Research On Push-pull Forward Buck Mode Grid-connected Inverter With High Frequency Link

Nowadays, with the problem of environmental pollution and exhaustion of energyresources is worse and worse, exploring and using of new energy becomes more and moreimportant. Grid-connected inverter as one of the important parts in grid-connected powergenerator system, its performance directly influences the efficiency of the use of power.Based on the detailed discussion to the actuality and development of grid-connectedinverter, the push-pull forward Buck mode grid-connected inverter with high frequency linkis proposed in this paper, which is specially fit for low-voltage and high current inputoccasion. The inverter is composed of the high frequency inverter, high frequencytransformer, rectifier, polarity reversal inverter and the filters. The inverter is controlled bytransient current SPWM control strategy.In this paper, circuit topologies, transient current control strategy, the characteristic ofsteady principle, working mode and design criteria for the key circuit parameters are deeplyinvestigated, and the design of output filter is also given.The analysis and simulation results of1kVA40~60VDC/220VAC50Hz the push-pullforward Buck mode grid-connected inverter with high frequency link have shown that theinverter has the advantages such as simple topology, high frequency electrical isolation,unidirectional power flow, three stage power conversion (DC-HFAC-HFPDC-LFAC),DC/DC stage controlled in SPWM, the power switches of polarity reversal inverterswitching under low frequency and ZVZCS etc. The correction and feasibility of theproposed Buck mode grid-connected inverter with high frequency link are fully verified bythe principle test.