Wide Range Output Voltage LLC Resonant Converter for Electric Vehicle Charging System

This paper presents the hybrid control of a fullbridge LLC series resonant converter as the application of an electric vehicle charging system. the hybrid control combines three control methods to achieve wide a output voltage range of about $75\sim 475 V$, three control methods including the pulse-frequency control method, phase-shift control method, and burst mode. finally, a wide-range output voltage LLC resonant converter prototype is realized. The specification of the prototype is a DC input voltage of SOO V, an output voltage of 75-475V, and maximum output power of 7.5 kW. The peak efficiency is 97.2 %.

I. Introduction

With the popularity and progress of electric vehicles, the power converters technology is also constantly improving. Due to the demand for high efficiency, high power and wide output voltage range. According to the Society of Automotive Engineers, the power level range of DC charger is about 20kW~240kW [1]. And the output voltage is about 150V~950V, which will be slightly different depending on the needs of each electric vehicle maker.