Motor drive device

A motor drive device to be mounted on a vehicle including an engine and a motor directly coupled to each other,

• the vehicle comprising a DC power supply device that is configured to supply electric power to the motor, and is charged by output of the motor,
• the motor drive device comprising:
• an inverter configured to convert DC electric power supplied from the DC power supply device into AC electric power, and to convert AC electric power obtained from, the motor to DC electric power;
• and
• a control device configured to control the inverter,
• the control device comprising:
• a DC power supply state determination unit configured to determine whether or not the DC power supply device is fully charged, to thereby determine whether or not current is inhibited from flowing from the motor to the DC power supply device;
• and
• a switching unit configured to, in response to the DC power supply state determination unit determining that the current is inhibited from flowing from the motor to the DC power supply device, select a control to be performed in the inverter from all-phase shut off and three-phase short circuit based on one of a motor rotation speed of the motor, and an induced voltage of the motor and a DC link voltage of the DC power supply device,
• wherein the switching unit is configured to:
• perform the all-phase shut off in the inverter when the induced voltage of the motor is equal to or less than the DC link voltage;
• and
• perform the three-phase short circuit in the inverter when the induced voltage of the motor is more than the DC link voltage.