Analysis and Quantification Method of Effective Rotor Anisotropic Components for SPMSM Under Pulsating High-Frequency Signal Injection

By exploiting inductance or resistance saliency, pulsating high-frequency (HF) signal injection is a good candidate for sensorless operations in surface-mounted permanent magnet synchronous motors (SPMSMs). However, accurate methods for quantifying inductance or resistance saliency remain incomplete, especially for motors with ultralow or even no inductance saliency. This article introduces a unique perspective to analyze and quantify the effective rotor anisotropic components. First, parallel equivalent circuits are established to decouple the HF current responses, thereby facilitating the separation of effective rotor anisotropic components under different saliency tracking methods. Second, pulsating HF excitations are injected into the finite-element analysis (FEA) models, and effective anisotropic components can be extracted at various position tracking errors. Third, to verify the proposed quantification method, rotating HF signals are employed to detect the rotor anisotropic characteristics, with HF equivalent parameters subsequently inverse-calculated via Fourier analysis. The FEA results demonstrate the accurate quantification of effective anisotropic components under different saliency-based tracking methods. Finally, experimental results prove the feasibility of the proposed method. In summary, this article provides an analysis guideline and quantification method for evaluating the rotor anisotropic characteristics.