Toyota Jidosha Kabushiki Kaisha

Takeshi Maenaka

Kenji Umayahara

Atsushi Imai

Kota Manabe

Takahiko Hasegawa

Michio Yoshida

In the event that at least a portion of unit cells in a fuel cell stack have experienced a significant drop in voltage, the fuel cell system will execute a voltage recovery process allowing them to recover generating capability. In the voltage recovery process, a controller measures impedance of the fuel cell stack, and based on these measurements, determines the hydration condition of the electrolyte membrane inside the fuel cell. If, during the determination of hydration condition, the controller has determined that the hydration level is low, a current limiting process for temporarily limiting output of the fuel cell in order to recover generating capability will be triggered under more lenient conditions, as compared to if determined that the hydration level is high.

Fuel cell system and method of controlling the same

Whether a gas leakage occurs or not is accurately determined in a simple configuration. When receiving a request for activation of a fuel cell, a control unit opens a main shutoff valve to start hydrogen gas supply from a hydrogen tank to the fuel cell. The control unit thereafter performs gas leakage determination processing for a hydrogen piping system. If it is determined in the gas leakage determination processing that a gas leakage occurs, a gas leakage alert is output to stop the activation of the fuel cell. If it is determined in the gas leakage determination processing that a gas leakage does not occur, a compressor is activated to start oxidant gas supply to the fuel cell, and the fuel cell continues being operated.

Fuel cell system and fuel cell activation method

It is possible to prevent excessive power generation of a fuel cell when a failure has occurred. When a start signal is input, a fuel cell system sets an open end voltage of the fuel cell as an initial value of the output voltage of the fuel cell corresponding to the output current zero of the fuel cell. When the failure is detected, the fuel cell system reads out the open end voltage of the preset initial value as the output voltage corresponding to the output current zero and controls the voltage so that the output voltage of the fuel cell coincides with the open end voltage.

Fuel cell system for preventing excessive power generation

A fuel cell system including a fuel cell for generating electric power upon receiving supply of a reactant gas and a controller for performing control for high potential avoidance with the upper limit of the output voltage of the fuel cell as a high potential avoidance voltage lower than the open end voltage thereof. The controller computes a larger system requirement power out of a system requirement power calculated from a load requirement and a system requirement power calculated from the high potential avoidance voltage as a system requirement power for the fuel cell.

Fuel cell system

A fuel cell system is turned off without using up the electric power of a secondary battery in the case where a fuel cell fails to start up, while reducing the startup time of the fuel cell system. When an ignition key is turned on, a controller calculates allowable waiting time for a fuel cell to start up on the basis of the electric power stored in a secondary battery. If the fuel cell fails to start up during the period of time from the instant the ignition key was turned on until the allowable waiting time elapses, then the controller turns on an alarm lamp which indicates the startup failure of the fuel cell. Meanwhile, in the case where the fuel cell starts up, the controller begins a normal operation in which a traction motor and the like are actuated by using the electric power generated by the fuel cell and the electric power stored in the secondary battery.

In order to more rapidly warm up a battery device in a power supply equipped with a fuel cell and a battery device, a fuel-cell-mounted vehicle driving system for driving and controlling a rotating electric machine installed on a vehicle comprises an inverter connected to the rotating electric machine; a power supply circuit having a battery device, a voltage converter, and a fuel cell; and a power supply control device for controlling the power supply circuit. The power supply control device includes an FC output voltage setting module for setting the output voltage of the fuel cell, an OCV avoidance module for, when an FC output voltage is set, avoiding a voltage around an OCV, a battery warm-up control determination module for determining whether the battery device is under warm-up control or not, and an OCV avoidance release module for, when the battery device is under the warm-up control, releasing the OCV avoidance.

Power supply control circuit

Provided is a fuel cell system that can change the number of active phases in a DC/DC converter in order to prevent overcurrent from flowing through one point (e.g., a reactor of the DC/DC converter) in the system. In step S, whether or not the system is in a state that causes a rapid change in a voltage command value is checked. If the system is in a state that causes a rapid change in the voltage command value, the processing goes to step S, and if not, the processing goes to step S. In step S, a DC/DC converter is prohibited from being driven in a single phase and the processing ends. In step S, the DC/DC converter is permitted to be driven in a single phase and the processing ends.

When the operation point of a DC/DC converter, which steps up/down the output voltage of a fuel cell stack, is in a range of reduction in response capability and further there is issued a request of determining an AC impedance, a controller switches numbers of the drive phases of the DC/DC converter to determine an AC impedance of the fuel cell stack. If the operation point of the DC/DC converter is in the range of reduction in response capability and further the precision of determining the AC impedance is reduced, then the determination of AC impedance in the range of reduction in response capability is inhibited and the switching of the phases of the DC/DC converter is implemented, thereby causing the operation point of the DC/DC converter to be out of the range of reduction in response capability, with the result that the precision of determining the AC impedance can be raised.

Controller in a fuel cell system that controls the measurement of AC impedance and drives the DC/DC converter

A converter control device includes a converter device formed by three converter circuits connected together in parallel between a secondary battery as a first power source and a fuel cell as a second power source. A control unit includes: a PID control module for controlling the converter device by PID control and executing a desired voltage conversion; a drive phase quantity changing module for changing the number of drive phases of the converter device in accordance with the passing power of the converter device; and an integration term correction function switching module which switches the PID control integration term correction function when changing the number of drive phases.

Converter control device

A fuel cell system repeats first processing and second processing when the system is started. In the first processing, a control section controls an electric power distribution section so that electric power generated by a fuel cell stack is supplied to accessories and a secondary battery. In the second processing, the control section controls the electric power distribution section so that electric power generated by the fuel cell stack and electric power discharged from the secondary battery are supplied to the accessories. An electric power calculation means of the control section calculates electric power generation by the fuel cell stack and inputs an output command, representing electric power, into air compressor drive/control means. The electric power calculation means gradually changes the magnitude of electric power generation by the fuel cell stack, represented by the output command, at the time of transition between the first processing and the second processing.

A converter device which is configured by connecting three converter circuits in parallel is provided between a secondary battery serving as a first power supply and a fuel cell serving as a second power supply. A control unit includes a PID control module which controls the converter device by PID control, for executing desired voltage conversion; a module for modifying the number of drive phases which changes the number of drive phases of the converter device in response to an electric power passing through the converter device; and a gain switching module which switches feedback gains in the PID control when the number of drive phases is changed.

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Toyota, Japan

Takeshi Maenaka