风力提水机可变行程之实现途径

描述了可变行程风力提水机与普通风力提水机相比的优点,探讨了可变行程的具体实现及控制方法,指出了可变行程风力提水存在的一些问题及今后的改进方向。     

变行程风力提水技术

研究了以变行程技术实现机械式风力提水机风轮与活塞泵在宽风速范围的高效匹配问题.文章对变行程风力提水技术的基本原理进行了分析;提出了风轮与活塞泵最佳匹配时行程随风速变化的关系式;研究了变行程提水机组的工作特性;采用瑞利分布对机组投运后的出力进行了预测.研究结果表明,变行程技术对改善风力提水机组的工作特性有明显效果.     

风力提水机低风速启动解决方案的研究

在分析传统风力提水机低风速启动方案的基础上,提出了变行程机构加配重的方案.设计了交行程机构,完成了配重的计算,并利用Pro/Engineer软件建立虚拟样机,通过仿真结果,得到最佳的配重.     

风力离心泵提水机组的应用与发展

扼要回顾了风力离心泵提 应用和发展历史，介绍了几个时期机型的特点和规格参数，分析了发展趋势。     

风力提水机性能的改进

在同样叶轮直径,同样运行条件下可对变行程与不变行程风力提水机进行了对比实验,实验结果表明,在低风速度下,可变行程风力提水机的性能与不变行风力提水机相比差别不大;但在高风速下,可变行程风力提水机具有提水量大,效率高,泵运行转速稳定等优点,极具开发利用价值。     

基于PID控制的变速恒频风力发电机组液压变桨距控制系统研究

文章分析了变桨距控制原理,对变速恒频风力发电机组各部分数学模型进行了分析与研究,在此基础上,建立了变速恒频风力发电机组PID液压变桨控制系统仿真模型,在matlab/simulink环境下对未加PID控制器与加PID控制器两种情况下的系统进行了仿真研究。仿真结果表明,PID控制器能改善风力机桨距控制效果,更好地捕获风能,稳定风力机功率输出。     

A variable speed wind turbine power control

To optimize the power in a wind turbine, the speed of the turbine should be able to vary with the wind speed. A simple control scheme is proposed that will allow an induction motor to run a turbine at its maximum power coefficient. The control uses a standard V/Hz converter and controls the frequency to achieve the desired power at a given turbine speed     

Multivariable control strategy for variable speed, variable pitch wind turbines

Reliable and powerful control strategies are needed for wind energy conversion systems to achieve maximum performance. A new control strategy for a variable speed, variable pitch wind turbine is proposed in this paper for the above-rated power operating condition. This multivariable control strategy is realized by combining a nonlinear dynamic state feedback torque control strategy with a linear control strategy for blade pitch angle. A comparison with existing strategies, PID and LQG controllers, is performed. The proposed approach results in better power regulation. The new control strategy has been validated using an aeroelastic wind turbine simulator developed by NREL for a high turbulence wind condition.     

变速变桨风力发电机组的优化控制

提出了大型变速变桨风力发电机组在不同控制阶段的优化控制策略。在低风速时,采用自适应转矩控制方式,实现机组的变速运行,追踪最佳风能利用系数。在额定风速以上时,为了解决传统桨距控制方式系统超调量大的问题,提出了一种新型气动转矩观测器,并将气动转矩与发电机转矩偏差输入控制器。通过Bladed外部控制器模块编程并进行仿真,结果表明,所提出的控制策略能够更好地追踪最大功率点,并改善桨距控制效果,稳定功率输出。     

大型风力发电机组独立变桨多目标控制

为限制大型风力发电机组在高风速时的功率输出和风力机气动载荷,首先,采用PID控制,设计独立变桨距功率和扭矩外环控制;其次,引入不依赖于系统数学模型的无模型控制,设计桨叶挥舞弯矩内环控制;最后,以外环控制输出桨距角为参考量,内环无模型控制期望桨距角为反馈量,利用PID控制,给出3个桨叶桨距角最终参考值。利用Matlab/Simulink仿真软件,搭建了3 MW风电机组仿真平台,仿真结果表明,所设计的独立变桨距多目标控制,能够完成在高风速时保持风力机组输出功率恒定、平衡3个桨叶所受扭矩以及兼顾3个桨叶所受挥舞弯矩的多目标控制任务。     

