风力机模拟平台的MPPT快速响应控制方法

作者开发了一种新的MPPT(Maximtm Power Point Tracking，MPPT)控制方法，和以往的MPPT、控制方法相比，主要不同之处是：(1)追踪步长根据风速的变化而变化，即变扰动MPPT控制方式；(2)为了消除逆变器死区所造成的风力机功率波动影响，MPPT控制周期和发电机的转速是同步的；(3)利用电磁转矩对风力机转速实行完全控制，即在适当的时候，给风力机提供能量使其加速，使风力机转速能跟踪快速变化的风速；(4)在MPPT的输出端使用低通滤波器来平滑风力机转速控制的指令值。采用风力机模拟平台的实验结果表明，该方法可以跟踪0．2Hz快速变化的风速，和传统的MPVT控制方法相比，当风速快速变动时，可以显著增加发电量，从而提高了风力发电的效率。     

基于模拟平台的永磁直驱风力发电MPPT新策略

基于直流电机驱动低速永磁同步发电机的风力发电模拟平台,提出了一种各种风速下最大风能捕获(MPPT)新型实现方法,即由上位机模拟风场,基于最佳叶尖速比(TSR)控制永磁发电机的转速,直接控制直流电动机的功率来模拟风力机捕获的最大风能。基于这种控制策略,对各种风速下的永磁发电机无速度传感器控制、变桨距控制、最大风能的单位功率因数并网控制进行了仿真;在额定风速以下,进行了发电机侧MPPT实验。仿真和实验结果验证了这种永磁直驱风力发电MPPT新策略的正确性和可行性。     

光伏发电MPPT的变论域自适应模糊控制

针对常规模糊控制器在光伏发电最大功率点跟踪(MPPT)控制中存在的功率波动、控制精度低和自适应性较差等问题,提出了一种基于变论域自适应模糊控制器的光伏发电MPPT控制,该控制器能根据光伏发电输出功率偏差的变化自动调整变量的论域,从而快速准确地跟踪光伏发电系统的最大功率点(MPP)。实验结果验证了该控制方法能有效实现光伏发电MPPT控制,提高了系统的效率和稳定性。     

独立运行风光互补发电系统能量优化管理协调控制策略

针对系统运行工况复杂、供电稳定性和安全性要求高的特点,深入分析并给出独立运行风光互补发电系统能量流动及工作模式转换关系图,采用风电优先、光电次之、蓄电池辅助的电能分配原则与功率供需动态平衡的能量优化管理机制,提出包括能量管理与工作模式控制、风力发电控制、光伏发电控制和蓄电池充放电控制在内的功率协调控制策略。风力和光伏子系统控制均具有功率电压双闭环控制结构,功率外环采用基于梯度变步长MPPT算法或基于梯度信息LPTC算法产生最佳功率点电压,电压内环实现最佳功率点电压的自动、快速、无差跟踪,同时可实现MPPT和LPTC算法之间的平滑切换。仿真研究结果表明,本文所论能量优化管理协调控制策略能够根据风速、光照强度、负载的变化及蓄电池工况,协调风力发电、光伏发电子系统和蓄电池的工作状态,实现系统不同工作模式下自动运行及合理转换,保持能量供需动态平衡,实现系统的优化及可靠运行。     

垂直轴永磁直驱风力发电系统全风速功率控制

垂直轴风力机(VAWT)发电系统是一种应用潜力良好的新型风力发电系统。为了提高机组的风能转化效率,研究了全风速运行范围内的功率控制策略。建立了整机系统的数学模型,讨论了VAWT的气动机械特性及其4种工作模式;在此基础上,分析了机组在额定风速以内MPPT运行模式下,基于最佳叶尖速比(TSR)跟踪原理的最大风功率吸收控制策略;针对在额定风速以上的恒功率运行模式,设计了基于二阶扩张状态观测(ESO)方法的实时气动转矩估计器以及基于恒额定功率发电的最佳角速度控制策略;最后给出了全风速功率控制的系统结构。通过仿真试验,验证了该功率控制策略在全风速运行范围内实现整机高风能转化效率的良好效果。     

