Sensorless Low/Zero Speed Estimation for Permanent Magnet Synchronous Machine Using a Search-Based Real-Time Commissioning Method

This article presents the sensorless low/zero speed estimation and control for permanent magnet synchronous machines (PMSMs) using the innovative search-based real-time commissioning method. An overview of continuous pulsating high frequency injection used in this article is given for different injection angles in the stationary frame of reference. The variations of the saliency at different injection angles and loading operating points of the machine are presented and analyzed. The commissioning, search, and offset of the proposed observer are also discussed. Experimental results showing the performance of the sensorless method are presented in both open-loop and sensorless closed-loop current control. In sensorless mode the PMSM drive is controlled through a rotor flux oriented algorithm which uses the estimated electrical rotor position instead of the encoder measurement. Results for both the estimated mechanical and electrical rotor positions are presented under varying load conditions and speed reversal through the zero-speed region.