宽范围输入高效LLC谐振变换器的研究

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300W的样机验证了其可行性。测试数据表明，该变换器可实现100V～400V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。

Research of LLC Resonant Converter with Wide Range Input and High Efficiency

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 when the wide range input. A method of combining variable frequency multiplier technique and burst-mode control strategy is proposed. The implementation process of this method are analyzed, and its feasibility is verified by a 300W prototype. The test data show that the converter can achieve 100V~400V wide range input, and under the input, the efficiency up to 94.8%~96.5% at more than 20% load, the efficiency can achieve more than 93.5% at 5%~20% load, the efficiency can achieve more than 87.8% at less than 5% load.