Map-Based Behavior of a Dual Three Phase Machine under Inter-Turn Short Circuit Faults

This paper investigates the behavior of a dual three phase permanent magnet synchronous machine (PMSM) under inter-turn short circuit (ITSC) faults. For this purpose, an analytical description of the short circuit current is presented, utilizing current-dependent inductances derived from Finite Element Analysis (FEA). Furthermore, a FEA based full motor model including parameterizable ITSC injection is created. For validating and comparing these methods, a test motor with modified winding system to induce defined ITSCs is used. It can be demonstrated that the analytically calculated and the FEA simulated results match well with the measured fault currents. Both approaches show the same characteristic behavior of ITSC in the I<inf>d</inf>-I<inf>q</inf>-map with a lower fault current at higher field weaking and in the torque-speed map with a higher short circuit current at higher torque and higher speed. The analytical model is further improved by considering the temperature dependency of the ohmic resistances and the magnet flux. In this way a root mean square error over the whole d-q-quadrant of 3.5 % can be reached.