风力发电实验用模拟风力机

在风力发电机控制、风力机最大功率点追踪控制(MPPT，Maximum Power Point Tracking)等相关的研究中，风力机是必备的实验设备，但是，在没有风的情况下，或在实验室，就无法进行这些实验和研究。作者开发了一种模拟风力机，有了它，就可以在实验室随心所欲地进行风力发电的初期实验研究工作，从而缩短研发的周期和减小实验研究的费用。首先用6次多项式来拟合风力机的转矩特性曲线。然后根据当前的风速和风力机转速来计算风力机的转矩，将此转矩作为转矩指令控制感应电机来模拟风力机，感应电机通过控制逆变器来驱动。最后，给出了用此模拟风力机所做的MPPT实验研究结果，验证了该模拟风力机的良好特性。     

基于新型变步长电导增量法的最大功率点跟踪策略

针对传统电导增量法在跟踪精度和跟踪过程响应速度方面的不足,文章提出一种新型变步长电导增量法。该方法首先采用固定电压法将光伏阵列工作点快速调整到最大功率点附近,然后利用基于反余切函数控制的变系数跟踪技术,动态调节追踪过程中的步长,缩短最大功率点的跟踪时间。仿真结果表明,与传统电导增量法相比,新型变步长电导增量法在一定程度上可以增加光伏系统的跟踪精度、响应速度,并减小MPPT仿真曲线的稳态振荡幅度,提高光伏系统的能量转换效率。     

小型风电系统MPPT模糊／PID控制仿真研究

根据最大功率点跟踪的基本原理及常用风力发电控制系统的特点,提出了一种模糊／PID双模控制。具有在线参数调整的自适应占空比扰动法,该方法同步精度高,动态响应快,能迅速调整发电机与负载之间的功率匹配,减少最大功率点的振荡,使风力机以最佳叶尖速比运行。通过仿真实验表明,采用模糊／PID控制电路,能够快速准确的跟踪风力发电系统的最大功率点,改善最大功率点的振荡,减少能量损失,提高能量转换效率。     

基于改进PSO的复杂环境下光伏MPPT控制

复杂环境下,传统算法实现光伏系统的最大功率点跟踪(MPPT)失效;常规粒子群优化算法(PSO)实现的MPPT控制易给系统引入较大跟踪振荡。针对上述问题,提出一种基于改进PSO的MPPT控制方法,通过引入线性调整因子,自适应调整环境突变时最大功率点电压的搜寻范围。结果表明:与常规PSO算法相比,改进的PSO算法跟踪速度更快、动态响应振荡更小、能量转换率更高,可实时准确跟踪复杂环境下的最大功率点。     

基于模糊自适应PI控制的光伏发电MPPT

介绍了光伏发电过程中最大功率点跟踪(MPPT)原理,并简要分析了常规控制算法在最大功率跟踪控制中的优缺点,提出将模糊自适应PI控制算法应用到光伏系统最大功率点跟踪的控制中,该控制方法能快速响应外界环境的变化,获得系统最大功率点,且可以有效消除系统在最大功率点附近的振荡现象,提高系统的稳定性。仿真结果表明,该方法能使系统稳定地工作在最大功率点,并且控制精度高,能灵敏反应外界环境的变化。     

残差灰色风速预测最大风能追踪策略研究

该文引入灰色预测理论,用以往时刻的风速信息预测下一控制时刻的风速,并用残差修正方法来提高预测精度。根据该预测风速的大小来确定下一时刻最优功率点搜索的起始风电机组转速,再利用变步长转速扰动的最大风能追踪策略(爬山法)找到最优功率点。仿真表明,残差灰色风速预测方法具有很好的预测效果,有效缩小了最优功率点的搜索区间,缩短了搜索时间,提高了机组的运行效率。     

永磁直驱风力发电系统MPPT控制的研究

文章首先介绍了风力机模型。然后介绍了一种改进型的变步长爬山算法,通过该算法改变直驱风力发电系统三重交错并联Boost变换电路的占空比,从而实现最大功率跟踪,获取最大风能。最后,利用MATLAB/SIMULINK建立直驱永磁风力发电系统仿真模型并进行研究。试验结果表明,改进型变步长爬山算法比传统爬山算法能更快跟踪最大功率点,控制系统具有较好的控制精度和稳定性。     

Novel power capture optimization based sensorless maximum power point tracking strategy and internal model controller for wind turbines systems driven SCIG

