摘要：本文論述了脫硫脫硝高壓交直流疊加電源中的交流電源部分，分析了電路工作在容性及感性狀態(tài)下的工作原理和實驗波形。為了提高系統(tǒng)的脫硫效率，有必要提高開關(guān)頻率,但是提高開關(guān)頻率必然導致器件損耗加大，因此需要采用軟開關(guān)方法降低開關(guān)損耗。本文分析了電路工作在感性條件下，利用全橋移相軟開關(guān)控制方法實現(xiàn)開關(guān)管的軟開通與軟關(guān)斷。 敘詞：脫硫脫硝供電電源，軟開關(guān)，全橋移相控制 Abstract：The AC power source of desulfurization and desalpetration power source, etc, a high DC power source added by a high voltage and high frequency AC power source, is presented in this paper. The principle and the waveforms of the system are analyzed.　In order to raise the efficiency of the system, it is necessary to raise switch frequency. But it will lead to increase switch loss, so soft switching is needed. In the paper and in the induction condition, using phase-shifted full-bridge control method to realize soft turn-on and soft turn-off is analyzed. Keyword：desulfurization and desalpetration power source，soft switching，phase-shifted full-bridge control