基于磁集成设计的超高频谐振反激变换器研究

Research on very high frequency resonant flyback converter based on integrated magnetic design

研究了一种基于磁集成设计的超高频谐振反激功率变换器,通过充分利用电路中的寄生参数,减小了电路中无源器件的数量,从而进一步提升变换器的功率密度.采用空心PCB电感构建松耦合变压器,利用其漏感作为谐振电感、功率管寄生电容作为谐振电容构建谐振网络.通过合理设计变压器电学参数,保证了功率器件软开关的实现.然后,基于Wheeler公式对空心变压器的几何结构进行估算.进一步地,基于有限元仿真对空芯变压器的结构进行调整,结合设计目标实现了空心变压器的精确设计.最后搭建了30 MHz,25 W的超高频谐振反激变换器样机.额定功率下,样机达到了80.5%的效率和5.5 W/cm^(3)的功率密度,验证了以上方法的有效性.

A VHF resonant flyback power converter based on integrated magnetic design was studied.By taking advantages of parasitic parameters in the circuit,total passive components count was reduced which further improves the power density.Firstly,a loosely coupled transformer was constructed with air-core PCB inductors.The leakage inductance of the transformer was used as the resonant inductor and the parasitic capacitance of the power switch was used as the resonant capacitor.By properly designing transformer electrical parameters,zero-voltage-switching(ZVS)of the power switch was achieved.Then,the initial transformer geometric structure was calculated with improved Wheeler formula.Furthermore,the transformer geometric structure was adjusted based on finite element simulations,so that to achieve the desired electrical parameters.Finally,a 30 MHz,25 W prototype was built.At rated power,the prototype achieves 80.5%efficiency and 5.5 W/cm^(3) power density,which verifies above method.