A Theoretical and Experimental Study of a Laboratory Wind Turbine Emulator using DC-Motor Controlled by an FPGA-Based Approach

Abstract

The aim of this study is to carry out a Wind Turbine Emulator (WTE) which represents the important hardware part to behave as a real wind turbine system with respect to the introduced wind timeseries for improving the wind power system technology control in laboratory. The proposed WTE consists of a variable speed drive which controls a DC motor as a prime mover coupled to a PMSG operated in open loop. The novelty appears in the modeling and configuration of wind timeseries, aerodynamic and mechanical aspects of the wind turbine and its control strategy by using Xilinx System Generator (XSG) as a dataflow design tool based on graphical user interface Simulink which ensures a rapid architectures prototyping. Moreover, the dynamic performance of the modeled system under Matlab/XSG environment is presented and discussed. The motor drive is performed by a DC/DC buck converter controlled by PWM strategy implemented on FPGA board. An experimental platform of the entire wind energy conversion system is built. Experimental results verified and validated the wind turbine emulator operation using a variable wind speed.     

Simulation of variable‐speed wind generation system using boost converter of permanent magnet synchronous generator

This paper proposes a variable‐speed wind generation system using the boost converter. The proposed system has three speed control modes for the wind velocity. The control mode of low wind velocity regulates the armature current of the generator with the boost converter to control the speed of wind turbine. The control mode of middle wind velocity regulates the DC link voltage with the vector controlled inverter to control the speed of wind turbine. The control mode of high wind velocity regulates the pitch angle of the wind turbine with the pitch angle control system to control the speed of the wind turbine. The hybrid combination of three control modes extends the variable‐speed range. The proposed system simplifies maintenance, improves reliability, and reduces the costs compared with the variable‐speed wind generation system using a PWM converter. This paper describes the control strategy and modeling for a simulation of the proposed system using Simulink of Matlab. It also describes the control strategy and modeling of a variable‐speed wind generation system using a PWM converter. The steady state and transient responses for wind velocity changes are simulated using Matlab Simulink. This paper verifies the fundamental performance of the system using a boost converter by discussing the simulation results of both systems. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(4): 37–54, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20902     

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.     

基于双重变换器的变速风力发电机组最大功率点快速追踪系统

针对变速风力发电系统提出了一个新的最大功率点(MPP)快速追踪策略。该系统采用AC-DC-DC-AC变换器将永磁电机发出的电能传输给电网。鉴于DC-DC直流环节在能量传输中的重要性,采用了双重Sepic变换器,并进行了详细分析。仿真结果证明了该控制策略及变流系统的正确性和可行性。     

基于遗传算法的直流电机风力发电系统最优励磁控制技术

针对风力发电系统发电机转速波动较频繁,难于同时对电压和频率的稳定性实施控制等特点,结合直流发电机的工作特性,提出了基于直流发电机的风力发电系统控制技术。采用基于遗传算法的最优励磁控制技术对发电机的励磁实施控制,使发电机获得了稳定的输出电压。从理论上分析了直流风力发电系统的可行性及其特点,重点分析和研究了基于遗传算法的直流风力发电机组最优励磁控制技术在稳定输出电压方面的性能,运用Matlab对该系统进行了仿真,并用直流电动机作原动机,通过调节电动机的转速模拟风速变化引起的风力机转速变化。在电力系统动态模拟试验室中进行了大量实验,通过比较和分析获取的数据和仿真结果,进一步验证了该方法的正确性和可行性。     

并网型双馈风电机组动态稳定性仿真

介绍了变速恒频双馈风电机组的基本结构，建立了双馈风电机组在d-q坐标系下的动态数学模型。应用Matlab/Simulink搭建了系统仿真模块，并对并网型双馈风电机组的动态稳定性做了仿真试验研究，结果表明：在风电系统中利用变速技术后可以提高风能的利用率，改善电力系统稳定性；变速双馈风电机组具有低电压穿越功能。     

