微网的改进下垂控制及协调控制

发布时间：2018-06-26 02:28

本文选题：微电网 + 下垂控制　；参考：《天津理工大学》2017年硕士论文

【摘要】：随着经济和社会的快速进步,传统大电网的规模在不停地扩大,其安全性和可靠性的缺陷也逐渐暴露出来。与此同时,环境污染和能源危机日益严重,能够有效解决这些问题的微电网便应运而生。微电网把分布式电源DG、控制装置、储能单元以及负荷组成一个单一可控的系统,不但可以并网运行,而且能在大电网故障时孤网运行。在微电网运行与控制的过程中有很多重要的问题亟待解决,因此本文对微电网的控制及稳定性进行研究。本文首先对微电网的研究目的及意义、基本概念及国内外研究现状、主要控制方式进行了综述,然后分析了各种坐标系下逆变器的数学模型,介绍了微网中各个分布式电源接口逆变器的三种控制方法。其次对逆变器的下垂控制的基本原理和功率传输特性进行了分析,论证了逆变器输出阻抗和线路阻抗与逆变器控制方法的关系。应用虚拟阻抗法对下垂控制进行改进,使得传统的P/f、Q/V下垂控制方式能够在低压微电网中使用,完成了有功与无功的解耦控制。使用频域法分析与对比了引入虚拟阻抗对于系统输出特性的作用,并经过对微电网的运行与仿真分析,验证了基于虚拟阻抗的下垂控制方法的有效性。最后,对孤网运行微电网的各个组成部分建立了小信号状态空间模型,并使用特征值法对其状态矩阵进行分析,然后从理论上分析了最优分散协调控制的工作原理,并给出了求解Levince-Athans方程组的具体方法,对微电网整体的状态空间模型使用最优分散协调控制,通过算例分析验证了最优分散协调控制对提高了系统的稳定性的作用。
[Abstract]:With the rapid progress of economy and society, the scale of the traditional large power grid is constantly expanding, and the defects of its safety and reliability are gradually exposed. At the same time, environmental pollution and energy crisis are becoming more and more serious. The microgrid makes up a single controllable system of DG, control device, energy storage unit and load, which not only can be connected to the grid, but also can be operated in the isolated network in the event of large power network failure. There are many important problems to be solved in the process of microgrid operation and control. Therefore, the control and stability of microgrid are studied in this paper. In this paper, the purpose and significance of microgrid research, the basic concepts, the current research situation at home and abroad, the main control methods are summarized, and then the mathematical models of inverter in various coordinate systems are analyzed. This paper introduces three kinds of control methods of each distributed power interface inverter in microgrid. Secondly, the basic principle and power transmission characteristics of droop control of inverter are analyzed, and the relationship between inverter output impedance and line impedance and inverter control method is demonstrated. The virtual impedance method is used to improve the droop control, which makes the traditional P / F / Q / V droop control method can be used in low-voltage microgrid, and the decoupling control of active power and reactive power is realized. The effect of introducing virtual impedance on the output characteristics of the system is analyzed and compared by frequency domain method. The effectiveness of the droop control method based on virtual impedance is verified by the operation and simulation analysis of microgrid. Finally, the small signal state space model is established for each component of the isolated microgrid, and its state matrix is analyzed by eigenvalue method. Then, the working principle of optimal decentralized coordinated control is analyzed theoretically. The concrete method of solving Levince-Athans equations is given. The optimal decentralized coordinated control is used for the state space model of microgrid. The effect of the optimal decentralized coordinated control on the stability of the system is verified by an example.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM727

【相似文献】