数字控制LLC谐振全桥变换器的应用设计

Application Design of LLC Resonant Full-Bridge Converter Based on Digital Control

针对模拟电源效率较低的现状,提出一种基于DSP的数字电源方案。在对LLC谐振全桥变换器工作原理简单分析的基础上,采用DSP TMS320F28335设计了一款输入为DC 300 V^400 V,输出为DC 48 V/12 A的原理样机。利用Saber仿真软件对其进行仿真与调试,仿真结果与实验数据表明,本文设计的LLC全桥谐振变换器能够在全负载范围内实现初级零电压开通(ZCS)以及次级零电流关断(ZVS),输出电压纹波小于±0.5%,效率达到95%以上,满足设计要求。结论表明,LLC谐振变换器符合电源高功率密度、高效率的发展要求。

In order to improve the efficiency of analog switching power supply,the design of digital power based on DSP is proposed. This paper analyzes the theory of LLC resonant converter that takes the full-bridge as the main circuit. A program for the full-bridge converter based on DSP TMS320F28335 is introduced. Finally a prototype of 300 V～400 V input ,48 V/12 A output was fabricated and tested. Saber software has been used to simulate and debug the full-bridge LLC resonate convertes in the design proceeding. The design of digital control and software system are given. ZCS and ZVS can be maintained in full load. The output ripple is less than 0.5%,efficiency is more than 95%,both of them achieve the design requirements.The result proved that the Full-bridge LLC resonant converter confirms the development trend of the power supply with the higher power density and efficiency.