Patent ID: 8660751
Filing Date: 2014-02-25
Classification: B62D,H02J,H02P

Abstract:
1. An electric power steering apparatus for generating a steering assist force by a motor, comprising: a motor drive circuit for driving the motor; a battery capable of supplying electric power to the motor; an auxiliary power supply comprising an electric double-layer capacitor capable of supplying electric power to the motor; a charge-discharge circuit that configures a circuit for charging the auxiliary power supply and a circuit for discharging the auxiliary power supply, the charge-discharge circuit being capable of configuring a discharge-preference circuit that enables only the discharge of the auxiliary power supply while avoiding the charge thereof; a complete discharge circuit for completely discharging the auxiliary power supply; and a control circuit for controlling the charge-discharge circuit and also for controlling the motor drive circuit in response to a required steering assist force, that performs a power latch operation of carrying on the control till the end of a predetermined period of time following an operation of turning off an ignition key, and that causes the charge-discharge circuit to configure the discharge-preference circuit thereby enabling steering assist accompanied by the discharge of the auxiliary power supply, the control circuit forcedly and completely discharging the auxiliary power supply by means of the complete discharge circuit after the end of the power latch operation.