Inter-turn Short Circuit Fault Detection in Permanent Magnet Synchronous Motors Based on Reference Voltage

This paper proposes a method for detecting inter-turn short circuit faults of surface-mounted permanent magnet synchronous motors (SPMSMs) based on reference voltage. The proposed method consists of three steps. First, from the mathematical model of faulty PMSM, a reference voltage vector in the dq-frame is separated into a healthy voltage and a faulty voltage. Second, the faulty voltage is further decomposed into a DC component and a 2nd harmonic component. Third, the relationship between these components and the inter-turn fault severity is identified. Based on the relationship, this paper proposes two fault indicators; DC bias and 2nd harmonic amplitude. Simulation results verify the effectiveness of the proposed method. The proposed method can detect inter-turn short circuit faults under low sampling rate and without the need for additional sensors. This strength can facilitate on-line fault detection.