JP2009232548A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system which performs power supply from a fuel cell to a drive motor with high efficiency in a vehicle mounting a fuel cell while guaranteeing performance in an assumed travel region. <P>SOLUTION: A fuel cell system 1 includes a fuel cell 5, a drive motor 3 for driving a vehicle 2, a first power supply section 9A for supplying the drive motor 3 with the output power from the fuel cell 5 while boosting the voltage, a second power supply section 9B for supplying the drive motor 3 with power from the fuel cell 5 in such a way that power loss during power supply in the normal traveling state is generated in the second power section 9B less than that of the first power supply section 9A, and a power supply control means 11 for controlling the first power supply section 9A and the second power supply section 9B according to the traveling state of the vehicle 2 so that power supply from the fuel cell 5 to the drive motor 3 is performed from the first power supply section 9A or the second power supply section 9B with less power loss. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell system.

  In recent years, a fuel cell has attracted attention as a power source excellent in operating efficiency and environmental performance. A fuel cell generates power by an electrochemical reaction between a fuel gas and an oxidizing gas. The electrochemical reaction between the fuel gas and the oxidizing gas is performed in a fuel battery cell that supports a catalyst.

In a fuel cell vehicle, power conversion processing or the like is performed in order to adjust the power between the output power of the fuel cell and the required power of the drive motor. For example, Patent Document 1 discloses a technique for suppressing an increase in power loss accompanying power conversion and miniaturizing a power storage device. Patent Document 2 discloses a technique for reducing the rated output power of a DC / DC converter while maintaining the rated output power for a load. Patent Document 3 discloses a technique for switching a DC / DC converter between one for high power and one for low power.
JP 2005-348530 A Japanese Patent No. 3888074 JP 2007-124850 A

  When a fuel cell is mounted on a vehicle and used as a drive power source for the vehicle, the power required by the drive motor changes according to the running state of the vehicle, so the power output from the fuel cell must be converted by a converter. . Here, since the devices that drive the vehicle are required to guarantee the operation even in all assumed driving conditions, the power converter mounted on the fuel cell vehicle does not leak into this, and the high load from the low load region is also avoided. It is required to guarantee its operation up to the load range.

  By the way, when traveling in an urban area or the like, it is rare to travel in a high load region, and in most cases it travels in a low load region or a region close thereto. Therefore, it is desirable that the power converter mounted on the fuel cell vehicle also has a peak power conversion efficiency in such a low load or a region close to this. However, while compensating for the operation in the high load drive region, It is difficult to develop a power converter that has a peak power conversion efficiency in a region close to a low load. This is because the power conversion efficiency is determined by the characteristics of the switching element to be used, and the region to be peaked changes according to the size of the vehicle and the environment in which the vehicle is used.

  The present invention has been made in view of such a problem, and in a vehicle equipped with a fuel cell, the power supply from the fuel cell to the drive motor is highly efficient while guaranteeing the operation in the assumed traveling region. It is an object to provide a fuel cell system to be performed.

  In order to solve the above-described problems, the present invention provides two power feeding units having different power losses during power feeding, and power is fed by the power feeding unit with the smaller power loss according to the traveling state of the vehicle.

Specifically, the fuel cell system includes a fuel cell that generates electric power by an electrochemical reaction between fuel gas and oxidizing gas, and a drive motor that drives the vehicle with electric power, the vehicle being in a normal running state. In a high-load running state where the load applied to the drive motor is large, a drive motor whose drive voltage exceeds the output voltage of the fuel cell, and a first power feeding unit that boosts the output power of the fuel cell and supplies power to the drive motor A second power feeding unit that feeds power from the fuel cell to the drive motor, wherein the second power feeding unit has less power loss than the first power feeding unit due to power feeding in the normal running state; and A power supply control means for controlling the first power supply unit and the second power supply unit according to a traveling state, wherein the power supply unit having the least power loss among the first power supply unit and the second power supply unit Comprises a power supply control means for controlling said first power supply unit and said second power supply unit so that power from the fuel cell to the drive motor is powered, the.

  The fuel cell system is assumed to be mounted on a motor-driven vehicle using the fuel cell as a main power source. In such a fuel cell system mounted on a vehicle, it is required to improve the fuel consumption efficiency while guaranteeing the driving of the motor in all assumed travel regions. Here, the high-load running state is a running state of the vehicle when the drive motor is operating at or near the upper limit of the required power set at the time of vehicle design. For example, the accelerator pedal of the vehicle This is the state when is most depressed. The normal running state is a running state when the vehicle is running with average power, for example, the vehicle running when the vehicle is running in an average running pattern of the vehicle that is statistically determined. It is a running state.

