Analytical modeling and investigation of transient response of PM machines with 3-phase short-circuit fault

This paper aims to find effective methods to avoid irreversible demagnetisation in permanent magnet machines by suppressing the short-circuit current. An analytical model is developed to predict the transient currents, overcoming the problems of previous steady state models which may significantly underestimate the short-circuit current. Although the developed analytical model is simple, it can accurately reveal the relationship between the short-circuit response and design parameters, as its high accuracy is validated by transient finite element analysis and experiment. The characteristics of short-circuit behavior are investigated and several guidelines for improving the short-circuit performance are obtained to aid the machine design.