A sensorless control for a variable speed wind turbine operating at partial load

This paper presents a sensorless control for a variable speed wind turbine (WT) operating at partial load in order to eliminate the direct measurement of the wind speed. In this proposal, the estimated aerodynamic torque is used to determine the optimal reference of the speed control for maximum energy conversion. The maximization of the efficiency on energy conversion and the minimization of detrimental dynamical loads are control trade-offs considered in the design of an optimal discrete-time feedback LQG/LTR controller for the Wind Energy Conversion System (WECS), which is based on the optimization of a quadratic cost function. The performance of the proposed control when the WT is submitted to a gust or step variation on wind speed is evaluated from computational simulations. It is also presented some proposals for sensorless control of the electrical generator.     

A novel line drop secondary voltage control algorithm for variable speed wind turbines

This paper addresses the design and implementation of the line drop secondary voltage control (LDSVC) for the doubly fed induction generator‐wind turbine (DFIG‐WT) complemented with reactive power allocation algorithm to achieve more efficient voltage regulation, reactive power compensation and to enhance the transient stability margin of the electric power system. The LDSVC is used to generate the local voltage reference, providing an improvement for overall voltage profile. The paper presents the influence of the integration of variable speed wind turbines‐based doubly fed induction generator (DFIG) while employing LDSVC for increasing the transient stability margin. This paper proposes an improved voltage control scheme, based on a secondary voltage controller complemented with an automatic gain controller (AGC). The scheme is applied to a wind energy system incorporating DFIG‐based wind turbines. The controller structure is developed and the performance of the self‐tuning AGC scheme is developed and analysed. The proposed controller is tested in response to system contingencies for different short circuit ratios. The performance of the secondary voltage control without and with AGC is verified. The influence of the AGC in improving the transient response and damping of voltage oscillations is verified. Copyright © 2010 John Wiley & Sons, Ltd.     

风力发电系统权系数独立变桨距矢量控制

风电系统具有多变量、非线性以及不确定等特点,为了减小叶片不平衡载荷造成的机组疲劳和振动,在2 MW风力发电系统中采用了基于权系数的独立变桨距矢量控制。在MATLAB软件中建立机组的数学模型,与统一变桨距系统的控制效果进行比较,通过仿真验证了权系数独立变桨距矢量控制方案的合理性和优越性。     

变速变桨风力机叶片载荷控制策略

针对变速变桨风力机叶片受力特点,提出叶片载荷控制策略。将叶片载荷分为静态和动态两部分。静态部分采取单神经元PID控制器对桨距角和电机转矩进行控制;动态部分采取多叶片坐标转换理论将变量从旋转坐标系转换到固定坐标系,再将力矩转换为桨距角,然后通过多叶片坐标逆变换将控制得到的参数转换为旋转坐标系中的参数。最后将动态部分的参数值和静态部分的单神经元PID控制器的输出桨距角相加,一起构成风力机变桨所需的控制值。采用风力机专业软件Bladed开发外部控制器,并对控制策略进行仿真研究。将外部控制器和内置控制器的控制性能进行了仿真对比,仿真结果表明:外部控制器能够有效降低叶片根部的倾斜力矩和叶片拍打力矩,外部控制器的控制性能更优,验证了所采用的叶片载荷控制策略的正确性。     

基于人工蜂群-RBF-PID的风力机液压变桨距控制系统设计

风力机液压马达变桨距系统存在高阶多耦合、不确定、非线性、难以控制的问题。为实现桨距角跟踪控制,文章通过动力学分析建立液压马达变桨距系统的数学模型,确定系统特性。根据液压马达变桨距系统原理,采用SimHydraulics建立液压马达变桨距系统仿真模型,设计基于人工蜂群算法结合RBF神经网络的PID控制器,并且采用自适应矩估计算法代替梯度下降法对PID参数进行在线优化。仿真结果表明,采用文章算法,系统响应快,桨距角跟踪精度高。