Modified multilevel buck–boost converter with equal voltage acrosseach capacitor: analysis and experimental investigations

Abstract

Recently, the circuitry of Multilevel Buck-Boost Converter (here, called MBBC 1 ) is suggested in the literature to attain high inverting voltage by increasing the output levels of the classical buck-boost converter. However, the only circuitry is suggested and detail investigations are not provided. The major drawbacks of MBBC 1 are the voltages across the load capacitors side are unequal and the input current is not continuous. Therefore, the MBBC 1 is not well suited to feed multilevel inverter where a stack of capacitors is required with equal voltage across each capacitor. A new modified MBBC called MBBC 2 is proposed to achieve continuous input current and equal voltage across each capacitor. The circuitry of MBBC 1 and MBBC 2 configurations are analysed with non-idealities to investigate its effects on the voltage conversion ratio. The Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) boundary conditions and modes of operation for MBBC 1 and MBBC 2 configurations are presented. The procedure for basics design and components selection is elaborated. Additionally, comparison of MBBC 1 , MBBC 2 and recently proposed a non-isolated DC-DC configuration is provided. The performances of MBBC 1 and MBBC 2 configurations are tested with simulation and experimental work, and obtained results consistently show a good agreement with the theoretical approach..