Patent ID: 8569981

Claim:
A motor drive apparatus for driving a motor with electric power supplied by a DC power source, the motor drive apparatus comprising: a plurality of power supply systems, each of which includes an inverter for converting the electric power of the DC power source to AC power and a winding set of the motor for receiving the AC power from the inverter; a failure check unit configured to check whether the plurality of power supply systems includes a failure system, in which at least one of the inverter and the winding set is in failure; a power supply interruption unit configured to interrupt supply of power from the DC power source to the inverter of the failure system in response to a failure determination by the failure check unit; and a power control unit configured to supply the electric power to the inverter based on an input current command value at a normal operation time, wherein: the power control unit is further configured to control the inverter of a normal system, which is other than the failure system in the plurality of power supply systems, to supplement electric power, which the failure system has supplied, by the inverter of the normal system, when the power supply interruption unit interrupts the power supply to the inverter of the failure system, the power control unit is further configured to control the inverter of the normal system to gradually change the electric power supplied by the inverter of the normal system after supplementing the power supply is started, the power control unit is configured to change an input value inputted to the power control unit from an input value inputted at the normal operation time after the failure determination by the failure check unit so that the electric power having been supplied by the inverter of the failure system is supplemented b the inverter of the normal system, and the power control unit is configured to control the inverter of the normal system to gradually reduce the electric power, which the inverter of the normal system supplements, after an elapse of a predetermined period from the failure determination by the failure check unit.