Design of EV Propulsion Motors with Rib-Less IPMSMs: A PWM Harmonic-Based Analytical Current Harmonic Model Approach

This paper presents the design of a 36kW V-type rib-less Interior Permanent Magnet Synchronous Machine (IPMSM) for EV propulsion, with a focus on optimizing motor efficiency through a PWM harmonic-based approach. The core of this design is an innovative analytical current harmonic model (ACHM) that specifically addresses iron losses in 3-phase 2-level voltage-source inverters. This model effectively captures the effects of PWM harmonics, significantly enhancing motor efficiency across various operating points. The efficiency improvements are vividly demonstrated in maps that highlight the impact of PWM harmonics on motor performance. The practical application of this PWM harmonic-focused design is validated through rigorous electromagnetic FEA and prototype testing, confirming its suitability for high-performance EV propulsion systems.