The Study Based On Variable Modality For Isolated DC/DC Converter With Wide Input Range

The thesis based on the new energy, researched on DC/DC converter with the wide input range. According to the review of the development and application of DC/DC converter, several possible solutions are proposed for two-stage and single-stage converter.For two-stage DC/DC converter, the common structure is Boost+LLC, Boost is controlled while LLC is just as DC step-up transformer in this structure. Unfortunately, the structure is patented by Vicor. The thesis proposed a variable control mode, when the input is low, Boost works and LLC works in fixed frequency just as DC step-up transformer, while the input voltage is high, Boost is short and LLC works in variable frequency. For wind generator, parasitic inductances are existed, and a single-switch Boost circuit is proposed to with the parasitic inductances as Boost inductors.For single-stage DC-DC, a variable topology (FBLLC-HBLLC) is proposed. Compared with traditional variable topology, this solution doesn’t add any circuit even device. This topology is suitable for step-up and step-down with the input voltage expending double in theory.For variable topology drive, the thesis proposes a novel drive solution Si8235to meet the duty cycle range of any Mosfet from logic0to1. The IC has the advantage of meeting the demands of safety、simple control、the well drive effect.