A model to estimate the effect of DC bus voltage on HEV powertrain efficiency

Mark Thompson, Kettering University
Craig Hoff, Kettering University
Jim Gover, Kettering University


The efficiency of the electric drive system in a Hybrid Electric Vehicle plays a significant role in overall hybrid propulsion system efficiency and influences design choices for other mechanical components in the system. Increasing the DC bus voltage is thought to improve overall powertrain efficiency. In this paper, models are developed to predict the effect of DC bus voltage on the power loss in a PWM inverter motor drive and a brushless DC electric machine. The models indicate that a higher bus voltage will improve powertrain efficiency in some, but not all, operating conditions.