Research And Design Of 2kW Hybrid Control LLC Resonant Converter

This paper studies a wide range of output voltage under high efficiency DC/DC converter.Full bridge LLC resonant converter with a simple circuit structure,the output wide load range to achieve the original side of the switch zero voltage open(ZVS),secondary side rectifier diode zero current shutdown(ZCS)characteristics.LLC resonant converter control strategy includes phase shift control mode(PS)and variable frequency control mode(PF),each with advantages and disadvantages.In this paper,we first discuss the working process of the converter under frequency conversion and phase shift control mode,and use the fundamental analysis method and the time domain analysis method to analyze the basic characteristics of the converter,derive the gain characteristic curve of the input and output voltage,and then build the simulation through matlab Model,to verify the principle.Combined with the wide range of output and high efficiency requirements,a hybrid control strategy is proposed.Under the condition of wide output voltage,the appropriate mode switching point is selected.When the output voltage is low,the phase shift mode is adopted and the output voltage is high,Frequency conversion mode.Finally,according to the technical indicators of the project,the design of the main circuit parameters,the selection of components and the completion of a 2kW input experimental prototype,the experimental results show that:1)converter and phase shift mode can be combined to achieve a wide range of output voltage Adjustment.2)converter inverter mode switch can achieve ZVS,with high efficiency;phase shift mode can be achieved when heavy load ZVS,The efficiency of light load changes with the change of phase shift angle.