100.

[0020] The control unit 6 controls the power generation operation of the fuel cell module 100 based on the required power value notified by the external load 200. Specifically, the control unit 6 controls the fuel gas supply device 2, the oxidant gas supply device 3, and the DC / DC converter 4 so that the power supplied from the fuel cell module 100 to the external load 200 approaches the required power value. At this time, the control unit 6 controls the power generation operation of the fuel cell module 100 using the measured values ​​of the voltage sensor V1, the current sensor A1, the voltage sensor V2, the current sensor A2, and the temperature sensor T.

[0021] In this embodiment, the control unit 6 is realized by a microcomputer (ECU: Electronic Control Unit) having a processor and a memory. In this case, the control unit 6 may be realized by one ECU or multiple ECUs.

[0022] The current sensor A1, acting as a first current sensor, measures the output current of the fuel cell stack 1. The voltage sensor V1, acting as a first voltage sensor, measures the output voltage of the fuel cell stack 1. Thus, the control unit 6 can detect the power generated by the fuel cell stack 1 by acquiring the measured values ​​of the current sensor A1 and the voltage sensor V1. Specifically, the power generated by the fuel cell stack 1 is obtained by calculating the product of the measured value of the current sensor A1 and the measured value of the voltage sensor V1. Note that in the following description, the power generated by the fuel cell stack 1 (i.e., the product of the measured value of the current sensor A1 and the measured value of the voltage sensor V1) may be referred to as the "FC power generation amount" or "gross power."

[0023] The current sensor A2 as a second current sensor measures the output current of the fuel cell module 100 (i.e., the current supplied to the external load 200). The voltage sensor V2 as a second voltage sensor measures the output voltage of the fuel cell module 100 (i.e., the input voltage of the external load 200). Thus, the control unit 6 can detect the power supplied from the fuel cell module 100 to the external load 200 by acquiring the measured values ​​of the current sensor A2 and the voltage sensor V2. Specifically, the power supplied from the fuel cell module 100 to the external load 200 is obtained by calculating the product of the measured value of the current sensor A2 and the measured value of the voltage sensor V2. In the following description, the power supplied from the fuel cell module 100 to the external load 200 (i.e., the product of the measured value of the current sensor A2 and the measured value of the voltage sensor V2) may be referred to as "module power" or "net power".

[0024] In this way, by acquiring the measured values ​​of the voltage sensor V1, the current sensor A1, the voltage sensor V2, and the current sensor A2, the control unit 6 can detect the power generated by the fuel cell stack 1 (i.e., the FC power generation amount) and the power supplied from the fuel cell module 100 to the external load 200 (i.e., the module power). In this embodiment, a part of the FC power generation amount is consumed by the auxiliaries in the fuel cell module 100. Also, losses occur in the DC / DC converters 4 and 5. Therefore, the module power is smaller than the FC power generation amount by the amount of the power consumption by the auxiliaries and the losses in the DC / DC converters. In the following description, the sum of the power consumption by the auxiliaries and the losses in the DC / DC converters may be referred to as the "loss in the module".

[0025] The temperature sensor T measures the temperature associated with the fuel cell stack 1. As an example, the temperature sensor T measures the temperature of cooling water for cooling the fuel cell stack 1. Then, the control unit 6 may limit the amount of power generation of the fuel cell stack 1 when the value measured by the temperature sensor T exceeds a predetermined threshold value.

[0026] 2 shows an example of power generation control by the control unit 6. In this embodiment, the control unit 6 includes a multiplier 11, a PI (Proportional-Integral) calculator 12, and an adder 13.

[0027] Multiplier 11 calculates the product of the module current and the module voltage, where the module current is measured by the current sensor A2 shown in Figure 1 and represents the output current of the fuel cell module 100. The module voltage is measured by the voltage sensor V2 shown in Figure 1 and represents the output voltage of the fuel cell module 100. Therefore, the output of multiplier 11 represents the power supplied from the fuel cell module 100 to the external load 200 (i.e., the module power).

