Real time efficiency observor of induction motor under a model considering iron loss

Induction motors (IM) usually operates at low efficiency under light load, which can cause significant energy loss in industry. In addition, the electrical vehicles require for high efficiency drive system. Therefore it is significant to develop a high efficiency control strategy for induction motor which can adapt to load condition for optimal flux finally for optimal efficiency. However, real time efficiency observer is necessary in such control strategy. Considering that conventional model of induction motor ignores the iron loss, a new model taking the iron loss into account must be built to get a full scale of energy loss so that the efficiency can be calculated. This article presents a method to observe the efficiency of induction motor instantaneously. Simulation and experiment results have demonstrated that the method performs well.