Influence of Mutual Inductance on High-Frequency Impedance Characteristics of Six-Phase PMSM under Inter-Turn Short-Circuit Fault

To improve the ability to identify the inter-turn short-circuit (ITSC) fault, which is one of the most frequent fault types, of six-phase permanent-magnet synchronous machines (PMSMs), the high-frequency impedance of six-phase PMSM under ITSC fault is analyzed with consideration of the mutual inductance characteristics. The model of coupled magnetic circuit between the fault turns and other phases is established, interpreting the characteristic of mutual inductances with different fault turns locations. The high-frequency impedances of both the ITSC fault phase and healthy phases are analyzed, and the impedance decreases of healthy phase caused by mutual inductance are evaluated. Fault diagnosis indicator utilizing the high-frequency current response is designed and the indicator reliabilities of different voltage injection methods are compared.