Loss Evaluation and Efficiency Enhancement of an LLC Converter

Toshiyuki WATANABE  Fujio KUROKAWA  

Publication
IEICE TRANSACTIONS on Communications   Vol.E103-B   No.9   pp.922-928
Publication Date: 2020/09/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2019EBP3170
Type of Manuscript: PAPER
Category: Energy in Electronics Communications
Keyword: 
phase-shift converter,  LLC converter,  high efficiency,  winding loss,  AC resistance,  

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Summary: 
This paper presents a comparative loss analysis performed between an LLC converter and a phase-shift converter under the same size conditions using a power supply manufactured for information communications equipment. It is also shown herein that the LLC converter has a much higher ratio of transformer loss to total loss than the phase-shift converter and that the cause is the difference in the number of transformer turns between the two converters. Further, the ON-resistance of the secondary-side rectifier element and the number of transformer primary turns are shown to determine which of the two converters is superior in terms of low loss.