大容量永磁同步风电机组系统谐振与抑制策略

风电机组变流器是变速恒频风电机组的核心部件,变流器电网侧滤波器在保证良好并网特性的同时也给系统带来了谐振稳定性问题.基于风电机组变流器网侧滤波器动态特性进行分析,揭示了风电机组谐振机理,提出了虚拟变阻尼谐振抑制策略.在MATLAB/Simulink中建立了2.0 MW直驱型永磁同步风电机组仿真模型,实现了风电机组谐振与抑制的全过程仿真.利用电网谐波发生模拟装置,首次在2.0 MW永磁直驱风电机组上进行了机组谐振与抑制现场试验.仿真与现场试验证明了理论分析的正确性与谐振抑制策略的有效性,对实际运行时风电机组的谐振问题和风电机组变流器设计具有指导意义.     

Speed control of grid-connected switched reluctance generator driven by variable speed wind turbine using adaptive neural network controller

In wind energy conversion system, variable speed operation is becoming popular nowadays, where conventional synchronous generators, permanent magnet synchronous generators, and doubly fed induction generators are commercially used as wind generators. Along with the existing and classical solutions of the aforementioned machines used in wind power applications, the switched reluctance generator (SRG) can also be considered as a wind generator due to its inherent characteristics such as simple construction, robustness, low manufacturing cost, etc. This paper presents a novel speed control of switched reluctance generator by using adaptive neural network (ANN) controller. The SRG is driven by variable speed wind turbine and it is connected to the grid through an asymmetric half bridge converter, DC-link, and DC-AC inverter system. Speed control is very important for variable speed operation of SRG to ensure maximum power delivery to the grid for any particular wind speed. Detailed modeling and control strategies of SRG as well as other individual components including wind turbine, converter, and inverter systems are presented. The effectiveness of the proposed system is verified with simulation results using the real wind speed data measured at Hokkaido Island, Japan. The dynamic simulation study is carried out using PSCAD/EMTDC.     

基于22kW笼型等功率风力机模拟系统研究

为更好地在实验室内开展风电技术研究,提出了一种带双齿轮箱的风力机模拟系统.该系统主要包括两个变频器、两个转矩转速传感器、一台原动机、一台发电机、一个PCI板卡、一台上位机和一个主控制界面,能够模拟兆瓦级和等功率风机特性.针对等功率风机特性中恒转速和恒风速两种典型情况进行了研究分析,实验结果表明,该平台能够准确地模拟出等...     

永磁风电系统低电压穿越控制策略研究

针对Boost升压型永磁直驱型风电系统,分析了其发电机侧和网侧变流器的控制策略.为增强其低电压穿越能力,提出了一种基于转子储能和网侧无功优先输出的控制策略.通过减小发电机的有功输出来降低直流侧过电压,通过控制网侧无功输出来提升电网电压.基于Matlab/Simulink 7.10搭建了仿真模型.仿真结果证明了该控制策略的有效性.     

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。     

分散式风电孤岛运行特性与孤岛检测试验研究

分散式风电靠近电网负荷端,风电机组必须自主实现孤岛状态的辨识。基于风电机组孤岛运行特性及功率扰动对并网点电压、频率影响的灵敏度分析,提出基于无功功率-频率正反馈与传统过欠压、过欠频相结合的风电机组孤岛检测方法,并进行了风机变流器无功功率扰动控制环设计。在Matlab/Simulink中建立了2.0 MW永磁同步风电机组仿真模型,实现了风电机组孤岛运行与孤岛状态辨识的全过程仿真。利用RLC负荷模拟装置,在2.0MW永磁同步风电机组上进行了孤岛检测现场试验。仿真与现场试验证明了理论分析的正确性与孤岛检测策略的有效性。     

Power maximization control of variable‐speed wind generation system using permanent magnet synchronous generator

