双馈风力发电机无速度传感器矢量控制

针对风力发电系统中的双馈电机提出一种转子感应电势定向矢量控制方法。通过调节双馈电机转子侧的瞬时有功电流和无功电流,实现对电机力矩和转子侧励磁电流的调节,进而实现双馈电机无功功率调节。在控制过程中只需检测交流侧电流电压,不需要位置传感器,所以可以应用无速度传感器。最终通过仿真试验证明该方法的正确性和实用性。     

Nonlinear control of the doubly-fed induction generator in wind power systems

This paper describes the models of a wind power system, such as the turbine, generator, power electronics converters and controllers, with the aim to control the generation of wind power in order to maximize the generated power with the lowest possible impact in the grid voltage and frequency during normal operation and under the occurrence of faults. The presented work considers a wind power system equipped with the doubly-fed induction generator and a vector-controlled converter connected between the rotor and the grid. The paper presents comparative results between proportional-integral controllers and neural networks based controllers, showing that better dynamic characteristics can be obtained using neural networks based controllers.     

双馈风力发电机运行控制及其空间矢量分析

以分析双馈风力发电机交流励磁的电磁本质为目标,运用空间矢量理论建立了双馈风力发电机的空间矢量模型;在此基础上,建立了变速变桨双馈风力发电机组的整机模型,给出了不同运行状态下的仿真曲线。在转子绕组自行闭合与加入转子交流励磁2种情况下,对双馈电机中定转子磁动势空间矢量的相位变化进行对比,揭示了交流励磁对于改变转子磁动势空间矢量相位的作用。研究结果表明,当双馈电机运行在亚同步状态时,通过控制交流励磁电流可以使转子磁动势空间矢量的相位超前于定子磁动势空间矢量的相位,从而使双馈电机在转速低于同步转速时也能处于发电状态。     

风力发电机齿轮增速箱的润滑监测

通过对国华（河北）新能源张家口尚义风电场第一期23台风机增速齿轮箱齿轮油的分析化验，评价了油品的常规理化性能，分析了总酸值、清洁度、元素光谱以及进行了磨损颗粒铁谱分析，对油品的运行状况给予了说明，对设备的运行状况进行了解释。     

小型风力发电机组的应用

早在两千多年以前，人类就已经认识到风的强大力量，开始利用风力引水灌田、碾米磨面、驾驭风帆披波斩浪……如今，风能作为一种清洁的可再生能源得到了进一步的开发与利用，旨在缓解能源压力，改善生态环境。     

适合于风力发电系统的电压跌落发生器

为满足在故障情况下的风力发电机控制策略的研究需要,给出了一种电压跌落发生器的拓扑结构,PC机与单片机通过串行通信来实现对电压跌落模式和跌落时间的控制.试验表明,该设备可以实现国外昂贵的电压跌落发生器的基本功能.     

Power variation control of a wind generator by using feed forward control

The pitch control of wind generators is usually made by a feed back control concept. However, under the conditions where a wind speed changes very frequently due to geographic reasons of the site and the target system has large rotor inertia, the feed back signal which is applied to the control system to compensate disturbance such as wind speed variations is delayed, and consequently the control strategy to keep the generated power at a constant value does not work well. If the wind speed shows too much variation, this will cause a violent variation of power and result in step out operation of the generator from the power system due to magnetic saturation. This paper proposes a control strategy to reduce the power variations by introducing feed forward control combining with the conventional feed back control.     

