Research On A Four-port DC-DC Converter For New Energy Generation System

With the development of power electronics technology,the application of new energy power generation is becoming more and more extensive.The renewable energy generation system is generally composed of power generation,energy storage and electricity consumption,which can effectively solve the energy crisis and environmental pollution problems.The study of the paper is a four-port DC-DC converter for renewable energy generation system which has the advantages of high efficiency and high power density.Firstly,this paper introduces the research status of multi-port converters at home and abroad,and lists the topology and working principle of four traditional three-port DC-DC converters.Taking the full-bridge three-port converter as an example,its working principle and advantages and disadvantages are summarized.This article focus on the four-port DC-DC converters studied,the converter integrates a non-isolated Buck-boost converter and an isolated full-bridge converter to realize the multiplexing of the primary switch tube,reduce the number of switching devices,increase power density and conversion efficiency.In order to further study the converter,the working principle of the main circuit is analyzed in detail,and based on the volt-second balance principle,the input and output relation expressions of the converter are deduced,and the zero-voltage implementation conditions of the primary switch of the transformer are analyzed.Secondly,it adopts the voltage and current double closed-loop control system,and designs a current inner loop and a voltage outer loop compensation network.The working principle of the phase shift control strategy of the UC3875 chip and the peripheral circuit design of the chip are described in detail.Finally,it uses the most common power simulation software Saber,and bases on PWM phase shift control of UC3875 chip,the double closed loop control system of the four-port DC-DC converter has carried on the circuit modeling and simulation analysis,the simulation results show that the four-port DC-DC converter and its control method is feasible and effective.