摘要
LLC谐振变换拓扑以其高效率、高频化及良好的电磁兼容(EMC)特性等优势获得广泛应用,但实际中空载问题是个难点,空载输出电压漂高是一种常见现象,经常出现超出稳压精度要求的情况,常见解决方案是空载下让LLC工作在打嗝模式或假负载的模式,但打嗝模式会导致较大的空载输出电压纹波,假负载会影响电源效率。总结分析了一种在解决产品实际问题时得出的实用方案,通过实验测试发现初级器件的振荡电压通过变压器传到次级,若开关频率达到设置的最高限制频率,必然导致空载情况下输出电压漂高。通过实验分析得出减小变压器次级绕组端电压振荡的解决方案,经实验验证并应用到实际产品中,取得了良好的效果。
LLC resonant converter topology has been widely used because of its characteristics of high efficiency,high frequency and good EMC.In practical applications,the solution of no-load problem is difficult,no-load output voltage drifting high is a common phenomenon,often beyonds the scope of the regulation accuracy requirements.The common solution is to let the LLC operating in modes of hiccup and dummy load,but the hiccup mode will result in large noload output voltage ripple and dummy load will affect the power efficiency.During solving the practical problems of product,it is found that primary side devices voltage oscillation is transmitted to the secondary side through the transformer, if the switching frequency has reached the highest limit frequency,it will inevitably lead to output voltage drifting high in the case of no-load,this paper proposes an effective solution to reducing secondary windings output voltage oscillation that lead to no-load problem by experiments,and it is applied to actual product and achieves good results.
出处
《电力电子技术》
CSCD
北大核心
2013年第1期26-27,共2页
Power Electronics
关键词
变换器
空载电压漂高
谐振电感
电压振荡
converter
no-load voltage drifting high
resonant inductor
voltage oscillation
