Secondary Saliency Tracking-Based Sensorless Control for Concentrated Winding SPMSM

Sensorless ac drives have been widely adopted in many industry applications. However, the characteristic of strong multiple saliencies is still a main drawback impeding applying sensorless control over several types of machine, e.g., surface-mounted permanent magnet synchronous machine with concentrated windings (cwSPMSM). This work proposes a novel secondary saliency tracking (SST) algorithm to implement the sensorless control exclusively for such machines at low speed range. The saliency signals of a typical cwSPMSM under consideration are experimentally investigated. The stator background and physical mechanism of its strong multiple saliencies are explained in detail. Instead of processing the primary saliency signal, secondary saliency signal that has a better signal to noise ratio and more precise resolution is processed by a specially designed bandpass filter, and an adaptive notch filter for speed and rotor position estimation. Finally, the effectiveness and accuracy of the newly proposed SST method are verified by experimental results.