永磁同步风力发电系统设计与低电压穿越控制研究

发布时间：2018-02-24 05:02

本文关键词： 风力发电永磁同步发电机低电压穿越功率跟踪切换功率曲线　出处：《广东工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着社会的发展,能源已成为制约人类社会发展的重要因素。大量化石能源的使用,特别是煤炭的大量燃烧、汽车尾气等对环境影响极大,国内各地雾霾日趋严重,已严重影响到人们的日常生活。以风能利用为代表的各类可再生能源,已成为解决这些问题的重要手段,日益受到重视。永磁同步风力发电系统运行效率高、维护成本低、控制方便,适于低风速环境运行,是风力发电的主流方向。近年来,并网风电容量不断增加,一旦发生电网电压跌落故障,严重时可能会引起风力机脱网,进而影响电网稳定性,甚至引发电网崩溃。因此,研究提高永磁直驱风电系统的低电压穿越能力,对提高电网稳定性,改善电能质量具有重大的意义。分析了国内外风力发电的历史与发展现状,研究多种提高永磁风电系统低电压穿越能力的方法。通过分析永磁风力发电机设计特点和方法,应用场路结合法完成了一台2MW直驱外转子永磁同步风力发电机电磁设计方案。应用ANSYS软件,建立发电机二维电磁场模型,研究发电机在空载、额定负载、短路工况下的磁链、反电势等电磁性能。通过分析永磁直驱风电系统的原理、工作特性及各部件运行特点,构建了风力机、永磁同步发电机、全功率变流器及直流环节等部件的数学模型,为研究低电压控制策略提供理论基础。研究了全功率变流器的控制策略：机侧变流器采用电流内环和功率外环双闭环控制策略,网侧变流器采用电压外环和电流内环的双闭环控制结构,分析了低电压跌落理论、永磁直驱风电系统在电压跌落过程中的动态响应过程。提出功率跟踪优化策略实现低电压穿越控制：通过切换功率曲线,将直流侧的电压不平衡转化为发电机的机械功率与电磁功率的不平衡,最后反映到发电机转速的变化。提出一种基于改进的控制策略,将反映发电机瞬时有功功率信息作为前馈补偿量,作为网侧d轴电流的给定,及时跟踪发电机输出有功功率的变化,实时稳定直流侧电压,并与采用Crowbar保护电路的方案进行了对比分析,在Matlab/simulink仿真平台上验证了所提方法的有效性。
[Abstract]:With the development of society, energy has become an important factor restricting the development of human society. The use of a large amount of fossil energy, especially the combustion of coal, the automobile exhaust and so on, have a great impact on the environment. The haze in various parts of China is becoming more and more serious. All kinds of renewable energy, represented by wind energy utilization, have become an important means to solve these problems, and have been paid more and more attention. Permanent magnet synchronous wind power system has high operating efficiency and low maintenance cost. In recent years, the capacity of grid-connected wind power has been increasing continuously, once the power grid voltage sag occurs, it may cause the wind turbine to get off the grid seriously. Therefore, to improve the low voltage traversing ability of permanent magnet direct drive wind power system, it is necessary to improve the stability of power grid. It is of great significance to improve the power quality. This paper analyzes the history and development of wind power generation at home and abroad, studies various methods to improve the low voltage traversing ability of permanent magnet wind power system, and analyzes the design characteristics and methods of permanent magnet wind generator. The electromagnetic design scheme of a 2MW direct-drive external rotor permanent magnet synchronous wind generator is completed by using the field-circuit method. Using ANSYS software, the two-dimensional electromagnetic field model of the generator is established, and the flux chain of the generator under no-load, rated load and short-circuit conditions is studied. By analyzing the principle, working characteristics and operation characteristics of permanent magnet direct drive wind power system, the mathematical models of wind turbine, permanent magnet synchronous generator, full power converter and DC link are built. In order to provide the theoretical basis for the study of low voltage control strategy, the control strategy of full power converter is studied: the current inner loop and the power outer loop are used in the machine side converter. The voltage outer loop and current inner loop are used in the grid-side converter, and the theory of low voltage drop is analyzed. Dynamic response process of permanent magnet direct drive wind power system during voltage drop. A power tracking optimization strategy is proposed to realize low voltage traversing control. The voltage imbalance of DC side is transformed into the imbalance of mechanical power and electromagnetic power of generator, and the change of generator speed is reflected at last. A new control strategy based on improved control strategy is proposed. The instantaneous active power information of the generator is used as feedforward compensation, and as a given d-axis current of the grid side, the change of the output active power of the generator is followed in time, and the DC side voltage is stabilized in real time. The proposed method is compared with the scheme using Crowbar protection circuit, and the effectiveness of the proposed method is verified on the Matlab/simulink simulation platform.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM614

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