A High-Frequency Signal Injection-Based Control Method for Low-Speed Sensorless Control of Permanent Magnet Synchronous Motor

To achieve accurate tracking of rotor position in the low-speed range without relying on position sensors, a novel control method based on high-frequency signal injection is proposed for permanent magnet synchronous motors (PMSMs). This method extracts rotor error information from the high-frequency response current and estimates the rotor position and speed using an expanded state observer that takes into account the dynamic processes. To facilitate computer calculation, discrete linear expanded state observer (DLESO) is designed. The proposed method is easy to implement and does not require mechanical parameters. Research results demonstrate that the proposed DLESO method operates stably and exhibits superior dynamic performance compared to traditional Phase-Locked Loop (PLL) methods.