An investigation of current harmonic influence on induction motor in hybrid electric vehicle application

When using induction motors for hybrid electric vehicle (HEV) applications, variable wide speed control system is always required to drive the induction motor up to 10,000rpm or more. Distorted voltage from the control system causes harmonic currents, which generate additional losses and reduce output torque and efficiency. This paper investigates the current harmonic influence in the induction motor performance of HEV application and evaluates the losses, torque and efficiency under the harmonic current in finite element analysis (FEA). The effect of the harmonic current is analyzed and simulated in both a conventional induction motor design and an improved reduced-loss induction motor design. The results show the efficiency is decreased by 2.7% due to the harmonic current in the conventional induction motor, and the harmonic current just causes a 0.69% decrease in the efficiency of the reduced-loss induction motor.