Analysis of Fault-tolerance Control Strategy of the Single Winding Bearingless PM Slice Motor

There always exists a problem towards multi-phase concentrated winding bearingless slice motor that the fault of the windings would lead to the motors’ abnormal running when the control strategy is not changed. Taking the six-phases single winding bearingless slice motor for example. Firstly, the short-circuit current of the fault winding was analyzed while each of the winding worked at short-circuit fault state and the expression of the short-circuit current was derived based on the voltage balance equation of the fault winding. Secondly, every possible fault state in this motor was analyzed, and the corresponding fault-tolerance control strategy was presented based on the stator-current reconfiguration principle. In the strategy, the stator-current mathematical model was derived based on the mathematical model of motor’s levitation force and torque. Finally, the fault-tolerance control strategy was verified by comparing levitation force’s pulse and torque’s pulse in the simulation.