Patent ID: 7983815

Claim:
An electric power steering control system, comprising: a torque detection means that detects a steering torque caused by a driver; an analog phase compensator that performs phase compensation on the output of the torque detection means by means of an analog circuit; a torque signal converter that A/D-converts the output of the analog phase compensator and fetches the output into a microcomputer; a torque controller that computes an auxiliary torque current, which assists the steering torque, using the output of the torque signal converter; a motor that generates a torque which assists the steering torque; a current detection means that detects a current value to be conducted to the motor; a rotating speed estimation means that estimates the rotating speed of the motor; and a damping controller that computes a damping current, which is added to the auxiliary torque current, using the estimate value of the motor rotating speed estimated by the rotating speed estimation means, wherein: the rotating speed estimation means includes a rotating speed observer that computes the estimate value of the rotating speed of the motor using the output of a torque opposite phase compensator which adjusts the phase and gain of the output of the torque signal converter, and the output of the current detection means.