Performance analysis of low-inductance PM brushless DC motors under stator inter-turn faults

The article presents a study of the faulty performance of low-inductance VSI-fed PM brushless DC motors under stator inter-turn short circuits. Performance characteristics of the drive system are obtained under normal operation through a discrete-time, lumped-parameter network model. The model is modified to accommodate a short circuit across certain number of turns on one stator phase. Fault current is introduced as an additional state variable in fault cases. A comparative study between system performance under healthy and faulty operations is conducted. Faulty performance is experimentally measured via a specialty wound machine at different operating conditions and various numbers of shorted turns. Good agreement between analytical and experimental results is obtained. Findings of this work can be used to develop fault detection schemes of the system under consideration.