IPMSM Loss Reduction Control Under High-Speed Conditions for Electric Vehicles

This article proposes an optimal clamped pulse-width modulation considering minimum loss (OCMLPWM) that works in conjunction with a voltage-feedback-based <tex-math notation="LaTeX">$dq$ </tex-math> -axis current compensation flux-weakening (VFCC-FW) method for interior permanent magnet synchronous motor (IPMSM) in electric vehicles (EVs). In OCMLPWM, determine zero-voltage vector based on the reference voltage and current amplitude, so that the clamp falls in the maximum current phase and reduces the switching loss. By optimizing the clamp phase, OCMLPWM realizes minimum switching losses at any power factor angle. Additionally, VFCC-FW is proposed under high-speed conditions to support OCMLPWM. Minimization of the dynamic back electromotive force (EMF) is achieved by introducing <tex-math notation="LaTeX">$dq$ </tex-math> -axis compensation currents, allowing the motor to operate with higher dc voltage utilization. Thus, VFCC-FW method reduces system losses while enhancing torque-speed output capability in flux weakening (F-W) region. As a result, the motor and VSI losses are reduced by OCMLPWM combined with VFCC-FW. The feasibility and effectiveness of the proposed method are verified through simulations and experiments.