Efficiency optimized speed control of field oriented induction motor including core loss

This paper presents an efficiency optimized speed control scheme of field oriented induction motor. In order to take core loss into account, we insert a core loss resistance in parallel to internal induced voltage branch into the d-q axes equivalent circuit. The optimum efficiency controller is to realize the optimum slip angular frequency to minimize the controllable losses composed of copper losses and core loss by rotor flux weakening under field oriented control. We construct the speed control system with efficiency optimization applied on optimal regulator theory. The effectiveness of this control scheme is confirmed by simulation results.