Research On Dual Buck-Boost Inverters With Large Boost Ratio

With the development of society and economy and the improvement of productivity,the environmental problems caused by traditional fossil energy are more and more concerned by people in the world.Countries around the world are paying more and more attention to the adjustment of energy structure,and clean energy such as solar energy has the advantages of not polluting the environment and being renewable..Therefore,vigorously developing the use of clean energy such as solar energy,wind energy and water energy has increasingly become the development trend of the world's energy utilization.Generally,new energy power generation devices such as solar power generation and wind power generation often have a low output voltage level,which cannot meet the requirements of grid connection or local load.Therefore,it is usually necessary to implement inverter and boost functions.On the basis of the traditional basic converter,the paper analyzes and studies a dual Buck-Boost inverter which is composed of two bidirectional Buck-Boost converters.Indepth theoretical analysis and simulation research on key technologies such as circuit topology,small signal modeling,closed-loop network design,key circuit parameters,and sampling circuit design have been conducted,and important conclusions have been obtained.The circuit topology of the double Buck-Boost inverter with large boost ratio and the voltage and current double closed-loop control strategy are proposed and analyzed.The circuit topology is composed of two identical bidirectional Buck-Boost converters connected across the load.,And replace the common inductance in the circuit with the tapped inductance,realize the single-stage inverter,and has the circuit characteristics of large step-up ratio.The circuit working mode of the double Buck-Boost inverter with large step-up ratio is deeply studied,small-signal modeling is carried out,and the closed-loop compensation circuit is designed to increase the stability and response speed of the system.The design criteria of key circuit parameters such as tap inductance,output filter capacitor,switch voltage and current stress,voltage and current sampling control are derived and designed.A 500VA30VDC/22050 Hz AC double Buck-Boost inverter with a large step-up ratio is designed,and simulation analysis using PSIM software confirms the feasibility of the proposed large-boost ratio inverter.The proposed double Buck-Boost inverter with a large boost ratio can realize a single-stage inverter and has the characteristics of a large boost ratio.It has the advantages of simple circuit structure,high voltage boost,and high output waveform quality.It provides an effective way for the low-voltage boost inverter output of the photovoltaic power generation system.