High Step-Up Ratio Flyback Converter With Active Clamp and Voltage Multiplier

Abstract

In this paper, an isolated high step-up ratio dc–dc converter aimed to be used in interface systems between low-voltage renewable energy sources, such as photovoltaic panels and fuel cells and the utility grid, is presented. The converter is based on the active clamp flyback topology with a voltage multiplier at the transformer secondary side. Such configuration, while naturally clamping the rectifier diode voltages thus avoiding the use of dissipative snubber circuits, allows the reduction of the circulating current during the active clamp operation due to the resonance involving the transformer leakage inductances and the diode parasitic capacitances. Experimental results taken from a 300-W-rated prototype are reported, showing the absence of parasitic oscillations after diodes and switch transitions and high efficiency, in agreement with the theoretical expectations

Closed Loop Contol of ZCS Interleaved High Step Up Converter for Sustainable Energy Applications

“…Each of the voltage multiplier cell is composed of the transformer winding with n 2 turns, clamp diode D c1 (2) , regenerative diode D r1 (2) ,clamp capacitor C c1 (2), multiplier capacitor C m1 (2). V in and V out are the input and output voltages, respectively.…”

Dead time optimization through loss analysis of an active-clamp flyback converter utilizing GaN devices

“…5 shows example partial ZVS waveforms when the inductor current is too small (a) and when the dead time is too short (b). The voltage across the device when it turns on, v ds , is calculated in (22). The switching loss due to this voltage, P sw , is calculated in (23).…”

“…In order to calculate the reverse conduction losses, the length of t dt2 needs to be determined by first calculating t dt1 , the length of time C r takes to discharge. This is done by setting v ds equal to zero in the device voltage equation shown in (22) and solving for time. (22) is rearranged in (24) and t dt1 is calculated in (25).…”

“…This is done by setting v ds equal to zero in the device voltage equation shown in (22) and solving for time. (22) is rearranged in (24) and t dt1 is calculated in (25). Now the length of t dt2 is calculated in (26).…”

An Isolated High Step-Up Converter with Non-Pulsating Input Current for Renewable Energy Applications

“…Therefore, a number of isolated step-up converters have been presented [16]- [18]. In [16], a converter integrating an active clamp flyback converter and a voltage multiplier is presented. However, the input current is pulsating, hence the high input current ripple.…”