一种实现风力机MPPT控制的加速最优转矩法

最优转矩法因其所需测量状态较少、易于实现的特点,被广泛应用于风力机的最大功率点跟踪(Maximum power point tracking, MPPT)控制. 传统的最优转矩法只考虑系统的稳态工作点,依靠系统本身的特性进行转速调节,在一定程度上限制了转速调节速度. 本文使用滑模变结构控制的思想,在最优转矩法的基础上设计得到 一种变结构控制器,增大了转速跟踪过程中的不平衡转矩,缩短了系统的调节时间. 仿真结果表明本文提出的改进方法可以获得良好的转速跟踪效果,从而提高风力机的风能捕获效率.     

基于参考输入优化的变速风电机组最大化风能捕获方法

变速风电机组在额定风速以下应用最大功率点跟踪实现最大化风能捕获. 然而, 大惯量风电机组在面对快 速波动的湍流风速时, 因转速调节慢而难以保持运行于最大功率点. 本文研究进一步发现, 平均转速跟踪误差与整 体的风能捕获效率并非单调关系, 这使得当前以减小转速跟踪误差为目标的控制器设计难以有效提升风电机组的 发电效率. 为此, 本文以提升风能捕获效率(而非减小转速跟踪误差)为目标, 提出一种基于参考输入优化的风电机 组最大化风能捕获方法. 考虑到参考转速对风能捕获效率的复杂影响难以准确建模, 本文借助深度确定性策略梯度 (DDPG)强化学习算法实现参考输入优化. 仿真结果表明该方法能够有效提升湍流风下变速风电机组的风能捕获效 率.     

基于二阶滑模控制的变速双馈风力发电系统最大功率点跟踪

本文提出一种超螺旋二阶滑模控制方案同时实现双馈变速风力发电系统最大风能捕获和无功功率调节.通过设计两个二阶滑模控制器,实现控制目标,降低机械磨损,提高控制精度,通过调节发电机转子电压,跟踪风机最优转速和转子电流设定值,实现额定风速以下的最大风能捕获和无功功率调节.采用二次型李雅普诺夫函数确定控制参数范围、确保系统有限时间稳定性.1.5 MW风机系统仿真实验验证所提方案有效性.     

双PWM直驱同步风力发电机最大风能捕获

以直驱同步风力发电机组为研究对象,为了提高发电机的系统的效率,降低电机的损耗,采用双PWM变流器拓扑结构,提出了一种最大风能捕获（MPPT）的控制方式。不需要风速信号、风机转速及与风力机系统参数有关的最大功率运行表格,仅需对输出功率进行跟踪计算,使得能达到捕获最大风能的控制效果。采用PSCAD／EMTDC软件进行仿真,仿真结果验证了控制方法的有效性。     

永磁同步发电机风能转换系统滑模控制仿真

针对由于风速的随机波动性而使基于线性定常控制器的风能转换系统稳定性较差的问题,提出了一种基于滑模控制的永磁同步发电机风能转换系统的设计方案;分析了该系统中风力机模型、传动装置模型和永磁同步发电机模型的建立原理,介绍了滑模控制策略的具体实现。仿真结果表明,该系统具有较好的速度跟踪特性,实现了最大风能捕获。     

一种基于指数趋近律的非线性系统变结构轨迹跟踪控制新方法

针对多输入多输出二阶不确定非线性机械系统中轨迹跟踪控制的问题,提出一种新的基于指数趋近律的滑模变结构控制方法,用于提高系统的平稳性和快速性。在滑模变结构控制器设计过程中采用一种新的指数趋近律以改进闭环系统的暂态和稳态响应性能,使系统跟踪误差收敛速度加快,特别是减少轨迹跟踪误差到达滑模面的时间,同时提高了系统轨迹跟踪过程的平稳性。通过采用边界层方法消除滑模控制输入抖振问题,避免控制过程中执行器的频繁切换,进一步提高所提出滑模控制器在实际系统中的实用性。基于李雅普诺夫稳定性理论证明了闭环系统的稳定性和跟踪误差的收敛性。数值仿真验证了所提出的控制方法的有效性。     

