宽范围输入高效LLC谐振变换器的研究∗

摘要

To solve the disadvantage of the LLC resonant converter is not suitable for wide range input, and the efficiency is low in the whole load range as the wide range input. A method of combining variable frequency multiplier technique and burst-mode control strategy is proposed. The implementation processes of this method are analyzed,and its feasibility is verified by a 300 W prototype. The test data show that the converter can achieve wide input range of 100 V~400 V. Under this range,the efficiency can reach 94.8%~96.5% at the load more than 20%and achieve more than 93.5% at the load 5%~20%,and in of load condition less than 5% the efficiency is higher than 87.8%.%针对LLC谐振变换器不适合宽范围输入，且在宽范围输入时整个负载范围内效率较低的缺陷，提出一种将可变倍频技术和Burst控制模式相结合的方法。分析了该方法的实现过程，并通过一台300 W的样机验证了其可行性。测试数据表明，该变换器可实现100 V~400 V的宽范围输入；在此输入下，当20％以上负载时效率可达到94.8％~96.5％，当5％~20％负载时效率能达到93.5％以上，当小于5％负载时效率能达到87.8％以上。