基于符号序列描述的一类分段光滑系统中分岔现象与混沌分析

从拓扑序列出发，提出了描述DC/DC变换器一类分段光滑系统中的分岔现象和混沌行为的符号序列方法，根据最大子序列的性态判别分岔的类型，以及检测边界碰撞分岔的发生.例如,当发生倍周期分岔时，最大子序列保持不变；当发生边界碰撞分岔时，最大子序列发生变化；混沌态则没有最大子序列.研究表明，占空比是表征DC/DC变换器一类分段光滑系统动力学行为的一个最本质的量，“饱和非线性”是引起边界碰撞分岔产生的根本原因. 关键词： 符号序列 分岔 混沌 分段光滑系统

Analysis of bifurcation and chaos in a class of piecewise smooth systems based on symbolic sequence

Based on the sequence of circuit topologies, a symbolic sequence method is proposed for analyzing the bifurcations and chaos in a class of piecewise smooth systems like DC/DC converters. The largest subsequence(LS) is used to distinguish the type of bifurcation and detect border collision bifurcation e. g., when a period doubling bifurcation occurs, the LS is unchanged; when border collision bifurcation occurs, the LS is changed; and when chaos occurs,the LS does not exist.It is shown that the duty ratio is an essential variable for describing the nonlinear dynamics of a class of piecewise smooth systems like DC/DC converters, and saturating nonlinearity is the root cause of border collision bifurcation.