【作者】 郝欣；

【导师】 张崇巍；

【作者基本信息】 合肥工业大学 ， 电气工程， 2013， 博士

【摘要】 随着社会经济的高速发展,能源和环境问题已成为当今世界各国面临的重大问题。开发新能源和发展可再生能源已成为了人类社会的共识,而风能作为一种清洁的可再生能源也越来越受到重视。本文以安徽省“十五”科技攻关项目和国家“十一五”科技支撑项目为依托,选择双馈型风力发电系统为研究对象,进行了从理论到实践、从仿真到实验的全面、深入研究。双馈电机的控制需要精确的转子速度和位置信号,传统的双馈调速风力发电机大多采用带速度位置编码器(码盘)的定子电压定向的矢量控制技术,但是速度传感器的存在增加了成本,降低了系统可靠性,给系统维护带来了诸多不便。因此,本文的研究工作主要围绕双馈风力发电系统无速度传感器控制展开。本文首先详细分析了双馈风力发电系统基本构成和运行原理,在此基础上对国内外现有的无速度传感器控制方法进行了介绍和分析,指出现有控制策略的优缺点。特别是双馈电机(DFIG)在实际风场运行时,需要在发电和电动两种状态、四个象限下运行,而现有对双馈电机的很多无速度传感器控制算法都是针对发电状态下进行研究,在电动状态下不能使用。本文提出的参考模型自适应的算法有效解决了以上问题,并通过理论分析、仿真和实验得到了验证。本文的主要研究工作和创新点可以总结如下：(1)简要介绍了我国风能资源的分布、国内外风力发展的概况和世界风电装机容量情况。列举了现有风力发电机组的几种主要类型,并分析了风力发电今后的发展的趋势。介绍了风力发电系统和风场运行的几种重要控制技术,如偏航变桨技术、无速度传感器技术和低电压穿越技术。(2)分析了双馈电机(DFIG)的工作原理、等效电路和双馈风力发电系统的优势。根据兆瓦级双馈风力发电机系统的控制方法,将其运行情况分为启动状态、最大功率跟踪状态、额定功率状态(恒功率控制)和停机状态,对每种状态做了简单介绍。基于双馈风力发电系统现场的几种运行状态,介绍了双馈风机的控制时序。对现有的双馈电机无速度传感器控制方法做了分析。(3)分别在三相静止A-B-C坐标系、两相静止α-β坐标系和两相旋转d-q坐标系下,对兆瓦级双馈风力发电系统中的双馈电机(DFIG)和变流器进行数学建模。分析了双馈风电系统中能量的流动关系,详细介绍了风机在四种运行工况下的功率流向和转换关系。介绍了目前风电系统中常见变流器的矢量控制方法并对基于定子电压和定子磁链的两种风机变流器的矢量控制方法进行了详细说明。(4)设计并搭建了110KW的双馈风力发电机模型对拖平台。实验平台由一台变频器控制的异步电机和一台双PWM变流器控制的双馈电机组成。双馈电机的控制系统由三部分组成：网侧控制器、机侧控制器和上位PC机。对实验平台的软硬件结构做了介绍,并对平台中的关键参数进行设计。(5)对双馈风力发电机的无速度传感器控制方法进行了研究：指出了传统编码器的缺点,分析了国内外现有的无速度传感器的控制方法的优缺点。对基于双馈电机定子电压或者电流的无速度传感器控制方法提出了改进,使之能适用于风场的实际运行。提出两种参考模型自适应的无速度传感器控制方法,并采用不同的控制理论方法证明了其可行性和稳定性。该控制方法实现简单,辨识准确,而且能够适用于双馈风机的各种运行状态,实现了双馈风力发电系统无速度传感器控制的关键技术要求。仿真和实验验证了算法的稳定性。更多还原

【Abstract】 With the development of global economy and human society, the energy sources and the environmental protection become two important issues of the world. The development of renewable energy sources has become a social consensus. As a clean renewable energy source, wind power generation is becoming more and more important and attractive. Based on the project as Supported program of Anhui Province during the10th Five-year Plan Period and the project as Supported program of the Ministry of Science and Technology during the11th Five-year Plan Period, this dissertation choses the doubly-fed induction generator (DFIG) as the research subject and makes a deep study on both the theory and practice, aided by simulations and experiments. The control system of DFIG requires accurate information of the rotor speed and rotor position, while the present control systems of DFIG use speed sensors to get information, but the sensors themselves bring a lot of problems, such as the cost increase and low reliability. That is why this dissertation focuses on the sensorless control of DFIGWith an analysis of the DFIG’s structure and operation theory, this dissertation makes an introduction of present DFIG’s sensorless control strategies and points out their respective merits and drawbacks. The DFIG must possess the capability to operate in both of the motor and generator mode while set in the real wind farm, but most sensorless control strategies can only be applied to generator mode. This paper proposes a new model reference adaptive control (MRAC) strategy that can solve this problem. The main research content included in this paper can be listed as follows:(1) Brief introduction of China’s wind energy distribution, the development of wind power system, the installed capacity of wind power generation in the world, the main types of wind power generators, as well as the trend of wind power generation in the future. Some hot engineering topics of the wind farm, such as the yawing, pitch control and low voltage ride through (LVRT) were also introduced..(2) The wind power generation system is been introduced and the operation theory with equivalent circuit of DFIG are analyzed following the discusion of the DFIG’s merits. On the control strategy of MW level DFIG, four operation modes such as start mode, MPPT mode, constant power control mode and stop mode are taken into study according to their sequence being put into operation.(3) The mathematic model of MW level DFIG is established respectively in the three phase A-B-C still frame, two phase α-β still frame and two phase synchronously rotating d-q frame. The energy flow within DFIG system is analyzed in four operation mode. Main types of wind power converter are introduced and the vector control strategies based on stator voltage and stator current are also proposed.(4) An110KW DFIG experimental prototype that integrates DFIG, back-to-back converters, controllers and monitor is built up in the laboratory to meet the requirements of theory verification, and the experiments demonstrate the feasibility of proposed methods.(5) With a study on the merits and drawbacks of various sensorless control strategy of DFIG, a new model reference adaptive control strategy is proposed in the dissertation, that can acquire correct rotor speed and better system performance compared to those previous strategy and is easy to be implemented.更多还原