Referencing position versus speed active flux based encoderless control of PM-RSM drives at ultra-low speeds without signal injection

In this paper, two encoderless control systems are comparatively presented working at ultra-low speeds. A novel referencing position encoderless control of PM-RSM drives is proposed, based on active flux observer, without using signal injection. To improve the drive dynamics, for the position and speed estimator a phase-locked loop mechanical tracking observer was developed. The referencing speed encoderless control, used for comparison, is also based on an active flux observer. Extensive comparative simulation results with good performances at ultra-low speed validate the proposed position encoderless control system. Therefore, the effectiveness of the proposed referencing position encoderless control is confirmed.