Modeling and controlling of six-phase induction machine driven trapezoidal phase current waveform
Airgap flux linkage orientated control of the AC machine is of the advantage that the airgap flux can be measured directly. But, the Park transformation should be used to realize the airgap flux oriented control and the control system is complicated due to large amount of computation. Based on shortcomings above, the paper proposed an airgap flux oriented control strategy that is trapezoidal wave phase current control which consists of field current and torque current components. At any instant, three neighboring phases form a field winding, while the other three neighboring phases form torque winding. The configuration of the current waveforms makes the six-phase machine operate like a DC machine allowing the field and torque currents to be controlled separately without complex Park transformations. The main performance of the six-phase machine including the machine modeling is determined with finite element (FE) analysis. Furthermore the control strategy proposed is experimentally verified by using the six-phase induction drive system built. The results show that the field and torque current components of the six-phase machine can be controlled separately without any coordinate transformation and the controller to realize the control scheme is simple.