减小LLC谐振变换器空载输出电压纹波的一种新方法

摘要

To solve the problems of no-load voltage stability and reducing no-load loss of LLC resonant converter, the widely used approach is to let the LLC operating in hiccup mode when near no-load,but the hiccup mode will result in large no-load output voltage ripple. The causes that lead to large output voltage ripple were analyzed in hiccup mode. A simple,low-cost and practical solution obtained from solving no-load problems of practical product was proposed,the problems of light load voltage stability and no-load loss were both solved by hiccup mode and output voltage ripple was minimized in this mode,through experimental verification,it has been applied to the actual product and achieved good results.%为解决LLC谐振变换器的空载稳压问题和降低空载损耗,通常让LLC变换器在接近空载下运行在打嗝模式,但打嗝模式会引起较大的空载输出电压纹波.分析了轻载打嗝模式输出纹波过大的原因,总结了一种在解决实际产品轻载问题中探讨得出的低成本实用化的新解决方案,既通过打嗝模式解决了空载电压稳定问题、降低了空载损耗,又大大减小了该模式下的输出电压纹波,经实验验证并应用到实际产品中,取得了良好的效果.