A novel high step-up DC-DC multilevel buck-boost converter using voltage-lift switched-inductor cell

This paper presents a novel high step-up DC-DC multilevel buck-boost converter using voltage-lift switched-inductor (VLSI) cell. To achieve high conversion ratio cascading of conventional DC-DC converter is not a practical solution. Thus high step-up multilevel buck-boost converters are employed to achieve high conversion ratio. The proposed high step-up DC-DC multilevel buck-boost converter is a non-isolated topology which combines the function of voltage-lift switched-inductors (VLSI) cell and voltage multiplier. In this paper voltage-lift switched-inductor (VLSI) cell is used to advance the boost capability of multilevel buck-boost converter. 2N+3 diodes, 2N capacitors, two inductors and single switch are needed to design proposed N-level buck-boost topology. Proposed DC-DC multilevel buck-boost topology can be synthesized by using low voltage rating devices because voltage stress across each power devices is less. The main advantage of proposed DC-DC multilevel topology is high conversion ratio is achieved without using coupled inductor, transformer and extreme duty cycle. The voltage gain of proposed buck-boost multilevel converter is depends upon the duty cycle and number of levels. The proposed buck-boost multilevel converter has been designed for three levels with rated power 200W and output voltage is 220V Input supply voltage is 12V, duty cycle is 70% and switching frequency is 50KHz. The proposed buck-boost multilevel converter topology is simulated in MATLAB/SIMULINK.