Sensorless control of permanent magnet synchronous motor based on random square wave injection

Abstract To mitigate high-frequency noise occurring during the zero-low-speed operation of the Interior Permanent Magnet Synchronous Motor (IPMSM) under compound control, a high-frequency signal injection technique was employed. This method involved injecting random square-wave voltage signals to address the noise issue, thereby reducing high-frequency noise during low-speed motor operation. In the high-speed range, a second-order Super-Twisting Sliding-Mode Observer was implemented, and the weighted switching method was adopted for the switching process. Consequently, sensorless control for the Permanent Magnet Synchronous Motor within the compound control framework was achieved. Through simulation, the feasibility of this approach was confirmed, demonstrating its effectiveness in suppressing high-frequency noise and exhibiting robust performance.