改进型变步长最大功率跟踪算法在风力发电系统中的应用

为了改善永磁直驱式风力发电系统最大功率跟踪算法的稳态跟踪准确度和动态跟踪速度,提出了一种改进型变步长爬山搜索寻优算法;它结合同步电机矢量控制技术,在同步旋转坐标系下,通过解耦控制电机交轴电流分量,达到对风力机转速的控制。变步长最大功率跟踪算法思路是:基于两点斜率比较,判断发电系统接近最大功率点,通过指数衰减步长抑制发电系统在最大功率点附近振荡;不依赖风速传感器,通过每个寻优周期动态设置风速突变检测阈值,准确辨识风速变化,并重新初始化步长提高对风速变化的快速跟踪性能。通过搭建风力发电系统的Matlab/Simulink仿真模型和硬件实验平台,验证了该算法的有效性,展示了其良好的工程应用价值。     

Power Electronic Interface with Maximum Power Point Tracking Using Line-commutated Inverter for Grid-connected Permanent Magnet Synchronous Generator

Abstract—This article presents a simple grid interactive system that extracts maximum power from a wind-driven permanent magnet synchronous generator using an integrated cascade boost converter and a three-phase line-commutated inverter. The firing angle of the line-commutated inverter is held constant at an appropriate value that provides a constant DC-link voltage, and only DC-link current is sensed for maximum power point tracking. For wide wind variation, maximum power from the permanent magnet synchronous generator is achieved using a simple load current (DC-link current) perturb and observe maximum power point tracking technique. This is obtained by varying the duty ratio of the integrated cascade boost converter with an adaptive incremental step that varies the load on the permanent magnet synchronous generator in accordance with changing wind. Experiments have been conducted on a 3-phase, 750-W, 500-rpm laboratory size permanent magnet synchronous generator. The operation and analysis of the proposed topology with a fixed firing angle for a line-commutated inverter is presented. The results obtained from MATLAB (The MathWorks, Natick, Massachusetts, USA) simulation are verified with experimental results, and a close correlation has been found, proving the efficacy of the system.     

变速恒频双馈风力发电系统最大风能追踪控制

分析了风力机的功率特性以及双馈感应电机的运行特性,探讨了最大风能追踪的控制策略,在定子磁链定向矢量控制策略下,基于S函数建立了双馈风力发电系统的仿真模型,并在两次阶跃风速下对所建模型的运行特性进行了仿真研究。仿真结果表明系统实现了最大风能追踪以及变速恒频运行,同时验证了所建模型以及控制策略的正确性。     

A New Three-mode Maximum Power Point Tracking Algorithm for Doubly Fed Induction Generator Based Wind Energy Conversion System

This paper proposes a new algorithm for maximum power point tracking of a wind energy conversion system, which is based on a doubly fed induction generator. The algorithm has three modes. In the first mode, the maximum power point is tracked and also the output power is smoothed. Once the turbine operating point reaches the optimal point, the second mode is activated to fix the speed of the turbine. In addition, this mode has a self-tuning capability. When the turbine operating point is far from the optimal value, the third mode is activated. In this mode, the optimal power curve along with the fuzzy logic is used to bring the turbine operating point rapidly to a point near the maximum power point. To verify the accuracy of the proposed algorithm, a large wind energy conversion system is simulated, and the simulation results are compared with the perturbation and observation algorithm.     

永磁直驱风电系统中最大功率点跟踪控制优化的仿真研究

分析了风力机特性、永磁直驱电机模型、变换器控制策略及各种功率跟踪控制算法优缺点,并提出一种基于爬山搜索法的最大功率点跟踪(MPPT)控制方法的优化。在MATLAB/Simulink环境下搭建了永磁直驱风力发电系统模型,仿真分析了控制方法对最大功率点的跟踪效果,结果表明当风机起动及风速变化时MPPT控制方法能够使系统快速稳定在新的工作点,捕获得最大功率。由此验证了改进优化后的控制方法及所搭建模型的准确性与有效性。     

直驱六相风力发电系统无速度传感器研究

采用六相永磁同步发电机(PMSG)结合双变频器并联方案以提高直驱式风电系统(WECS)的机组容量和可靠性.为消除系统因测速码盘带来的故障,采用无速度传感器矢量控制方案.给出基于模型参考自适应系统的永磁电机转速和转子位置估计方法,提出一种将最优叶尖速法与爬山法相结合的风力发电最佳风能捕获方法.采用六相电机矢量控制策略,对风速突变时六相电机的最佳风能追踪过程进行仿真并在此基础上,设计了一套风电变流器控制系统,实验结果表明,该变流器控制系统具有良好的动、静态控制特性,为整个风电控制系统提供了基础.     