  The fuel cell system includes a first power feeding unit that boosts the power of the fuel cell in order to supply power to the drive motor when the vehicle is in a high-load running state, and the required power of the drive motor has increased. In this case, the output voltage of the fuel cell, which decreases in some cases, is boosted to ensure the supply of power from the fuel cell to the drive motor. Here, the peak of the curve of the conversion efficiency of the first power feeding unit that performs power conversion required in such a high-load traveling state does not necessarily match the normal traveling state. In the following, supplementary explanation will be given by way of example. Most power converters have a peak conversion efficiency curve in a region close to the rated power, whereas the motor power consumption of a vehicle in a normal running state is half of the rated power. It is less than. Therefore, the fuel cell system eliminates the difference between the peak of the conversion efficiency of the power converter and the peak of the conversion efficiency that is actually required in order to eliminate the difference between the peak of the conversion efficiency and the peak of the conversion efficiency that is actually required. Two feeding parts are provided. By appropriately controlling these two power supply units by the power supply control means, it is possible to supply power from the fuel cell to the drive motor with high efficiency while guaranteeing the operation in the assumed travel region.

  Further, the drive motor has a drive voltage that exceeds the output voltage of the fuel cell even in the normal running state, and the second power feeding unit boosts the output voltage of the fuel cell and then feeds the drive motor, The first power feeding unit may be configured such that power loss associated with power feeding in the high load traveling state is smaller than that of the second power feeding unit. According to this, even when boosting is performed in both the normal traveling state and the high load traveling state, it is possible to supply power from the fuel cell to the drive motor with high efficiency.

  The drive motor has a drive voltage equal to or lower than the output voltage of the fuel cell in the normal running state, and the second power feeding unit does not increase the output power of the fuel cell in the normal running state. Power may be supplied to the drive motor. According to this, since the process of boosting the output power of the fuel cell is not required in the normal traveling state, the power supply from the fuel cell to the drive motor is performed with high efficiency while guaranteeing the operation in the assumed traveling region. It is possible.

The first power supply unit and the second power supply unit may control the voltage of the fuel cell by adjusting a potential difference between the drive motor and the fuel cell. The fuel cell has a prescribed current-voltage characteristic because of its internal resistance. Therefore, since the current can be adjusted by controlling the voltage of the fuel cell, the output control of the fuel cell, the step-up ratio of the power converter, the adjustment of the processing power amount, etc. can be achieved. Therefore, it is possible to increase the efficiency of power supply to the drive motor. When controlling the voltage of the fuel cell, for example, a control target value at which the conversion efficiency of the power converter and the power generation efficiency of the fuel cell become high efficiency is determined from a predetermined map or the like, and the control target value is determined by the fuel cell voltage. Control to be.

  The first power supply unit may control the voltage of the fuel cell by adjusting a potential difference between the drive motor and the fuel cell. According to this, since it is possible to adjust the current by controlling the voltage of the fuel cell when the vehicle is in a high load running state, the output control of the fuel cell, the boost ratio of the power converter, the amount of processing power Adjustment and the like can be achieved, and the efficiency of power supply from the fuel cell to the drive motor in a high-load traveling state can be increased.

  And a power storage unit that is a constant voltage power source capable of storing electric power, and a voltage conversion unit connected between the drive motor and the power storage unit, and the drive motor and the power storage unit You may make it further provide the voltage control part which controls the voltage of the electric power input into this drive motor by adjusting the potential difference between. According to this, since the voltage input to the drive motor can be controlled, the drive force of the drive motor can be controlled.

  In a vehicle equipped with a fuel cell, it is possible to provide a fuel cell system that performs high-efficiency power from the fuel cell to the drive motor while ensuring operation in an assumed travel region.

  Hereinafter, a fuel cell system according to an embodiment of the present invention will be described.

