Research On Four-Switch Buck-Boost Converter Based On Three-Mode Control

In recent years,DC/DC converters with wide input voltage range are urgently needed in the fields of new energy power generation and electric vehicle charging;traditional DC/DC converters cannot meet the requirements of modern electronic technology development.The four-switch Buck-Boost converter(FSBB)has a wide range of applications in power supply circuits due to its buck-boost function,wide input voltage range.The development of electronic technology has made digital control gradually replace traditional analog control technology with its unique advantages,which has been favored by people.In this paper,the digital control of FSBB converter is researched and designed.Based on the analysis of the working principle of FSBB converter,the power transmission and energy loss of the converter are briefly analyzed.According to the gain characteristics of the converter,the control method of FSBB converter is analyzed and compared.Finally,the three-mode control strategy of buck,buck-boost and boost is adopted.Secondly,based on the modeling of the state space of the FSBB converter,the closed-loop controller design of the converter is carried out.At the same time,the component parameters,digital control chip and hardware and software circuits of FSBB converter are selected and designed.The simulation model of FSBB converter is built by using MATLAB software,and the circuit is simulated and analyzed to achieve the purpose of verifying the theoretical analysis.Finally,a prototype with input voltage of 24~72V,output of 48 V and rated power of 240 W was developed,which verified the correctness of theoretical analysis and control strategy.Figure[73] Table[3] Reference[54].