Study on efficiency calculation model of induction motors for electric vehicles

The efficiency of induction motors for electric vehicles must be researched deeply over the entire operating speed region. Up to now, the calculation models of the efficiency of the induction motor for electric vehicles are less accurate over some operating regions, such as owing to omitting the variations of the motor parameters with frequency. The paper puts forward a calculation model of the induction motor efficiency in the entire region of operation, including the constant-power region and the constant-torque region. And in this paper, the new methods of the iron loss calculating and stray loss calculating are deduced. With the model, the efficiency influenced by motor parameters can be considered at the stage of the motor design. So the optimal design could be done for the high efficiency of motors. The validity of the model has been verified by the experiment results of the 30 kW induction motor.