<Configuration of Embodiment>
FIG. 1 is an overall configuration diagram of a fuel cell system 1 according to an embodiment of the present invention. This fuel cell system 1 is assumed to be mounted on a vehicle 2 that uses an electric motor as a drive source, and to supply electric power to a drive motor of the vehicle 2 (hereinafter simply referred to as “motor 3”). The vehicle 2 is self-propelled and movable when the driving wheel is driven by the motor 3. The motor 3 is a so-called three-phase AC motor, and operates by receiving AC power from the inverter 4. The inverter 4 converts DC power supplied from a fuel cell 5 as a main power source of the fuel cell system 1 and a battery 6 as a secondary battery into AC power and supplies the AC power to the motor 3.

  The fuel cell system 1 is mounted on a vehicle 2 that is a moving body and supplies power to the motor 3 of the vehicle 2. However, the fuel cell system 1 is used for a moving body such as a ship or a robot or a power consuming device that does not move. Is applicable.

Here, the fuel cell 5 generates power by an electrochemical reaction between hydrogen gas stored in the hydrogen tank 7 and oxygen in the air that is pumped by the compressor 8. An FC converter 9 that is a DC-DC converter is electrically connected between the fuel cell 5 and the inverter 4. Thereby, the voltage of the electric power output from the fuel cell 5 is stepped up / down to an arbitrary voltage by the FC converter 9 and applied to the inverter 4. The detailed configuration of the FC converter 9 will be described later. The battery 6 is a constant-voltage power storage device that can be charged and discharged, and is a step-up type so that the inverter 4 is in parallel with the FC converter 9 between the battery 6 and the inverter 4. A battery boost converter 10 is electrically connected. Thereby, the voltage of the power output from the battery 6 is boosted to an arbitrary voltage by the battery boost converter 10 and applied to the inverter 4. The battery boost converter 10 detects the voltage of power input to the motor 3 with a voltage sensor (not shown), and the voltage boost ratio so that the voltage of power input to the motor 3 becomes a motor required voltage (Vmot) described later. To control. Since the battery 6 is a constant voltage power source, the voltage input to the motor 9 can be set to a predetermined control target value (Vmot) by adjusting the boost ratio of the battery boost converter 10. As shown in FIG. 1, in the fuel cell system 1, a step-up / step-down converter capable of a step-up operation and a step-down operation can be employed instead of the step-up type battery step-up converter 10. In the following embodiments, the description will be given mainly assuming that the battery boost converter 10 is a boost converter. However, there is no intention to limit the use of the step-up / step-down converter, and appropriate adjustments are made in the adoption. .

  The vehicle 2 includes an electronic control unit (hereinafter referred to as “ECU11”). ECU11 is electrically connected with each control object mentioned above, and controls each apparatus which comprises a system. For example, the vehicle 2 is provided with an accelerator pedal that receives an acceleration request from the user, the opening degree thereof is detected by the accelerator pedal sensor 12, and the detection signal is electrically transmitted to the ECU 11. The ECU 11 is also electrically connected to an encoder that detects the number of rotations of the motor 3, whereby the number of rotations of the motor 3 is detected by the ECU 11. The ECU 11 can perform various controls based on these detected values.

  In the fuel cell system 1 configured as described above, the accelerator pedal opening degree that the user of the vehicle 2 has stepped on is detected by the accelerator pedal sensor 12, and the ECU 11 is based on the accelerator opening degree, the rotation speed of the motor 3, and the like. The power generation amount of the fuel cell 5 and the charge / discharge amount from the battery 6 are appropriately controlled. Here, in order to improve the fuel consumption of the vehicle 2 that is a moving body, the motor 3 is a PM motor of high voltage and low current specifications. Therefore, since the motor 3 can exhibit a high torque at a low current, it is possible to reduce heat generation in the windings and other wirings inside the motor, and to reduce the rated output of the inverter 4. It becomes possible. Specifically, in the motor 3, the counter electromotive voltage is set to be relatively high in order to enable a relatively large torque output at a low current, while the motor 3 has a high rotational speed against the high counter electromotive voltage. The supply voltage from the fuel cell system 1 is set high so that it can be driven. At this time, the FC converter 9 is provided between the fuel cell 5 and the inverter 4, and the battery boost converter 10 is also provided between the battery 6 and the inverter 4, thereby increasing the supply voltage to the inverter 4. .

  In this way, by configuring the fuel cell system 1 to include the FC converter 9, the motor 3 can be driven by the boost operation of the FC converter 9 even when the output voltage (terminal voltage) of the fuel cell 5 itself is low. Is possible. Accordingly, it is possible to reduce the size of the fuel cell 5 by reducing the number of stacked cells. As a result, the weight of the vehicle 2 can be reduced, and the fuel efficiency improvement can be further promoted.

