基于逆变器的微电网无缝切换控制策略研究

发布时间：2018-05-15 00:17

本文选题：微电网 + 孤岛/并网运行　；参考：《山西大学》2014年硕士论文

【摘要】：能源危机和环保问题已经成为制约社会发展的主要因素之一,再加上传统大规模电力系统日渐显现出来的结构老化、能源利用效率较低等弊端,使得人们不得不思考对可再生能源的利用。由于具有环保、节能、经济等优势,分布式发电受到各界的广泛关注,微电网是高效利用分布式能源的有效形式,近几年来成为电力工业界广大科技工作者研究的热点之一。微电网的任务是为用户提供清洁、可靠、优质的电力服务。将微电网与大电网并列运行,不但能够节省投资、提高电能质量,还可以保证电力系统的稳定性和灵活性。微电网有孤岛运行和并网运行两种模式,在这两种模式切换的过程中,由于硬件电路和软件程序所用时间的不同,造成在过渡过程中并网逆变控制器的控制方式切换和运行模式切换的不同时性,最终导致并网电流和负载电压出现冲击,无法达到无缝切换。本文首先论述了太阳能光伏发电、风力发电、微型燃气轮机、蓄电池的发电原理,并建立了相应的数学模型；论述了上述微电源逆变器的工作原理,建立了它们的数学模型。其次,在论述了太阳能光伏发电、风力发电、微型燃气轮机及蓄电池逆变器控制原理的基础上,给出PQ控制器、V/f控制及加权电压、电流控制策略,搭建了微电源及控制的仿真模型,验证了控制策略的有效性及可行性。最后,利用电磁暂态软件PSCAD/EMTDC建立了整个微电网及控制模型,对微电网双运行模式的切换进行仿真。由于微电网双运行模式在切换过程中存在的问题,本文提出了加权控制算法。在逆变控制器双环控制的基础上,通过改变加权因子的值,并网过渡过程中加入电压加权控制,离网过渡过程中加入电流加权控制。在改变控制策略后,能够抑制并网电流的冲击,稳定负载电压,最终达到微电网双运行模式的无缝切换。
[Abstract]:The energy crisis and environmental protection problems have become one of the main factors restricting the development of the society. In addition, the traditional large-scale power system has become increasingly apparent structural aging, energy use efficiency is low, and so on. People have to think about the use of renewable energy. Because of the advantages of environmental protection, energy saving, economy and so on, distributed power generation has received extensive attention from all walks of life. Microgrid is an effective form of efficient use of distributed energy. In recent years, it has become one of the hot spots of research for the vast number of scientific and technological workers in power industry. The mission of microgrid is to provide clean, reliable and high quality power service to customers. Parallel operation of microgrid and large power grid can not only save investment, improve power quality, but also ensure the stability and flexibility of power system. There are two modes of island operation and grid-connected operation in microgrid. In the process of switching between these two modes, due to the difference of time between hardware circuit and software program, In the process of transition, the switching of control mode and operation mode of grid-connected inverter controller is different, resulting in the impact of grid-connected current and load voltage, and the seamless switching can not be achieved. In this paper, the principles of solar photovoltaic power generation, wind power generation, micro gas turbine and battery generation are discussed, and the corresponding mathematical models are established, and the working principle of the micro power inverter mentioned above is discussed and their mathematical models are established. Secondly, on the basis of discussing the control principle of solar photovoltaic power generation, wind power generation, micro gas turbine and battery inverter, the control strategy of VR / f control and weighted voltage and current control of PQ controller is given. The simulation model of micro power supply and control is built to verify the effectiveness and feasibility of the control strategy. Finally, the whole microgrid and its control model are established by using the electromagnetic transient software PSCAD/EMTDC, and the switching between the two operation modes of the microgrid is simulated. Due to the problem of dual operation mode in the switching process of microgrid, a weighted control algorithm is proposed in this paper. On the basis of double loop control of inverter controller, voltage weighting control is added in the transition process of grid connection and current weighted control is added in the process of off-grid transition by changing the value of weighting factor. After changing the control strategy, it can restrain the impact of the grid-connected current, stabilize the load voltage, and finally achieve the seamless switching of microgrid dual operation mode.
【学位授予单位】：山西大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM727;TM464

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