Direct decoupling current demodulation algorithm-based improved high-frequency rotating voltage injection method

In the permanent magnet synchronous motor (PMSM) high-frequency (HF) rotating voltage injection method, a current demodulation process is usually used to improve the rotor position estimation accuracy. Current demodulation is usually realized by the synchronous frame high-pass filter (SFHF) algorithm. However, the current demodulation process is complicated, and the position estimation error changes with the rotation speed. To this end, an improved HF rotating voltage injection method based on the direct decoupling (DD) current demodulation algorithm is proposed. This method takes into account the comprehensive matching optimization of both the position error cancelation compensation and the current demodulation simplification. In addition, it completely solves the problems of insufficient position estimation accuracy and complex algorithm implementation. Finally, a three-phase PMSM is taken as the research object to verify the effectiveness of the proposed method.