In Fig. 9 is shown the speed response at 1 (pu) under step torque application during the interval of the proposed control
scheme (with transient optimum flux recovery) in comparison with the case without transient optimization(with transient rated flux recovery) and the case without efficiency improvement (rated flux). The Fig. 9 shows that the overshot of speed response without efficiency improvement is better (lower and shorter convergence). The speed overshot of the proposed method with flux optimum recovery in transient state is shorter and bigger than the case of efficiency improvement without flux control in transient state. The speed overshot with the optimum flux recovery in transient state increases 40% approximately comparing to that with rated flux transient operation, since has better convergence. Due to the shorter convergence of a transient duration, the proposed control system achieves more input energy saving compared with the rated flux recovery.