全桥LLC谐振变换器在宽范围输入下的仿真研究

Simulation Research of Full-bridge LLC Resonant Converter with Wide Input Range

随着新能源发电的迅速发展,比如光伏发电、风力发电等一些场合对后级的DC/DC变换器提出了宽输入、高效率的要求。而全桥LLC谐振变换器(FB-LLC)由于原边所有开关管均可实现零电压导通(ZVS)、副边二极管均可实现零电流关断(ZCS),整体效率较高。为了满足宽输入的要求,采用变模态控制,当输入电压较低时,采用全桥模态;当输入电压较高时,采用半桥模态。通过对全桥LLC谐振变换器的工作原理进行分析,建立了全桥LLC谐振变换器工作在变模态控制下的增益模型,并通过仿真进行了验证。

With the rapid development of new energy power generation,the requirements of wide input and high efficiency for DC/DC converters in the latter stage are put forward by photovoltaic power generation and wind power generation.The primary side switching tubes of full-bridge LLC resonant converter(FB-LLC)can achieve zero voltage conduction(ZVS)and all secondary diodes can achieve zero current turn-off(ZCS),which results in the higher efficiency in operation.Variable mode control is adopted to meet the requirements of wide input.The full-bridge mode is used when the input voltage is low,and the half-bridge mode is used when the input voltage is high.In this paper,by analyzing the working principle of the full-bridge LLC resonant converter,the gain model of full-bridge LLC resonant converter operating under variable mode control is constructed and verified through simulation.