Black-Box Method of Identification and Diagnosis of Abnormal Noise Sources of Permanent Magnet Synchronous Machines for Electric Vehicles

This paper presents a quick and effective black-box method for identification and diagnosis of abnormal noise sources of permanent magnet synchronous machines (PMSMs) for electric vehicles. The black-box method is divided into three steps. In the first step, a black-box testing theory model with the rotational speed as the input signal and the noise frequency as the output signal is proposed. The main abnormal noise sources of PMSM for electric vehicles are taken into account in this model, such as harmonic currents, switching frequency of pulsewidth modulation, eccentricity, sliding bearing, and resonance. In the second step, a black-box testing experiment of noise of PMSM is applied under acceleration conditions and the sound quality of PMSM is analyzed with objective acoustic indicators, and psychoacoustic indicators as well. In the third step, abnormal noise sources are identified and diagnosed by means of the black-box testing theory and the black-box testing experiment. Noise contribution to psychoacoustic indicators is further analyzed. The proposed method is independent of detailed internal parameters of PMSM, such as structural parameters and electromagnetic parameters, and observably raises analyzing efficiency.