The noise emitted by Electric Drive Units (EDU) of Hybrid Electric Vehicles or full Electric Vehicles (HEV/EV) is a key contributor to the overall perceived quality of the vehicle. This article focuses on one of the sources of acoustic noise in EDU, the switching noise, also called Pulse Width Modulation (PWM) noise. The physics of PWM generation principle is first recalled, from voltage to magnetic excitation harmonics. The automated test-bench used to obtain a corpus of multiple noise recordings of EDU running at constant speed with different switching parameters is then described. The psychoacoustic study is introduced by a semantic evaluation to identify the most relevant adjectives to characterize the noise of electric machines. The recordings are divided into representative clusters based on their sound quality (SQ) metrics profile (acoustic loudness, sharpness and tonality). One recording per cluster is finally presented to a jury. Jury test results bringing insight of the perceived sound quality, are linked to the SQ metrics and the choice of parameters for the EDU switching strategy.