一种小型风电机组的优化最大功率点跟踪控制算法

为提高小型风机发电机组的风能转换效率,提出一种最大功率优化跟踪控制算法.以小型风力发电机组中发电机的P-ω特性曲线上各点斜率来确定占空比的扰动步长,通过模糊控制来对最大功率点进行跟踪,增强最大功率点搜索的快速性和稳定性.通过在MATLAB/Simulink仿真环境下搭建小型风电系统模型和优化最大功率点跟踪(MPPT)控制算法模型进行仿真,得出不同风速下发电机的输出功率仿真结果.结果表明:该控制算法能有效提高小型风电系统最大功率点的跟踪速度,减少最大功率点附近的振荡现象,提高小型风力发电机组的风能转换效率.     

双馈风力发电系统最大风能追踪控制的研究

在分析了风力机功率特性和DFIG运行特性的基础上,通过对双馈机转速控制进行最大风能追踪具体过程的深入研究,提出了一种基于最大风能追踪的双馈电机有功、无功功率的解耦控制方法。建立了基于发电机定子磁链定向矢量控制的双馈风力发电系统最大风能追踪系统模型,并利用PSCAD/EMTDC对其进行仿真,结果验证了控制策略的正确性。     

光伏系统最大功率点追踪的一种改进方法及其仿真

光照变化条件下基于改进的扰动观察法是一种最大功率点跟踪（MPPT）优化算法,可分离来自光照变化的影响,追踪扰动,并根据光照变化,用这些信息来优化追踪。当光照快速变化时,这种策略可以更迅速、更好地追踪,而且在稳态条件下使得在最大功率点处振荡更小。仿真结果显示,该方法在光照变化环境下可以快速、准确地追踪到最大功率点。     

基于改进扰动观察法的光伏阵列MPPT研究

针对常规扰动观察(P&O)法由于环境快速变化带来的失效性问题,提出一种基于改进P&O法的最大功率点跟踪(MPPT)算法。采用一种压阻可变的方法模拟光伏阵列的输出特性。改进P&O法通过控制Boost变换器的占空比改变变换器的输入电压,从而实现MPPT。以DSP芯片TMS320LF2407A为控制电路主处理器,以Boost变换器为主拓扑电路,搭建了模拟光伏阵列MPPT实验系统。实验结果表明,该改进算法能有效地跟踪光伏阵列最大功率点(MPP)。     

双级矩阵变换器直驱风力发电系统最大风能追踪

提出了一种双级矩阵变换器(two stage matrixconverter,TSMC)直驱风力发电系统最大风能追踪控制策略。基于爬山法,通过引入中间变量实现对系统捕获风能状态进行判断,在此基础上,提出基于集成控制的最大风能追踪(maximum power point tracking,MPPT)算法。在Matlab中建立了TSMC风电系统仿真模型。仿真结果表明:新的MPPT算法通过对风力发电系统逆变级无功功率分阶段性的控制,不仅具有较好的准确性和稳定性,而且加快了系统捕获最大风能的速度。     

太阳能光伏发电最大功率跟踪系统研究

针对太阳能光伏发电系统中的最大功率跟踪问题,提出了一种基于AVR单片机控制的新方案。系统运用三重Boost DC/DC变换器对光伏电池输出功率进行有效调节,采用最优梯度控制算法搜索最大功率点。对该系统进行了Matlab/Simulink仿真,并在硬件电路的基础上进行了试验。结果表明,该系统能较快地跟踪太阳能的最大功率,并具有较高的跟踪精度。     

基于最佳功率给定的最大风能追踪控制策略

采用双馈异步发电机(DFIG)的交流励磁发电技术不但能在变速情况下实现恒频发电,更能通过对DFIG输出有功、无功功率的解耦控制,实现最大风能的追踪.为能在不检测风速的条件下实现最大风能的捕获,提出了基于参考功率优化计算模型的最大风能追踪控制策略,其本质是通过控制DFIG的输出有功功率来间接控制风电机组转速以追踪风力机最佳功率曲线.在此基础上,建立了基于矢量变换控制技术的完整的变速恒频(VSCF)风力发电控制系统.仿真和实验结果验证了该最大风能追踪控制策略的可行性、有功与无功解耦控制的有效性及工程应用的现实性.     

一种开关磁阻风力发电机最大风能跟踪方法

对开关磁阻风力发电机的运行原理和风轮机的功率输出特性进行了介绍,提出了一种不依赖风轮机运行参数即可实现最大风能自动跟踪的变步长控制方法.使用Matlab/Simulink构建了整个系统的模型,进行了仿真,使用直流电动机模拟风力机对提出的最大风能跟踪控制方法进行了测试,系统仿真和试验结果证明该方法是可行的.     