机器人的非奇异终端神经滑模轨迹跟踪控制

针对具有不确定性的机器人系统,为提高系统的稳态跟踪精度,提出一种非奇异终端神经滑模轨迹跟踪控制方案.控制器采用改进的非奇异终端滑模面,并基于径向基函数神经网络自适应调整控制律的切换项,不但克服了在设计中需要知道系统不确定性的上界的限制,而且平滑了控制信号.可应用Lyapunov稳定性理论证明了系统的渐近稳定性和跟踪误差的渐近收敛性.仿真结果验证了控制方法不仅能够保证机器人系统轨迹跟踪控制的快速性和鲁棒性,而且有效地削弱了抖振,可见方案是可行且有效的.     

基于LabVIEW的风力机最大功率点跟踪仿真研究

基于风力机的发电效率因环境风速变化而改变,本文选用LabVIEW为仿真平台建立风力机最大功率点的追踪系统。首先根据风力机的风能捕获输出功率公式,在LabVIEW平台上搭建了风力机系统模块、风力机控制模块、风轮转速调节模块、风速变化判断模块等。为了弥补传统扰动法存在的追踪精度等问题,利用变步长的扰动观测法对输出功率进行最大功率点追踪,使风力机的输出功率保持在最大输出功率。实验结果表明该系统在不同的仿真风速环境下,能有效的追踪风力机最大输出功率点。     

直驱式风电机组功率控制系统优化建模仿真北大核心CSCD

为使风电机组的实际输出功率最佳,提高风能的利用率,采用风电机组最大功率点跟踪(Maximum Power Point Tracking,MPPT),就是控制风力机在不同风速下的转速跟踪最优参考转速。但现有的MPPT控制策略虽然能实现最大功率点的快速,稳定跟踪,但控制精度过度依赖风速,功率等参数的准确测量。为了更好的实现最大功率点的快速有效跟踪,提出了模糊变步长MPPT算法,利用模糊推理的方法得到永磁同步风力发电机组的参考转速。通过对金风1.5MW直驱式风电机组进行仿真研究,结果表明改进控制算法能够使风电机组快速根据风速变化实现最大功率点跟踪,特别是与变桨距系统联合后,控制效果更加显著。     

一类非线性系统准滑模控制的稳态误差分析

针对一类具有未知控制增益的不确定非线性系统准滑模跟踪控制,通过分析跟踪误差和滑模变量之间的关系,利用有界输入有界输出稳定的思想,分别推导了采用Slotine形式的传统滑模面和传统积分滑模面时系统的稳态跟踪误差的界.将其与现有的几种方法进行比较,该方法求得的稳态跟踪误差界更精确.根据给定的稳态跟踪误差要求,可设计出适合抑制抖振的饱和函数.通过仿真算例验证了所提出方法的有效性.     

基于有效风速估计与预测的风电机组自适应最大风能跟踪控制

针对如何在有效风速未知情况下实现风电机组最大风能跟踪(MPPT)的问题,本文使用支持向量回归(SVR)和自适应控制原理,提出基于有效风速估计与预测的自适应MPPT控制方案.首先,使用机组的历史运行数据,训练得到基于SVR的风速估计与预测模型,为MPPT控制提供实时参考输入.其次,结合在线学习估计器(OLA)和减小转矩增益(DTG)控制原理,设计自适应MPPT控制器,该控制器能够较好应对系统未知动态特性和干扰,且能降低传动链载荷.最后,使用李雅普诺夫原理证明闭环系统所有信号都是有界的.仿真结果表明本文提出的方法能够获得良好的MPPT效果,进而提高机组产能.     

Adaptive backstepping control of variable speed wind turbines

Variable speed wind turbines maximize the energy capture by operating the turbine at the peak of the power coefficient, however parametric uncertainties in mechanical and electrical dynamics of the system may limit the efficiency of the turbine. In this study, we present an adaptive backstepping approach for the variable speed control of wind turbines. Specifically, to overcome the undesirable effects of parametric uncertainties, a desired compensation adaptation law (DCAL) based controller has been proposed. The proposed method achieves global asymptotic rotor speed tracking, despite the parametric uncertainty on both mechanical and electrical subsystems. Extensive simulation studies are presented to illustrate the feasibility and efficiency of the method proposed.     

