Sensorless control with high-frequency signal injection for FTPMSM with low rotor magnetic saliency

The high-frequency signal injection (HFSJ) sensorless control method is commonly employed for estimating the rotor position of permanent magnet synchronous motor (PMSM) at low speeds. The HFSJ method relies on rotor magnetic saliency and is more suitable for interior PMSM (IPMSM) with high rotor magnetic saliency. Due to the low rotor magnetic saliency of surface PMSM (SPMSM), the signal-to-noise ratio (SNR) is extremely low. To increase the SNR of HFSJ for fault-tolerant PMSM (FTPMSM) with low rotor magnetic saliency, this paper adopts an approach to enhance the rotor magnetic saliency by injecting d-axis current and reduce current sampling noise through oversampling. The method achieves the sensorless control of FTPMSM with low rotor magnetic saliency.