本論文著重於研發與電網連接的電能反流器，並對併網同步機制、併網實虛功控制與反流器的柔切效果進行改善。轉換器於併網前須經過併網程序，使本地電壓與電網電壓之電壓振幅、角頻率與相位同步，本論文提出新型相位同步機制，達成快速的相位同步並降低併網瞬間之暫態電流。而在併網後，將由垂降控制維持功率輸送之穩定，而當參考功率命令發生改變，實功與虛功間的耦合關係，將導致其中一者的變化會於另一者產生耦合暫態誤差，所提之新型垂降控制架構將抑制耦合暫態，並保持精確的輸出功率。最後當轉換器具有功因調控時，轉換器之電壓與電流將存在相位差，傳統以載波為基礎之三相六開關反流器零電壓柔性切換策略並無法因應該情形，而使零電壓柔性切換的效果降低。本文所提出的零電壓柔性切換控制策略能延展操作的功率輸出範圍，在有功因調整下將能維持ZVS效果，以提升整體電路之效能。;In this thesis, the grid-connected inverter with synchronization mechanism, droop control and the soft-switching strategy are proposed. Before the converter connected to the grid, it is necessary to process the grid synchronization mechanism. The synchronization mechanism can make the amplitude, frequency and phase of the local voltage synchronize with the grid voltage. When the inverter is operated in grid-connected mode, the droop control is needed to regulate the output of the active power and reactive power. When the power reference command is changed, it will cause a transient error in the power transmission due to the coupling effect of the active power and reactive power. In this thesis, a new droop control scheme is proposed to reduce the coupling and reach accurate output power control. Finally, when the converter controlling the power flow with different power factor, there exists a phase shift between the output voltage and output current. The conventional carrier-based zero voltage soft switching strategy for three-phase six-switch inverters cannot deal with the phase shift, and it will decrease the effect of zero voltage soft switching. In this thesis, a novel active clamping zero voltage soft-switching strategy is proposed to increase the inverter efficiency under power conditioning.
