Research And Design Of Non-inverting Buck-boost Converter

With the development of power electronic technology,the application of DC/DC converter is more and more extensive.However,traditional buck-boost DC/DC converters cannot meet the needs of fields such as aerospace,new energy power generation,and consumer electronics due to their own limitations.In these fields,there is an urgent need for a DC/DC converter with a wide voltage input range and capable of realizing the buck-boost function.The non-inverting Buck-Boost(NIBB)converter has a wide input voltage range and can also realize the buck-boost function.Compared with the traditional buck-boost converter,it has the advantages of the same input and output voltage polarity,less electrical stress on the switch tube,and less passive components.Therefore,it is very meaningful to study the topology and control strategy of the NIBB converter.Firstly,according to the classification rules of DC/DC converters,the isolated DC/DC converters and non-isolated DC/DC converters are respectively introduced in this paper.And the common non-isolated DC/DC converters are compared,and the advantages of the NIBB converter are reflected through the comparison.The topology and working principle of the NIBB converter are analyzed in detail,and four working modes of the converter are studied.On this basis,the basic principle and corresponding modulation strategy of the converter under the traditional control strategy are analyzed in detail.And deduce the expression of inductor current in the converter under the traditional control strategy and decide to adopt the modulation strategy of dual modulation wave-single carrier in the subsequent control strategy.Secondly,starting from the actual circuit,the principle that the NIBB converter produces the operational dead zone when the input voltage and the output voltage are close is analyzed,and a four-mode control strategy to eliminate the operational dead zone is further proposed.According to the principle of the four-mode control strategy,the inductor current expression of the converter under the four-mode control strategy is deduced.At the same time,the corresponding converter small-signal model is established for the four-mode control strategy,and a compensator that combines lead correction and PI control is designed.Comparing the four-mode control strategy with the traditional single-mode,two-mode,and three-mode control strategies in terms of inductor current ripple,average value,and effective value.The comparison found that the four-mode control strategy has smaller inductor current ripple,average value and effective value in the entire working range,which reflects the advantages of the fourmode control strategy.Finally,the four-mode control strategy of the NIBB converter is simulated and verified in MATLAB/Simulink software,and the simulation results are consistent with the theoretical analysis.The hardware circuit of the converter was designed in Altium Designer software,a prototype of the converter was developed,and the corresponding experimental platform was built.The four-mode control strategy of the NIBB converter is experimentally verified,and the experimental results prove the feasibility and effectiveness of the four-mode control strategy.