MultiReference Frame Based OpenPhase Fault Modeling and Control for Asymmetrical SixPhase Interior Permanent Magnet Motors

Multireference frame based asymmetric sixphase interior permanent magnet motor (IPMM) modeling and control strategy under single openphase fault are investigated in this paper. The motor modeling under healthy operation is firstly established based on a dual dqaxis synchronous rotating frame. With this dual dqaxis frame, the motor modeling considering the magnetic saturation effect under openphase fault has been derived. By introducing a dualdirection rotating frame, the stator current under single openphase fault can be treated as the sum of a positive current sequence and a negative current sequence. With this dualdirection rotating frame, the two current sequences can be transformed into two DC components for faulttolerant operation. Faulttolerant control schemes with maximum torque per ampere (MTPA) for copper loss minimization and torque maximization are developed, respectively. Finally, the validity of the proposed modeling and control are evaluated by experiments under both steady and transient scenarios.