Frontiers in Energy Research (Jun 2023)

Synchronous rectification of LLC resonant converters based on resonant inductor voltage

  • Zuohao Luo,
  • Zuohao Luo,
  • Zaijun Wu,
  • Xiangjun Quan,
  • Xingfeng Xie,
  • Xingfeng Xie,
  • Xiaobo Dou,
  • Qinran Hu

DOI
https://doi.org/10.3389/fenrg.2023.1199397
Journal volume & issue
Vol. 11

Abstract

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Synchronous rectification (SR) technology has been a critical technology for LLC converters to achieve high efficiency and power density. However, conventional SR driving methods face challenges in terms of light-load condition, module size, switching accuracy, and circuit complexity. This paper proposes an SR driving strategy based on resonant inductor voltage (RLV) to address those issues. This RLV-SR driving strategy does not require current sensors and is insensitive to rectifier parasitic parameters. In addition, the RLV-SR driving strategy can be applied in a relatively wide operating frequency range and load conditions. Experimental results based on a 100-W/24-V LLC converter are presented to verify the effectiveness of the proposed RLV-SR driving strategy. Furthermore, the error of turn-on time caused by stray inductance is significantly reduced compared with the conventional VDS-ON sensing method, which improves the power converter’s efficiency.

Keywords