拓扑变换

Soft switching can improve the converters efficiency and reduce EMI. In comparison of some methods of approaching soft switching, this thesis presents a Diode Auxiliary Resonant Commutating Network which is composed by an auxiliary bridge and a resonant commutating inductor. This topology not only well realizes zero voltage switching, but also overcomes the parasitic oscillation in the secondary side Diodes. Simultaneously, this topology makes both the secondary side diodes and auxiliary diodes operate on the soft switching state too, which reduces more switching losses and provides requirement for the system to run stably under the condition of self-cooled.

软开关能够提高变换器的效率和降低EMI，通过比较目前多种实现软开关技术方案，本文研究了一种由辅助桥臂和谐振电感组成的二极管辅助谐振换流网络，不但很好地实现了ZVS，并且克服了副边二极管上寄生振荡；同时，该拓扑也使副边二极管和辅助二极管都工作于软开关状态，进一步降低了开关损耗，为系统能够在自冷的条件下稳定运行创造了条件。

First, the principle and the topologies of sin...

首先，针对单相DC/AC变换器，分析了它们的主电路拓扑结构、工作原理以及脉宽调制方式。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。