Fuel cell system installed in vehicle

A fuel cell system installed in a vehicle, the fuel cell system comprising:

• a fuel cell;
• a secondary battery;
• a load including a drive motor having a function of a motor generating a driving force of the vehicle and a function of a generator generating a regenerative electric power, and an air compressor configured to supply oxygen to the fuel cell by rotating in one direction;
• a fuel cell converter configured to boost electric power from the fuel cell and output electric power to the load;
• a secondary battery converter that is provided between the secondary battery and the load, that is configured to boost electric power from the secondary battery and output electric power to the load, and that is configured to step down electric power from the load for charging the secondary battery;
• a failure detection unit configured to detect an operation failure of the secondary battery converter;
• a first state determination unit configured to determine whether the vehicle is in a first state in which an actual traveling direction that is an actual direction in which the vehicle travels and a required traveling direction that is assumed based on a rotation direction of the drive motor do not match;
• a reverse rotation detection unit configured to detect a reverse rotation that is a rotation in a direction opposite to the one direction in the air compressor;
• and
• a control unit configured to control the fuel cell, the fuel cell converter, and the secondary battery converter, wherein the control unit is configured to
• stop supplying electric power to the load via the fuel cell converter and perform a limp-home traveling control for supplying electric power from the secondary battery to the drive motor with the secondary battery converter in a conductive state, when the operation failure of the secondary battery converter is detected,
• the control unit configured to, in the limp-home traveling control:
• prohibit regeneration of the drive motor when the vehicle is not in the first state;
• apply a reactive current to the air compressor to cause the air compressor to consume regenerative electric power of the drive motor when the vehicle is in the first state;
• and
• not apply the reactive current to the air compressor after the reverse rotation of the air compressor is detected when the reactive current is applied to the air compressor and the reverse rotation is detected.