【作者】 杨亮；

【导师】 石季英；

【作者基本信息】 天津大学 ， 电工理论与新技术， 2004， 硕士

【摘要】 DC-DC开关变换器运行过程中出现的不明电磁噪声、控制系统的不稳定、甚至运行状态的突然崩溃等现象是变换器工作在混沌状态的体现。混沌现象是DC-DC开关变换器非线性特性的一种外在表现，目前已成为电力电子研究领域的一个前沿课题。但是，由于开关变换器的非线性，复杂性，研究仍然处于初始阶段。本文以基本DC-DC变换器(Boost和Buck变换器)为对象，从变换器工作过程，离散建模，混沌分析等几个方面，进行了深入的理论研究和模拟仿真。本论文的具体内容如下：(1)简要介绍了DC-DC变换器中混沌现象的研究现状以及变换器混沌建模的一般方法，为软开关变换器离散数学模型的建立以及变换域分析方法的引入奠定了数学基础。(2)采用模块化的思想，简化了电压反馈控制方式零电流开关Boost和Buck变换器工作状态的分析，建立了变换器不连续导电模式下的系统离散混沌数学模型，为进一步的理论分析和模拟仿真打下基础。(3)根据系统稳定性判据确定了稳定工作区域，得出主要元件参数的稳定工作范围，并根据仿真结果分析了谐振元件的加入对于变换器运行稳定性和混沌特性的影响。(4)首次将变换域的思想引入到DC-DC变换器混沌理论分析当中，建立了电流控制Boost和Buck变换器连续模态和不连续模态下的差分方程，基于Z变换获得了变换器离散系统函数。(5)根据Z变换下离散时间系统稳定性判据确定了系统参数的稳定工作范围，根据仿真结果验证了电流误差反馈系数变化时，系统由不稳定运行状态逐渐发展到混沌运行的变化过程，并探讨了变换器工作模态和反馈控制方式对于系统混沌现象的决定性影响作用。更多还原

【Abstract】 The appearance of strange or irregular phenomenon , including intangible electromagnetism noise，control system’s instability and system state’s abrupt collapse is a representation of chaotic operation of power converters. Chaos is the exterior representation of nonlinear character of DC-DC converters. Now the chaos research has been a most popular topic in power electronics research field. But, because of the nonlinear and complexity, the study of chaos is still in a elementary phase. Based on Boost/Buck converters, this paper has studied and simulated deeply in the aspect of operation procession, discrete-time modeling, bifurcation discussion of converters.The main work of this paper is shown in details as follows:(1) Briefly introduce the former study of chaos and the common method of chaos modeling. These content has set a foundation of time-discrete modeling of the soft-switching converters and the introduction of transform-domain analysis method.(2) Based on module theory, the operation state analysis of voltage-feed ZCS Boost converter has been simplified and the time-discrete mathematic modeling of DCM mode has been setup.(3) The stability operation parameter range has been decided according to the stability criterion, and the analysis of influent of resonance inductance and capacitance to converter’s chaos character is carried out.(4) The transform-domain analysis method is firstly introduced into the nonlinear analysis of DC-DC converters. The mathematic model of current-control Boost/Buck converters operating under CCM/DCM mode is proposed, and the time-discrete system function is established based on Z-transformation.(5) The stability parameter range is decided according to the time-discrete system stability criterion under Z-transformation. The change procession of DC-DC converters from instability to chaos is validated according to Pspice simulation. And the decisive influence of operation mode and feedback control method is discussed.更多还原