三电平软开关逆变器研究

发布时间：2018-06-24 09:31

本文选题：逆变器 + 软开关　；参考：《合肥工业大学》2016年硕士论文

【摘要】：随着世界能源结构的变化,各国对清洁能源的需求越来越高,近年来光伏能及风能的发展受到格外重视。逆变器作为新能源转换中的核心部件,如何使其更加高效、小型化、低谐波污染、高可靠性已成为各国学者的研究重点。而软开关技术则可以很好地解决上述问题,其可以降低开关损耗,减少电磁干扰及高频电磁噪声,并且使得功率开关管的可靠性进一步提高。因此研究软开关三电平技术具有重要价值。(1)文章首先介绍了三电平软开关技术的研究背景：简述了逆变器的发展现状以及软开关在逆变器应用概况。(2)由于软开关技术需要研究IGBT微观过程,为此建立了IGBT的等效模型,并对其开通和关断过程进行了分析,在此基础上得出IGBT开关损耗的计算公式。同时介绍了T型三电平逆变器及其换流过程,阐述了本文使用空间矢量脉宽调制法的基本原理以及载波实现方法,并对T型三电平逆变器的损耗进行分析。(3)文章对三电平软开关逆变器的工作过程进行详尽的理论分析并建立了数学模型,通过仿真验证该拓扑可以实现零电压关断和零电流导通。根据其换相过程给出了缓冲电感及缓冲电容的选型依据,并通过实验验证其可行性,对软硬开关条件下的开关过程及损耗进行对比研究。(4)本文对三电平软开关逆变器死区条件进行优化,针对正死区、负死区及无死区不同模式进行研究,详细分析了不同工况下换相过程的区别、开关损耗的变化以及对输出电流基波、电流THD的影响,得出最优工况。同时分析了线路中寄生电感对软开关效果产生的不利影响。最后分析软开关逆变器换相过程后谐振机理,并给出了阻容并联的谐振抑制方法。(5)最后,搭建了以DSP28335芯片和CPLD为控制核心的三电平软开关逆变器平台,对本文的理论分析进行实验验证,证明文中理论分析的正确性。
[Abstract]:With the change of energy structure in the world, the demand for clean energy is becoming higher and higher. In recent years, the development of photovoltaic and wind energy has been paid more and more attention. As the core component of new energy conversion, how to make inverter more efficient, miniaturized, low harmonic pollution and high reliability has become the research focus of scholars all over the world. The soft switching technology can solve the above problems well. It can reduce the switching loss, reduce the electromagnetic interference and high frequency electromagnetic noise, and further improve the reliability of the power switch. Therefore, the study of soft-switching three-level technology is of great value. (1) the research background of three-level soft-switching technology is introduced firstly. The development of inverter and the application of soft-switching in inverter are briefly described. (2) due to soft switching, the application of soft-switching in inverter is introduced. Technology needs to study the micro process of IGBT, In this paper, an equivalent model of IGBT is established, and the switching on and off processes are analyzed. On this basis, the formula for calculating the switching loss of IGBT is obtained. At the same time, the T type three-level inverter and its commutation process are introduced, and the basic principle and carrier realization method of space vector pulse width modulation method are described in this paper. The loss of T type three-level inverter is analyzed. (3) the working process of three-level soft-switching inverter is analyzed in detail and the mathematical model is established. Simulation results show that the topology can realize zero voltage turn-off and zero current conduction. According to the commutation process, the selection basis of the buffer inductance and the buffer capacitance is given, and the feasibility is verified by experiments. The switching process and loss under soft and hard switching conditions are compared and studied. (4) the dead-time conditions of three-level soft-switching inverter are optimized, and the different modes of positive dead zone, negative dead time and no dead zone are studied. The difference of commutation process, the change of switching loss and the influence on the output current fundamental wave and current THD are analyzed in detail, and the optimum working condition is obtained. At the same time, the adverse effect of parasitic inductance on soft switch effect is analyzed. Finally, the resonant mechanism of soft-switching inverter after commutation is analyzed, and the resonant suppression method of resistive and capacitive parallel connection is given. (5) finally, a three-level soft-switching inverter platform with DSP28335 chip and CPLD as the control core is built. The theoretical analysis in this paper is verified by experiments, and the correctness of the theoretical analysis is proved.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM464

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