【作者】 袁立强；

【导师】 赵争鸣； 李崇坚；

【作者基本信息】 清华大学 ， 电气工程， 2004， 博士

【摘要】 将新型的大容量开关器件、多电平拓扑结构、高性能的系统控制策略结合起来,对变换器进行系统优化设计,是当前实现大容量电力电子变换器的有效途径和发展方向。论文主要以基于IGCT的三电平二极管箝位式变换器为研究对象,对IGCT应用特性与模型、多电平结构基本拓扑单元、多电平变换器中瞬时能量分析和优化设计以及相关控制策略等方面进行了系统而深入的研究。电力电子器件是电力电子变换器的基础,本论文提出了适合电路仿真的IGCT器件模型,该模型具有足够的计算精度,计算速度快,参数求解简单,是掌握IGCT应用特性的有效工具。以一个具体型号的IGCT为例,详细描述了该模型的等效电路、结构以及参数求解过程。设计和实现了IGCT测试电路,IGCT模型仿真结果和试验结果相符合。从高频合成理论的角度出发,提出了基于理想开关的多电平结构的基本拓扑单元。将其与开关器件特性结合,提出了基于开关特性的多电平变换器基本单元。根据该单元的性质,描述了多电平变换器吸收电路设计的一般规则,对吸收电路的关键参数进行了优化设计。以IGCT模型、基于IGCT特性的基本拓扑单元和相应的控制策略为基础,提出了变换器的计算机仿真和辅助设计系统,成为变换器系统优化设计的有效手段之一。在综合考虑器件、拓扑和控制策略等因素,对变换器中的瞬时能量变化进行分析时,提出了按照时间量级进行分类的方法。根据具体问题来选择相应的电路原理图,同时做到计算时间和准确度的良好结合。对容量为5MVA的三电平变换器进行仿真和优化设计,并给出该变换器的部分试验结果。搭建了变频器-异步电机试验平台,对当前交流变频调速领域中具有代表性的两种控制策略(矢量控制和直接转矩控制)进行了实验特性比较。同时,为进一步控制变换器直流母线能量,本论文实现55kW低压三电平变换器配套的能量回馈系统样机,并对该系统在中高压变换器中使用提出了改进设想,形成具有能量双向流动能力的整流电路,对其性能进行了分析。更多还原

【Abstract】 The switching devices with high performance, application of multilevel topology and advanced control strategies became the effective approach and development tendency to achieve high power converters for many applications, such as adjustable speed drive, FACTs and so on. The three-level Neutral Point Clamped (NPC) inverter based on IGCTs is selected to be the main study focus in this thesis. The investigation includes the operation characteristics of IGCTs, the basic cell of multilevel topology, the analysis of instantaneous energy variation in the converter, optimizing design of the converter, and the control strategies. The power electronic device is the base of power electronics and its application equipments. A functional model of IGCTs is investigated in this thesis, which is based on the main physical characteristics of IGCTs, especially the anode current and the terminal voltage. The model is of the key features such as certain accuracy, high simulation speed and easy parameter solution. The equivalent circuit, structure, and parameters determination of the model for a specific type of IGCT are described in details. The simulation accuracy of the model is proved through experiments with the IGCTs test circuit, which is also designed in this thesis.Based on the analysis of converters with Waveform High Frequency Synthesis, the basic cells of multilevel topology with ideal switches and IGCTs are both proposed. According to the characteristics of the basic cell, the design rules and optimized snubbers for IGCT-based inverters are presented. Based on the models, basic cell with IGCTs and the relevant strategy, the simulation and computer aided-design software package for the IGCT-based three-level NPC converters is described, which is the efficient tool for analysis and optimization of the converter. And a novel solution method, in which the transients are classified according to the time frame, is proposed for the analysis of instantaneous energy variation in the converter. Then, the different simulation <WP=5>schematic diagram is selected for different transient in this package. The simulation, analysis and experiment results for a 5MVA converter are given in this thesis.Vector Control and Direct Torque Control, which are both widely used in the adjustable speed drive systems, are discussed. Based on the theoretical analysis of both strategies, many comparison experiments are accomplished with an advanced inverter-fed induction motor test platform. To control DC link voltage for the three level NPC converters with the rating power of 55kW, the energy-feedback equipment is implemented, and the improved scheme for high power converters is explained.更多还原