[0028] The PI calculator 12 executes a PI calculation on the required power value notified by the external load 200 and the measured module power value calculated by the multiplier 11. The PI calculation is expressed by equation (1).

number

[0029] The first term on the right side is a proportional term, and Kp represents a constant. The second term is an integral term, and KI represents a constant. e represents the error between the two inputs. In the PI calculator 12 shown in Fig. 2, e corresponds to the error between the required power value notified by the external load 200 and the measured module power value obtained by measurement.

[0030] The adder 13 adds the output value of the PI calculator 12 to the required power value. The value obtained by the adder 13 is then output as a power generation command. The power generation command is used to control the power generation amount of the fuel cell stack 1. As an example, the control unit 6 controls the fuel gas supplying device 2 and / or the oxidizing gas supplying device 3 based on the power generation command value so as to reduce the error between the required power value notified by the external load 200 and the module power measurement value obtained by measurement. As a result, the power supplied from the fuel cell module 100 to the external load 200 (i.e., the module power) approaches the required power value.

[0031] In this way, the power generation command indicates the amount of power generation of the fuel cell stack 1. That is, the power generation command essentially represents the FC power generation amount. Here, the power generation command is obtained by adding the output value of the PI calculator 12 to the required power value. Therefore, in a steady state, the power generation command is equivalent to the value obtained by adding the output value of the PI calculator 12 to the module power. On the other hand, the module power is obtained by subtracting the loss in the module from the FC power generation amount. Therefore, the output value of the PI calculator 12 essentially corresponds to the loss in the module.

[0032] Incidentally, the fuel cell module 100 according to the embodiment of the present invention operates in a limited power generation mode that limits the amount of power generated by the fuel cell stack 1 when a predetermined abnormal state is detected. That is, the operation modes of the fuel cell module 100 include a normal power generation mode and a limited power generation mode. Specifically, when a predetermined abnormal state is detected, the control unit 6 shifts the operation mode of the fuel cell module 100 from the normal power generation mode to the limited power generation mode. Furthermore, when the abnormal state is resolved, the control unit 6 returns the operation mode of the fuel cell module 100 from the limited power generation mode to the normal power generation mode.

[0033] 3 shows an example of an operation map indicating the operation when an abnormal state is detected. The voltage sensor V1 measures the output voltage of the fuel cell stack 1 and is also capable of measuring the output voltage of each fuel cell that constitutes the fuel cell stack 1. The temperature sensor T measures the temperature of the cooling water for the fuel cell stack 1.

[0034] FIG. 3(a) shows an example of an FC current limiting map. The horizontal axis represents the minimum value of the output voltage of each fuel cell (minimum cell voltage). In FIG. 3(a), the minimum cell voltage is represented as a difference from a reference output voltage of the fuel cell. In this embodiment, the reference output voltage of the fuel cell is a fixed value determined by the material constituting the fuel cell, etc. The vertical axis represents the upper limit value of the output current of the fuel cell stack 1. It is assumed that this map has been created in advance and stored in the memory of the control unit 6.

[0035] The control unit 6 constantly monitors the output voltage of each fuel cell. When the output voltage of any fuel cell drops by 0.1 V or more below the reference output voltage, the control unit 6 limits the output current of the fuel cell stack 1 in accordance with this map. At this time, the control unit 6 executes, for example, a process of reducing the supply amount of fuel gas / oxidizing gas and / or a process of reducing the duty ratio of the switching pulse of the DC / DC converter 4.

[0036] Fig. 3(b) shows an example of an FC power generation amount limiting map. The horizontal axis represents the temperature of the cooling water of the fuel cell stack 1. The vertical axis represents the upper limit of the power generation amount of the fuel cell stack 1. The control unit 6 constantly monitors the temperature of the cooling water of the fuel cell stack 1. Then, when the temperature of the cooling water exceeds 75°C, the control unit 6 limits the power generation amount of the fuel cell stack 1 in accordance with this map. At this time, the control unit 6 reduces the supply amount of fuel gas / oxidizing gas.

