Research on Initial Rotor Position Detection for Permanent Magnet Synchronous Motors

Permanent Magnet Synchronous Motors (PMSMs) are widely applied in the field of electrical drives due to their advantages such as high efficiency, simple structure, and high power density. The traditional method of using Hall sensors to detect the initial rotor position has issues like high cost, large size, and low reliability. Thus, sensorless position technology has become a current research focus. This paper studies the strategy of measuring the initial rotor position based on the high-frequency square-wave voltage injection method with a filter, solving the problem that four special angles cannot converge correctly. Then, according to the characteristics of the high-frequency square wave, a detection method without a filter is further proposed, which simplifies the signal extraction process and reduces system delay. Finally, the effectiveness of the proposed scheme is verified through simulation experiments.