High efficiency series chopper power train for electric vehicles using a motor test bench

Many researchers have studied electric vehicles (EVs) for improving their efficiency to increase the driving range. The system design of an electrical power train has significant influence on the total driving range per charge and has been widely researched. A series chopper power train using a buck-boost chopper has been proposed as an electrical power train system. This electrical power train achieves high efficiency due to low and high inverter input voltage in the low and high speed regions, respectively. In previous studies, a high efficiency control optimizing the chopper output voltage was proposed, and a motor test bench with characteristics similar to actual EVs was constructed by using a battery emulation system with voltage variation characteristics, which occur due to the state of charge (SOC) and internal resistance. This paper shows the effects of optimizing the chopper output voltage on the driving range per charge in both efficiency estimation and the motor test bench experiment. This allows the verification of the usefulness of optimizing the chopper output voltage for increasing the efficiency. The results indicate an improvement of 0.9% and 2.7% in the driving range per charge during efficiency estimation and the motor test bench experiment, respectively.