电源电路器件建模及WCA技术研究

发布时间：2018-01-07 07:26

本文关键词：电源电路器件建模及WCA技术研究　出处：《西安电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：最坏情况电路分析(Worst Case Analysis,WCA)是一项在设计限度内预测电路性能稳定性的技术。在航天应用中对电源系统的可靠性要求很高,最坏情况分析是必须执行的一步。然而,国内各个设计分析单位没有统一的电路分析工具,缺少航天专用元器件的测试参数,进行最坏情况电路分析的单位很少,少数进行WCA的单位使用的分析方法也不一致,难以对分析结果进行统一的评判。本文主要研究电源电路的最坏情况分析技术,并针对行业内广泛应用的Saber工具,给出了元器件建模、最坏情况分析的具体方法及详细流程。具体研究内容如下:1.研究了最坏情况分析技术的方法论。介绍了最坏情况电路分析的相关概念,包括参数容差分析技术、灵敏度分析技术、最坏情况电路性能分析和最坏情况元器件应力分析,比较了WCA的三种方法,并提出了基于Saber工具的电路设计与WCA流程,提出建立一个完备的宇航专用器件数据库以及建立完善的元器件模型库是利用软件工具进行电路设计与WCA的关键,而且直接影响到仿真分析结果的精度。2.研究了在Saber仿真环境下的元器件建模方法。总结了Saber工具中常用的几种建模方法,并针对常用元器件(二极管、三极管、MOSFET、运放和数字元器件等)分别给出了建模方法,对比了同类器件的不同建模方法与适用性,而且每类器件的建模都给出了具体的实例与电路验证方法。3.研究了开关电源的基本原理。讨论了开关电源的类型、工作原理和控制方式,并在Saber仿真环境下,设计了一个Boost型电压变换器,将12V输入电压转换为20V输出电压,仿真验证了其满足各项性能指标。4.研究了利用Saber工具对电路进行设计与WCA的方法。介绍了Saber集成的灵敏度分析工具、Monte Carlo分析工具、最坏情况分析工具、应力分析工具的使用方法与特点。并以本文设计的Boost电路为例进行了最坏情况分析,利用不同方法进行WCA。仿真表明:利用Saber的最坏情况分析工具分析得到的电路性能参数最劣,该工具采用快速搜索算法能较快得到极值点;利用Monte Carlo分析工具的分析结果依赖于抽样的次数以及电路参数容差的分布,在抽样次数不多时,存在抽不到电路最坏情况的可能性,但是可以得到电路性能参数的分布。通过灵敏度分析与最坏情况分析对电路的性能进行了改善,减小了输出电压的偏差范围。对电路进行最坏情况应力分析发现电流采样电阻和电感过应力,证明了WCA的重要性,即使电路性能参数满足要求,但是依然存在可靠性问题,通过WCA可以发现电路的薄弱环节,辅助设计者进行元器件选型和电路加固。
[Abstract]:Worst Case Analysis. WCA is a technique to predict circuit performance stability within design limits. In aerospace applications, the reliability of power supply systems is very high, and the worst case analysis is a necessary step. There are no uniform circuit analysis tools for each design and analysis unit in China, and the test parameters of special aerospace components are lacking, and very few units carry out the worst case circuit analysis. The analysis methods used by a few units carrying out WCA are also inconsistent, so it is difficult to judge the analysis results uniformly. This paper mainly studies the worst-case analysis technology of power supply circuits. According to the widely used Saber tools in the industry, the component modeling is given. The concrete method and detailed flow of the worst-case analysis are as follows: 1. The methodology of worst-case analysis technique is studied, and the related concepts of the worst-case circuit analysis are introduced. It includes parameter tolerance analysis, sensitivity analysis, worst-case circuit performance analysis and worst-case component stress analysis. Three methods of WCA are compared. The circuit design and WCA flow chart based on Saber tools are also presented. It is proposed that the establishment of a complete database of special aerospace devices and the establishment of a perfect model library of components are the key to the circuit design and WCA using software tools. And directly affect the accuracy of simulation analysis results. 2. The modeling method of components in Saber simulation environment is studied. Several modeling methods commonly used in Saber tools are summarized. The modeling methods for common components (diodes, transistor MOSFETs, operational amplifiers and digital components etc.) are given, and the different modeling methods and applicability of similar devices are compared. And the modeling of each kind of devices gives concrete examples and circuit verification methods. 3. The basic principle of switching power supply is studied. The type, working principle and control mode of switching power supply are discussed. In the environment of Saber simulation, a Boost voltage converter is designed to convert 12V input voltage to 20V output voltage. Simulation results show that it meets the performance requirements. 4. The method of designing circuit and WCA using Saber tool is studied. The sensitivity analysis tool of Saber integration is introduced. Monte Carlo analysis tool, worst-case analysis tool, stress analysis tool use method and characteristics. And taking the Boost circuit designed in this paper as an example, the worst-case analysis is carried out. The simulation results show that the circuit performance parameters are the worst by using the worst-case analysis tool of Saber, and the extremum can be obtained quickly by using the fast search algorithm. The analysis results using Monte Carlo analysis tool depend on the number of sampling and the distribution of circuit parameter tolerance. When the sampling number is small, there is the possibility that the worst case of the circuit can not be pumped. However, the distribution of circuit performance parameters can be obtained. The performance of the circuit is improved by sensitivity analysis and worst-case analysis. By analyzing the worst-case stress of the circuit, it is found that the current sampling resistance and the inductor overstress prove the importance of WCA, even if the circuit performance parameters meet the requirements. However, there is still a reliability problem. The weak links of the circuit can be found by WCA, and the component selection and circuit reinforcement can be assisted by the designer.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN86

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