Comparison of saliency-based sensorless control techniques for AC machines

This paper analyzes saliency-based sensorless control methods for AC machines. The paper focuses on three different methods, which utilize the following signals: negative-sequence carrier-signal current, zero-sequence carrier-signal voltage, and pulse width-modulation-switching zero-sequence voltage. Applicability of these methods for both rotor position estimation (tracking of rotor-position-dependent saliencies) and flux position estimation (tracking of flux-dependent saliencies) is studied for each method, as well as aspects of their implementation.