This paper proposes sensorless output power maximization control of a wind generation system. A permanent magnet synchronous generator (PMSG) is used as a variable speed generator in the proposed system. The generator torque is suitably controlled according to the generator speed and thus the power from a wind turbine settles down on the maximum power point by the proposed MPPT control method, where the information on wind velocity is not required. Moreover, the maximum available generated power is obtained by the optimum current vector control. The current vector of PMSG is optimally controlled according to the generator speed and the required torque in order to minimize the losses of PMSG considering the voltage and current constraints. The proposed wind power generation system can be achieved without mechanical sensors such as wind velocity detector and a position sensor. Several experimental results show the effectiveness of the proposed control method. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(2): 11–19, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20043     

虚拟风场和风力机模拟系统的实验研究

在不具备风场环境或风力机的条件下,建立虚拟风场和风力机模拟系统,对风力发电系统的研究具有重要作用。根据风速变化规律,建立了基于谱密度分析的自回归理论的风速模型。在此风速模型基础上,考虑涡流效应,对叶片进行受力分析,根据叶素理论和权系数分配叶素的方法建立风轮转矩模型,利用转矩控制直流电动机模拟风力机,搭建了虚拟风场和风力机模拟系统实验平台。虚拟风场的建立为虚拟风力机暂态或连续性实验提供了良好的基础。风力机模拟系统实验不仅验证了风轮转矩模型的准确性,反映了风速变化时模拟输出风轮转矩的快速跟随性能,而且可用于变速恒频风力发电系统的研究,证明其控制策略的正确性。     

Wind Velocity Sensorless Maximum Power Point Tracking Algorithm in Grid-connected Wind Energy Conversion System

This article proposes a wind velocity sensorless hill-climb searching algorithm in the grid-connected field-oriented controlled permanent magnet synchronous generator based wind energy conversion system. The proposed method improves the speed and accuracy of initial tracking. Pseudo-optimum points are used to track the exact optimum points using the power versus speed characteristics of a wind turbine for various wind velocities. This research emphasizes that the pseudo-optimum points using the power versus speed characteristics are always less than and much nearer to the exact optimum points. The small-step forward tracking after pseudo-optimum points improves the accuracy of this algorithm. Moreover, this method improves the tracking speed for various wind velocities. The system used for this research consists of a back-to-back sinusoidal pulse-width modulation converter between the generator and the grid. The performance of the proposed method is analyzed mathematically and verified by simulation using MATLAB/Simulink software (The Mathworks, Natick; Massachusetts, 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。     

兆瓦级变速恒频风力发电机组控制系统

基于定子磁链定向的双馈电机控制理论，采用双PWM变换器结构，完成了兆瓦级变速恒频双馈风力发电机组的控制系统。其网侧变换器采用电压电流双闭环控制策略，转子侧变换器并网前采用转子电流开环控制策略，并网后采用有功、无功电流闭环解耦控制策略。该系统完成了亚同步、超同步运行时的系统满载实验以及模拟风速变化情况时系统有功、无功功率解耦控制的实验。实验结果验证了控制系统的可行性。     

风力发电系统的暂态仿真模型研究

详细归纳了不同类型风力发电系统的暂态仿真模型,研究了包括空气动力系统、风机轴系系统、桨距控制系统和变频器在内的动态仿真模型,以双馈风力发电机为例,研究了变桨距恒频/变速风力发电系统的控制系统模型。最后,在电力系统分析软件DigSILENT PowerFactory上分别对异步风力发电机、双馈风力发电机和全换相同步风力发电机进行建模,模拟变风速条件下不同类型风力发电机的动态特性。仿真结果进一步验证了所研究模型的正确性。     

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PSCAD/EMTDC的双馈式风力发电机建模与仿真分析

在交流励磁双馈发电机的数学模型基础上,详细分析了交流励磁双馈发电系统在PSCAD/EMTDC软件环境下的建模方法,包括风力机模型、网侧换流器模型、机侧换流器模型及其控制系统模型.搭建了双馈式变速恒频风力发电系统的电磁暂态模型,并对双馈风力发电机组整体模型进行了联调仿真分析,实现了最大风能捕获,有功功率和无功功率的解耦控制以及变速恒频运行的控制目标.