电力电子变压器DC-DC变换器的设计

发布时间：2018-03-18 20:03

本文选题：电力电子变压器　切入点：LLC谐振变换器　出处：《中国矿业大学》2016年硕士论文　论文类型：学位论文

【摘要】：煤矿井下存在着各种电压等级的电源以及电气设备,供电系统十分复杂。为了满足不同电压等级的要求,目前井下常用传统电力变压器来进行变压和能量传递。这种变压器制作工艺简单、可靠性高,但是其价格高、体积庞大、空载损耗严重、控制不灵活,而且,如果出现电压不平衡、谐波、闪变等现象,无法维护电力设备的正常工作。所以,现在亟待解决的问题是如何保证电气设备在安全工作的情况下,给用户供应可靠稳定的电能。电力电子变压器(PET)应运而生,它除了拥有传统变压器的功能外,还具备解决上述难题的能力,作为一种新型变压器,值得深入研究。PET的DC-DC变换器是影响其工作效率和装置体积重量的重要部分,本文以PET中DC-DC变换器为主要研究对象,分析了DC-DC变换器的作用以及带来的问题,尝试将软开关技术应用其中来降低损耗,促进PET中DC-DC变换器的高频化,在提高系统效率的同时,减小装置体积和重量。本文首先通过对比不同应用软开关技术的变换器,确定了谐振变换器的优势,最终选择全桥LLC谐振变换器为PET中DC-DC变换器。在对全桥LLC谐振变换器工作模式分析的基础上,利用基波等效原理建立模型,通过分析直流增益特性、输入阻抗特性、短路特性和空载特性,确定合适的k值与Q值,确定原边开关管实现零电压开通(ZVS)的条件。基于全桥LLC谐振变换器的拓扑结构,分析其效率,研究其损耗主要来源,对各来源进行分析并给出计算方法。然后,根据给出的指标,对全桥LLC谐振变换器的主电路进行了详细的设计,主要有谐振参数的设计,利用磁集成思想,设计磁集成变压器,可以大大减小变换器的体积和重量,并在参数设计的基础上完成器件的选型。此外,对基于UCC25600的全桥LLC谐振变换器的控制电路进行了设计,并根据给出的参数,计算出各部分损耗,进而计算出效率,结果满足设计效率的要求。最后,利用PEmag和Maxwell仿真软件设计磁集成变压器,验证磁集成变压器参数。运用Matlab/simulink对PET中DC-DC变换器进行仿真分析,根据理论研究及仿真结果,研制一台全桥LLC谐振变换器样机并搭建系统测试平台,并对PET中DC-DC变换器进行实验研究,通过对测试得到的波形的分析,验证了DC-DC变换器的理论研究和设计方法的正确性及有效性。
[Abstract]:In order to meet the requirements of different voltage levels, the power supply system is very complicated because of the existence of power supply and electrical equipment of various voltage levels in coal mine. At present, conventional power transformers are commonly used in downhole for transformer voltage and energy transfer. This kind of transformer has simple fabrication process and high reliability, but its price is high, volume is huge, no-load loss is serious, control is inflexible, and, If the voltage imbalance, harmonic, flicker and other phenomena, can not maintain the normal operation of power equipment. Therefore, the problem to be solved now is how to ensure the electrical equipment to work safely. Power electronic transformer (PET) emerges as the times require. It not only has the function of traditional transformer, but also has the ability to solve the above problems, as a new type of transformer. The DC-DC converter worth studying deeply is an important part that affects its working efficiency and device volume and weight. This paper takes the DC-DC converter in PET as the main research object, and analyzes the function and problems of DC-DC converter. The soft switching technology is applied to reduce the loss, promote the high frequency of DC-DC converter in PET, and reduce the volume and weight of the device while improving the system efficiency. The advantages of the resonant converter are determined, and the full-bridge LLC resonant converter is selected as the DC-DC converter in the PET. Based on the analysis of the operating mode of the full-bridge LLC resonant converter, the model is established by using the fundamental equivalent principle, and the DC gain characteristics are analyzed. The input impedance characteristic, short circuit characteristic and no-load characteristic, the appropriate k value and Q value, and the condition of realizing zero voltage switching on ZVS are determined. Based on the topology structure of full-bridge LLC resonant converter, the efficiency of the converter is analyzed. This paper studies the main source of loss, analyzes each source and gives the calculation method. Then, according to the index given, the main circuit of full-bridge LLC resonant converter is designed in detail, including the design of resonant parameters. By using the idea of magnetic integration, the design of magnetic integrated transformer can greatly reduce the volume and weight of the converter and complete the selection of the device on the basis of parameter design. The control circuit of full-bridge LLC resonant converter based on UCC25600 is designed. According to the given parameters, the loss of each part is calculated, and then the efficiency is calculated. The results meet the requirements of design efficiency. The magnetic integrated transformer is designed by using PEmag and Maxwell simulation software, and the parameters of the magnetic integrated transformer are verified. The DC-DC converter in PET is simulated and analyzed by Matlab/simulink. According to the theoretical research and simulation results, A prototype of a full-bridge LLC resonant converter is developed and a system testing platform is built. The experimental study of the DC-DC converter in PET is carried out, and the waveform obtained from the test is analyzed. The correctness and validity of the theoretical research and design method of DC-DC converter are verified.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM41;TM46

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