自持移相LCC谐振变换器稳态分析及参数设计

摘要

The SSPSM(Self-Sustained Phase-Shifted Mode) LCC resonant converter with capacitive output filter guarantees the ZVS(Zero Voltage Switching) in whole load range,but its analysis and design become burdensome due to its nonlinearity.The equivalent circuit of SSPSM-LCC converter is established,which models the high-frequency transformer,secondary-side rectifier and output filter as the complex impedance based on the improved FHA(First Harmonic Approximation).Its steady-state characteristics are analyzed,including voltage conversion ratio,peak resonant current and ZVS features.The influence of key parameters such as input impedance angle,rectifier non-conduction angle and the resonant capacitor ratio,on the steady-state characteristics is explored and their design principles are given.A parameter design method for constraining the input impedance angle is introduced.Experimental results verify the correctness of theoretical analysis and parameter design.%采用单电容滤波器的自持移相LCC谐振变换器能够在全负载范围内实现软开关,但非线性特性显著,增加了分析与设计难度.基于改进基波近似法将高频变压器、副边整流器及输出滤波电容作为一个整体等效为一个复数阻抗的形式,建立了自持移相LCC谐振变换器的等效电路模型.分析了电压增益、谐振电流峰值、软开关区域等稳态特性.指出了输入阻抗角、副边整流关断角和谐振电容比等关键电路参数对变换器稳态特性的影响以及设计原则,并提出一种限定输入阻抗角的参数设计方法.实验结果验证了理论分析及参数设计的正确性.