Electric power steering system

Abstract

An assist command value calculation circuit includes a torque shift control circuit, a phase lag compensation control circuit, a basic assist control circuit, and a phase lead compensation control circuit. A determination circuit determines whether a motor has been continuously under high load or not based on a current command value and a current limit value. The determination circuit determines whether the motor has been continuously under high load or not by comparing the current command value with the current limit value and comparing a basic assist controlled variable with the current limit value, and outputs a phase compensation restriction flag. The phase lag compensation control circuit and the phase lead compensation control circuit restrict phase restriction when the phase compensation restriction flag is ON, and continues phase compensation when the phase compensation restriction flag is OFF.

Dependencies are inferred from the claim text.