基于单周期控制的分布式能源并网技术研究

发布时间：2018-08-13 09:18

【摘要】：摘要：风／光、燃料电池等可再生能源发电是改善能源结构和应对气候变化的重大举措。但随着新能源在分布式发电(Distributed power generation, DG)系统中的不断应用,其波动性和间歇性对电网的负面影响愈来愈显著,主要表现为谐波污染、功率因数不合格、并网逆变器控制及无功不平衡等。本文对并网技术进行了深入研究,意在将新能源不同水平的交直流电转换成高性能、低谐波的正弦交流电,实现分布式能源的安全高效并网。文章主要从下面几个方面开展工作：首先,分析了分布式发电的国内外研究现状、分布式能源并网对电网的影响及相关并网标准；通过研究比较常见并网逆变技术,提出将单周期控制(One-Cycle Control, OCC)技术引入到我国分布式发电并网系统中。针对DG并网系统中的谐波污染、功率因数不合格问题,采用了基于单周控制的有源功率滤波技术OCC-APF及功率因数校正技术OCC-PFC。文章建立了三相整流器的数学开关模型及双并联Boost等效拓扑,推导出核心控制方程,搭建了OCC-APF控制模块(OCC-PFC模块的搭建同APF)。仿真和试验结果表明,此方案有效实现了单位功率因数校正和低电流畸变率,优于双闭环等传统控制策略。针对DG并网系统中的并网逆变器控制,采用了基于单周期控制的并网逆变器控制策略OCC-GTI。文章建立了三相GTI的数学开关模型及双并联Buck等效拓扑,推导出核心控制方程,搭建了OCC-GTI控制模块。仿真及试验结果表明,此方案可实现单位功率因数并网,低谐波含量,且具有良好无功补偿性能。针对DG并网系统中的无功不平衡问题,现有SVC、STATCOM策略的控制复杂、实时性差,提出一种基于单周期控制的实时无功补偿控制策略OCC-STATCOM。基于经典单周期控制,采用直流电压外环控制和电感电流斜坡调制,实时跟踪负载和电压变化,实现动态无功补偿,并通过仿真及试验验证该方法的可行性和精确性。最后,总结得出了单周期控制的统一核心控制方程和统一矢量控制器；并在背靠背式风力发电并网系统中进行了仿真实验,整体性验证本文所提出控制策略的正确性和有效性。
[Abstract]:Abstract: renewable energy generation such as wind / light, fuel cells is an important measure to improve energy structure and combat climate change. However, with the continuous application of new energy in the distributed generation (Distributed power generation, DG) system, its volatility and intermittency have more and more negative effects on the power grid, mainly reflected in harmonic pollution and unqualified power factor. Grid-connected inverter control and reactive power imbalance and so on. In this paper, the grid-connected technology is deeply studied. The purpose of this paper is to convert different levels of AC / DC power from new energy to sinusoidal AC with high performance and low harmonics, so as to realize the safe and efficient grid connection of distributed energy sources. The main work of this paper is as follows: firstly, the research status of distributed generation at home and abroad, the influence of distributed energy grid connection and related grid connection standards are analyzed, and the common grid-connected inverter technology is studied. A single cycle control (One-Cycle Control, OCC) technique is introduced to the distributed generation grid-connected system in China. In order to solve the problem of harmonic pollution and unqualified power factor in DG grid-connected system, the active power filter (OCC-APF) based on one-cycle control and the power factor correction (PFC) technology OCC-PFC are adopted. In this paper, the mathematical switching model of three-phase rectifier and the equivalent topology of double-parallel Boost are established. The core control equation is deduced, and the OCC-APF control module (OCC-PFC module is built with APF).) is built. The simulation and experimental results show that this scheme can effectively realize unit power factor correction (PFC) and low current distortion rate, and is superior to traditional control strategies such as double closed loop. To control grid-connected inverter in DG grid-connected system, OCC-GTI-based control strategy of grid-connected inverter based on single-cycle control is adopted. In this paper, the mathematical switching model of three-phase GTI and the equivalent topology of double-parallel Buck are established, the core control equation is derived, and the OCC-GTI control module is built. The simulation and experimental results show that this scheme can realize the unit power factor grid-connected, low harmonic content, and has good reactive power compensation performance. Aiming at the problem of reactive power imbalance in DG grid-connected system, the existing SVCS-STATCOM strategy is complex in control and poor in real-time performance. A real-time reactive power compensation control strategy OCC-STATCOM-based on single cycle control is proposed. Based on classical single-cycle control, DC voltage outer loop control and inductor current ramp modulation are used to track load and voltage changes in real time, and dynamic reactive power compensation is realized. The feasibility and accuracy of this method are verified by simulation and experiment. Finally, the unified core control equation and the unified vector controller for single-cycle control are obtained, and the simulation experiments are carried out in the back-to-back wind power grid connection system, which verifies the correctness and effectiveness of the proposed control strategy.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM761

【参考文献】