一款高效率AC-DC开关电源管理系统的环路设计

发布时间：2018-05-17 09:19

本文选题：反激 + 高效率　；参考：《电子科技大学》2014年硕士论文

【摘要】：开关电源的动态特性是其众多性能指标中的一种,拥有良好动态特性的开关电源对负载变化具有快速响应能力,更高的调节精度和更好的稳定性能。对开关电源环路进行小信号建模是分析和设计其动态特性的一种常用方法。然而在实际应用中,由于大量使用开关电源管理芯片以及隔离变压器等非线性器件,给开关电源环路小信号建模带来了一定困难。本文从工程实际应用出发,详细推导了一款高效率反激式开关电源管理芯片应用拓扑的建模过程,并对其环路稳定性进行了分析和设计以获得良好的动态响应特性。充分理解和掌握常见开关变换器基本拓扑的工作原理和控制过程是对开关变换器进行小信号建模的基础。文章首先从开关电源的工作原理出发,分析了几种基本拓扑的工作原理,并且介绍了适用于各种拓扑的基本建模方法,包括小信号建模法、状态空间平均法、开关器件模型等效法。接下来,为了设计反激式开关电源管理芯片应用电路的补偿网络,本文做了以下工作:首先,对本文采用的电源管理芯片基本原理进行简要介绍。为了使反激变换器拓扑的开环特性分析过程更加简明,还对应用电路进行了模块化处理。然后,在分析脉宽调制器(PWM)过程中,特别介绍了一款多模式PWM控制器的设计过程。该款控制器以多模式工作方式提高了对不同负载的适应能力,极大地降低了开关损耗,从而实现高效率的目的。这种多模式的引入虽然在电路设计上带来了一定难度,但从理论分析知这并没有使环路分析复杂化。最后,建立主电路模型并获得传递函数,结合之前的PWM传递函数得到电路除补偿部分的传递函数。根据设计目标和开关电源补偿准则,使用数学分析软件设计补偿网络以获得最好的动态响应。仿真和测试结果都表明,本文的设计工作基本满足预期要求。这对工程实践具有很好的参考意义。
[Abstract]:The dynamic characteristic of switching power supply is one of its many performance indexes. The switching power supply with good dynamic characteristics has the ability of quick response to load change, higher regulation precision and better stability. Small signal modeling of switching power supply loop is a common method to analyze and design its dynamic characteristics. However, in practical application, it is difficult to model the small signal of switching power supply loop because of the large use of switching power management chip and isolation transformer and other nonlinear devices. In this paper, the modeling process of the application topology of a high-efficiency flyback switching power supply management chip is derived from the practical engineering application, and its loop stability is analyzed and designed to obtain good dynamic response characteristics. Understanding and mastering the working principle and control process of common switching converter topology is the foundation of small signal modeling of switching converter. Starting from the working principle of switching power supply, this paper analyzes the working principles of several basic topologies, and introduces the basic modeling methods suitable for various topologies, including the small signal modeling method, the state space averaging method, the small signal modeling method and the state space averaging method. Switching device model equivalent method. Then, in order to design the compensation network of the application circuit of the flyback switch power supply management chip, this paper does the following work: firstly, the basic principle of the power management chip used in this paper is briefly introduced. In order to make the open-loop characteristic analysis of flyback converter topology more concise, the application circuit is modularized. Then, in the process of analyzing the pulse width modulator (PWM), the design process of a multi-mode PWM controller is introduced. The controller improves the adaptability to different loads and greatly reduces the switching loss so as to achieve the purpose of high efficiency. Although the introduction of this kind of multi-mode has brought some difficulties in circuit design, it can be seen from theoretical analysis that it does not complicate the loop analysis. Finally, the main circuit model is established and the transfer function is obtained. Combined with the previous PWM transfer function, the transfer function with the compensation part of the circuit is obtained. According to the design goal and switching power supply compensation criterion, the compensation network is designed with mathematical analysis software to obtain the best dynamic response. The simulation and test results show that the design of this paper basically meets the expected requirements. This has very good reference meaning to the engineering practice.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

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