Cascade Hybrid Decoupling Control Scheme for Synchronous Reluctance Motor Current Dynamic With Adaptive Backstepping Disturbance Compensation

The performance of synchronous reluctance motor (SynRMs) is strongly dependent on the current loop dynamic characteristics. However, existing drawbacks in simplifying the nonlinear behaviors restrict the complete decoupling of the dynamics, inducing current overshoot and oscillation. In this article, a cascade hybrid decoupling control scheme is proposed to mitigate the negative effects of magnetic circuit nonlinearity (MCN) on current dynamics. A nonlinear model is first established to describe the current dynamics with considerations of MCN. Then, the coupling mechanism between dq-axis current dynamics is classified and analyzed. The dynamic decoupling condition is derived involving both back electromagnetic force (EMF) and cross-induced electromotive force. Furthermore, an adaptive backstepping current controller is presented to cope with changes in operating point caused by self-saturation. Uncertainties caused by model errors and unmeasurable disturbances are adaptively compensated. Comprehensive experimental results demonstrate that the proposed scheme could reduce torque and current ripple while improving response performance.