Wind turbine emulator based on blade element momentum theory for variable‐speed wind power generation system

This paper proposes a wind turbine emulator (WTE) based on the blade momentum theory, and tests the variable‐speed wind power generation system using a pulse‐width modulation (PWM) converter to verify the accuracy of the emulator. The behavior of the wind turbine for natural wind is reproduced by the WTE based on the proposed theory. The variable‐speed wind power generation system employs a vector control system to control the torque and speed of the permanent magnet synchronous generator in the converter side. The windmill rotational speed is controlled to maximize the efficiency of the wind turbine against wind velocity. And the active power and reactive power are controlled in the inverter side, and the generated power is sent to the grid while controlling the DC link voltage to be constant at the same time. The behaviors of the WTE are compared with the simulation results and experimental results using a real wind turbine. These experimental and simulation results show that the test bench with the proposed WTE has sufficient performance and accuracy to verify variable‐speed wind generator systems. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于超级电容器储能的STATCOM对直驱风力机并网性能改善的研究

本文主要研究了采用基于超级电容器的静态同步补偿器(STATCOM)的永磁(PMSG)直驱变速风力机控制策略。基于Matlab/Simpower实现对风力发电机侧整流器最大功率提取、电网侧逆变器和STATCOM的控制策略,采用不同容量超级电容器储能的STATCOM系统在电网出现故障或者受到干扰时提升风力发电系统稳定状态和动态性能。大量仿真结果表明:与传统的STATCOM相比,采用基于超级电容器的STATCOM能有效改善并网过程中出现的电压闪变及波动,减小频率的波动,并能对故障期间的电流进行有效控制,从而较为显著地改善了直驱风力发电系统的有功、无功功率,提升了风电并网系统故障穿越能力和动态性能。     

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.     

双馈风力发电机组系统接入与稳定运行仿真

分析了包含大量异步风力发电机组的风电场并网运行后对电力系统静态和动态稳定性的影响。从系统接入和稳定运行的角度研究了双馈风力发电机组及普遍采用的定子磁链定向矢量控制策略在提高风电系统稳定性方面的优势与不足。以实际机组为例在PSCAD/EMTDC平台上建立了仿真模型,结果表明双馈风力发电机组在风速发生变化时不仅能够以变速恒频方式运行并追踪最大风能,且电网电压也比传统鼠笼式风力发电机组更为稳定。在系统发生最严重的三相接地故障时,风电场具有更好的暂态稳定性。     

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).     

直驱永磁同步风力发电机的最佳风能跟踪控制

与双馈交流励磁风力发电系统相比,直驱永磁同步风力发电系统具有结构简单、发电效率及运行可靠性高等优点。文章采用双脉宽调制(pulse-width modulation,PWM)变换器作为直驱永磁同步发电机的并网电路,根据风力机和发电机的运行特性提出了一种基于最佳功率给定的发电机最大风能跟踪控制策略。建立了基于双PWM变换器的直驱永磁同步风力发电实验系统,实验结果验证了所提出控制策略的正确性。该发电系统可实现最大风能跟踪控制、并网有功和无功功率独立控制以及变速恒频发电运行。     

定子Crowbar电路模式切换的双馈风力发电机组低电压穿越控制策略

针对转子Crowbar电路的双馈风力发电机组低电压穿越需要闭锁变流器控制脉冲、直流母线电压波动无法较好地抑制,提出了一种定子Crowbar电路模式切换的双馈风电机组低电压穿越控制方案。电网发生故障时,定子Crowbar电路接入系统,双馈风电机组切换至感应发电机组模式下,转子侧变流器采用转子功率外环控制,网侧变流器采用功率协调控制方案,将机侧功率当作前馈量引入到网侧变流器控制策略中并向电网注入无功功率。仿真分析表明,所提控制方案在确保实现双馈风电机组低电压穿越的同时,能够有效地降低转子暂态电流、稳定直流母线电压,并向电网提供无功功率。     

基于STATCOM的超级电容储能系统的风电并网

为了提高电网的电能质量,探讨了一种与永磁同步发电机(PMSG)相连接的电网控制和运行策略。该电机以直驱变速风电机组和静止同步补偿器(STATCOM)为基础,STATCOM的应用是通过风力涡轮机的不脱网运转能力来提高了系统性能,发电机侧变换器的控制策略是应用STATCOM控制器实现传输效率最大化。通过Matlab对其进行了仿真验证。仿真结果表明,带有STATCOM的超级电容器能量存储系统能够提高风能系统电网故障或扰动时的稳态和动态性能。     

开关磁阻风力发电技术

开关磁阻发电机用于风电系统可实现变速直驱发电,具有低速性能好、成本低、发电效率高、可靠性强等优点,有着十分广阔的发展前景.简要介绍了开关磁阻发电机的工作原理与运行模式,对开关磁阻风力发电系统的结构和最大风能跟踪控制方法作了分析,并介绍了其并网逆变器和并行式发电系统.     

