Analysis and experimental verification of the high voltage DC bus current and voltage ripple in electric vehicles

Abstract

Electric vehicles (EV) require the main inverter to convert the DC current of the high voltage traction battery to an AC current suitable for the electrical motor. By switching its semiconductors, the inverter produces a current ripple on its AC and DC side which can propagate through the high voltage DC bus and can accelerate the aging of the traction battery. To improve the understanding of the current ripple and in order to detect critical drive scenarios, this paper presents a validated model which describes the current and voltage ripple of the DC bus depending on rotational speed and torque of the electrical motor. The model of the DC bus is based on the international standard ISO 21498-2, and the state of the art control schemes space vector pulse width modulation (SVPWM) and maximum torque per amp (MTPA) are used for inverter and machine control in the fundamental speed range and field-weakening region.