A Voltage-Based Approach for Fault Detection and Separation in Permanent Magnet Synchronous Machines

Different faults in permanent magnet synchronous machines (PMSMs) cause various and independent changes to the machine magnetic flux distribution, which affect the machine parameters and performance. These changes are reflected in the machine flux linkages and can be estimated from the machine voltages. In this paper, we continue the work of Haddad et al., where a method was proposed to detect and separate three types of faults in PMSMs: 1) static eccentricity; 2) demagnetization; and 3) turn-to-turn short circuit. The method proposed here is based on using the change in the commanded d- and q-axis voltages, while the machine is operating at steady state, for fault detection and separation. Simulation tests using finite element analysis (FEA) software (MAGSOFT-Flux2D) were performed under healthy and the tested fault conditions on a three-phase ten-pole fractional-slot concentrated-winding PMSM. An analytical method is proposed to estimate the commanded voltages at any operating condition, and a classification algorithm is implemented for fault detection and classification. Experimental tests were carried out and compared with FEA. The effects of the variation in the operating speed and temperature were simulated and tested to validate the detection method under different operating conditions.