Asymmetric Phase Winding Based Pulsating HF Signal Injection Technique for Surface PMSMs

Magnetic saliency based techniques have been widely used in permanent magnet synchronous motor (PMSM) drives to detect rotor position and speed, especially during the starting and low speed operations. Among these techniques, pulsating high frequency signal injection (PHFSI) stands out as a commonly used technique in various industrial applications. However, a significant limitation arises when applying the PHFSI technique in surface PMSMs (SPMSMs) due to the absence of magnetic saliency. To overcome this drawback, this article proposes a novel asymmetric phase windings (APWs) based PHFSI technique for rotor position detection in SPMSMs. By changing the number of turns in one phase, this technique introduces a disparity between d- and q- axes inductances, which will introduce magnetic saliency into SPMSMs, to overcome the drawbacks of existing techniques. The change in number of turns can be easily implemented during the design stage without compromising the overall performance of the motor. The proposed technique is experimentally validated through a prototype of a 760 W, 36-pole SPMSM. The results are presented showing the viability of proposed technique in rotor position detection for SPMSMs.