Improved Sliding Mode Control of Wheel PMSM Under Bounded Disturbance Rate of Change Conditions

In this paper presents a Traditional hub-mounted Permanent Magnet Synchronous Motor (PMSM) drives in electric vehicles often rely on vector control with PI controllers, which are sensitive to parameter mismatches and load disturbances. These issues lead to degraded performance in terms of speed and torque response. To overcome these limitations, this work proposes an Improved Sliding Mode Control (ISMC) strategy designed to operate under bounded disturbance rate of change conditions. A novel sliding surface is introduced in the speed loop to ensure fast tracking and finite-time convergence, even under varying loads. Additionally, an improved exponential reaching law is adopted to suppress high-frequency chattering. In the current loop, a per-unit-based control method enhances parameter robustness and improves decoupling between the d- and q-axes. Simulation results confirm that ISMC significantly improves both transient and steady-state performance. Compared to PI control, it reduces speed regulation time and overshoot while achieving accurate current tracking without steady-state error, making it suitable for high-performance EV drive systems.by using matlab simulink software 2024a.

Keywords:

PMSM, novel sliding mode surface, improved exponential reaching law, per-unit model, parameter robustness