No abstract

As it has been widely and wrongly believed that noises at any frequency of permanent magnet synchronous motor (PMSM) are positively correlated with subjective annoyance, reducing sound pressure level or sound power level of PMSM is mostly regarded as the only optimisation goal of sound quality (SQ). This study presents a sensitive critical band (SCB) diagnostic method for SQ of PMSM for electric vehicles (EV). First, a new acquisition method of near-field noises without sound attenuation of PMSM was proposed and a neural network model for SQ evaluation was established to determine the specific operating condition with the worst SQ. Second, the band-pass filter of CB (BPFCB) and band-stop filter of CB (BSFCB) were designed to diagnose positive SCBs or negative SCBs in which noises were positively or negatively correlated with the subjective annoyance, respectively. Finally, the major excitation sources of abnormal noises in SCBs were diagnosed by using the analytical calculation. An 8-pole-48-slot PMSM was considered as a case study to testify to the effectiveness and practicability of the proposed method. It may provide a new route for the precise SQ optimisation of PMSM.

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Due to the local inhomogeneous magnetic saturation of the core of interior permanent magnet synchronous motor (IPMSM), the magnetic field changes nonlinearly, which makes the analytical calculation of the magnetic field difficult. Therefore, the calculation of the magnetic field mostly relies on the finite element method (FEM). However, the high computation cost of FEM restricts the efficiency of design and analysis of IPMSM. In this paper, an analytical model (AM) of slotless open-circuit air-gap magnetic field (OC-AG-MF) of IPMSM with V-shaped segmented skewed poles is derived by combining subdomain method (SDM) and magnetic equivalent circuit method (MEC), and then the analytical model of slotted OC-AG-MF of IPMSM with V-shaped segmented skewed poles is obtained by introducing the complex relative permeance. To show the effectiveness of the novel analytical model, the OC-AG-MF and cogging torque of an IPMSM with V-shaped segmented skewed poles for electric vehicles is calculated by the analytical model and FEM respectively. The spatial order, amplitude-frequency characteristics and the 3-D spatial distribution of the OC-AG-MF are analyzed. Finally, the accuracy of the analytical model is experimentally verified by direct measurement of OC-AG-MF and no-load back electromotive force (EMF) of the motor. The analytical model proposed in this paper is shown to accurately calculate the radial and tangential components of OC-AG-MF of IPMSM with V-shaped segmented skewed poles considering rotor magnetic bridge saturation effect and stator slotting effect. Meanwhile the efficiency of design and analysis of the motor is expected to be improved due to the reduced computational effort compared to the prevalent finite element method.