单相级联H桥整流器控制算法研究与实验平台设计

发布时间：2018-03-25 04:10

本文选题：电力电子变压器　切入点：级联H桥整流器　出处：《西南交通大学》2017年硕士论文

【摘要】：随着我国高速铁路的快速发展,客运列车的不断提速还面临着众多挑战,轻量化是高速列车发展与进一步提速的关键技术。使用电力电子变压器替代传统工频牵引变压器是高速列车牵引传动系统轻量化和高功率密度化研究的一个重要方面。采用单相级联H桥整流器与中高频隔离DC-DC变换器结合的电力电子变压器是无工频牵引变压器牵引传动系统的主要研究方向,因此开展级联H桥整流器系统的分析与研究具有重要的工程应用价值与意义。本文以电力电子变压器前端单相级联H桥整流器为研究对象,从级联H桥整流器控制调制算法、小功率实验平台的设计搭建、实验平台控制程序设计三个方面展开工作,主要工作内容如下:首先,对单相级联H桥整流器的拓扑结构、工作原理和数学模型进行了分析和计算,分析了级联整流器直流电容电压不平衡的原因和负载不平衡程度的约束条件,结合传统两电平整流器的控制方法,分析了单相级联H桥整流器的控制、调制和电压平衡控制的方法,分析和仿真结果表明:瞬态直接电流控制和电流DQ解耦控制适用于对单相级联H桥整流器的控制;载波移相调制可在较低载波频率下实现较高的等效开关频率,有助于改善谐波特性;直流侧负载不平衡是引起直流电压不平衡的主要原因,通过对调制比增量进行调节可实现直流电压平衡控制。其次,设计并搭建了包含三个H桥模块的实验平台以进行实验验证,实验平台设计功率220V/2.2kW,主要有控制、驱动、检测和功率电路,此外还包含预充电、滤波器和保护等辅助电路。给出了详细的电路设计和参数计算过程,实验结果表明所设计的实验平台性能良好,并实现较好的控制效果。最后,编写了基于TMS320F28335的单相级联H桥整流器控制程序,为贴近工程实际应用,所设计的实验平台控制程序包含了电路预充电、轻载启动、额定运行和停止等过程,并编写了上电自检和过压检测等保护程序以保障实验的安全性,所设计的程序实现了级联H桥整流器的控制目标,具有良好的动态响应和谐波性能,验证了本文理论分析及所采用控制调制算法的正确性和有效性。
[Abstract]:With the rapid development of high-speed railway in China, the increasing speed of passenger trains is still facing many challenges. Lightweight is the key technology for the development and further increase of speed of high-speed trains. It is important to use power electronic transformers to replace traditional power frequency traction transformers in the study of lightweight and high power density of traction transmission system of high-speed trains. Power electronic transformer, which combines single-phase cascaded H-bridge rectifier with DC-DC converter with middle and high frequency isolation, is the main research direction of traction drive system of no-power frequency traction transformer. Therefore, the analysis and research of cascaded H-bridge rectifier system has important engineering application value and significance. This paper takes the front-end single-phase cascaded H-bridge rectifier of power electronic transformer as the research object, and controls the modulation algorithm from the cascaded H-bridge rectifier. The design and construction of the low-power experimental platform and the design of the control program of the experimental platform are carried out. The main work is as follows: first, the topology of the single-phase cascaded H-bridge rectifier, The working principle and mathematical model are analyzed and calculated. The causes of voltage imbalance in DC capacitor of cascade rectifier and the constraint condition of load unbalance are analyzed, and the control method of traditional two-level rectifier is combined. The control, modulation and voltage balance control methods of single-phase cascaded H-bridge rectifier are analyzed. The analysis and simulation results show that the transient direct current control and current DQ decoupling control are suitable for single-phase cascaded H-bridge rectifier control. The carrier phase shift modulation can achieve higher equivalent switching frequency at lower carrier frequency, which is helpful to improve the harmonic characteristics, and the unbalanced load on the DC side is the main cause of the imbalance of DC voltage. The DC voltage balance control can be realized by adjusting the modulation ratio increment. Secondly, an experimental platform including three H-bridge modules is designed and built for experimental verification. The design power of the experimental platform is 220 V / 2.2 kW, which is mainly controlled and driven. The detection and power circuits also include auxiliary circuits such as precharge, filter and protection. The detailed circuit design and parameter calculation process are given. The experimental results show that the designed experimental platform has good performance. Finally, the control program of single-phase cascaded H-bridge rectifier based on TMS320F28335 is written. In order to be close to the practical application of engineering, the control program of the experimental platform includes circuit precharge, light load start, and so on. In order to ensure the safety of the experiment, the program is designed to realize the control target of cascade H-bridge rectifier, and has good dynamic response and harmonic performance. The theoretical analysis and the validity of the control modulation algorithm are verified.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM461

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