基于风电机组无功响应速度的风电场闪变研究

针对风电机组无功响应速度对风电场并网点电压闪变的影响,从风力发电机组特性出发,基于DIg SILENT建立了含风电机组的电网仿真模型,研究风速波动时风机无功响应速度对风电场并网点电压波动与闪变的影响。算例结果表明:风电机组无功响应速度对并网点电压闪变的影响程度与系统短路容量密切相关,加快风电机组无功响应速度能有效抑制风电场并网点的电压闪变。     

Controlled power transfer from wind driven reluctance generator

The paper describes the dynamic performance of a wind-driven reluctance generator connected to an electric power network of large capacity. A controller that makes possible the regular flow of power to the network has been considered. Controller parameters that successfully suppress unwanted mechanical and electrical stresses and overshoots due to wind gusts, have been estimated. The performance of the controller has also been examined for short-circuit faults at the terminals of the generators     

Simulation of grid connection and maximum power point tracking control of brushless doubly-fed generator in wind power system

In this paper, based on the analysis of the mathematical model in a common synchronous reference frame of the brushless doubly-fed generator (BDFG), the grid connection strategy and maximum energy extraction control were both analyzed. Besides, the transient simulation of no-load model and generation model of the BDFG have been developed on the MATLAB/Simulink platform. The test results during cutting-in grid confirmed the good dynamic performance of grid synchronization and effective power control approach for the BDFG-based variable speed wind turbines.     

双馈风力发电机组的间谐波问题分析

分析了双馈风力发电机组的间谐波产生原理和DFIG间谐波的特点,然后对目前电力系统IEC框架下间谐波检测和存在的问题进行研究。文章采用高斯窗调节因子的S变换来检测变速风力发电机组的间谐波,并与IEC标准中的检测方法进行了对比,通过分析风电机组现场运行数据,说明DFIG输出的间谐波具有明显的特征频次,而这些特征采用已有的标准无法体现出来。     

Reactive power capability of a wind turbine with doubly fed induction generator

The aim of the work is to derive a steady state PQ‐diagram for a variable speed wind turbine equipped with a Doubly Fed Induction Generator. Firstly, the dependency between optimal rotor speed and wind speed is presented. Secondly, the limitations in reactive power production, caused by the rotor current, the rotor voltage and the stator current are derived. Thirdly, the influence of switching from Δ to Y coupling of the stator is investigated. Finally, a complete PQ diagram for a wind turbine is plotted. It is concluded that the limiting factor regarding reactive power production will typically be the rotor current limit, and that the limit for reactive power absorption will be the stator current limit. Further, it is concluded that the rotor voltage will only have a limiting effect at high positive and negative slips, but near the limitation, the reactive power capability is very sensitive to small changes in the slip. Copyright © 2007 John Wiley & Sons, Ltd.     

Fault-tolerant control of an open-winding brushless doubly-fed wind power generator system with dual three-level converter

To improve the fault redundancy capability for the high reliability requirement of a brushless doubly-fed generation system applied to large offshore wind farms, the control winding of a brushless doubly-fed reluctance generator is designed as an open-winding structure. Consequently, the two ends of the control winding are connected via dual three-phase converters for the emerging open-winding structure. Therefore, a novel fault-tolerant control strategy based on the direct power control scheme is brought to focus in this paper. Based on the direct power control (DPC) strategy, the post-fault voltage vector selection method is explained in detail according to the fault types of the dual converters. The fault-tolerant control strategy proposed enables the open-winding brushless doubly-fed reluctance generator (BDFRG) system to operate normally in one, two, or three switches fault of the converter, simultaneously achieving power tracking control. The presented results verify the feasibility and validity of the scheme proposed.     

风力发电机风速放大器的研究与优化设计

研究设计了一种适用于风力发电机的风速放大器,该装置具有显著的聚风和提高风速作用。小于3m/s的风从进口端进入,经过聚风增速,在安装涡轮叶片的出口端可获得较大的风速,使风力发电机能够在风速较低的条件下正常启动和运行,提高单位面积风能利用率。文章以额定功率为1 k W的风力发电机组的风速放大器为例,对设计参数(倾斜角α,长度L,进口直径D)、出口端风速分布及变化规律、风速放大效果进行了研究和Fluent仿真优化。研究结果表明:风速放大器最高可提高风速5.32倍;在风速为0.56 m/s的条件下,风机即可启动;在风速为2 m/s时,风机可在额定功率下运行。     

Sensor-less maximum power point tracking control for wind generation system with squirrel cage induction generator

This paper proposes a technique that determines the optimal windmill operation speed and the optimal rotor flux. Moreover, the position and speed sensor-less wind generation system using the electromotive voltage observer to estimate rotor position and full-order observer to estimate rotor speed and the windmill output torque are proposed. The position and speed sensor-less maximum power point of wind power generation system is controlled by using the above estimated values, optimized windmill operation speed for maximum output power and optimized rotor flux for minimum generator losses. The effectiveness of the position and speed sensor-less maximum power point tracking control for wind power generation system with squirrel cage induction generator is verified by simulations. The simulation results confirm that the proposed method can estimate the operation speed efficiently.     

