Open AccessPulse‐width modulation control strategy for high efficiency LLC resonant converter with light load applications
Author(s) -
Pan Haiyan,
He Chao,
Ajmal Farooq,
Chen Henglin,
Chen Guozhu
Publication year - 2014
Publication title -
iet power electronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.637
H-Index - 77
eISSN - 1755-4543
pISSN - 1755-4535
DOI - 10.1049/iet-pel.2013.0846
Subject(s) - pulse width modulation , resonant converter , modulation (music) , pulse frequency modulation , pulse (music) , control (management) , materials science , electrical engineering , optoelectronics , physics , electronic engineering , computer science , optics , pulse amplitude modulation , converters , engineering , acoustics , voltage , artificial intelligence
LLC resonant converters, generally adopting frequency modulation control, can hardly achieve high efficiency under both heavy and light load conditions. Especially under light load conditions, the high‐switching frequency seriously degrades converter's efficiency. This study propose a new pulse‐width modulation (PWM) control strategy for LLC resonant converters under light load applications on the premise of no change in the main circuit structure. The voltage gain of the converter is regulated by varying duty ratio instead of increasing switching frequency and therefore zero‐current switching for rectifier diodes can be realised under light load conditions. With the proposed PWM control strategy, the gain is not affected by the load variations and an optimal design of the magnetic components is possible, therefore the efficiency is further improved by reducing both the switching losses and the losses in magnetic components. Experimental results demonstrate the effectiveness of the proposed PWM strategy by increasing the efficiency of LCC resonant converter, especially under light load conditions.