Hybrid position-sensorless control of PMSM for EV based on EtherLab technique

A kind of hybrid control algorithm of PMSM without position sensor is presented to realize the estimation of rotor position and speed in full speed range. The back-EMF method was used at higher speed, while in lower even zero speed range, high frequency injection method was used to make up for the inadequacy of back-EMF method. In order to get smooth transition of these two methods, a weighted value is calculated by linear proportional distribution in the hybrid mode. The hybrid algorithm was tested in real-time with EtherLab technique, and the experimental results show that the hybrid method can avoid the larger fluctuation generated in the switching process effectively.