Here, the features of the FC converter 9 will be described in detail. FIG. 2 is a circuit diagram showing in detail the electrical path of the fuel cell system 1. As shown in FIG. 2, the FC converter 9 includes two converters 9A and 9B. Converters 9A and 9B are connected between fuel cell 5 and inverter 4 so as to be electrically parallel to each other. Converters 9A and 9B have different power conversion capabilities. FIG. 3 is a graph showing the relationship between the power conversion efficiency and the output of each converter 9A, 9B. As shown in FIG. 3, the converters 9A and 9B have different conversion capacities, and the converter 9B (CONV2) is configured to be capable of converting more outputs of the fuel cell 5 than the converter 9A (CONV1). ing. The “maximum output point” in the graph of FIG. 3 is the maximum output of the load (the output required for the converter 9B when the motor 3 is driven at the maximum output, and corresponds to the high load running state referred to in the present invention. The converter 9B is set so that the vehicle 2 can convert the output voltage of the fuel cell 5 in any travel region. On the other hand, the converter 9A is set so that the conversion capability is smaller than that of the converter 9B, and cannot cope with the maximum output of the load, but the peak of conversion efficiency is in an output region lower than that of the converter 9B. Is set. That is, the converter 9A is configured with a small-capacity switching element or the like rather than the converter 9B, and is configured so that the loss generated in the switching operation at the time of low output is reduced. Here, when the conversion efficiency of converter 9A reaches a peak (corresponding to the normal running state referred to in the present invention. Converter 9A that performs a boost operation in the normal running state thus has a peak conversion efficiency in the normal running state. Output is an average value of the output required by the load, and in this embodiment, the average value of the output required by the vehicle 2 in a normal use state (specifically, 10 · 15). Average value of output required in the driving state of the mode). That is, converter 9A is provided for the purpose of compensating the power conversion capability at the maximum output, whereas converter 9B is provided for the purpose of improving fuel efficiency by maximizing the power conversion efficiency at the normal output. ing. Note that CH shown in FIG. 3 indicates a switching point of the converter. That is, if the output is less than CH, it is more efficient to convert power using converter 9A, and if the output is higher than CH, it is more efficient to convert power using converter 9B.

<Operation Flow of Embodiment>
Next, control of the fuel cell system 1 will be described. FIG. 4 is a control flow diagram of the fuel cell system 1. Hereinafter, the control flow of the fuel cell system 1 will be described with reference to the control flow diagram of FIG.

  (Step S101) When the fuel cell system 1 is activated, the ECU 11 controls the hydrogen tank 7 and the compressor 8 to supply hydrogen, which is a fuel gas, and oxygen, which is an oxidizing gas, to the fuel cell 5. The flow rates of the fuel gas and the oxidizing gas supplied to the fuel cell 5 depend on the required power generation amount calculated based on the required torque detected by the accelerator pedal sensor 12, the input / output current of the battery 6, the consumption current of the motor 3, and the like. Determined. That is, the amount of hydrogen consumed and the amount of oxygen consumed with respect to the required power generation amount are determined from the operation model of the fuel cell 5 stored in advance in the ECU 11, and the hydrogen tank is supplied so that the determined amount of hydrogen and oxygen is supplied to the fuel cell 5. The opening degree of the outlet valve 7 and the rotation speed of the compressor 8 are controlled. Thereby, the electrochemical reaction of hydrogen and oxygen starts in the fuel cell 5, and power generation is started. Here, the ECU 11 calculates the maximum torque that the motor 3 can output at maximum, corresponding to the actual rotational speed of the motor 3 detected by the encoder. Specifically, the ECU 11 has a map in which the rotation speed of the motor 3 is associated with the maximum torque corresponding thereto, and the maximum torque of the motor 3 is obtained by accessing the map according to the detected rotation speed. Calculated. When the ECU 11 finishes the process of step S101, it executes the process of S102.

