Open AccessEfficiency optimization strategy of LLC resonant converter based on Hybrid PWM and PFM digital control mode
Author(s) -
Hehui Xun,
Hanxin Shen,
Wenxiang Chen
Publication year - 2021
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1941/1/012023
Subject(s) - pulse width modulation , pulse frequency modulation , modulation (music) , resonant converter , electronic engineering , voltage , engineering , pulse (music) , electrical engineering , control theory (sociology) , converters , computer science , control (management) , physics , pulse amplitude modulation , acoustics , artificial intelligence
There is a problem that the overall efficiency of LLC resonant converter decreases due to large switching loss under light load, in order to solve it, an efficiency optimization strategy based on hybrid PWM and PFM digital control mode was proposed to improve the efficiency of LLC Resonant Converter in the full load range. In order to adapt to different loads, Boost LLC converter circuit topology was proposed. The former Boost circuit was controlled by pulse width modulation (PWM), and the latter LLC was controlled by pulse frequency modulation (PFM). Pulse width modulation (PWM) control of the front Boost circuit can improve the bus voltage of the rear LLC circuit and adapt to different loads. Under the pulse frequency modulation (PFM), the efficiency of the rear LLC resonant converter under light load can be further improved by adjusting the resonant frequency. The experimental results showed that the proposed digital control efficiency optimization method could enable the Boost LLC converter to achieve high efficiency in the whole load range, and the overall conversion efficiency was not less than 94%.