Sensorless Speed Control of a PMSM Using Super-Twisting Sliding Mode Control for Three-Wheel Electric Vehicle Propulsion

This study proposes a sensorless speed control strategy for a permanent magnet synchronous motor (PMSM) applied to a three-wheel electric vehicle propulsion system. A super-twisting sliding mode controller (STSMC) is employed in the speed loop to ensure robust, chattering-free performance under varying load conditions. The d–q axis current loops are regulated using genetic-algorithm-tuned PI controllers. The PMSM, vehicle dynamics, and an SVPWM-based inverter are accurately modeled and implemented in MATLAB/Simulink, while a nonlinear extended state observer (ESO) is utilized for sensorless speed estimation. The proposed controller is comparatively evaluated against PI control, conventional sliding mode control (SMC), SMC with exponential reaching law (SMC-ERL), and fractional-order SMC (FOSMC) in terms of dynamic response, disturbance rejection, and chattering suppression. At a reference speed of 100 rad/s, conventional SMC exhibits a settling time of 0.1163 s with an overshoot of 1.9928 rad/s, SMC-ERL achieves 0.0807 s and 0.1030 rad/s, and FOSMC shows a slower response with 0.6964 s settling time and 3.8707 rad/s overshoot. In contrast, the proposed STSMC achieves a settling time of 0.0619 s with a minimal overshoot of 0.1507 rad/s. These results confirm that the proposed STSMC-based sensorless control strategy offers superior dynamic performance, strong robustness to load disturbances, and effective chattering suppression, making it well suited for high-performance electric vehicle propulsion applications.