Robust finite-time speed regulation of SRM drive using improved sliding mode control with super-twisting load observer based on DITC for EVs

A robust control strategy combining full-order terminal sliding mode control (FOTSMC) with a super-twisting load observer (STLO) is proposed for the speed loop to enhance disturbance rejection and dynamic performance in switched reluctance motor (SRM) drive systems. Unlike existing FOTSMC methods that suffer from steady-state speed errors under sudden load changes due to the lack of integral action , the proposed approach introduces a novel gain-with-integrator modification to the reference torque, which minimize the steady-state error while maintaining fast transient response. The STLO estimates total disturbances within the direct instantaneous torque control (DITC) scheme for feed-forward compensation. The proposed method enhances robustness, ensures finite-time convergence, reduces chattering, and suppresses torque ripple. Closed-loop stability is verified via Lyapunov analysis, and experimental results on a 12/8 SRM prototype validate its superior performance.