Position Sensorless Control System of IPM Motor Based on Voltage Injection Synchronized with PWM Carrier

Abstract

This paper presents a new position sensorless control system of an IPM motor. The proposed method is based on an injected voltage vector that is synchronized with a PWM carrier of an inverter. From the relation between the injected voltage vector and the saliency of the rotor, it is estimated the pole position. The first current difference vector is detected when the injected voltage vector in the calculated pole position direction is added to the motor control voltage vector. Next, the second current difference vector is detected when the injected voltage vector in the opposite direction of the calculated pole position is added to the same motor control voltage vector. Then, the pole position of the rotor with anti-saliency can be estimated from the first and second current difference vectors. This method needs neither motor parameters nor band-pass-filters. By the proposed control system, the IPM motor can be operated over a wide speed range including zero speed, and controlled with a quick response.