Research On DC/DC Converter For HVDC Input ASI

Because of many attractive characteristics, such as low switch voltage stress, inherent anti-break-through capability, high reliability, Two-Transistor Forward Converter(TTFC) has become one of the most widely used topology. This thesis presents the research on DC/DC converter for high voltage dc(HVDC) input Aeronautical Static Inverter(ASI). The converters presented are composed of the TTFC topology cell.Based on comparison between the parallel-parallel and parallel-serial combination TTFC, a novel two-transistor forward converter with parallel-serial/serial combination is proposed. This converter reduces greatly the current overshoot of the primary side switches and the voltage overshoot of the rectifying diodes. Moreover, the size and weight of the converter can also be reduced by interleaving technique and increasing frequency. The operation principle and parameter design of power circuits, LCD camping circuits and control circuits are proposed and A 6KW prototype is successfully developed.A novel DC/DC transformer is proposed in this thesis. This converter not only retains the advantages of TTFC but also has only two camping diodes. Moreover the proposed converter operates at nearly unity duty-ratio for very high efficiency and eliminates the voltage overshoot of the output rectifying diodes. The operation principle, output characteristics, the condition of ZVS turn-on of the switches and parameter design are illustrated. And the simulation and experimental results are also included in this thesis.