A Modified FOC Strategy With Optimal Rotor Flux for FTC of Star-Connected TPIMDs Against Single-Phase Open Fault

In this research, a modified field-oriented control (MFOC) strategy with optimal rotor flux for fault-tolerant control (FTC) of star-connected three-phase induction machine drives (TPIMDs) against single-phase open fault (SPOF) is proposed. First, an FTC scheme based on using an unbalanced transformation matrix (TM) for stator current components in order to control the TPIMD during SPOF is presented. Then, the model of the losses based on the extended mathematical model of the machine in the rotational reference frame is calculated. The minimum losses of the drive system are determined by the calculation of optimal flux at any operating condition. The optimal flux is then used as the reference flux in the presented FTC system. The introduced strategy with some changes can be used during normal and SPOF conditions. Simulation and experimental results are given to confirm this new FTC approach. It will be shown that the introduced method gives good results both in normal and SPOF operations.