Analysis and Design of Half-Bridge LLC Resonant Converter for 36V Light Electric Vehicle Battery Packs

LLC resonant converters are a preferred topology in high power applications due to their high efficiency. One of the biggest advantages of LLC converters is that they greatly reduce switching losses with Zero Voltage Switching (ZVS). In an LLC converter, the output voltage can be changed by changing the switching frequency, and the quality factor of the resonance tank is a determining factor in the waveform of the voltage conversion ratio. In this study, the basic structures of an LLC resonant converter are examined step by step and the effect of the quality factor on the voltage conversion ratio is emphasized. By selecting an appropriate quality factor, the design and simulation of a half bridge LLC converter circuit for 36-42 V light electric vehicle batteries was carried out. The resonance frequency of the circuit is 400 kHz, and to operate in the ZVS region, the switching frequency of the circuit is 400 kHz and above.