Patent ID: 8669731

Claim:
A motor drive apparatus for driving a motor, which includes a plurality of coil sets, the motor drive apparatus comprising: a plurality of inverters for converting DC power of a DC power source to AC power, the inverters being paired with the coil sets of the motor; a failure detection circuit for detecting failure in the inverters or the coil sets by detecting currents flowing in the inverters or the coil sets; a power interruption section capable of interrupting power supply from the DC power source to the inverters; a control circuit for setting a current command value of a current outputted from each inverter to a paired coil set and setting a current supply limitation value, which is an upper limitation value of the current command value; and a torque sensor for detecting steering torque, by which a driver operates a steering wheel; wherein the control circuit performs a vibration application processing only when a steering torque detection value outputted by the torque sensor exceeds a predetermined torque threshold value; when the failure detection circuit detects the failure in any one of the inverters or the coil sets, the power supply interruption section interrupts power supply to the inverter that corresponds to the inverter or the coil set, which is detected as having failure, and the control circuit performs the vibration application processing, which adds a vibration component having predetermined amplitude and frequency to the current command value for the inverter operating normally.