Under the trends to using renewable energy sources as alternatives to the traditional ones, it is important to contribute to the fast growing development of these sources by using powerful soft computing methods. In this context, this paper introduces a novel structure to optimize and control the energy produced from a variable speed wind turbine which is based on a squirrel cage induction generator (SCIG) and connected to the grid. The optimization strategy of the harvested power from the wind is realized by a maximum power point tracking (MPPT) algorithm based on fuzzy logic, and the control strategy of the generator is implemented by means of an internal model (IM) controller. Three IM controllers are incorporated in the vector control technique, as an alternative to the proportional integral (PI) controller, to implement the proposed optimization strategy. The MPPT in conjunction with the IM controller is proposed as an alternative to the traditional tip speed ratio (TSR) technique, to avoid any disturbance such as wind speed measurement and wind turbine (WT) characteristic uncertainties. Based on the simulation results of a six KW-WECS model in Matlab/Simulink, the presented control system topology is reliable and keeps the system operation around the desired response.     

Development of a comprehensive MPPT for grid‐connected wind turbine driven PMSG

This paper proposes a comprehensive MPPT method by which extraction of maximum power from wind turbine and its subsequent transfer through various power stages and final delivery to the connected grid are realized. In the proposed system, the operation of the wind turbine at its maximum efficiency point is maintained by control of grid‐tied inverter such that the shaft speed of the generator is set to result the desired optimum tip speed ratio of the turbine. The proposed comprehensive MPPT estimates the required DC link voltage for each wind speed using a unified system model, uses a loss factor to account for the system losses, and then controls the inverter to push the WT extracted maximum power into the grid. The comprehensive MPPT is developed and is validated in MATLAB/Simulink platform in a wide range of operating wind speed. The results ascertain that the wind turbine is made to operate at its maximum efficiency point for all wind speeds below the rated one.     

Maximum Power Tracking Control for a Wind Turbine System Including a Matrix Converter

This paper focuses on maximum wind power extraction for a wind energy conversion system composed of a wind turbine, a squirrel-cage induction generator, and a matrix converter (MC). At a given wind velocity, the mechanical power available from a wind turbine is a function of its shaft speed. In order to track maximum power, the MC adjusts the induction generator terminal frequency, and thus, the turbine shaft speed. The MC also adjusts the reactive power transfer at the grid interface toward voltage regulation or power factor correction. A maximum power point tracking (MPPT) algorithm is included in the control system. Conclusions about the effectiveness of the proposed scheme are supported by analysis and simulation results.      

基于PSCAD/EMTDC的直驱式风力发电接入系统建模与仿真

针对频率可变的多极直驱式同步风力发电机接入系统,该文在考虑风力机大转动惯量的情况下,采用电网电压矢量定向和双闭环控制技术,实现了基于背靠背VSC换流器的有功无功独立控制。研究了不依赖于风速测量的直驱式机组最大功率追踪策略,桨距角控制器设计以及变风速下风电机组对电网的无功支持问题。最后通过PSCAD/EMTDC搭建了该接入系统模型,阶跃和随机风速下的仿真结果验证了该模型的合理性及控制策略的有效性。     

A fast and low cost analog maximum power point tracking method for low power photovoltaic systems

Low power photovoltaic (PV) systems are commonly used in stand-alone applications. For these systems, a simple and cost-effective maximum power point tracking (MPPT) solution is essential. In this paper, a fast and low cost analog MPPT method for low power PV systems is proposed. By using two voltage approximation lines (VALs) to approximate the maximum power point (MPP) locus, a low-complexity analog MPPT circuit can be developed. Theoretical derivation and detailed design procedure will be provided in this paper. The proposed method boasts the advantages such as simple structure, low cost, fast tracking speed and high tracking efficiency. To validate the correctness of the proposed method, simulation and experimental results of an 87 W PV system will also be provided to demonstrate the effectiveness of the proposed technique.     

Intelligent approach to maximum power point tracking control strategy for variable-speed wind turbine generation system

To achieve maximum power point tracking (MPPT) for wind power generation systems, the rotational speed of wind turbines should be adjusted in real time according to wind speed. In this paper, a Wilcoxon radial basis function network (WRBFN) with hill-climb searching (HCS) MPPT strategy is proposed for a permanent magnet synchronous generator (PMSG) with a variable-speed wind turbine. A high-performance online training WRBFN using a back-propagation learning algorithm with modified particle swarm optimization (MPSO) regulating controller is designed for a PMSG. The MPSO is adopted in this study to adapt to the learning rates in the back-propagation process of the WRBFN to improve the learning capability. The MPPT strategy locates the system operation points along the maximum power curves based on the dc-link voltage of the inverter, thus avoiding the generator speed detection.