[0037] FIG. 4 is a diagram illustrating the problems that arise when returning from the limited power generation mode to the normal power generation mode. In this embodiment, before time T1, the fuel cell module 100 operates in the normal power generation mode. The normal power generation mode refers to an operation mode in which power is generated according to a requested power value without being subject to the restrictions shown in FIG. 3(a) or FIG. 3(b). When the fuel cell module 100 operates in the normal power generation mode, the power supplied from the fuel cell module 100 to the external load 200 (i.e., module power) is approximately equal to the requested amount of power, as shown in FIG. 4.

[0038] At time T1, due to some abnormality, the restriction shown in Fig. 3(a) or 3(b) is initiated. That is, at time T1, the operation mode of the fuel cell module 100 transitions from the normal power generation mode to the limited power generation mode. This reduces the amount of power generated by the fuel cell stack 1, and the module power also decreases. As a result, the difference between the required power value and the module power increases.

[0039] After that, the above-mentioned abnormality is resolved, and at time T2, the operation mode of the fuel cell module 100 returns from the limited power generation mode to the normal power generation mode. Then, the restrictions shown in Figure 3(a) or 3(b) are removed, and the power generation amount of the fuel cell stack 1 returns to its original value. As a result, the module power approaches the required power value.

[0040] However, in this embodiment, as shown in Fig. 2, the control unit 6 executes a PI calculation based on the error between the required power value and the measured module power value, and uses the calculation result to control the power generation amount of the fuel cell stack 1. Here, the error between the required power value and the module power immediately before returning from the limited power generation mode to the normal power generation mode is a relatively large value. Therefore, due to the integral term of the PI calculation, a situation occurs in which the module power temporarily exceeds the required power value by a large amount. In other words, in the control method shown in Fig. 2, the tracking ability of the module power to the required power value may deteriorate when returning from the limited power generation mode to the normal power generation mode.

[0041] In the control system shown in FIG. 2, the amount of power generated by the fuel cell stack is controlled using the measured value of the module power. In this case, control is performed between the fuel cell module and the external load based on the required power value / module power value, while the amount of power generated by the fuel cell stack is controlled within the fuel cell module. However, due to losses within the module, the required power value / module power value and the amount of power generated by the fuel cell stack do not match. As a result, in the control system shown in FIG. 2, the ability of the module power to follow the required power value may deteriorate. Taking this into consideration, the fuel cell module according to the embodiment of the present invention is provided with a function for improving the ability of the module power to follow the required power value.

[0042] Fig. 5 shows an example of power generation control according to an embodiment of the present invention. In this embodiment, the control unit 6 includes a multiplier 11, a PI calculator 12, an adder 13, a multiplier 21, a subtractor 22, a multiplier 23, a comparator (min) 24, a subtractor 25, and a comparator (min) 26. Note that the multiplier 11, the PI calculator 12, and the adder 13 are substantially the same in Fig. 2 and Fig. 5.

[0043] The multiplier 21 calculates the product of the FC current value and the FC voltage value. Here, the FC current value is measured by the current sensor A1 shown in Fig. 1 and represents the output current of the fuel cell stack 1. The FC voltage value is measured by the voltage sensor V1 shown in Fig. 1 and represents the output voltage of the fuel cell stack 1. Therefore, the calculation result of the multiplier 21 represents the power generated by the fuel cell stack 1 (i.e., the FC power generation amount or gross power).

[0044] The subtractor 22 subtracts the calculation result of the multiplier 11 from the calculation result of the multiplier 21. Here, the calculation result of the multiplier 11 represents the power supplied from the fuel cell module 100 to the external load 200 (i.e., the module power or the net power) as described above. Therefore, the calculation result of the subtractor 22 represents the difference between the FC power generation amount and the module power. In other words, the calculation result of the subtractor 22 represents the loss in the module.

