压接式IGBT串联时动态电压不均衡特性的研究

发布时间：2018-06-28 05:11

本文选题：压接式IGBT + 串联　；参考：《华北电力大学》2014年硕士论文

【摘要】：高压大功率直流输电技术在远距离输电、可再生能源发电、城市配电网及分布式发电等诸多领域发挥着越来越重要的作用,而换流系统是直流输电系统的核心部件。随着电力电子技术的发展,基于绝缘栅双极型晶体管(insulation gate bipolar transistor, IGBT)的电压源换流器开始在直流输电中得到广泛应用。由于柔性直流输电系统中直流电压等级较高,远大于单个IGBT所能承受的电压,所以IGBT模块的串联技术对于实现高压大功率输出至关重要。串联技术对于IGBT的动作一致性要求较高,但是由于IGBT自身参数以及外围电路参数都具有分散性,加上其开关动态过程较为短暂,各个串联IGBT模块在开关动态过程中的电压分布不均衡问题尤为突出,严重情况下可导致某些器件因为承受较高的过电压而损坏。因此,为确保换流器阀安全运行,研究影响串联IGBT电压分布不均衡的因素并量化分析,从而在此基础上提出相应的均压保护措施十分必要。本文针对IGBT串联时的电压不均衡问题,在IGBT的建模、串联IGBT电压分布不均衡的影响因素分析以及栅极RCD均压策略等方面进行了深入研究与分析,开展的工作如下：首先,根据IGBT器件的结构及工作原理,基于saber软件建立了压接式IGBT的动态行为模型,详细研究了模型参数的选取及模型有效性验证方法,使模型可以准确的反映IGBT的开关动态过程。其次,搭建了两个IGBT串联的仿真电路,深入分析总结了影响IGBT串联时电压分布不均衡的因素,并对各个影响因素的影响程度进行了量化分析。再次,在前文分析的基础上,针对电压源换流器一个阀段内的七个串联IGBT模块,建立了等效电路并对串联IGBT工作时的电压分布不均衡问题进行了分析,分析结果可为串联IGBT电路的设计提供参考。最后,根据上文的研究和分析结果,分析了栅极RCD均压策略的均压效果,并对均压回路中各参数的选取原则进行了讨论,仿真结果证明了此均压方法的有效性及参数匹配策略的合理性。
[Abstract]:HVDC technology plays a more and more important role in many fields, such as long-distance transmission, renewable energy generation, urban distribution network and distributed generation, etc. Commutation system is the core component of HVDC transmission system. With the development of power electronics technology, the voltage source converter based on insulated gate bipolar transistor (insulation gate bipolar transistor,) has been widely used in HVDC transmission. The series technology of IGBT module is very important to realize high-voltage and high-power output because of the higher DC voltage level in the flexible DC transmission system, which is much larger than the voltage that a single IGBT can withstand. Series technology requires high consistency of IGBT action, but because of the dispersion of IGBT parameters and peripheral circuit parameters, the dynamic process of IGBT switch is relatively short. The unbalanced voltage distribution of each series IGBT module in the switching dynamic process is particularly serious, which can lead to the damage of some devices because of the high overvoltage. Therefore, in order to ensure the safe operation of converter valve, it is necessary to study the factors that affect the voltage distribution imbalance in series IGBT and analyze it quantitatively. In order to solve the problem of voltage imbalance in series IGBT, the modeling of IGBT, the influence factors of voltage distribution in series IGBT and the voltage sharing strategy of grid RCD are studied and analyzed in this paper. The work is as follows: firstly, according to the structure and working principle of IGBT device, the dynamic behavior model of IGBT is established based on saber software, and the selection of model parameters and the validation method of model validity are studied in detail. The model can accurately reflect the switching dynamic process of IGBT. Secondly, two simulation circuits of IGBT series are built, and the factors that influence the voltage distribution in series are analyzed and summarized, and the influence degree of each factor is analyzed quantitatively. Thirdly, on the basis of the previous analysis, the equivalent circuit is established for seven series IGBT modules in one valve section of the voltage source converter, and the unbalanced voltage distribution in the series IGBT operation is analyzed. The results can provide reference for the design of series IGBT circuit. Finally, according to the above research and analysis results, the voltage equalizing effect of grid RCD is analyzed, and the selection principle of the parameters in the voltage sharing circuit is discussed. The simulation results show the effectiveness of the method and the rationality of the parameter matching strategy.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM721.1

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