A Mixed Model based Sensorless Control Method for Permanent Magnet Synchronous Machine

In general, sensorless control methods for Permanent Magnet Synchronous Machine (PMSM) are classified into saliency tracking based method and fundamental model based method. In the fundamental model based method, the rotor position and speed can be estimated based on the mathematical model of PMSM. The typical fundamental models for sensorless control are classified into current model and voltage model. In this paper, a mixed model is proposed as a fundamental model for sensorless control. The mixed model has characteristics of both models. The current model is dominant in low speed range, and the voltage model is dominant in high speed range. Thus, the mixed model based sensorless control method is robust in wide speed range. For the sensorless control, the mixed-model based back electromotive force (EMF) state observer and speed estimator are proposed in this paper. The validity of the proposed sensorless control method is verified by the experimental results with 3.7 kW PMSM drive system.