Fuel cell system and method of controlling fuel cell system
AssigneeToyota Jidosha Kabushiki Kaisha
InventorMichio Yoshida
Life of this patent
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Abstract
A fuel cell system is equipped with a fuel cell, a DC/DC converter that is electrically connected to the fuel cell, and a control unit that controls the supply of a fuel gas and an oxidizing gas to the fuel cell and issues a voltage command to and drives the DC/DC converter to perform high potential avoidance control of restraining an output voltage of the fuel cell from exceeding a high potential avoidance voltage lower than an open circuit voltage. The control unit continues to drive the DC/DC converter so as to perform the high potential avoidance control for a predetermined time after stopping supplying the fuel cell with hydrogen and air in response to the inputting of a system operation stop command.
Claims15
A fuel cell system comprising:
- a fuel cell that is supplied with a fuel gas and an oxidizing gas to generate an electric power;
- a DC/DC converter that is electrically connected to the fuel cell;
- and
- a control unit that controls supply of the fuel gas and the oxidizing gas to the fuel cell and issues a voltage command to and drives the DC/DC converter to execute a high potential avoidance control to restrain an output voltage of the fuel cell from exceeding a high potential avoidance voltage corresponding to the voltage command which is lower than an open circuit voltage, wherein
- the control unit continues to drive the DC/DC converter to execute the high potential avoidance control for a first prescribed time period after the supply of the fuel gas and the oxidizing gas to the fuel cell is stopped in accordance with a system operation stop command;
- the control unit performs control of lowering the voltage command for the DC/DC converter from a first value corresponding to the high potential avoidance voltage to a second value while performing the high potential avoidance control after the system operation stop command is input to the control unit;
- and
- the control unit increases the voltage command for the DC/DC converter to the first value after reducing the voltage command for the DC/DC converter from the first value to the second value.
(canceled)
(canceled)
A method of controlling a fuel cell system including a fuel cell that is supplied with a fuel gas and an oxidizing gas to generate an electric power;
- a DC/DC converter that is electrically connected to the fuel cell;
- and a control unit that controls supply of the fuel gas and the oxidizing gas to the fuel cell, wherein the control unit issues a voltage command to and drives the DC/DC converter to execute a high potential avoidance control to restrain an output voltage of the fuel cell from exceeding a high potential avoidance voltage corresponding to the voltage command which is lower than an open circuit voltage, comprising:
- stopping the supply of the fuel gas and the oxidizing gas to the fuel cell when a system operation stop command is input to the control unit;
- and
- continuing to drive the DC/DC converter to execute the high potential avoidance control for a first prescribed time period after the system operation stop command is input to the control unit,
- wherein the voltage command for the DC/DC converter is raised to the first value after performing the control of lowering the voltage command for the DC/DC converter from the first value to the second value.
(canceled)
Dependencies are inferred from the claim text.