基于内模控制器的变速恒频风力发电并网控制方法

在分析定子磁链定向的双馈电机控制的基础上,将矢量控制技术和内模控制器结合起来应用于定子电压并网控制中,得到了一种新型的并网控制方法.该控制方法并不需要建立精确的感应电机模型,动态响应快,无超调,控制器结构简单,参数单一,工程上易于实现.利用Matlab进行的仿真结果表明,该方法具有优良的动态性能.     

风道式风力发电机迎风及调速方法

为降低风道式风力发电机的成本,提出了一种风力发电机迎风及调速方法。在风道装置始终正对风向的条件下,由于偏心机构和凸轮机构的共同作用,在风速低时,风轮正对着风向,在风速超限时,风轮相应侧偏,以限制风轮转速。基于空气动力学基本理论,推导出其结构参数的表达式,并叙述了各结构参数的选取原则。该方法可有效地起到大风限速的作用,提高风力发电机工作的稳定性。该调速机构结构简单、成本低,安装维护方便。     

分散式风力发电机组的电压控制

风电的分散式开发不同于大规模开发和分布式开发,由于分散风电靠近负荷中心,直接接入配电网,且不加装无功补偿调节装置SVC,配网中较大的电压波动给分散风电的并网运行带来影响。文章讨论了配网对分散风电的电压控制特点和要求,结合风电机组无功控制能力,并推导出满足配网电压调节要求的风电机组无功控制范围和对机组设备的要求。     

Modeling and control of a wind turbine driven doubly fed induction generator

This paper presents the simulation results of a grid-connected wind driven doubly fed induction machine (DFIM) together with some real machine performance results. The modeling of the machine considers operating conditions below and above synchronous speed, which are actually achieved by means of a double-sided PWM converter joining the machine rotor to the grid. In order to decouple the active and reactive powers generated by the machine, stator-flux-oriented vector control is applied. The wind generator mathematical model developed in this paper is used to show how such a control strategy offers the possibility of controlling the power factor of the energy to be generated.     

Review of direct‐drive radial flux wind turbine generator mechanical design

The direct‐drive radial flux synchronous generator is considered as the modern wind turbine drive train. Both the electrically (e.g., Enercon) and permanent magnet (PM; e.g., Siemens) excited direct‐drive generators are gaining popularity on the market today. Compared with the matured geared counterpart, the electrically excited direct‐drive generator is heavier and more expensive but more reliable per unit capacity. The PM‐excited generator is expensive, is simpler in electromechanical design, has a high power‐to‐weight ratio, and yields a higher energy conversion efficiency than its electrically excited equivalent. The PM generator technology has the potential to yield the highest energy‐to‐cost ratio. However, standardization of this direct‐drive generator parts/subassemblies may overcome the existing cost barrier. Most current literature focuses on PM generator wind turbine technology, specifically on generator energy conversion optimization, and the scalability of technologies to capacities in access of 5 MW. Strangely, PM generator's mass and cost reductions through optimized structural design incorporating manufacturing, transportation, and installation constraints are less studied. This paper solely focuses on the mechanical and structural design aspects of large radial flux synchronous PM generators specific to direct‐drive wind turbines. Generator topologies such as the common iron‐cored and unconventional air‐cored generator are discussed. However, design considerations specific to the iron‐cored generator topology are studied. The design considerations investigated involve the geometries and the configurations of rotor/stator active and inactive structures, the interfaces, and the conductor/PM mounting methods. Copyright © 2011 John Wiley & Sons, Ltd.