Direct Instantaneous Torque Control for Six-Phase SRM with Non-singular Fast Terminal Sliding Mode Controller

A hybrid strategy based on non-singular fast terminal sliding mode control (NFTSMC) and direct instantaneous torque control (DITC) is proposed for six-phase switched reluctance motors (SRM) to reduce the torque ripple and improve dynamic response. First, to improve the torque control capability of DITC under high-speed conditions, an improved dynamic conduction strategy in the commutation region is designed to exploit the phase torque generation potential and minimize the switching loss. In addition, there exists a contradiction between fast response and chattering in conventional NFTSMC. To achieve rapid convergence while minimizing chattering, an improved reaching law is proposed. Finally, the dynamic performance is affected due to the inherent nonlinear disturbances of the SRM. A disturbance sliding mode observer (DSMO) is introduced to estimate the perturbation online and improve the robustness of the system. Experiments with a 6-phase SRM prototype substantiate the effectiveness of the proposed method.