恒流输出模式下LCC谐振变换器的特性与设计

The character and design of LCC resonant converter for constant current applications

LCC谐振变换器具有良好的恒流特性,是中大功率LED照明灯具较理想的驱动电源。依据LCC谐振变换器在并联谐振电容容量远小于串联谐振电容时,变压器初级绕组端电压仍可近似为方波的特征,采用了基于一次谐波分析法(FHA)获取电流增益曲线。根据电流增益曲线的特征提出了最佳工作区域选择策略,详细给出了LCC谐振腔、变压器参数的计算方法,接着借助一台输入电压为395 V、输出电流为2 A、输出电压为16～48 V的样机验证了设计思路的正确性。

LCC resonant converter has a good feature of constant current characteristics,which is the ideal driver for medium and high-power LED lighting.In this paper,based on a LCC resonant converter characteristic that the transformer primary side voltage can still be approximated as a square wave when the parallel resonant capacitor capacity is much smaller than the series resonant capacitor,the first harmonic analysis(FHA)is adopted to obtain current gain curve.According to the characteristics of the current gain curve,the optimal operating region selection strategy is proposed,and the calculation method of the LCC resonator and transformer parameters is given in detail.Lastly,a driver with an input voltage of 395 V,an output current of 2 A and an output voltage range of 16 V to 48 V was designed to verify the rationality of the method.