DC current rejection for a half-bridgecurrent-mode control grid-connected inverter

摘要

the dc current rejection of a single phase half-bridge grid-connected inverter with a line-frequencyisolation transformer is researched in this paper. Theimpact of the magnetic dc bias of the transformer is givenout from the mathematic model of the transformer incurrent-mode control. For the half-bridge current-modeinverter, the dc current rejection method is presented basedon the relationship of dc current component and voltagesacross the filter capacitors of the dc bus. Simulation andexperiment results indicate that the dc component ofinverter current saturates the transformer and degrades thequality of current injected into the grid. With voltagebalance control of the filter capacitors, the dc currentcontrol of half-bridge current-mode grid connected inverteris realized.