微电网平滑切换控制方向的研究

发布时间：2018-04-20 15:01

本文选题：微电网 + 并网/孤岛运行　；参考：《西安理工大学》2017年硕士论文

【摘要】：随着近些年新能源的广泛应用,小型光伏发电和风能发电发展,人们将目光纷纷投向了更加环保、高效的微电网。它是由分布式发电系统(DG)、储能系统、负荷及保护装置组成的,微电网可以分为并网和孤岛两种运行模式。微电网安全稳定的运行受模式间的平滑切换的影响很大,所以微电网的平滑切换控制很重要,本文以风光储微电网系统为研究对象,建立数学模型,并采用相应的控制策略,主要研究微电网并网和孤岛两种运行模式的切换过程。首先,简要说明了光伏发电系统、蓄电池和风力发电系统的结构及其工作原理,分别搭建光伏电池发电系统、蓄电池系统和风力发电系统的数学模型,并组成综合微电网系统模型,实现光伏电源的最大功率跟踪和蓄电池的恒电压放电控制。其次,概述微电网的两种运行模式及其工作原理,针对微电源的不同特性提出相应的控制策略。在分析微电网的运行控制策略的基础上,对逆变器PWM控制电路和数学模型进行研究;提出改进的锁相环技术,主要由电网相位检测、相位预同步、相位生成等模块组成,并将其适用于主从控制的微电网模型中;简要说明孤岛检测技术,并给出逆变型分布式电源的孤岛检测电路模型。最后,针对微电网在模式切换过程中出现的电压和频率暂态波动问题,提出改进的状态跟随控制策略,在微电网并网运行时,主控逆变器采用恒功率控制,并以一个负反馈信号作为恒压恒频控制的输入信号,使恒压恒频控制器的输出能够跟随恒功率控制器的输出,保证微电网运行方式的平滑切换。使用PSCAD/EMTDC软件对主从控制的风光储微电网系统模型进行计算仿真,仿真结果验证所提控制策略的有效性。
[Abstract]:With the wide application of new energy in recent years, the development of small-scale photovoltaic and wind power generation, people have turned their attention to more environmentally friendly and efficient microgrid. It is composed of distributed generation system (DG), energy storage system, load and protection device. The microgrid can be divided into two operation modes: grid-connected and islanding. The safe and stable operation of microgrid is greatly affected by the smooth switching between modes, so the smooth switching control of microgrid is very important. In this paper, a mathematical model is established and the corresponding control strategy is adopted. The switching process of two operation modes, grid-connected and islanding, is studied in this paper. Firstly, the structure and working principle of photovoltaic system, storage battery and wind power system are briefly described, and the mathematical models of photovoltaic system, battery system and wind power system are built, respectively. The integrated microgrid system model is constructed to realize the maximum power tracking of photovoltaic power supply and the constant voltage discharge control of battery. Secondly, two operation modes and their working principles of microgrid are summarized, and corresponding control strategies are put forward according to the different characteristics of micro-power supply. On the basis of analyzing the operation control strategy of microgrid, the PWM control circuit and mathematical model of inverter are studied, and an improved phase-locked loop technology is proposed, which is mainly composed of power grid phase detection, phase pre-synchronization, phase generation and so on. It is applied to the microgrid model of master-slave control, the islanding detection technology is briefly described, and the islanding detection circuit model of inverter distributed power generation is given. Finally, aiming at the transient fluctuation of voltage and frequency during mode switching, an improved state following control strategy is proposed. When the microgrid is connected to the grid, the main inverter adopts constant power control. A negative feedback signal is used as the input signal of constant voltage and constant frequency control so that the output of constant voltage constant frequency controller can follow the output of constant power controller and ensure smooth switching of operation mode of microgrid. The PSCAD/EMTDC software is used to simulate the system model of the master and slave control system of the solar microgrid. The simulation results verify the effectiveness of the proposed control strategy.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM727

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