准谐振软开关变换器精确建模及分叉现象分析

Discrete Mapping Modeling and Bifurcation Phenomena Analysis for Quasi-Resonant Soft Switched Converter

软开关电力电子线路存在的高阶、多模态、工作频率负载依赖等特性限制了适用于硬开关电路的基于固定周期的离散时间映射建模方法在软开关电路中的应用。该文试图提出一种基于变周期的离散时间映射模式,将固定周期的离散时间映射建模方法拓展应用到软开关电路系统,并基于该建模方法对电流型准谐振软开关变换器中出现的频率跃变分叉现象进行了分析,得出了系统负载电阻变化所引起的多零相位解是导致该分叉现象产生的主要原因的结论,其分析结果与模型仿真结果达到了较好的一致。

The Characteristics of high order, multi operating mode, running frequency uncertainty rooted in softswitched circuit system limits the application of fixed time discrete mapping modeling method , which is suitable for hard switching circuit system,to the soft - switched circuit system. This paper proposes a novel discrete time mapping modeling method adapted for varied period characteristic and carries out a series bifurcation analysis on frequency abrupt transition phenomena from high frequency orbit to a lower one. Based on impedance phase angle analysis, this paper concludes that the absence of multi - frequency solutions along with load resistance variation is the trigger of frequency bifurcation. The analysis results has verified the simulation result of the novel model.