Modeling and robust control of a twin wind turbines structure

The control of a new structure of twin wind turbines (TWT) is presented in this paper. This new concept includes two identical wind turbines ridden on the same tower, which can pivot face the wind with no additional actuator. The motion of the arms carrying the TWT is free. The control law based on sliding mode controller is designed to track the maximum power, by controlling the rotor speed of the TWT and the yaw rotation but without yaw actuator. Finally, performances of the proposed control strategy are compared to standard proportional integral controller, for several scenarios (time varying direction or magnitude of the wind, error on the inertia of the system, …).     

Fully sensorless robust control of variable-speed wind turbines for efficiency maximization

This paper focuses on a sensorless robust power generation control strategy for a variable speed wind energy conversion system based on a permanent magnet synchronous generator. The proposed control strategy combines a robust observer of the aerodynamic torque, a simple technique for extracting rotor position using electrical signals, a robust observer of rotor speed, and a sliding mode based field oriented control strategy. The robust vanishing of the observation errors and tracking error is proved. Reported numerical simulations show that the proposed control policy is effective in terms of efficiency maximization and it is robust with respect to bounded parameter variations affecting the mechanical system.     

Asymptotic Tracking Control for Wind Turbines in Variable Speed Mode

This paper presents a variable speed control strategy for wind turbines in order to capture maximum wind power. Wind turbines are modeled as a two-mass drive-train system with generator torque control. Based on the obtained wind turbine model, variable speed control schemes are developed. Nonlinear tracking controllers are designed to achieve asymptotic tracking for a prescribed rotor speed reference signal so as to yield maximum wind power capture. Due to the difficulty of torsional angle measurement, an observer-based control scheme that uses only rotor speed information is further developed for global asymptotic output tracking. The effectiveness of the proposed control methods is illustrated by simulation results.      

A control strategy for variable-speed variable-pitch wind turbines within the regions of partial- and full-load operation without wind speed feedback

In this paper, the control of a variable-speed variable-pitch wind turbine in the whole wind speed range is addressed, without any feedback measurement of wind speed. In addition to an aerodynamic torque observer able to ensure the tracking of the maximum delivered power in the partial-load region, a novel wind speed observer is proposed for power regulation in the full-load region, along with a sliding surface ensuring finite-time set-point stabilization of the speed tracking error. The proposed control solution has been validated on the National Renewable Energy Laboratory 5-MW three-blade wind turbine model using the recognized high-fidelity simulation tool FAST.     

小型风电系统变步长扰动MPPT控制仿真研究

最大功率跟踪(MPPT)策略是提高风电系统功率转换效率的重要方法.文中提出了变步长扰动MPPT策略,并在MATLAB仿真环境中,开发了带有此策略的小型风电系统仿真模型.该模型包括风力机模型、永磁发电机(PMSG)模型、DC/DC斩波器模型、负载功率采样模型和MPPT控制模型等.利用该模型进行计算机仿真,给出了一定风速下负载功率和发电机输出功率的仿真结果.结果表明:实现了变步长扰动MPPT策略控制的仿真,与传统固定步长MPPT策略相比,提高了最大功率跟踪的快速性和准确性,进而提高了风能转换效率.     

Robust Wind Speed Estimation and Control of Variable Speed Wind Turbines

In this work, a robust control scheme for variable speed wind turbine system that incorporates a doubly feed induction generator is described. The sliding mode controller is designed in order to track the optimum wind turbine speed value that produces the maximum power extraction for different wind speed values. A robust sliding mode observer for the aerodynamic torque is also proposed in order to avoid the wind speed sensors in the control scheme. The controller uses the estimated aerodynamic torque in order to calculate the reference value for the wind turbine speed. Another sliding mode control is also proposed in order to maintain the dc‐link voltage constant regardless of the direction of the rotor power flow. The stability analysis of the proposed controller under disturbances and parameter uncertainties is provided using the Lyapunov stability theory. Finally, the simulation results show that the proposed control scheme provides a high‐performance turbine speed control, in order to obtain the maximum wind power generation, and a high‐performance dc‐link regulation in the presence of system uncertainties.