Research On A Combined Input-series Output-parallel DC-DC Converter

Non-Grid-Connected Wind Power is directly applied in High Energy-Consuming Industriesthrough simple transformation, which avoids Grid-Connected problem on a certain extent. This paperstudies a combined Input-series Output-parallel full-bridge (ISOP-FB) direct current converter thatcontains the composite structure of full-bridge direct current transformer (DCT) and full-bridge directcurrent converter where high voltage will be transformed to low voltage that is supplied to a load bythe two classes’ module, the modular design of the converter is realized and the circuit structure andthe control strategy are simplified.The full-bridge direct current transformer works at the biggest duty cycle without filterinductance output, with rapid response speed and proportional relation between input voltage andoutput voltage, the switches are ZVS easily. It is suitable for high voltage and power occasion, whichcan naturally realize the stability of the modules via the clamping action of output capacitance voltage.The full-bridge series resonant converter acts as full-bridge direct current converter module. It canboth reduce the input voltage and control the output power of the combined ISOP-FB direct currentconverter. The operation principle, output characteristics and the influence of the related parametersof the full-bridge direct current transformer is analyzed theoretically, output characteristics andoperation principle of the full-bridge series resonant converter is illustrated. Simulation results aregiven to verify the design method, principle prototype is designed on this basis and the experimentalresults verify the effectiveness of the converter.To realize safe and reliable working of the combined ISOP-FB direct current converter, the inputvoltage and the output current of the converter must be controlled within permissible errors. Thispaper analyzes the relationship between input voltage and output current, the reasons and influencefactors of the module input filter capacitor voltage being different, including input filter capacitance,transformer ratio, leakage, duty, switching frequency, the switch’s voltage drop etc. The problem ofinput filter voltage un-sharing is finally analyzed under the environment of transition of input voltageand load. Simulation model and principle prototype consisting of two the full-bridge direct currenttransformer and one phase-shifted full bridge series resonant converter is built in the lab. Thesimulation and experimental results verify the effectiveness of the propose design.