微电网三相逆变器优化控制策略研究

发布时间：2018-05-03 22:45

本文选题：微电网 + 三相逆变器　；参考：《东南大学》2016年硕士论文

【摘要】：微电网是一种由分布式电源、储能装置、能量转换装置、负荷、监控和保护装置等组成的小型发配电系统,且是一个能够实现自我控制、保护和管理的自治系统。微电网的稳定运行依赖于各可控微源的有效控制。三相逆变器作为大多数可控微源,特别是储能装置、不间断电源(UPS)等接入微电网的常用电力电子变换器,其在微电网不同运行模式下的控制策略的研究显得尤为重要。本文以此类三相逆变器为主要研究对象,在研究其运行特点、拓扑结构以及控制目标的基础上,针对微电网不同的运行方式下的控制要求,分别提出了相应的微电网三相逆变器优化控制策略,并深入分析了其合理性及有效性。全文的主要内容如下：1、介绍了本课题的研究背景以及微电网的前景,从微电网系统控制、微电网运行方式以及三相逆变器控制三个层面介绍了微电网的国内外研究现状,阐明了微电网三相逆变器需要可靠、有效及灵活的控制策略来实现微电网的稳定运行。此外,还介绍了本文的工程应用背景。2、在分析交流微电网的拓扑结构的基础上,系统地介绍了微电网中三相逆变器的分类及对应的结构特点和控制目标,然后从三相逆变器外环控制和内环控制两个方面介绍了已有的基本控制策略,并给出相应的数学理论依据以及控制框图。3、针对微电网并网、孤岛两种运行模式,分别设计相应的三相逆变器优化控制策略。主要包括：(1)分析微电网两种运行模式下逆变器的控制特点,并建立相应的逆变系统数学模型。在参考滤波器元件取值约束的条件下,如谐振频率、总电感量及谐波抑制能力等,选取合适的滤波器参数,并分析验证其合理性：(2)在分析传统的基于dq0旋转坐标系下的三相逆变器控制策略局限性基础上,提出了基于aβ静止坐标系的双闭环控制策略,引入比例谐振(PR)及准比例谐振(QPR)控制器,消除稳态误差。同时分析微电网并网、孤岛两种运行模式下影响微电网稳定性的因素,引入基于Luenberger状态观测器理论的负载电流观测器及并网电压观测器,实现对孤岛模式下负载电流及并网状态下并网电压的实时观测,并作为控制策略的前馈,融入进控制结构中,优化控制系统的动态性能；(3)利用根轨迹法选取并优化控制器参数,然后利用闭环零极点图及频率特性图的方式分析本文设计的控制策略的稳定性。4、为验证文中的各项研究内容,本文建立了基于模块化语言的MATLAB/Simulink仿真平台,开展了仿真研究工作,同时建立基于DSP-FPGA的物理实验平台,设计实验所需的电路,并完成本文设计的控制策略及控制环路的实验验证。
[Abstract]:Microgrid is a small power generation and distribution system composed of distributed power generation, energy storage device, energy conversion device, load, monitoring and protection device, and it is an autonomous system that can realize self-control, protection and management. The stable operation of microgrid depends on the effective control of each controllable microsource. As most controllable microsources, especially energy storage devices, uninterruptible power supply (UPSs) and other power electronic converters, it is very important to study the control strategy of three-phase inverter in different operation modes of microgrid. This paper takes this kind of three-phase inverter as the main research object, on the basis of studying its operation characteristic, topology structure and control target, aiming at the control requirements under different operation modes of microgrid. The corresponding optimal control strategy of microgrid three-phase inverter is proposed, and its rationality and effectiveness are analyzed. The main contents of this paper are as follows: 1. This paper introduces the research background of this topic and the prospect of microgrid, and introduces the research status of microgrid at home and abroad from three aspects: microgrid system control, microgrid operation mode and three-phase inverter control. The reliable, effective and flexible control strategy is needed to realize the stable operation of microgrid three-phase inverter. In addition, the engineering application background of this paper is introduced. On the basis of analyzing the topology structure of AC microgrid, the classification of three-phase inverter in microgrid, the corresponding structure characteristics and control objectives are introduced systematically. Then it introduces the existing basic control strategies from two aspects of external loop control and inner loop control of the three-phase inverter, and gives the corresponding mathematical theory basis and control block diagram .3. aiming at the two operation modes of microgrid grid-connected and isolated island, the paper introduces the basic control strategy of three-phase inverter in two aspects: outer loop control and inner loop control. Corresponding optimal control strategies of three-phase inverter are designed respectively. The control characteristics of inverter in two operation modes of microgrid are analyzed, and the corresponding mathematical model of inverter system is established. The appropriate filter parameters are selected under the constraints of reference filter elements, such as resonant frequency, total inductance and harmonic suppression ability, etc. Based on the analysis of the limitation of traditional three-phase inverter control strategy based on dq0 rotation coordinate system, a dual-closed loop control strategy based on a 尾 stationary coordinate system is proposed. The proportional resonance (PR) and quasi-proportional resonance (QPR) controllers are introduced to eliminate the steady-state error. At the same time, the factors that affect the stability of microgrid under two operation modes of island are analyzed, and the load current observer and grid-connected voltage observer based on Luenberger state observer theory are introduced. The real-time observation of load current in islanding mode and grid-connected voltage in grid-connected state is realized. As feedforward of control strategy, the dynamic performance of the control system is optimized and the parameters of the controller are selected and optimized by the root locus method. Then, the stability of the control strategy designed in this paper is analyzed by means of closed loop zero pole diagram and frequency characteristic diagram. In order to verify the research contents in this paper, the MATLAB/Simulink simulation platform based on modular language is established, and the simulation research work is carried out. At the same time, the physical experiment platform based on DSP-FPGA is established, and the circuit needed for the experiment is designed, and the control strategy and the experimental verification of the control loop are completed.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM464

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