一种无源无损缓冲电路的工程设计方法

介绍了一种具有较强工程实用价值的无源无损缓冲电路的工作过程,它利用辅助电感和辅助电容在主功率管开关过程中进行谐振,为开关管提供零电流开通(ZCON)和零电压关断(ZVOFF)条件,实现了软开关。详细讨论了这种缓冲电路的工程设计问题,提出一种基于缓冲电路损耗最小的优化设计方法。搭建了一台400V输入、110V/10A输出、开关频率为100kHz的带有该无源无损缓冲电路的Buck变流器样机,以验证无源无损缓冲电路的设计,并给出了实验波形和效率曲线。实验结果表明,缓冲电路有效地降低了开关管的电流和电压应力,抑制了主二极管反向恢复过程,变流器效率提高了约2%。实验中测得变流器的最高效率为95.2%。

Engineering Design Method of Passive Lossless Snubber

The principle of a passive lossless snubber which is valuable in engineering applications is analyzed. In order to realize the ZCON (Zero-Current On) and ZVOFF (Zero-Voltage Off) of the main MOSFET, the resonant process between the auxiliary inductor and auxiliary capacitors of the snubber is utilized when MOSFET is switching. Then the design problem of the snubber is detailed, and an optimal engineering design method based on diminishing mostly the power loss of the snubber is proposed. A prototype with 400V input, 110V/10A output and 100kHz switching frequency is constructed to verify the design of the snubber, and the experiment waveforms and the efficiency curve are provided as well. Experiment results indicate that the current stress and the voltage stress on the main switch are effectively reduced, the reverse recovery process of the main diode is inhibited, and the efficiency of the Buck converter is improved about 2%. The highest converter efficiency of 95.2% is observed in the experiment.