[0045] The multiplier 23 calculates the product of the FC voltage value and the FC current limit value. As described above, the FC voltage value represents the output voltage of the fuel cell stack 1. The FC current limit value is determined based on the FC current limit map shown in FIG. 3(a). Thus, the FC current limit value is determined based on the lowest voltage (i.e., the lowest cell voltage) among the output voltages of the fuel cells constituting the fuel cell stack 1. Specifically, when the lowest cell voltage has not decreased relative to the reference output voltage, the FC current limit value is the same as the output current of the fuel cell stack 1 in the normal power generation mode. In this case, the calculation result of the multiplier 23 is substantially the same as the power generation amount of the fuel cell stack 1 in the normal power generation mode. In contrast, when the lowest cell voltage decreases by more than a predetermined level relative to the reference output voltage, the FC current limit value is set to a value smaller than the FC current value according to the map shown in FIG. 3(a). In this case, the calculation result of the multiplier 23 is smaller than the power generation amount of the fuel cell stack 1 in the normal power generation mode.

[0046] In this way, the calculation result of the multiplier 23 corresponds to the power generation amount of the fuel cell stack 1 when taking into consideration limiting the output of the fuel cell stack 1 according to the state (here, the minimum cell voltage) of the fuel cell module 100. Therefore, the calculation result of the multiplier 23 is an example of a power generation amount limit value.

[0047] Comparator 24 compares the calculation result of multiplier 23 with the FC power generation amount limit value, and outputs the smaller value. Here, the FC power generation amount limit value is determined based on the FC power generation amount limit map shown in FIG. 3(b). Therefore, the FC power generation amount limit value is determined based on the temperature of the cooling water of fuel cell stack 1. Specifically, if the temperature of the cooling water is equal to or lower than a predetermined threshold value, the FC power generation amount limit value is the same as the power generation amount of fuel cell stack 1 in normal power generation mode. In contrast, if the temperature of the cooling water exceeds the threshold value, the FC power generation amount limit value becomes smaller than the power generation amount of fuel cell stack 1 in normal power generation mode.

[0048] In this way, the comparator 24 outputs the smaller of a value representing the power generation amount determined based on the FC current limit map shown in Figure 3(a) or a value representing the power generation amount determined based on the FC power generation amount limit map shown in Figure 3(b). In other words, the output value of the comparator 24 represents the smaller of the power generation amounts of the fuel cell stack 1 that are set based on the map shown in Figure 3(a) or 3(b). Therefore, in the following description, the output value of the comparator 24 may be referred to as the "FC power generation amount set value."

[0049] Subtractor 25 subtracts the calculation result of subtractor 22 from the output value of comparator 24. That is, the intra-module loss value is subtracted from the FC power generation set value. Here, the intra-module loss value is essentially the difference between the FC power generation representing the power generated by the fuel cell stack 1 and the module power representing the power supplied from the fuel cell module 100 to the external load 200. Therefore, the output value of subtractor 25 corresponds to the module power set value when taking into account a situation in which the output power of the fuel cell stack 1 is limited. Therefore, in the following description, the output value of subtractor 25 may be referred to as the "module power set value."

[0050] The comparator 26 compares the required power value notified by the external load 200 with the module power set value output from the subtractor 25, and outputs the smaller value. Here, when the fuel cell module 100 is operating in the normal power generation mode, the amount of power generation of the fuel cell stack 1 is not limited, so the module power set value is controlled to approach the required power value. On the other hand, when the fuel cell module 100 is operating in the limited power generation mode, the amount of power generation of the fuel cell stack 1 is limited in accordance with the map shown in Figure 3(a) or Figure 3(b), so the module power set value is smaller than the required power value. Therefore, in the limited power generation mode, the comparator 26 selects and outputs the module power set value.

