Analysis and fault-tolerant control of inter-turn short-circuit fault for five-phase permanent-magnet synchronous machine

For the demand of high reliability in the aerospace field, multi-phase electric machines have become a research hotspot for the fault-tolerant ability. Inter-turn short-circuit fault is one of the main fault forms in the electric machine. The fault mechanism, diagnosis method and fault-tolerant control strategy of inter-turn short-circuit fault of the open-winding five-phase permanent-magnet synchronous machine that is used as the starter/generator system are studied in this paper. Firstly, the fault mechanism of the inter-turn short-circuit fault (ITSCF) is analyzed. The characteristics of phase voltage, inter-turn short-circuit current and torque ripple are compared using the phase winding open-circuit method and the phase winding short-circuit method. Secondly, a fault diagnosis method based on the information fusion is proposed, which determines the fault phase firstly and then identifies the inter-turn short-circuit ratio. According to the fault mechanism, a fault-tolerant control method is proposed, in which the accurate inter-turn short-circuit ratio and inter-turn short-circuit current are not required. The proposed fault-tolerant control method has similar torque ripple compared with the control method using accurate inter-turn short-circuit ratio and inter-turn short-circuit current. Finally, the effectiveness of the proposed fault-tolerant control method has been verified by experimental results.