Title: Linear and trapezoidal-inverted sub-cycle period VFPWM-based torque ripple reduction of interior PMSMs for electric vehicle applications

Authors: Meera Khalid; Anjaly Mohan; A.C. Binojkumar

Addresses: Department of Electrical Engineering, Government Rajiv Gandhi Institute of Technology, Kottayam, India; A.P.J. Abdul Kalam Technological University, Kerala, India ' Department of Electrical Engineering, Government Rajiv Gandhi Institute of Technology, Kottayam, India; A.P.J. Abdul Kalam Technological University, Kerala, India ' Department of Electrical Engineering, Government Rajiv Gandhi Institute of Technology, Kottayam, India; A.P.J. Abdul Kalam Technological University, Kerala, India

Abstract: PWM techniques with a constant switching frequency can create distinct tonal bands in the harmonic spectrum of stator current of an AC machine. These tonal bands can negatively impact acoustic noise, vibrations, and electromagnetic interference. Reducing the magnitude of dominant harmonics by spreading the harmonic energy spectrum is one method to mitigate this problem. Harmonic energy is spread effectively using variable switching frequency PWM schemes. Another significant issue in AC drives for electric vehicles is the presence of ripples in the electromagnetic torque generated. The electromagnetic torque ripple is effectively reduced along with the spreading of harmonic energy, by the application of the suggested linear and trapezoidal-inverted variable switching frequency schemes. The effectiveness of the presented schemes are tested both below and above base speed, by using an interior type PMSM which is suitable for EV applications.

Keywords: permanent magnet synchronous motor; PMSM; torque ripple reduction; variable switching frequency PWM; VFPWM; field oriented control; spread spectrum technique; PWM inverter.

DOI: 10.1504/IJPELEC.2026.156025

International Journal of Power Electronics, 2026 Vol.22 No.5, pp.548 - 565

Received: 22 Feb 2025
Accepted: 29 Sep 2025
Published online: 01 Sep 2026 *

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