(Step S <b> 102) The ECU 11 calculates the required torque requested to be output from the motor 3 based on the accelerator pedal opening detected by the accelerator pedal sensor 21. If the full opening of the accelerator pedal is defined as requiring the maximum torque at the current rotational speed of the motor 3, the required torque is calculated according to the following formula, assuming that the coefficient when fully opened is 100% and the coefficient when fully closed is 0%. Is calculated. When the ECU 11 finishes the process of step S102, it executes the process of S103.
(Required torque) = (Maximum torque) x (Coefficient according to accelerator pedal opening)

(Step S103) The ECU 11 calculates a required output, which is an output required for the motor 3, based on the calculation results in S101 and S102, according to the following equation. When the ECU 11 finishes the process of step S103, it executes the process of S104.
(Request output) = (Request torque) x (Motor speed)

(Step S <b> 104) The ECU 11 requires a motor required voltage (a voltage to be applied to the inverter 4) such that necessary power is supplied to the motor 3 based on the required output calculated in S <b> 103 and the rotation speed of the motor 3. Vmot) is calculated. Specifically, the ECU 11 has a motor required voltage map in which a function F formed by the rotation speed (rpm) of the motor 3 and the required output (P) and a motor required voltage are associated with each other. The required voltage of the motor is calculated by accessing this map according to the motor speed and the required output. The required motor voltage map can be determined in advance by experiments or the like. As an example, the required voltage value should be increased because the counter electromotive voltage increases as the rotational speed of the motor 3 increases. Since the required voltage value should be increased in order to achieve its output with less current as the value of becomes higher, these points are reflected in the correlation between the function F and the required motor voltage. When the ECU 11 ends the process of S104, the ECU 11 executes the process of S105.

  (Step S <b> 105) The ECU 11 detects the output voltage (Vfc) of the fuel cell 5 in which power generation is performed according to the accelerator pedal opening detected by the accelerator pedal sensor 21. This detection is performed via a voltage sensor (not shown).

  (Step S106) When the process of Step S105 is completed, the ECU 11 calculates the step-up ratio Rt (= Vmot / Vfc) by dividing the required motor voltage calculated in S104 by the output voltage of the fuel cell 5 detected in S105. .

  (Step S107) The ECU 11 controls the FC converter 9. That is, the ECU 11 controls the FC converter 9 based on the boost ratio Rt calculated in the process of S106.

  Here, the processing in step S107 will be described in detail. FIG. 5 is a processing flowchart showing the detailed processing contents of step S107. As shown in FIG. 5, the ECU 11 that has executed the process of step S106 determines which of the converters 9A and 9B to use based on the calculated boost ratio Rt (in other words, based on the output of the fuel cell 5). (Step S201). FIG. 6 is a correlation diagram showing the relationship between the required motor voltage (Vmot) and the output voltage (Vfc) of the fuel cell 5 according to the output. As indicated by Vmot in FIG. 6, the counter electromotive voltage of the motor 3 increases as the speed of the vehicle 2 increases, so that the motor required voltage also increases as the vehicle speed increases. Here, in the correlation between the output voltage Vfc of the fuel cell 5 and the required motor voltage Vmot, it is conceivable that the system is configured such that Vfc is higher than Vmot in all speed regions of the vehicle 2. In this embodiment, the FC converter 9 is provided to adjust the output voltage of the fuel cell 5 and the required voltage of the motor 3 in order to increase the size of the fuel cell 5. Here, when the output is higher than CH, the ECU 11 converts power using the converter 9B (S202). Moreover, ECU11 converts electric power using converter 9A, when an output is lower than CH (S203). In addition, when converting electric power using the converter on the side different from the converter used in the process of S201, the converter is switched as follows. That is, when the converter is switched (from 9A to 9B or from 9B to 9A), first, the control target value of the switching destination converter is set to the target step-up ratio, and the boost ratio of the FC converter 9 as a whole is set by this converter. To be kept. Next, the control target value (step-up ratio) of the switching source converter is gradually lowered. Since the boosting ratio between the input and output of the switching source converter is maintained by the switching destination converter, the switching source converter whose control target value has been lowered lowers the switching frequency to lower the boosting ratio. As a result, the current flowing through the switching source converter becomes almost zero, and the transfer of the current to the switching destination converter is completed. When the process of step S107 configured by steps S201 to 203 is completed, the ECU 11 starts the process of step S101 again. In addition, a series of processes comprised by said step S201-203 are corresponded to control of the electric power feeding part according to the driving state of the vehicle said by this invention. Thus, when controlling the converter, the ECU 11 refers to parameters such as the required electric energy of the motor 3, the output electric energy of the fuel cell, and the opening degree of the accelerator pedal, and changes according to the traveling state of the vehicle 2. Control according to the amount of power processing required for the converter 9 is executed.

