Mathematical Approach to Generate Efficiency Maps for Induction Motor and Optimization for EV

Motor efficiency in electric vehicles (EV) plays a very important role in the enhancement of its range, therefore a scope of improvement is always explored. This paper describes an approach to analytically obtain efficiency contour map of an induction motor at various speed and torque, which is mostly presumed as FEA activities. The proposed method involves modeling of various losses by utilizing the equivalent circuit parameters of the motor. It helps in quick analysis of a given motor, to analyze an EV powertrain and its optimal operation. This paper also demonstrates how the efficiency map can be utilized to analyze average efficiency for a given drive cycle, that helps in the betterment of the complete powertrain. Moreover, it suggests the scope of further efficiency improvement by optimizing the equivalent circuit parameters of an induction motor. All the computations have been carried out with Matlab scripts, considering a 75 kW asynchronous machine example available in the Simulink library.