A Physical Faulty Model Based on Coil Sub-Element for Direct-Drive Permanent Magnet Synchronous Motor With Stator Winding Short-Circuit Faults

Abstract

As winding short-circuit faults (WSF) in a direct-drive permanent magnet synchronous motor (DDPMSM) degrade its reliability and may cause serious catastrophes, fault detection and diagnosis for the DDPMSM are necessary. The performances analyses of motor under WSF are the basis of fault detection and diagnosis. An efficient and accurate faulty model is a great tool for evaluating motor performances under various WSF. Hence, this paper proposes a novel physical faulty model (PFM) based on the coil sub-element for the DDPMSM with the WSF. Fault position can be examined by differentiating the inductance and the electromotive force of the coil sub-element. This model can evaluate motor performances under various WSF, especially inter-turn short-circuit fault in different positions of the same slot, without changing the internal structure of model. The faults are set by connecting the desired taps as in the practical motor. First, the structure and parameters of the DDPMSM are reported. Second, the inductance calculation matrix, which considers the spatial position of the fault, is constructed. Then, the proposed PFM is established. The motor performances under various WSF are evaluated. Finally, the results of PFM, finite element model and experiment are compared. The results validate the correctness of the proposed PFM.