混合级联型电力电子变压器降阶建模与控制策略研究

发布时间：2018-05-17 08:40

本文选题：配电网 + 电力电子变压器　；参考：《东北电力大学》2017年硕士论文

【摘要】：传统电力电子变压器多采用多级结构,采集变量、控制变量以及控制目标较多,随着电压、容量等级增大,控制系统相当复杂,且由于级联模块数的增加,其体积及成本直线上升。这些问题都制约着电力电子变压器推广和应用。本文正是围绕这些问题,在传统电力电子变压器的拓扑结构及控制策略的基础上,对电力电子变压器的拓扑结构、建模方法及控制策略展开研究。首先,对现有的几种典型电力电子变压器拓扑结构及优缺点进行分析,在此基础上,将谐振变换器及两电平方波变换器引入到传统级联型电力电子变压器,提出一种适用于中高压配电网的新型电力电子变压器拓扑结构。与传统电力电子变压器相比,所提拓扑的优势在于可以显著减少体积,提高运行效率,并能够灵活切换于纯有功模式及无功补偿模式。其次,对所提拓扑结构及工作原理进行了详细的论述,并提出一种基于谐振变换器恒定电压增益特性的电力电子变压器统一降阶建模方法,并建立了系统的交流侧及直流侧的统一降阶模型。在此基础上,结合谐振变换器的工作特性提出了一种单级统一控制策略,简化了电力电子变压器的控制系统,使其控制复杂度不再随着级联模块数的增加而增加。并在PET仿真环境中搭建了10kV/1.5MW的电力电子变压器模型,仿真结果表明了所提拓扑结构及其控制策略的可行性和有效性。
[Abstract]:Traditional power electronic transformers adopt multi-stage structure, collect variables, control variables and control targets. With the increase of voltage and capacity, the control system is quite complex, and because of the increase of the number of cascaded modules, the control system is very complex. Its volume and cost rise in a straight line. These problems restrict the promotion and application of power electronic transformers. On the basis of the traditional topology and control strategy of power electronic transformer, the topology structure, modeling method and control strategy of power electronic transformer are studied in this paper. Firstly, the topology, advantages and disadvantages of several typical power electronic transformers are analyzed. On this basis, resonant converters and two electric square wave converters are introduced into the traditional cascaded power electronic transformers. This paper presents a new topology of power electronic transformers for medium and high voltage distribution networks. Compared with traditional power electronic transformer, the advantage of the proposed topology is that it can significantly reduce the volume, improve the operation efficiency, and can flexibly switch to the pure active power mode and reactive power compensation mode. Secondly, the proposed topology and working principle are discussed in detail, and a unified reduced-order modeling method for power electronic transformer based on constant voltage gain characteristics of resonant converter is proposed. The unified order reduction model of AC side and DC side of the system is established. On this basis, a single stage unified control strategy is proposed to simplify the control system of power electronic transformers, which makes the control complexity no longer increase with the increase of the number of cascaded modules. The power electronic transformer model of 10kV/1.5MW is built in the PET simulation environment. The simulation results show that the proposed topology and its control strategy are feasible and effective.
【学位授予单位】：东北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM41

【参考文献】