Assessment of Interturn Short-Circuit Faults in PMSMs With Parallel-Connected Winding

Interturn short-circuit (ITSC) is one of the most common faults in permanent-magnet synchronous machines (PMSMs), and ITSCs in PMSMs with parallel-connected winding (PCW) are generally more difficult to detect than those in PMSMs with series-connected winding. In this article, the mathematical model of PCW PMSM with ITSC is established first, and the main fault features of ITSC such as the third harmonics in phase currents, negative sequence of phase voltages and circulating current are also modeled. Then, the reasons for the weak fault features in PMSMs with PCW are analyzed. Furthermore, the effects of ITSC modes, including single-branch ITSC and branch–branch ITSC, and short-circuit position on these fault features are investigated. It is shown that branch–branch ITSCs are more difficult to detect, especially when the short-circuit position is close to the midpoint of phase winding. Experimental tests are carried out on a PCW PMSM with ITSC, and the experimental results agree well with the theoretical analysis.