不平衡电网下双馈风力发电控制系统的研究

发布时间：2018-01-13 17:34

本文关键词：不平衡电网下双馈风力发电控制系统的研究　出处：《哈尔滨理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：双馈电机(Doubly fed induction generator,DFIG)风力发电系统由于所用变换器容量小、成本低和平滑并网性好的优点而被广泛应用,但是随着风力机组容量不断的增加,轻微的电网故障将会导致不可预料的后果。由于电网不是严格对称的或者总有不可避免的故障发生,这时按照理想电网下建立的系统数学模型和所用的控制策略将不能确保系统稳定的运行,同时还会进一步影响电网电能质量。所以本文就不平衡电网下的DFIG风力发电系统变换器的数学模型及控制策略展开研究,通过分析比较,设计了两个全控型变换器的控制方案,最后通过仿真验证了方案的有效性。本文主要进行了如下工作:首先,对DFIG风力发电系统的发电机理进行了详细的分析研究,推出了变速恒频运行时满足的条件,同时进行了整个系统的能量流动分析,对整个控制系统的功能有一个清晰直观的了解。其次,建立了DFIG与网侧变换器在平衡电网条件下的数学模型,分析了不平衡电网时各变量的组成及相序分离方法,在此基础上,建立了两者在不平衡电网情况下的数学模型。再次,基于数学模型详细分析推导了平衡电网下系统网侧与机侧变换器的传统矢量控制系统,对所需定子磁链幅值的计算作了详细的分析。针对不平衡电网下负序分量的影响,提出一种基于正向同步速旋转坐标系下比例积分谐振(Proportional integral resonant,PIR)控制器的矢量控制策略,就其中想要实现的控制目标给出了电流指令值的算法。最后,就本文提出的控制方法对系统进行仿真分析,比较理想电网传统控制策略与不平衡电网下的控制策略在一相电网电压降落时的仿真结果,结果表明,本文所提方法可大大减弱故障所带来的影响。选择STM32F103RB作为核心控制器搭建了实验平台,进行系统在理想电网条件下采用传统矢量控制的实验研究,实验结果表明该系统可实现变速恒频运行和平滑并网。
[Abstract]:The Doubly fed induction Generator (DFIGG) wind power system has a small capacity because of its small capacity. The advantages of low cost and good smoothness are widely used, but with the increase of wind turbine capacity. Minor grid failures can lead to unpredictable consequences. Because the grid is not strictly symmetrical or there are always inevitable failures. At this time, the system mathematical model and control strategy established under the ideal power grid will not ensure the stable operation of the system. At the same time, it will further affect the power quality of the grid. So this paper studies the mathematical model and control strategy of DFIG wind power system converter under unbalanced power grid, through analysis and comparison. Two full control converter control schemes are designed. Finally, the effectiveness of the scheme is verified by simulation. The main work of this paper is as follows: first. The generator theory of DFIG wind power system is analyzed in detail, and the condition of variable speed constant frequency operation is deduced. At the same time, the energy flow analysis of the whole system is carried out. The function of the whole control system has a clear and intuitive understanding. Secondly, the mathematical model of DFIG and grid-side converter under the condition of balanced power grid is established. The composition of each variable and the method of phase sequence separation in unbalanced power network are analyzed. On this basis, the mathematical model of the two variables in the case of unbalanced power grid is established. Thirdly. Based on the mathematical model, the traditional vector control system is derived for balancing the power system between the network side and the machine side. The calculation of stator flux amplitude is analyzed in detail. A vector control strategy based on proportional integral resonance (Pi) controller in forward synchronous rotating coordinate system is proposed. The algorithm of the current instruction value is given for the desired control target. Finally, the simulation analysis of the control method proposed in this paper is carried out. The simulation results of ideal traditional control strategy and unbalanced control strategy in one-phase network voltage drop are compared, and the results show that. The method proposed in this paper can greatly reduce the impact of the fault. STM32F103RB is selected as the core controller to build the experimental platform. The experimental results show that the system can realize variable speed constant frequency operation and smooth grid connection.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM614

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