级联式无刷双馈发电机的仿真研究

介绍了级联式无刷双馈发电机的结构和发电原理,根据异步电机的电压方程和坐标变换理论,推导出无刷双馈电机的转子机械速dq坐标系下的数学模型,并进行了Matlab建模和仿真.仿真结果验证了该数学模型的正确性,并为级联式无刷双馈变速恒频发电系统的进一步研究提供了理论基础.     

变速恒频无刷双馈风力发电机的建模与仿真

建立了包括风速、风力机和风力机机械控制部分、变速恒频无刷双馈风力发电机的整体动态数学模型：应用MATLAB软件中的SIMULINK环境,以建立的数学模型为基础搭建了变速恒频无刷双馈风电机组仿真模型。以渐进风和随机风为例．对仿真模型进行分析。仿真结果表明了变速恒频尤刷双馈风力发电机良好的运行特性及模型的正确性,并为无刷双馈电机在风力发电系统的进一步应用研究提供了可靠的理论依据。     

级联式无刷双馈变速恒频发电机控制策略的仿真研究

通过对级联式无刷双馈发电机(CBDFG)转子机械速dq坐标系下的数学模型进行建模和仿真,验证了其具备良好的变速恒频发电性能,为进一步研究CBDFG的变速恒频控制策略引入磁链矢量定向控制(FOC)方法.首先建立了CBDFG定子同步速MT坐标系下的数学模型,并由此推导出一套基于磁链定向控制思想的CBDFG控制策略,利用NMaqtlab/Simulink工具和S函数编写构建系统仿真模型,并进行了空载运行、负载运行和空载并网仿真研究,仿真结果验证了该控制策略的正确性.     

开绕组无刷双馈风力发电机的直接功率控制研究

为了提高无刷双馈风力发电机系统的控制灵活性和故障冗余能力,进一步减小所需变频器容量,实现最大功率跟踪,提出一种具有开绕组结构的无刷双馈风力发电机及其直接功率控制系统。将无刷双馈发电机(brushless doubly-fed generator,BDFG)的控制绕组端设计为开绕组结构,采用双端供电式级联型两电平逆变器与控制绕组两端连接对开绕组BDFG(open-winding BDFG,OW-BDFG)进行励磁,可对各相控制绕组电流进行独立控制。针对该种由双逆变器馈电的OW-BDFG,提出采用混合矢量直接功率控制(direct power control,DPC)方法以实现最大功率跟踪,该种控制方法结构简单,计算量小,且无需观测磁链大小,实时性好。最后,通过仿真研究验证所提出OW-BDFG直接功率控制系统的有效性和可行性。     

变速恒频无刷双馈风力发电机的直接转矩控制

针对变速恒频无刷双馈风力发电系统,分析无刷双馈发电机的最大吸收功率与转速之间的关系,提出采用直接转矩控制方法,通过控制发电机转矩和功率因数来调节其有功功率,进而实现最大风能捕获,提高发电效率。此外,还针对无刷双馈发电机内部磁场关系复杂的特点,提出一种新型的速度观测方法,以两相静止坐标系作为参考坐标系,通过估算转子磁链同步旋转速度和转差速度来估测发电机转速,进而实现无速度传感器控制,以提高系统可靠性。由仿真结果可以看出,通过快速调节发电机转矩可以有效获得最大吸收功率,所设计的速度观测器也能快速准确地估算出发电机转速。     

变论域模糊控制的无刷双馈风机调速系统的仿真研究

基于无刷双馈电机具有结构简单、所需变频器小等优点,根据无刷双馈电机基于转子速d-q双同步坐标系下的数学模型,借助Matlab/Simulink仿真软件搭建了无刷双馈电机的仿真模型,提出和设计了变论域模糊控制器并用于无刷双馈电机的转速调节.仿真结果表明,该控制方法有助于提高调速系统的调节时间、增强系统鲁棒性.     

无刷双馈风力发电机组的自抗扰功率解耦控制

对无刷双馈风力发电机组稳态运行时的功率分配关系进行了详细分析,在此基础上确定了最大风能捕获的控制策略.将自抗扰控制应用到无刷双馈电机有功功率与无功功率的解耦控制,将功率控制系统分解为有功功率子系统和无功功率子系统,从而建立了风力发电机组完整的功率控制模型.基于Matlab/Simulink的仿真结果表明无刷双馈风力发电机组自抗扰控制成功实现了有功功率与无功功率的解耦控制,不仅能够实现最大风能捕获,而且可以根据电网的实际需求调节机组无功功率的输出,验证了控制算法的有效性.     

