HESO Based Motor-Level Traction Torque Balancing Strategy for Dual PMSMs in Distributed Rear-Wheel-Drive EV Under Single-Wheel Slip

In distributed rear-wheel-drive electric vehicles (DRWDEVs), traction torque balance between the two driving wheels is usually achieved through chassis-level coordinated control of the dual permanent magnet synchronous motors; however, such coordination imposes certain demands on controller communication, vehicle motion sensors, and computational resources. To simplify control and provide safety redundancy under emergency conditions, this article proposes a motor-level coordinated control strategy. A single observer based on differential motor states replaces the traditional dual-observer scheme, and a hybrid extended state observer is developed. Experimental comparisons with a sliding-mode extended state observer demonstrate the superior performance of the proposed method. Furthermore, a relationship between the traction torque difference and the observer gain is established via a specially designed smooth nonlinear function, achieving a balanced improvement in dynamic and steady-state performance. The proposed approach attains traction torque balance during single-wheel slip in straight-line DRWDEV operation using only bottom layer motor control, without the need for vehicle motion sensors, vehicle dynamic models, or a hierarchical control architecture, thereby greatly reducing control complexity. Experimental results verify the effectiveness and superiority of the proposed control strategy in traction torque balancing.