Zero Torque Ripple Operation of Seven-phase Concentrated-full-pitch Winding Induction Motor Under Open Circuit faults

In order to achieve zero torque ripple operation of seven phase concentrated-full-pitch winding induction motor under single phase open, the fundamental stator current space vector of the conventional strategy is controlled to move along the circular anticlockwise trajectories. However, according to the steady state model in terms of symmetrical components, there are still other possible fundamental current commands to achieve the zero torque ripple. In this digest, all possible fundamental current commands are deduced and their performance in terms of average torque, total loss (stator loss and rotor loss) and efficiency are compared. Furthermore, zero torque ripple operation can be also achieved with two phase open and this is not reported in the previous literatures. In addition, the possibility of zero torque ripple operation in terms of two more phase open conditions and harmonic current injection is discussed. Finally, the optimum control strategies are selected and their effectiveness is verified through the simulation analysis.