Auxiliary power supply design of electric drive system in electric vehicle

XV Zhi， LI Hong-mei， FENG Zhi-jian
（Department of Electrical Engineering， Hefei University of Technology， Hefei 230009， China）

Abstract： Aiming at auxiliary power supply of electric drive system to achieve wide range of voltage input and isolated multiple output，after the comparison of various multiple-output technologies of switching power supply，the single-ended flyback multi-output converter was chosen as main circuit topology of auxiliary power supply. Based on a single-ended flyback converter and current mode PWM control chip TL2844B，the design scheme of single-ended flyback multi-output switching power supply was first given. Then，the design process of the high-frequency transformer，leakage inductance snubber circuit，start-up circuit and voltage and current feedback circuit were introduced in detail，and various suppression methods of high-frequency noise were given. Finally，auxiliary power prototype was tested. System experiments results indicate that the suppression of high-frequency noise of important output was achieved by using Y capacitor to reduce high-frequency oscillation and to lower obviously the peak-to-peak of high-frequency noise，the suggested design scheme can satisfy the initial design demand of auxiliary power supply of electrical drive system in electric vehicle （EV），with good performance.
Key words： electric vehicle（EV）； electric drive system； auxiliary power supply； flyback switching power supply； multi-output