  In the explanation of the processing from S101 to S107, for the sake of simplicity of explanation, the explanation has been given focusing only on the correlation between the fuel cell 5 and the motor 3. However, the fuel cell system 1 Power supply from the battery 6 is also possible. When power is supplied from the battery 6, the output voltage from the battery 6 is boosted by the battery boost converter 10 and then applied to the inverter 4. Here, since the battery boost converter 10 is a so-called boost converter, in order to supply power from the battery 6 to the inverter 4, the outlet voltage of the battery boost converter 10 (the voltage on the inverter 4 side, (Equivalent to the outlet voltage) must be the same or higher than its inlet voltage (battery 6 side voltage).

<Effect of embodiment>
As described above, according to the present embodiment, since the converter is switched according to the required amount of power, the power conversion is high in the normal traveling state in an urban area or the like while guaranteeing the operation in all the traveling states from the high load to the low load. Since the process is performed with efficiency, the fuel consumption efficiency of the entire system can be improved. In the above embodiment, the boosting process is performed by the FC boost converter in both the normal traveling state and the high load traveling state. However, the present invention is not limited to such an embodiment. That is, as shown in FIG. 7, if the system configuration is such that the output voltage (Vfc) of the fuel cell 5 exceeds the motor required voltage (Vmot) at the normal output point, the converter 9B can be replaced with a simple cable and switch. It is also possible to change to a configuration having a bypass route. In this case, since the power boosting process is not performed in the normal driving state, it is possible to greatly improve the fuel consumption.

The block diagram of a fuel cell system. The circuit diagram of a fuel cell system. The graph which shows the relationship between the conversion efficiency of the electric power of a converter, and an output. The control flow figure of a fuel cell system. The processing flowchart which shows the detailed processing content of step S107. The correlation diagram which showed the relationship between a motor required voltage and the output voltage of a fuel cell. The correlation figure which showed the relationship between a motor required voltage and the output voltage of a fuel cell (modification).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell system 2 ... Vehicle 3 ... Motor 4 ... Inverter 5 ... Fuel cell 6 ... Battery 7 ... Hydrogen tank 8 ... Compressor 9 (A, B) ... FC boost converter 10 ... Battery boost converter 11 ... ECU
12 ... Accelerator pedal sensor

Claims (6)

A fuel cell that generates electricity by an electrochemical reaction between a fuel gas and an oxidizing gas;
A drive motor for driving the vehicle with electric power, wherein the drive voltage exceeds the output voltage of the fuel cell in a high-load running state in which the load applied to the drive motor is larger than that in the normal running state; ,
Boosting the output power of the fuel cell and feeding a power to the drive motor;
A second power feeding unit that feeds power from the fuel cell to the drive motor, wherein the second power feeding unit has less power loss than the first power feeding unit due to power feeding in the normal running state;
A power feeding control means for controlling the first power feeding unit and the second power feeding unit according to a traveling state of the vehicle, wherein the power feeding unit has a smaller power loss between the first power feeding unit and the second power feeding unit. Power supply control means for controlling the first power supply unit and the second power supply unit so that electric power is supplied from the fuel cell to the drive motor.
Fuel cell system. The drive motor has a drive voltage that exceeds the output voltage of the fuel cell even in the normal running state,
The second power supply unit boosts the output voltage of the fuel cell and then supplies power to the drive motor,
The first power feeding unit has less power loss due to power feeding in the high load traveling state than the second power feeding unit,
The fuel cell system according to claim 1. The drive motor has a drive voltage equal to or lower than the output voltage of the fuel cell in the normal running state,
The second power feeding unit feeds power to the drive motor without increasing the output power of the fuel cell in the normal running state.
The fuel cell system according to claim 1. The first power feeding unit and the second power feeding unit control the voltage of the fuel cell by adjusting a potential difference between the drive motor and the fuel cell.
The fuel cell system according to claim 2. The first power supply unit controls a voltage of the fuel cell by adjusting a potential difference between the drive motor and the fuel cell;
The fuel cell system according to claim 3. A power storage unit that is a constant voltage power source capable of storing electric power, and a voltage conversion unit connected between the drive motor and the power storage unit, between the drive motor and the power storage unit A voltage control unit for controlling a voltage of electric power input to the drive motor by adjusting a potential difference;
The fuel cell system according to any one of claims 1 to 5.

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