Sensorless speed control and initial rotor position estimation of an IPMSM

This paper presents the initial rotor position estimation and the sensorless control for IPM synchronous motor. In sensorless drive, it is important to know the exact information of the initial rotor position. The initial position estimation method is based on the peak current changed according to the rotor position owing to the saliency. A speed sensorless control based on an instantaneous reactive power is proposed for the IPMSM drives. In the proposed algorithm, the current observer estimates the line currents and the estimated speed can be yielded from the voltage equations because the information of speed is included in back EMF. To minimize the estimation error, the speed estimator is compensated by using the instantaneous reactive power.