Multiphysics Evaluation of Stator Winding Configurations in Dual-Winding PMSMs for Electric Power Steering

This paper evaluates the multiphysics characteristics of various stator winding layouts for a dual-winding permanent magnet synchronous motor (PMSM) intended for electric power steering (EPS) applications. Dual-winding PMSMs offer enhanced fault tolerance; however, practical EPS applications require the simultaneous satisfaction of thermal stability, vibration response, packaging, and manufacturability constraints, in addition to electromagnetic performance. In this study, five winding layouts for an EPS motor are compared under identical design conditions in terms of electromagnetic, thermal, structural vibration, and manufacturability characteristics under both normal operating conditions and an open-circuit fault in one winding set. The analysis results show that the winding layout has only a limited effect on performance under normal operating conditions, whereas it becomes a major design factor under open-circuit fault conditions, significantly affecting torque ripple, localized temperature rise, housing vibration, and implementation complexity. Therefore, the design of fault-tolerant EPS motors requires an integrated evaluation that considers multiphysics characteristics and manufacturability rather than relying solely on a single electromagnetic performance metric. The selected layout is subsequently evaluated using a prototype under normal dual-inverter operation and a single-inverter gate-block condition at a 1 N·m operating point. The principal contribution of this work is an integrated winding-selection procedure that links electromagnetic, transient thermal, structural vibration, and manufacturability/packaging results for five existing winding layouts.