A continuous efficiency optimization controller for induction motor drives

In this paper, an on-line efficiency optimization controller is proposed for induction motor drives after a detailed analysis of motor losses. The controller searches for a minimum motor drive input power by continuous variation of a control variable, resulting in a smooth system performance, which is not possible by the conventional stepwise change of the control variable. The search period is short. Thus, the controller can be applied effectively to applications with frequent changes of speed and load. Also, under the proposed controller, more energy saving is achieved. Extensive simulation is performed for the induction motor under the proposed and conventional efficiency optimization controllers. The results prove the superiority of the proposed controller.