集成电动汽车充电及牵引供电系统的直流微电网研究

发布时间：2018-05-31 08:48

本文选题：直流微电网 + 直流牵引供电系统　；参考：《华北电力大学》2017年硕士论文

【摘要】：微电网是集发、配、用电为一体的自治系统,构建了全新的能源技术公平竞争体系,具有长久的技术、经济、环境和社会效益,而直流微电网作为一种新型的电网形式,符合当前清洁能源和能源互联网的发展需求。另一方面,随着能源危机和环境问题的加重,电气化轨道交通车辆和电动汽车将是未来城市电网负荷的重要组成部分,其供电系统安全运行的意义重大。在此背景下,根据牵引供电系统和电动汽车充电的特点,同时考虑可再生能源的有效利用,提出了集成电动汽车充电及牵引供电系统的直流微电网架构,描述了系统的基本组成和拓扑结构,为了保证此系统安全稳定地运行,重点研究了系统的控制策略。首先,介绍了传统下垂控制,并从环流大小、输出电压和输出电流三方面对下垂控制下并联分布式电源系统进行了稳态分析,得到了影响传统下垂控制性能的因素。进一步提出了一种基于自适应虚拟阻抗的改进下垂控制策略,可以根据分布式电源间功率分配的差额,自动调节下垂虚拟阻抗,从而实现功率均分。仿真结果验证了所提改进下垂控制策略的有效性。其次,针对单边供电的情况,提出了基于功率分层的协调控制策略。对系统各单元进行了划分和简介,确定了系统运行所需的约束条件,分别介绍了该协调控制策略的能量管理和功率分配方案,阐述了并网运行、孤岛运行及过渡运行状态下的协调控制流程,分析了系统各单元变换器的控制方法,并搭建了仿真模型对所提控制策略进行了验证。最后,针对双边供电的情况,提出了一种基于DBS的直流微电网改进协调控制策略,将系统运行划分为四种工作模式,并通过电压信号同步预处理环节对各模式间的切换信号进行了优化。该控制策略省去了中央控制器,同时结合了基于自适应虚拟阻抗的改进下垂控制策略,提高了系统整体的可靠性和精确性。仿真结果表明,该控制策略可以维持直流母线电压的稳定,实现系统的功率平衡。
[Abstract]:Microgrid is an autonomous system that integrates distribution, distribution and power consumption. A new fair competition system of energy technology is constructed. It has long-term technical, economic, environmental and social benefits, while DC microgrid is a new type of power grid. In line with the current clean energy and energy Internet development needs. On the other hand, with the aggravation of energy crisis and environmental problems, electrified rail transit vehicles and electric vehicles will be an important part of the future urban power grid load, and the safe operation of its power supply system is of great significance. Under this background, according to the characteristics of traction power supply system and electric vehicle charging, and considering the effective utilization of renewable energy, a DC microgrid architecture integrating electric vehicle charging and traction power supply system is proposed. The basic composition and topological structure of the system are described. In order to ensure the safe and stable operation of the system, the control strategy of the system is studied emphatically. Firstly, the traditional droop control is introduced, and the steady state analysis of shunt distributed power system under droop control is carried out from three aspects: circulation size, output voltage and output current, and the factors that affect the performance of traditional droop control are obtained. Furthermore, an improved droop control strategy based on adaptive virtual impedance is proposed, which can automatically adjust the droop virtual impedance according to the difference of power distribution between distributed power sources, so as to realize the average power distribution. Simulation results verify the effectiveness of the proposed improved droop control strategy. Secondly, a coordinated control strategy based on power stratification is proposed for unilateral power supply. Each unit of the system is divided and introduced, and the constraint conditions for the operation of the system are determined. The energy management and power allocation scheme of the coordinated control strategy are introduced respectively, and the grid-connected operation is expounded. The coordinated control flow of isolated island operation and transition operation is analyzed. The control methods of each unit converter of the system are analyzed and the simulation model is built to verify the proposed control strategy. Finally, an improved coordinated control strategy for DC microgrid based on DBS is proposed, which divides the operation of the system into four working modes. The switching signals between different modes are optimized by voltage signal synchronization preprocessing. The control strategy eliminates the central controller and combines the improved droop control strategy based on adaptive virtual impedance to improve the reliability and accuracy of the system as a whole. The simulation results show that the control strategy can maintain the stability of DC bus voltage and realize the power balance of the system.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM727

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