A simplified high frequency injection method for PMSM sensorless control

This paper presents a simplified HF injection method for permanent magnet synchronous motor (PMSM) sensorless control. The discussed HF injection scheme utilizes motor magnetic saliency property which contains the information of the rotor position due to magnet saturation. A high frequency voltage signal is injected into the d-axis winding in order to detect the magnetic saliency and estimate the rotor position. Then filters are used to analyze motor d-axis current and to extract rotor position information. In the proposed method, a band pass filter used in signal processing loop is omitted in order to avoid its phase shift and magnitude decrease. Thus fewer filters are used than those conventional HF injection schemes. The simulation and experimental results are presented based on the analysis of the proposed control strategy.