Efficiency analysis of hybrid electric vehicle (HEV) traction motor-inverter drive for varied driving load demands

It is a well-understood fact that power electronic converters and electric propulsion motors are extremely critical for every hybrid electric vehicle (HEV) system. It is essential that the traction motor must meet demands of varied driving schedules, and at the same time, it should run at its most optimal operating points to achieve higher drive train efficiency. Therefore, modeling the motor-inverter losses/efficiencies over typical city and highway driving schedules is the key to observe and analyze practical drive train efficiency and vehicle performance. Considered as a "black box," the motor-inverter functions as an energy conversion block. It provides known outputs when certain inputs are applied. In this paper, a detailed efficiency analysis of a typical traction motor-inverter drive system, more specific to a parallel HEV, is presented. The HEV system is tested over a range of different driving load demands, which include 3 stop-and-go type low-speed driving patterns and 3 highspeed driving patterns. The motor-inverter efficiency analysis is carried out based on the resulting efficiency map data. The advanced vehicle simulator (ADVISOR) software is used for modeling and simulation purpose. Efficiencies under both motoring mode and regenerative braking mode are monitored and summarized.