Modeling and control of a variable-speed constant-frequency synchronous generator with brushless exciter

This paper presents the modeling, control, and implementation of a novel variable-speed constant-frequency power generation system for renewable and distributed energy applications. The generation system consists of a wound-rotor generator, a brushless exciter and a low-rating controlled power converter. The main generator is a doubly fed induction machine which is operated as a synchronous generator. The advantages of the proposed system are reduced harmonic injection to power grid, wide speed operation range covering both subsynchronous and super-synchronous speeds, self var support, and increased reliability. It can be directly applied to wind power generators, small-scale hydroelectric generators, stand-alone diesel and gasoline generators, and aerospace and naval power generation systems where a variable speed turbine/engine is employed. An equivalent circuit model of a doubly fed generator was developed incorporating stator and rotor iron losses. Then the control of a standalone generation system is developed based on the mathematical model. Detailed implementation procedure is given. An experimental system and its control were implemented using an embedded real-time digital signal processor. Measurements of the experimental system validated the system design and readiness for prototyping in a relatively large power range.     

液力变矩型同步风力发电机低电压穿越的控制原理及测试分析

液力变矩型同步风力发电机是一种基于液力变矩器和无刷同步发电机耦合的前端调速式风力发电机组,关键技术在于采用前端调速技术,使发电机转速恒定可以实现同步并网。风机在低速传动链上采用转速模糊闭环控制,高速传动链上采用液力变矩技术闭环控制转矩平衡,使风机在发生低电压穿越时转速与转矩控制的动态响应速度和精准度得到了较大改善。同时,同步发电机励磁系统采用强励模式,迅速提高发电机电动势及时补偿电磁功率的损失,并为电网提供无功能量支撑维持电网稳定。该机型低电压穿越性能经过现场实地认证测试,结果充分验证了其控制策略的有效性和可行性。     

永磁同步直驱风力发电系统并网的仿真研究

风力发电技术是分布式发电技术的重要组成部分,而永磁同步直驱风力发电系统的应用日益广泛.但直驱风力发电机产生的电能存在着电压幅值频率随风速变化、功率不稳定等诸多问题.为解决该问题,基于永磁同步直驱风力发电系统各个部分的工作原理,采用现代电力电子技术结合先进的控制技术,分析并设计出适合于直驱风力发电系统的逆变装置.在此基础...     

Performance and efficiency control enhancement of wind power generation system based on DFIG using three-level sparse matrix converter

Nowadays, the power generation systems based on wind turbines is increasing continuously in the world. Hence, there are intense efforts provided by researchers for the development of this area. In high power system applications, multilevel converters are a competitive alternative to the two-level inverters. In this paper, a three-level sparse matrix converter (SMC3l) associated to a grid connected variable speed wind generation (VSWG) scheme using a doubly fed induction generators (DFIGs) is investigated. Therefore, the dynamic behavior of a wind generator, including models of the wind turbine, DFIG, SMC3l control algorithm and power control is studied. Simulation results of the dynamic models of the wind generator are presented, for different operating modes sub-synchronous, synchronous and hyper-synchronous, to show the good performance and the efficiency control enhancement of the VSWG system using the proposed SMC3l.     

变速直驱永磁风力发电机控制系统的研究

在直驱永磁风力发电系统中,永磁发电机的输出电压的幅值和频率随风速的波动而变化,不可直接并网。根据风力机运行特性和最佳风能利用原理,本文设计了由不可控AC/DC整流器和可控DC/AC逆变器组成的控制系统,通过控制逆变器的输出电压或电流实时跟踪给定值,来控制永磁发电机电磁转矩,实现最大风能的获取和无功功率可调。本文在理论上分析了方案的可行性,并搭建了基于DSPTMS320LF2407的实验室硬件平台。     

Recurrent modified Elman neural network control of PM synchronous generator system using wind turbine emulator of PM synchronous servo motor drive

