Investigation into the effect of unbalanced supply voltage on detection of stator winding turn fault in PMSM

In recent years, permanent magnet synchronous motors (PMSM) are becoming popular in industrial applications. It is difficult to have perfectly balanced 3 phase ac supply voltages in power system. In fact, line supply voltages typically differ by a few volts or more, and hence unbalanced supply voltages can exist anywhere in a three-phase power distribution system. This paper presents a study of PMSM with stator winding turn fault and different load conditions under balanced and various unbalanced supply voltages. Three-phase PMSM is simulated for healthy and faulty conditions with stator turn fault at different loads using finite element analysis. Experimental laboratory results validate the analysis and demonstrate that the proposed approach can be used for both balanced and unbalanced supply voltage, as a reliable indicator for detecting different insulation failure percentages of stator winding at different load conditions.