移相全橋ZVS變換器整流橋寄生振蕩的抑制

摘要：移相全橋ZVS變換器是中大功率DC/DC變換場合的理想拓撲之一，但在其輸出整流二極管反向恢復時，整流橋產生寄生振蕩，二極管上存在很高的尖峰電壓。這將帶來電路損耗，并影響整流橋的使用壽命。本文分析了振蕩產生的原因，并介紹了抑制的方法。重點分析了一種原邊加箝位二極管的緩沖電路形式，制做了一個5.5kW樣機，并給出了對比實驗結果。 敘詞：寄生振蕩；尖峰電壓；箝位二極管 Abstract：There exists a problem of the Phase-shifted full-bridge zero-voltage-switching(PS-FB-ZVS) PWM converter, which is widely used at medium and high power levels, that the output rectifier diodes suffer the parasitic oscillation and voltage spike resulted by the reverse recovery of the rectifier diodes. In this paper, the reasons and restraining methods are discussed, and a novel ZVS converter is proposed which adopts two clamping diodes in the first side of transformer. The operation principle of the novel converter is analyzed and the experimental results of a 5.5kW prototype converter are also given. Keyword：parasitic oscillation; voltage spike; clamping diodes