配电网静止同步补偿器的改进无差拍控制研究

发布时间：2018-03-17 14:02

本文选题：无功补偿　切入点：配电网静止同步补偿器　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：在电能质量问题越来越受关注的今天,电网的无功污染作为其中的重要组成部分已不容忽视。配电网静止同步补偿器(Distribution STATic synchronous COMpensator,D-STATCOM)是新一代无功补偿装置,能对配电网中的无功功率进行有效补偿,是无功补偿领域的发展趋势。而实际的配电网中,由于接入负载的变化,无功电流经常发生变动,因此如何保证电网中的无功功率快速得到补偿对维持电网线路安全可靠运行具有重要的现实意义。本文针对快速补偿无功的目标,在分析了现有的控制策略基础上,基于三相两电平电压源型换流器拓扑结构的D-STATCOM系统,提出了一种改进的无差拍控制策略。首先,本文在两相静止坐标系下建立了D-STATCOM的数学模型,推导出其无差拍形式,并进行模型简化。在此基础上,设计了无差拍控制器作为电流内环,PI控制器作为外环的控制结构,并分析了电流环的稳定性,对无差拍控制器加以改进。由于采样、计算等数字系统固有的延时存在,对电网电压、指令补偿电流等变量做了提前两拍的预测,以实现真正的无差拍控制。无差拍控制是一种基于系统模型的控制方法,对系统参数变化敏感。对此,本文采用加权递推最小二乘法对滤波电感参数进行在线辨识,以提高D-STATCOM无差拍控制系统的稳定性。同时,为了提高控制精度,本文设计了一种重复状态预测器对下一拍的补偿电流进行预测,并对整个电流环做了稳定性分析。鉴于重复控制方法容易受电网频率波动的影响,本文提出了一种改进的基于FIR数字滤波器的重复预测器,使其具备对电网频率波动的适应性。在理论分析的基础上,本文运用Matlab/Simulink软件对所提出的控制策略进行了仿真分析。同时,借助实验室的d SPACE半实物实验平台进一步开展了实验验证。仿真和实验结果证明,采用本文提出的基于重复预测的无差拍控制策略的D-STATCOM装置能快速补偿负载无功,具有很好的稳态性能和动态性能。
[Abstract]:Nowadays, the problem of power quality has attracted more and more attention, and reactive power pollution is an important part of it. Distribution STATic synchronous compensatorD-STATCOMG is a new generation of reactive power compensator. It is a developing trend in the field of reactive power compensation to compensate reactive power effectively in distribution network. But in actual distribution network, reactive current often changes because of the change of connecting load. Therefore, how to ensure the rapid compensation of reactive power in the power network has an important practical significance for maintaining the safe and reliable operation of power lines. This paper analyzes the existing control strategies for the goal of rapid reactive power compensation. Based on the D-STATCOM system with three-phase two-level voltage source converter topology, an improved deadbeat control strategy is proposed. Firstly, the mathematical model of D-STATCOM is established in two-phase stationary coordinate system, and its non-beat form is deduced. On the basis of this, the control structure of the non-beat controller is designed as the current inner loop Pi controller as the outer loop, and the stability of the current loop is analyzed, and the non-beat controller is improved. In order to realize the true non-beat control, the time-delay of the digital system such as calculation is predicted two beats in advance for the variables such as the grid voltage and the command compensation current, which is a control method based on the system model. In order to improve the stability of D-STATCOM deadbeat control system, a weighted recursive least square method is used to identify the parameters of filter inductors on line. At the same time, in order to improve the control accuracy, In this paper, a repetitive state predictor is designed to predict the compensation current of the next beat, and the stability of the whole current loop is analyzed. In this paper, an improved repetitive predictor based on FIR digital filter is proposed to make it adaptive to the frequency fluctuation of power network. In this paper, the proposed control strategy is simulated and analyzed by using Matlab/Simulink software. At the same time, with the aid of the d SPACE hardware-in-the-loop experimental platform in the laboratory, further experimental verification is carried out. The simulation and experimental results prove that, The D-STATCOM device proposed in this paper based on repeated prediction deadbeat control strategy can compensate the load reactive power quickly and has good steady-state and dynamic performance.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM761.12

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