Novel bipolar output high step-up sepic DC/DC converter with parasitical parameters self-balance

Purpose The purpose of this study is to propose a converter that can maintain voltage balance between the bipolar outputs against the effects of parasitical parameters of all components, except for those of the clamped diode. Design/methodology/approach The single-switch bipolar output Sepic DC/DC converter based on coupled inductor is analyzed. Its theoretical analysis and principal operation are discussed in detail. Finally, an experimental prototype is established to verify its performance. Findings The effect of the drive signal of the power switch on the voltages of bipolar outputs is completely eliminated by the proposed converter. The use of a two-winding coupled inductor shared by two step-up cells in the proposed converter not only effectively reduces the size but also eliminates the issue of coupling inductor winding difficulties caused by the need to match the parasitic parameters of different windings, which leads to bipolar output voltage imbalance. Therefore, there is an almost perfect voltage balance in bipolar outputs of the proposed converter. Originality/value The proposed converter offers several advantages, including continuous input current, a full range duty cycle, a coupled inductor composed of two windings, high voltage gain and zero-current switching for both switch and diodes. Besides, there is low voltage stress on the components and low output voltage ripple in this converter, attributed to its bipolar output.