Motor driven power steering device

Abstract

An electric power steering apparatus includes a motor 1 which produces an auxiliary steering force in accordance with, for example, a steering torque detected by a torque sensor 7; a motor drive circuit 2 which controllably drives the motor 1; a power supply voltage detecting circuit 17 which detects the power supply voltage VB of the motor drive circuit 2; and a microcomputer 9. The microcomputer 9 detects terminal voltages VM+ and VM− of the motor 1 when the power supply voltage detecting circuit 17 determines that the power supply voltage AB is higher than a predetermined value. Then, the microcomputer 9 makes a decision to determine whether the detected terminal voltages VM+ and VM− are not predetermined values VTHH and VTHL, respectively. If it is determined that the terminal voltages VM+ and VM− are not the predetermined values VTHH and VTHL, respectively, then the microcomputer 9 determines that a fault has occurred on the lines connected to the motor 1.

Dependencies are inferred from the claim text.