Voltage Gain Neutral-Point Shifter Converter With Step-Up/Down Capability for Wide Voltage Range Application

In order to solve the problem of poor performance of traditional step-up/down converter, a novel converter with voltage gain neutral-point shifter is proposed in this paper. Compare to traditional buck-boost converter, only one series-capacitor is externally added. The coupling capacitor in proposed converter is series connected in charging power path, and therefore, the voltage stress of switches is reduced. Furthermore, when appropriately adjusting the duty cycle, half voltage stress of conventional buck-boost converter can be obtained. By using interleaved control strategy, the proposed converter has lower inductor current ripple and also has the character of higher step-down conversion ratio without any other auxiliary circuit. Moreover, the inherent current sharing character could be achieved when the duty cycle of main switch is less than 0.5. Based on these merits, the efficiency of the proposed converter can be improved. In this paper, the operational principle, the related analysis including inductor current ripple and voltage stress analysis, loss comparison analysis of the proposed converter are given. Finally, experimental prototype with 72 W is established to verify the character of the proposed converter.