摘要
以LLC为代表的DC/DC串联谐振变换器对效率有着较高的要求,往往需要在宽电压范围内实现软开关特性,并且能够在宽负载条件下工作。然而,当变换器负载较轻时不可避免地会出现增益失真,导致输出电压升高,损耗增加,效率降低。针对CLLC型谐振变换器轻载电压漂高和效率损耗现象,提出一种变频PFM调制+间歇BBCC的混合控制策略。在变换器正常工作时,采用PFM调制进行变频控制,在变换器处于轻载运行时,采用间歇模式的Bang-Bang电荷控制(BBCC)。仿真结果表明,文中提出的控制策略可以有效抑制CLLC型DC-DC串联谐振变换器轻载运行时电压漂高,减小功率损耗,提高轻载工作效率,实现全负载范围内稳定高效运行。
The series resonant DC/DC converter regarding LLC as representative has a high efficiency requirement.It often needs to realize the soft switching characteristic in a wide voltage range and can work under a wide load condition.However,when the load of the converter is light,the gain distortion will inevitably occur,resulting in rise of the output voltage,increase of the loss and decrease of the efficiency.In order to eliminate the phenomena of output voltage drift and efficiency loss,which appear in light load output of CLLC resonant converter,a hybrid control strategy of variable frequency PFM(pulse frequency modulation)plus intermittent BBCC(Bang-Bang charge control)is proposed.When the converter is working normally,PFM works for variable frequency control.When the converter is in light load operation,BBCC in intermittent mode works.The simulation results show that the proposed control strategy can effectively suppress the high voltage drift and reduce power loss when the CLLC DC-DC series resonant converter works in light load,and can improve the efficiency of light load operation and achieve stable and efficient operation within the full load range.
作者
吴洋洋
刘运
郝鹏飞
WU Yangyang;LIU Yun;HAO Pengfei(College of Electrical and Control Engineering,Shaanxi University of Science and Technology,Xi’an 710021,China)
出处
《现代电子技术》
2021年第14期11-17,共7页
Modern Electronics Technique
基金
国家自然科学基金资助项目(51272148)
国家自然科学基金资助项目(51772180)。
