三相交错LLC谐振变换器空载问题的研究

Research on no load optimization of three phase interleaved LLC Resonant Converter

三相LLC谐振变换器在轻载工况运行时,会出现输出侧电压漂高失控的现象,这是由于变压器匝间电容与副边整流管的结电容的存在共同形成寄生电容,在重载时,寄生电容对变换器输出的影响特别小,可以忽略不记,但是在轻载时,寄生电容被充电后放电过程对变换器输出的影响特别大,会改变直流增益曲线的状态,所以要对寄生电容做特殊考虑,以不至于影响变换器负载工况全范围的工作,通过合理设计Q值、k值使变换器稳定运行。

When the 3-phase LLC resonance sensor is operating under light load,the voltage on the output side will fall out of control.This is because the parasite capacity is formed by the existence of the transformer’s interrotation capacity and the node capacity of the secondary rectifier.In the case of heavy loads,the influence of the parasite capacity on converter output is particularly small and can be ignored,but in light loads,Once the parasite capacitor is charged,the discharge process has a major impact on the converter output,which will change the DC curve.Therefore,particular attention should be paid to the parasite capacitor so that it does not affect the entire load conditions of the converter and makes the converter function stable.