微电网并离网运行控制策略的研究

发布时间：2018-11-01 15:38

【摘要】：微电网的运行模式包括并网运行和孤岛运行,微电网能否平稳的运行取决于这两种模式能否顺利的转换,然而关于这两种模式的转换以及它们之间如何进行控制的问题是非常值得深入研究的。对传统的配电网来说,分布式电源的接入对其产生了较大的影响,由原先的单电源辐射状配电网转变成了一个遍布电源和负荷的多电源系统,这就使微电网的控制系统也变得更加的复杂。传统的集中式大电网供电系统供电模式单一,集中且不灵活,而分布式发电系统供电模式多样、分散且高度灵活。因此,分布式发电系统成为了电力工业的研究热点和发展方向。逆变器是连接大电网与分布式发电单元之间的核心器件,研究逆变器及其控制策略显得尤为重要,当然这是在保证输出的电压和电流满足并网要求和负荷需求的前提下开展的。本文以分布式发电系统逆变器为研究对象,对基于分布式发电系统并网与孤岛运行模式之间的无缝切换控制进行了研究。首先,在微电网进行并离网运行时,对逆变器的控制方式(PQ控制、V/f控制)进行了研究。其次,提出了一种以间接电流控制为基础的协调控制,以解决控制策略发生变化的问题,以便逆变器在分布式发电系统的运行模式下切换时能够实现平滑切换。进而主逆变器中两种控制方式得以实现无缝切换也是由于采用了协调控制这一环节。同时,建立了基于上述控制策略的分布式发电系数学模型,通过分析仿真结果从而验证了所提控制策略的正确性。
[Abstract]:The operation mode of microgrid includes grid-connected operation and islanding operation. The smooth operation of microgrid depends on the smooth conversion of these two modes. However, the transformation of these two patterns and how to control them are worthy of further study. For the traditional distribution network, the access of distributed generation has a great impact on it, from the original single source radiation distribution network to a multi-power system with power and load. This makes the control system of microgrid more complex. The traditional centralized power supply system is single, centralized and inflexible, while the distributed generation system is diverse, dispersed and highly flexible. Therefore, distributed generation system has become the research hotspot and development direction of power industry. Inverter is the core device between large power grid and distributed generation unit. It is very important to study the inverter and its control strategy. Of course, this is carried out on the premise that the output voltage and current meet the requirements of grid connection and load. In this paper, the seamless switching control between grid-connected and islanded operation mode of distributed generation system is studied, taking the inverter of distributed generation system as the research object. Firstly, the inverter control mode (PQ control, V / F control) is studied when the microgrid is running and running off the grid. Secondly, a kind of coordinated control based on indirect current control is proposed to solve the problem of the change of control strategy, so that the inverter can realize smooth switching when switching in the distributed generation system. Furthermore, the two control modes in the main inverter can realize seamless switching due to the use of coordinated control. At the same time, the mathematical model of distributed generation system based on the above control strategy is established, and the correctness of the proposed control strategy is verified by analyzing the simulation results.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM727

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