Acoustic noise sources in Hybrid Electric Vehicles or full Electric Vehicles (HEV/EV) must be controlled to guarantee an adequate level of acoustic comfort to both passers-by, drivers, and passengers. This article focuses on switching noise resulting from power electronics, also called Pulse Width Modulation (PWM) noise, which may be responsible for unpleasant sounds in Electric Drive Units (EDU). The physics of PWM generation principle is first reminded, from voltage to magnetic excitation harmonics, and noise radiation. An original testbench setup to automatically evaluate the impact of the choice of commutation scheme (e.g., SPWM, SVPWM and DPWM) and frequency is described. Finally, a corpus of motor noise recordings with various PWM strategies is analyzed by means of sound quality metrics and the results are interpreted.
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