电网电压畸变与不平衡情况下并网逆变器控制策略

发布时间：2018-05-28 05:44

本文选题：并网逆变器 + 分布式发电　；参考：《燕山大学》2014年硕士论文

【摘要】：随着太阳能、风能等可再生能源装机容量的增加，可再生能源在我国未来能源结构中的地位将会越来越重要。电力电子变换器在分布式发电(DG)系统和可再生能源集中并网系统中扮演了重要的角色。大电网中接入的DG系统越来越多，DG系统稳定性会对大电网产生影响，同时大电网的波动也会影响DG系统的运行。电网电压中的谐波和不平衡负序分量将会对分布式发电系统的输出产生影响，，进而影响分布式发电并网系统运行的安全性和稳定性。所以，研究三相并网逆变器的控制技术，抑制电网电压中的谐波和不平衡负序分量对逆变器输出的影响，保证并网逆变器在电网电压畸变和不平衡情况下高效稳定运行具有重要意义。本文主要是针对三相并网逆变器控制策略进行讨论和研究。首先介绍了分布式发电系统的发展概况以及并网逆变器控制策略的国内外研究现状。然后分析了LCL滤波器的参数设计及三相并网逆变器的建模，并对并网逆变器αβ轴电流的比例积分(PI)控制和比例谐振积分(PRI)控制的理论分析和仿真，仿真结果表明PRI控制在对交流量的无静差控制方面是优于PI控制的。针对电网电压畸变和不平衡对并网逆变器控制的影响，在准PRI控制的基础上，加上谐波谐振控制器(Resonant HamonicController，RESH)，得到准PRI+RESH控制器。分析了准PRI+RESH控制器的控制原理以及在应用上的局限性，从而设计出一种改进的控制策略，即准比例反馈谐振积分(Proportional-Feedback-Resonant-Integral，PFRI)+RESH控制策略。仿真结果表明，改进得到的准PFRI+RESH控制策略相对于改进前的控制策略，对整数次谐波附近的间谐波的抑制作用变好，对参考电流信号中基波分量的跟踪更加精确，并网电流的THD值减小，获得了更好的并网电流质量。搭建了以TMS320F2812为主控芯片的3KW三相并网逆变器实验平台，并在此基础上对本文中提到的控制策略进行了实验验证。实验结果表明本文设计的控制策略能够在电网电压畸变且不平衡情况下改善并网电流质量，保证逆变器高效稳定运行。
[Abstract]:With the increase of the installed capacity of renewable energy such as solar energy and wind energy, the status of renewable energy will become more and more important in the future energy structure of our country. Power electronic converter plays an important role in distributed generation DG system and renewable energy centralized grid-connected system. More and more DG systems connected to large power grids will have an impact on the stability of DG systems, and the fluctuation of large power grids will also affect the operation of DG systems. The harmonic and unbalanced negative sequence components in the grid voltage will affect the output of the distributed generation system, and then affect the security and stability of the distributed grid connected system. Therefore, the control technology of three-phase grid-connected inverter is studied to suppress the influence of harmonic and unbalanced negative sequence components in grid voltage on the output of inverter. It is of great significance to ensure the efficient and stable operation of grid-connected inverter under the condition of voltage distortion and imbalance. The control strategy of three-phase grid-connected inverter is discussed and studied in this paper. Firstly, the development of distributed generation system and the research status of grid-connected inverter control strategy at home and abroad are introduced. Then, the parameter design of the LCL filter and the modeling of the three-phase grid-connected inverter are analyzed. The theoretical analysis and simulation of the proportional integral control and the proportional resonance integral control of the 伪尾 axis current of the grid-connected inverter are presented. The simulation results show that PRI control is superior to Pi control in the static error control of AC quantity. Aiming at the influence of voltage distortion and imbalance on the control of grid-connected inverter, the quasi-PRI RESH controller is obtained by adding the harmonic resonance controller Resonant Hamonic Controller on the basis of quasi-PRI control. The control principle of quasi-PRI RESH controller and its limitation in application are analyzed, and an improved control strategy is designed, that is, the quasi-proportional feedback resonance integral control strategy, which is called quasi-proportional feedback resonance integral control strategy. The simulation results show that the improved quasi-PFRI RESH control strategy has better suppression effect on the interharmonics near integer harmonics and more accurate tracking of the fundamental component in the reference current signal compared with the control strategy before the improvement. The THD value of grid-connected current is reduced and better grid-connected current quality is obtained. The experimental platform of 3KW three-phase grid-connected inverter based on TMS320F2812 is built, and the control strategy mentioned in this paper is verified experimentally. The experimental results show that the proposed control strategy can improve the grid-connected current quality and ensure the efficient and stable operation of the inverter under the condition of voltage distortion and unbalance.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464

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