不对称故障下双馈风力发电机的低电压穿越策略研究

发布时间：2018-02-21 04:12

本文关键词： 双馈风力发电机低电压穿越协同控制线性自抗扰控制器　出处：《天津理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着风力发电在全世界的高速增长,风电机组的装机容量在电力系统中所占的比重日益剧增,而在风力发电系统当中,变速恒频双馈风力发电机以控制灵活、调速范围宽以及所需励磁变换器容量小等优点,目前已成为在风电场中的主流风电机型。双馈风机由于本身结构的限制,其控制能力很容易受到电网故障的影响,因此如何提高双馈风机的低电压穿越能力已成为风电行业的研究热点。本文以双馈风机在电网不对称故障下的数学模型为基础,对提高双馈风机的低电压穿越技术进行了详细探讨,主要内容如下:1、建立双馈风力发电机在三相静止坐标系和两相同步旋转坐标系下的数学模型,同时对网侧变换器进行建模分析,构建双馈风机在电网不对称故障下的传统控制方法,并通过仿真对传统控制方法的各个电气量进行详细分析。2、为充分利用双馈风电系统中转子侧变换器和网侧变换器的快速无功调节能力,以使得在故障期间对端电压进行有效快速支撑,则通过详细探讨不对称矢量的正负序分量的常规分离方法,提出了一种改进的正负序分离方法,并应用到转子侧变换器和网侧变换器的协同控制之中,在一定程度上提高了双馈风机的低电压穿越能力。3、对网侧变换器的数学模型进行详细分析,在此基础上设计一阶线性自抗扰控制器(Linear Active Disturbance Rejection Controller,LADRC)作为电压外环控制器,以使得系统的高功率因数运行。利用LADRC完全独立于被控对象的具体数学模型和抗干扰能力强的特点,使系统整体具有较好的补偿精度和抗干扰特性。由于一阶LADRC是一个反馈系统,其本质问题是系统的稳定性,利用经典控制理论对二阶线性扩张状态观测器(Linear Extended State Observer,LESO)进行了详细的稳定性证明,并通过仿真验证了LADRC的加入,极大提高了双馈风机的低电压穿越能力。
[Abstract]:With the rapid growth of wind power generation in the world, the installed capacity of wind turbines in the power system is increasing rapidly. In wind power systems, variable speed constant frequency doubly-fed wind generators are used to control flexibility. With the advantages of wide speed range and small capacity of excitation converter, it has become the mainstream wind power model in wind farm at present. The control ability of doubly-fed fan is easily affected by power network fault due to its own structure limitation. Therefore, how to improve the low voltage traversing ability of doubly-fed fan has become a research hotspot in wind power industry. This paper is based on the mathematical model of doubly-fed fan under the asymmetric fault of power network. The low-voltage traversing technology of doubly-fed fan is discussed in detail. The main contents are as follows: 1. The mathematical model of doubly-fed wind turbine in three-phase stationary coordinate system and two-phase synchronous rotating coordinate system is established. At the same time, the modeling and analysis of grid-side converter is carried out, and the traditional control method of doubly-fed fan under the asymmetric fault of power network is constructed. In order to make full use of the fast reactive power regulation ability of the rotor side converter and the grid side converter in the doubly-fed wind power system, the electrical parameters of the traditional control method are analyzed in detail by simulation. In order to support the terminal voltage effectively and quickly during the fault period, an improved method of separating the positive and negative sequence components of the asymmetric vector is proposed by discussing the conventional separation method of the positive and negative sequence components of the asymmetric vector in detail. It is applied to the cooperative control of rotor side converter and grid-side converter. To a certain extent, the low voltage traversing ability of doubly-fed fan is improved. The mathematical model of grid-side converter is analyzed in detail. On this basis, a linear Active Disturbance Rejection controller (LADRC) is designed as a voltage outer loop controller to make the system run with high power factor. The LADRC is completely independent of the specific mathematical model of the controlled object and has strong anti-interference ability. The whole system has good compensation accuracy and anti-interference characteristics. Because the first-order LADRC is a feedback system, its essential problem is the stability of the system. Using the classical control theory, the stability of the second order linear extended state observer linear Extended State observer is proved in detail. The addition of LADRC can greatly improve the low voltage traversing ability of the doubly-fed fan.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM614;TM315

【相似文献】