Patent ID: 7336047

Claim:
A motor vehicle steering system that drives a multi-phase motor by PWM (Pulse Width Modulation) control in response to an operation of an operation member, to apply a driving force from the multi-phase motor to a steerable vehicle wheel of a vehicle, comprising: a motor driving circuit connected between a power supply and a ground for driving the multi-phase motor; PWM signal generating unit for generating an each-phase PWM signal for controlling a current flowing through each of phases of the multi-phase motor and applying the generated PWM signal to the motor driving circuit; a single current sensor connected between the motor driving circuit and the power supply or the ground; and each-phase current value computing unit for finding an each-phase current value flowing through each of the phases of the multi-phase motor on the basis of an output of the current sensor, wherein the PWM signal generating unit shifts a fall or rise timing of carrier waves of the each-phase PWM signals from one another by a predetermined phase shift amount.