Patent ID: 7880411
Filing Date: 2011-02-01
Classification: B62D

Abstract:
1. A motor controller of an electric power steering device, the motor controller comprising: a main power supply that supplies electric power to a motor of the electric power steering device; an auxiliary power supply connectable in series with the main power supply to supplement the voltage of the electric power supplied to the motor by the main power supply; a diode that is provided in an electric path through which electric power is supplied from the main power supply to the motor, the diode preventing a sneak current from the auxiliary power supply to the main power supply; a semiconductor switching element that is connected in parallel with the diode; and a control/driving circuit that turns on the semiconductor switching element when electric power is supplied from the main power supply to the motor, and turns off the semiconductor switching element when electric power supplied to the motor is supplemented with the auxiliary power supply.