一种新颖的耦合电感无源无损缓冲电路及其设计方法

Novel Passive Lossless Snubber Circuit with Coupled Inductors and Its Design Method

无源无损软开关技术是一种通过附加无源器件实现开关管软开关的手段,因其控制简单易于实现,在工程应用中得到了广泛的应用。但传统无源无损软开关技术应用于大功率场合时,流入缓冲电路二极管的电流较大,造成了成本上升和散热困难等一系列问题。首先分析了传统无源无损软开关技术应用于大功率Boost变换器上存在的不足,随后提出了一种新型耦合电感无源无损缓冲电路以及该电路谐振元件参数的设计方法。该设计以避免谐振回路参与主电路的续流过程为主要思路,降低流过二极管与缓冲电感的电流,提升变换器的转换效率。通过设计一台15 kW的样机,验证了该缓冲电路的正确性与可行性。

The passive lossless soft switching technology achieves soft switching by adding passive components in the power circuit.It has been widely applied in engineering applications owing to its simple control and easy implementation.However,when the traditional passive lossless soft switching technology is applied under high-power scenarios,the current flowing into the diode in the snubber circuit will be relatively large,which causes a series of problems such as rising costs and difficult heat dissipation.In this paper,the shortcomings of the traditional passive lossless soft switching technology applied to high-power Boost converters are analyzed at first.Then,a novel passive lossless snubber circuit with coupled inductors is proposed,and a design method for the parameters of its resonance components is also given.Its main idea is to avoid the resonance circuit participating in the freewheeling process of the main circuit,reduce the current flowing through the diode and the resonance inductor,and improve the conversion efficiency of the converter.A 15 kW prototype was designed to verify the correctness and feasibility of the proposed snubber circuit.