Interior permanent magnet synchronous machine rotor demagnetization characteristics under fault conditions

This paper presents the dynamic response of an interior permanent magnet synchronous machine (IPMSM) drive to various fault conditions and their effects on the PM demagnetization characteristics. Attention is focused on modeling the IPMSM drive including nonlinear magnetic behavior under asymmetrical inverter fault conditions, demonstrating the significant risks of irreversible demagnetization caused by the large transient fault currents. Other types of inverter faults are discussed, including phase-leg open-circuit fault and uncontrolled generator (UCG) mode fault. Finite element (FE) analysis is used to simulate the demagnetization characteristics under a variety of fault conditions. Three-phase symmetrical short circuit fault characteristics for several different IPM machine designs are discussed.