An improved fault tolerant for a five-phase induction machine under open gate transistor faults

Of the different outstanding merits of multiphase machines is their ability to run steadily with some phases open. Commonly, optimal current control (OCC) to remaining healthy phases is usually engaged to ensure a certain optimization criterion. Most of the available literature investigates the fault case where one of the motor phases is completely disconnected due to a failure in one of the inverter legs. To maintain pre-fault operating conditions, the machine experiences a 53% increase in the total copper loss; otherwise, the machine should be deloaded. Under open gate fault condition of one of the upper or lower switching devices, the corresponding switch will be open, while the other switch in the same leg can be still used to enhance the machine performance under this case. This paper proposes an improved control strategy to optimize a five-phase induction motor drive under a gate failure of one of the inverter switching devices using a half cycle optimal current control (HCOCC) technique. When compared with a conventional OCC, the proposed controller can effectively reduce the excessive copper loss by 50%, improve efficiency, and decrease the corresponding derating factor. The proposed controller is verified using a five-phase induction machine based on a simulation case study using MATLAB/SIMULINK.