新型无刷双馈变速恒频风力发电系统的建模与数字仿真

无刷双馈变速恒频风力发电系统具有可靠性高和能够最大限度地实现风电能量转换等一系列优点。介 绍了无刷双馈风力发电机及其变速恒频风电系统的组成,建立了基于Simulink技术的发电机仿真模型,研究了该 种发电机的变速恒频控制技术。仿真研究初步验证了发电机模型与控制策略的正确性。     

无刷双馈风力发电机的变速恒频最大功率跟踪

针对风力发电用变速恒频无刷双馈发电机系统,提出采用直接转矩控制方法,通过控制无刷双馈发电机的转矩和功率因数来调节其有功功率,采用最大功率因数原则设定控制绕组的磁链给定,以提高发电效率,改善电能质量,且在估计转矩时使功率绕组侧输出电压在并网前满足并网条件,以同时实现最大功率跟踪控制和变速恒频运行。此外,为了改善无刷双馈发电机直接转矩控制系统的低频性能,采用模型参考自适应辨识技术来设计控制绕组的磁链观测器,以控制绕组的电流作为比较信号,同时考虑控制绕组的电阻变化对磁链观测的影响,并利用Lyapunov稳定性定理来推导自适应率。最后通过仿真分析和实验研究验证了所提出控制方案的正确性和可行性。     

变速恒频风力发电系统及其控制技术研究

为了最大限度地利用风能,风力发电系统应采用变速恒频控制策略。分析了鼠笼异步发电系统、双馈发电系统、无刷双馈发电等变速恒频风力发电系统的原理、性能及特点,通过对比各种风力发电机和各种控制方法的优缺点,对未来风力发电机和风力发电控制技术的发展趋势做了展望: 风力发电机大型化;采用变桨距和变速恒频技术;风力发电机采用直接驱动;采用智能化控制等。     

Automatic generation control of a wind farm with variable speedwind turbines

Wind farms are considered to be negative loads from the point of view of a utility manager. Modern variable-speed wind turbines offer the possibility for controlling active and reactive power separately. This paper presents a new integrated control system of a wind farm according to the utility manager's requirements. This control system is based on two control levels: a supervisory system controls active and reactive power of the whole wind farm by sending out set points to all wind turbines, and a machine control system ensures that set points at the wind turbine level are reached. The system has been validated by numerical simulation using data from a wind farm with 37 variable-speed wind turbine situated in the North of Spain. An automatic generation control of these characteristics promises improved performance of the system and a better grid integration of the wind energy without significant extra costs     

大型风电机组独立变桨控制技术研究

通过对风力机简化模型的分析,推导出风力机的运动方程和输出方程;通过卡尔曼坐标变换将塔架前后运动方程和载荷输出方程所代表的线性时变系统解耦为线性时不变系统,在此基础上提出带3个独立控制环的独立变桨控制策略;利用"GH Bladed"软件对独立变桨控制策略进行仿真试验研究,仿真试验结果表明,采用独立变桨控制技术不但能实现转速控制功能,还能有效减小叶片根部挥舞力矩、轮毂倾翻力矩、偏航力矩的波动,从而能有效降低变桨轴承、主轴、轮毂、偏航轴承、塔架上的疲劳载荷。     

Modelling and control of variable speed wind turbines for power system studies

Modern wind turbines are predominantly variable speed wind turbines with power electronic interface. Emphasis in this paper is therefore on the modelling and control issues of these wind turbine concepts and especially on their impact on the power system. The models and control are developed and implemented in the power system simulation tool DIgSILENT. Important issues like the fault ride‐through and grid support capabilities of these wind turbine concepts are addressed. The paper reveals that advanced control of variable speed wind turbines can improve power system stability. Finally, it will be shown in the paper that wind parks consisting of variable speed wind turbines can help nearby connected fixed speed wind turbines to ride‐through grid faults. Copyright © 2009 John Wiley & Sons, Ltd.     

风电场风电机组机载风速仪状态自确认

以风电机组机载风速仪为例,提出一种传感器状态自确认方法。利用多台风电机组风速的相关性,通过动态时间规整算法,选定一组风电机组群。构建基于自联想神经网络的风电机组群风速仪预测模型,采用历史正常数据通过麻雀搜寻优化算法对模型进行训练,根据实际值与预测值的关系对风速仪状态进行识别。通过仿真实验证明该方法可识别风速仪模拟异常状态,最后对某风场实际风速进行检测,结果显示能有效识别出风速仪的状态,实现风电机组风速仪状态的自确认。     

基于二阶滑膜-PID控制的风力发电机最大功率跟踪策略研究

针对风电机组最大功率跟踪(MPPT)及其控制过程稳定性需求,该文提出一种二阶滑膜-PID(PSOSMC)最大功率跟踪控制策略.为了实现对发电机转矩的稳定控制,通过结合二阶滑膜控制策略与PID控制,由比例积分导数(PID)构建滑模面进而推导出转矩控制律,建立基于PID滑模面的二阶滑膜控制系统模型,并利用Lyapunov稳...     