The recurrent modified Elman neural network (NN) controlled a permanent magnet (PM) synchronous generator system, which is driven by wind turbine emulator of a PM synchronous motor servo drive, is developed to regulate output voltage of rectifier (or AC to DC power converter) and inverter (or DC to AC power converter) in this study. First, the wind turbine emulator of a closed loop PM synchronous motor servo drive is designed to produce the maximum power for the PM synchronous generator system. Then, the rotor speed of the PM synchronous generator, the output DC bus voltage and current of the rectifier are detected simultaneously to yield maximum power output of the rectifier through DC bus power control. Because the PM synchronous generator system is a nonlinear and time varying dynamic system, the online training recurrent modified Elman NN control system is developed to regulate DC bus voltage of the rectifier and AC line voltage of the inverter in order to improve the control performance. Furthermore, the online training recurrent modified Elman NN control system with the variable learning rate is derived based on Lyapunov stability theorem, so that the stability of the system can be guaranteed. Finally, some experimental results are verified to show the effectiveness of the proposed recurrent modified Elman NN controlled PM synchronous generator system.     

永磁直驱风电机组的双PWM变换器协调控制策略

永磁直驱风力发电系统中可采用全功率双脉宽调制（PWM）变换器作为永磁同步发电机（PMSG）的并网电路,当风速变化时,双PWM变换器的直流链电压会随着PMSG输出功率的改变而出现大幅度波动,这将不利于变换器功率器件的安全运行及整个发电系统的稳定运行。结合永磁直驱同步风力发电系统的运行特点,提出一种适用于永磁直驱风电机组的双PWM变换器协调控制策略。系统仿真和实验结果验证了所提出的控制策略的正确性,该方案可显著提高风速变化时双PWM变换器的直流链电压的稳定性,有助于提高发电系统的安全稳定运行能力。     

基于双模控制的永磁直驱型风力发电机组高电压穿越控制策略的研究

为提高永磁直驱型风力发电机组的高电压穿越能力,在研究电网电压骤升下风力发电机组运行特性基础上提出一种基于双模控制的永磁直驱型风力发电机组高电压穿越控制策略。以电网电压骤升幅度及直流母线电压的升高程度为依据,利用选择器进行网侧变流器控制模式的转换,从而使直驱型风力发电机组具备高电压穿越能力。基于PSCAD仿真平台的仿真结果及应用结果表明,该控制策略不仅可以保证直驱型风力发电机组在电网电压骤升期间不脱网连续运行,还可以有效提高风力发电机组的无功补偿能力,有利于电网的安全稳定运行。     

基于PSCAD/EMTDC的双馈感应风电机组变桨距控制仿真分析

提出一种简化的风力机变桨距控制模型,通过发电机转速和风力机输出功率的反馈信号分别调节桨距角,控制发电机的转速恒定和风力机输出功率平稳.采用PSCAD/EMTDC仿真软件建立该变桨距控制模型,对整个风力发电系统(包括双馈电机和并网装置等)进行仿真,验证该风力机变桨距控制方法的可行性.     

VRB储能系统对风电场LVRT特性影响分析

为满足电网规定的并网风电场必须具有低电压穿越能力（LVRT）要求,提出一种在风电场并网点加入直接功率控制的钒液流电池（VRB）储能系统的拓扑结构来提高风电场LVRT.根据目前风电机组发展趋势风电场采用基于全功率双脉宽调制AC/DC/AC控制策略的逆变器的永磁直驱风电机组（PMSG）,VRB储能系统逆变器采用DC/AC双向功率流动的控制策略.所提出的控制策略通过协调控制风电机组机侧整流器、网侧逆变器和VRB变换器,实现平抑风电场出力和电压跌落时PCC点电压稳定控制及向电网提供一定的无功补偿.仿真结果表明,风速波动和系统电压跌落时,提出的方案可以有效平抑风电场出力波动,提高风电场LVRT能力,减小对系统安全稳定运行的负面影响.     

单周控制变速恒频风力发电机并网仿真研究

双馈式风力发电机的变速恒频控制是风力发电系统研究中的热点。在空间矢量控制的基础上．结合异步电机的变速恒频控制理论,通过单周控制技术产SVPWM波形,对Ac—DC／DC—Ac变频器进行控制,快速跟踪调节转差频率,实现定子输出电压频率同步电网频率,实现转子功率双向流动。在Matlab／Simulink环境下建立双馈式感应电机、变频器、转子频率控制器的双馈式风力发电机仿真模块并进行仿真研究。证明单周控制器能很好地实现双馈式风力发电机的变速恒频运行。