Smoothing of Wind Power Fluctuations for Permanent Magnet Synchronous Generator-Based Wind Energy Conversion System and Fault Ride-through Consideration

Due to the increment of penetration level of wind power generation, output power fluctuation is one of the most important issue's that can destabilize the power system operation. This article mainly deals with the smoothing of the output power fluctuations of a wind energy conversion system based permanent magnet synchronous generator and fault ride-through enhancement during a grid fault. The concerned wind energy conversion system based permanent magnet synchronous generator adopts an AC-DC-AC converter system. The proposed control method limits the wind energy conversion system output power by adjusting the pitch angle of the wind turbine blades when wind speed is above the rated wind speed. In the grid-side converter, a fuzzy logic controller is used to determine the torque reference for which the kinetic energy stored by the inertia of wind turbine can smooth the output power fluctuations of the permanent magnet synchronous generator. Also, the DC-link voltage, controlled by the grid-side inverter, is adjusted in accordance with the output power fluctuations of the permanent magnet synchronous generator using a voltage smoothing index. Moreover, in this aticle, the proposed method ensures that the wind turbine stays operational during grid faults and provides fast restoration once the fault is cleared. To show the effectiveness of the proposed method, simulations under different conditions have been performed by using MATLAB/Simulink® (The Math Works, Natick, MA, USA).     

Coordinated Controller Design of Grid-connected Variable-speed Wind Energy Conversion System with Model-based Predictive Control Using Response Surface Methodology

This paper presents an optimum design procedure for the coordinated tuning of machine side converter (MSC) and grid side converter (GSC) controllers of grid connected permanent magnet synchronous generator (PMSG). Model based predictive controller (MBPC) is used to control the MSC. MBPC based speed control design consists of two steps. A linearized state space model is employed to predict the future output (rotor speed). An optimal control law is derived by minimizing a quadratic performance index that considers the control effort and the difference between the predicted rotor speed and the reference rotor speed. A proportional-integral (PI) controller is used to control the GSC. The MSC and GSC controller parameters are determined by simultaneously optimizing the controller performance indices. The coordinated controller design is carried out in two steps. The analytical expression that relates the performance indices and the controller parameters is arrived using response surface methodology (RSM). The determination of controller parameters is posed as a constrained multi-objective optimization problem and solved employing NSGA-II (non-dominated sorted genetic algorithm II). The proposed methodology is tested on a sample power system with PMSG based WECS (Wind Energy Conversion System). Simulation results demonstrate the effectiveness of the proposed methodology.     

风光互补发电系统设计及最大功率点跟踪控制

为解决传统风电和光伏发电系统独立运行时受天气影响较大、能量利用率不高及蓄电池充放电控制不合理等问题,充分利用风电和光伏系统之间良好的互补性,设计了风能和光能互补的发电系统。提出一种以定电压法启动结合功率前馈的变步长电导增量法最大功率点跟踪(MPPT)算法,减小功率追踪过程中的能量损耗,改善最大功率点附近的振荡问题。利用风能和光能系统与蓄电池之间的能量流动状态,协调控制蓄电池充放电电流,延长蓄电池寿命,提高系统整体稳定性。实验结果证明了系统设计和控制策略的正确性和有效性。     

直驱式风力发电系统最大风能追踪策略研究

充分利用风能是风力发电控制的主要目的之一,为达此目的,基于原有的直驱式风力发电系统电路拓扑结构,在整流器和逆变器之间加入了Buck-Boost电路,通过控制该电路中开关器件的开断,保证该风力发电系统输出有效电压,从而保证有功功率流向电网或负载,实现风力发电系统的最佳功率系数.基于风力发电机输出功率特性曲线,详细阐述了采用该风力发电系统实现最大风能利用的搜索算法.该算法具有不再需要测风速和电机转速的优点.通过实验验证比较,新系统能实现风能的最大利用.     

基于MPPT算法的风力永磁发电系统的仿真研究

作为一种绿色能源,风力发电在我国发展迅猛。采用永磁同步发电机的直驱式风力发电系统,因为其具有效率高,制造方便,控制效果好的优点,逐渐成为人们研究的焦点。使用Matlab/Simulink对基于永磁同步发电机的风力发电系统及其最大功率追踪算法进行了仿真研究,并给出了仿真结果。仿真结果验证了该类风力发电系统具有更高的风能利用效率,系统工作稳定可靠的优点。     

光伏系统中最大功率点跟踪方法的研究

在光伏发电系统中,光伏电池的最大输出功率取决于温度和光照条件,采用最大功率跟踪(Maximum PowerPoint Tracking,简称MPPT)方法可以使光伏电池持续输出最人功率.研究了光伏系统中的最大功率控制部分,提出了MPPT控制器的设计,介绍了几种常用的MPPT方法,其中重点研究了电导增量(Incremental Conductance,简称INC)法.给出了INC法的软件流程的设计,并在Matlab中建立了光伏电池的仿真模型.最后通过实验验证了MPPT控制器的可行性,其MPPT的响应速度和控制精度均达到了预期要求.