Effects of seismic and aerodynamic load interaction on structural dynamic response of multi-megawatt utility scale horizontal axis wind turbines

Horizontal axis wind turbines can experience significant time varying aerodynamic loads that has the potential to cause adverse effects on structural, mechanical, and power production. The progress in the wind industry has caused the construction of wind farms in areas prone to high seismic activity. With the advances in computational tools, a more realistic representation of the behavior of wind turbines should be performed. One of the simulation platforms was developed using the 5 MW NREL utility scale reference turbine model. The performed simulations will be used to evaluate the effects of aerodynamic and seismic load coupling on the power generation and structural dynamics behavior of this structure. Different turbine operational scenarios such as (i) normal operational condition with no earthquake, (ii) idling condition with the presence of seismic loads, (iii) normal operational condition with earthquake, and (iv) earthquake-induced emergency shutdown will be simulated with various loading conditions to show the differences in generated power and dynamic response. The results of this paper provide formulations for calculating generated power and design deriving parameters by considering different intensity measures. Moreover, the effects of aerodynamic damping and pitch control system are presented to shows reduction in the resulting design demand loads.     

Nonstationarity in correlation matrices for wind turbine SCADA-data

Modern utility-scale wind turbines are equipped with a Supervisory Control And Data Acquisition (SCADA) system gathering vast amounts of operational data that can be used for analysis to improve operation and maintenance of turbines. We analyze high-frequency SCADA-data from the Thanet offshore wind farm in the United Kindom and evaluate Pearson correlation matrices for a variety of observables with a moving time window. This renders possible a quantitative assessment of nonstationarity in mutual dependencies of different types of data. We show that a clustering algorithm applied to the correlation matrices reveals distinct correlation structures for different states. Looking first at only one and then at multiple turbines, the main dependence of these states is shown to be on wind speed. This is in accordance with known turbine control systems, which change the behavior of the turbine depending on the available wind speed. We model the boundary wind speeds separating the states based on the clustering solution. Our analysis shows that for high-frequency data, the control mechanisms of a turbine lead to detectable nonstationarity in the correlation matrix. The presented methodology allows accounting for this with an automated preprocessing by sorting new data based on wind speed and comparing it to the respective operational state, thereby taking the nonstationarity into account for an analysis.     

基于随机组合赋权模糊评价的风电机组健康状态评估

由于健康指标权重随机性会导致风电机组状态评估灵敏度降低,提出一种评估风电机组健康状态的随机组合赋权模糊评价方法。首先,通过相关性、方差、偏度等多角度分析风电场采集与监视控制系统（SCADA）数据,结合IEC61400-1标准建立机组健康状态评估指标架构,并基于随机因子优化组合权重得到赋权公式,提高评估指标层权重的准确性。其次,为充分覆盖评估指标数据劣化度,基于岭型分布函数建立健康指标劣化隶属度计算函数。结合随机组合权重和隶属度函数,构建风电机组健康状态模糊综合评价数学模型。通过分层评估风电机组健康状态指标架构,得到机组健康等级并实现故障预警。最后,对大连驼山风电场多台机组进行评估试验,结果表明：该文方法能准确评估出风电机组健康状态等级,相比组合赋权云模型方法,灵敏度提高了1.85%。     

基于MATLAB的风力发电机组建模和仿真研究

变桨距控制技术是风力发电机组提高对风能的利用的有效方法,由于外界环境的随机性和控制变量的多样性,风力发电系统是一个非线性的系统,其数学模型的建立和仿真是一个难点。本文基于Matlab软件平台,采用机理建模法建立了风力发电机组的各个分系统的子模型,组合成整个机组的数学模型,并采用PID控制算法实现风力发电机组在不同风速下对风能利用的最大化,仿真结果验证了系统模型和控制算法的正确性,为风机控制的创新奠定了理论基础。     

Large eddy simulation of dynamically controlled wind turbines in an offshore environment

Accurate modelling of transient wind turbine wakes is an important component in the siting of turbines within wind farms because of wake structures that affect downwind turbine performance and loading. Many current industry tools for modelling these effects are limited to empirically derived predictions. A technique is described for coupling transient wind modelling with an aero‐elastic simulation to dynamically model both turbine operation and wake structures. The important feature of this approach is a turbine model in a flow simulation, which actively responds to transient wind events through the inclusion of controller actions such as blade pitching and regulation of generator torque. The coupled nature of the aero‐elastic/flow simulation also allows recording of load and control data, which permits the analysis of turbine interaction in multiple turbine systems. An aero‐elastic turbine simulation code and a large eddy simulation (LES) solver using an actuator disc model were adapted for this work. Coupling of the codes was implemented with the use of a software framework to transfer data between simulations in a synchronous manner. A computationally efficient simulation was developed with the ability to model turbines exhibiting standard baseline control operating in an offshore environment. Single and multiple wind turbine instances were modelled in a transient flow domain to investigate wake structures and wake interaction effects. Blade loading data were analysed to quantify the increased fluctuating loads on downwind turbines. The results demonstrate the successful implementation of the coupled simulation and quantify the effect of the dynamic‐turbine model. Copyright © 2012 John Wiley & Sons, Ltd.