Research On Full-bridge CLL Resonant Converter For Wide Input Voltage Applications

DC/DC resonant converters with wide input voltage applications have been widely used in new energy generation,transportation and other fields.Compared with the traditional Variable Frequency Control(VFC)control,the hybrid control resonant converter only improves the converter in terms of control,without adding additional power devices and passive components.And has the advantages of simple structure,narrow range of switching frequency and high efficiency.In this research,the hybrid control of VFC and primary side phase shift control(PS-PSC)of full-bridge CLL resonant converter is studied.The working principle of VFC and PS-PSC of converter is analyzed,separately.The voltage gains characteristics of the VFC mode and the PS-PSC mode of the converter are analyzed using the fundamental component method and the energy conservation method,respectively.The conditions of zero voltage switching(ZVS)of the primary side switches in PS-PSC mode are analyzed in detail.The 500 W prototype is designed to verify the hybrid control of the VFC and PS-PSC full-bridge CLL resonant converter.Secondly,in order to further reduce the range of switching frequency variation and improve the efficiency of the high-voltage input of the converter,a secondary side phase shift control(SS-PSC)is added to the hybrid control of VFC and PS-PSC.The working principle and voltage gain characteristics of SS-PSC are analyzed.In addition,the design method of the CLL resonant converter that realizes the hybrid control of three modes is also given.The 500 W prototype was designed to verify the hybrid control of SS-PSC,VFC and PS-PSC.Finally,the application of variable inductors(VI)in full-bridge CLL resonant converters is studied in detail.Aiming at the application of variable inductance in resonant converter,the full-bridge CLL resonant converter was chosen as the basic current to study the variable inductance controlled resonant converter.The working principle of the variable inductor is analyzed in detail,and the design method of the variable inductor is given.The working principle of the variable inductor is analyzed in detail,and the design method of the variable inductor is given.The feasibility verification and experimental results analysis of the variable inductance control were carried out by the prototype.