[0051] In the control unit 6 configured as above, the PI calculator 12 performs a PI calculation on the error between the output value of the comparator 26 and the output value of the multiplier 11. Here, the output value of the comparator 26 is the required power value or the module power setting value. Also, the output value of the multiplier 11 represents the module power of the fuel cell module 100.

[0052] Fig. 6 is a diagram for explaining the effect of the power generation control according to the embodiment of the present invention shown in Fig. 5. In the example shown in Fig. 6, similarly to the case shown in Fig. 4, the power generation mode shifts from the normal power generation mode to the limited power generation mode at time T1, and returns from the limited power generation mode to the normal power generation mode at time T2.

[0053] In the limited power generation mode, the comparator 26 outputs a module power setting value. Therefore, in the limited power generation mode, the output value of the comparator 26 represents a value close to the measured value of the module power. As a result, compared to the cases shown in Figs. 2 and 4, the error between the two values ​​input to the PI calculator 12 is smaller, and the integral term calculated by the PI calculation is also smaller. As a result, after the operation mode of the fuel cell module 100 returns from the limited power generation mode to the normal power generation mode, the module power converges to the required power value in a short time. In other words, even immediately after the operation mode of the fuel cell module 100 changes, the power actually supplied to the external load 200 accurately tracks the required power value.

[0054] In this way, when the amount of power generation of the fuel cell stack 1 is limited due to the state of the fuel cell module 100, the fuel cell module 100 cannot supply power according to the required power value. For this reason, when control is performed to bring the measured module power closer to the required power value, the error between the two values ​​input to the PI calculator 12 becomes large, and as shown in Figure 4, the tracking ability of the power generation control deteriorates immediately after returning to the normal power generation mode.

[0055] Therefore, in an embodiment of the present invention, when the amount of power generation of the fuel cell stack 1 is limited, a module power corresponding to the limited amount of power generation is set. Then, the fuel cell module 100 performs control to bring the measured value of the module power closer to the set value of the module power. This reduces the error between the two values ​​input to the PI calculator 12, and improves the tracking of the power generation control immediately after returning to the normal power generation mode, as shown in FIG. 6.

[0056] Fig. 7 is a flowchart showing an example of the process of the control unit 6. The process of this flowchart is executed, for example, periodically. Note that in this flowchart, the procedure of limiting the amount of power generation according to the map shown in Fig. 3 is omitted.

[0057] At S1, the control unit 6 obtains a required power value notified by the external load 200. At S2, the control unit 6 obtains measurements from the current sensor A1 and the voltage sensor V1 to obtain a measurement value of the power generation amount of the fuel cell stack 1. At S3, the control unit 6 obtains measurements from the current sensor A2 and the voltage sensor V2 to obtain a measurement value of the module power supplied from the fuel cell module 100 to the external load 200.

[0058] In S4, the control unit 6 calculates an intra-module loss value by subtracting the measured module power from the measured power generation amount of the fuel cell stack 1. In S5, the control unit 6 calculates a set value for the power generation amount of the fuel cell stack 1 based on the state of the fuel cell module 100 (minimum cell voltage, coolant temperature) and the operation map shown in Fig. 3. In S6, the control unit 6 calculates a set value for the module power by subtracting the intra-module loss value from the set value for the power generation amount of the fuel cell stack 1.

[0059] In S7, the control unit 6 compares the required power value with the set value of the module power. If the required power value is equal to or less than the set value of the module power, the control unit 6 generates a power generation command based on the required power value in S8. On the other hand, if the set value of the module power is smaller than the required power value, the control unit 6 generates a power generation command based on the set value of the module power in S9.

[0060] <Variations> 5, the measured values ​​of the current sensor A1 and the voltage sensor V1 are input to the control unit 6, and the control unit 6 calculates the product of these values ​​to calculate the amount of power generation in the fuel cell stack 1, but the embodiment of the present invention is not limited to this configuration. For example, as shown in FIG. 8, a configuration in which a value representing the amount of power generation in the fuel cell stack 1 is input to the control unit 6 may be used.

