Current control, efficient drive, and salient-pole phase estimation of synchronous reluctance motors with magnetic DQ-cross coupling

Firstly, this paper reconstructs a dynamic mathematical model of synchronous reluctance motors (SynRMs) with magnetic dq-cross coupling. This model consists of three self-consistent basic equations of circuit, torque evolution, and energy transmission equations. Secondly, based on the model, this paper reveals analytically that for the SynRMs, there always exists a reference frame called “magnetic salient-pole reference frame” where no magnetic axis-cross coupling occurs, and that the mathematical model in the frame turns out to be formally identical to the ideal one without dq-cross coupling in the dq-synchronous reference frame. Thirdly, this paper proposes new design and realization methods for a current controller, command converter for efficient drive, and salient-pole phase estimator for the SynRMs. The proposed methods perform all the necessary operations in the magnetic salient-pole reference frame instead of the dq synchronous reference frame, and they could achieve high performance and simplicity. The effectiveness and usefulness of the proposed methods are verified through extensive numerical experiments. © 2020 The Institute of Electrical Engineers of Japan.