Analysis and Tests of the Sensorless Rotor Position Detection of Ringed-Pole Permanent-Magnet Motor

To the aim of creating a high-frequency (HF) anisotropy in a surface-mounted PM machine conductive rings are placed around each pole such rings modify the d-axis HF impedance of the machine. A novel strategy is adopted to evaluate the HF signal injection response of such a ringed-pole electrical machine. The self-sensing capability of the machine is evaluated by means of a small-signal model of the machine in the d-q reference frame and finite-element simulations. The impact of the rings on the HF signals achieved in the analysis is validated by the comparison with experimental results.