[0061] 5, the measured values ​​of the current sensor A2 and the voltage sensor V2 are input to the control unit 6, and the control unit 6 calculates the product of these values ​​to calculate the module power, but the embodiment of the present invention is not limited to this configuration. For example, as shown in FIG. 8, a configuration in which a value representing the module power is input to the control unit 6 may be used. Alternatively, the input current and input voltage measured in the external load 200 may be notified to the control unit 6.

[0062] 1, the voltage sensor V1 directly measures the output voltage of the fuel cell stack 1, but the embodiment of the present invention is not limited to this configuration. For example, the voltage sensor V1 may measure the output voltage of each fuel cell that constitutes the fuel cell stack 1. In this case, the output voltage of the fuel cell stack 1 is calculated by calculating the sum of the output voltages of each fuel cell.

[0063] The voltage sensor V2 and the current sensor A2 may be attached to the external load 200 as long as they can measure the output voltage and output current of the fuel cell module 100 (i.e., the input voltage and output current of the external load 200). In other words, the voltage sensor V2 and the current sensor A2 may be attached to the outside of the fuel cell module 100 as long as the control unit 6 of the fuel cell module 100 can recognize the signals.

[0064] In the embodiment shown in FIG. 5, the power generation command is generated using a PI calculation. However, instead of the PI calculation, the power generation command may be generated using a PID (Proportional-Integral-Derivative) calculation. [Explanation of symbols]

[0065] 1. Fuel cell stack 2. Fuel gas supply device 3. Oxidizing gas supply device 4, 5 DC / DC Converters 6. Control Unit 11 Multiplier 12 PI calculator 13 Adder 21, 23 Multiplier 22, 25 Subtractor 24, 26 comparator (min) 100 Fuel Cell Module 200 External Load

Claims

1. A fuel cell module electrically connected to an external load so as to be able to supply power thereto, A fuel cell; a control unit that controls a power generation operation of the fuel cell based on a required power value notified by the external load, The control unit is Controlling the power generation operation in a normal power generation mode or a limited power generation mode that is executed due to detection of an abnormal state of the fuel cell module; calculating a module power setting value representing a setting value of the power to be supplied from the fuel cell module to the external load based on a first power value representing a measured value of the power generated by the fuel cell, a second power value representing a measured value of the power to be supplied from the fuel cell module to the external load, and a power generation limit value representing an upper limit of the power generation amount of the fuel cell determined according to a state of the fuel cell module; performing a PI calculation on an error between the smaller value of the required power value or the module power setting value and the second power value; The power generation operation of the fuel cell is controlled using the results of the PI calculation. A fuel cell module comprising:

2. The control unit calculates the module power setting value by subtracting a difference between the first power value and the second power value from the power generation amount limit value.

2. The fuel cell module according to claim 1 .

3. The first power value is calculated by multiplying a measurement value by a first current sensor that measures the output current of the fuel cell and a measurement value by a first voltage sensor that measures the output voltage of the fuel cell.

2. The fuel cell module according to claim 1 .

4. The second power value is calculated by multiplying a measurement value by a second current sensor that measures a current supplied from the fuel cell module to the external load by a measurement value by a second voltage sensor that measures an output voltage from the fuel cell module to the external load.

2. The fuel cell module according to claim 1 .

5. a DC / DC converter for converting an output voltage of the fuel cell into a predetermined DC voltage; The second current sensor measures the output current of the DC / DC converter, and the second voltage sensor measures the output voltage of the DC / DC converter.

5. The fuel cell module according to claim 4.

6. The power generation limit value is preset with respect to the minimum value of the temperature of the cooling water of the fuel cell or the output voltage of each fuel cell constituting the fuel cell.

2. The fuel cell module according to claim 1 .

Images