直驱永磁同步风电机组在全风速范围内的控制策略研究

为实现直驱式永磁同步风电机组在全风速范围内的高效、稳定运行,提出了一种基于最优转速给定的最大功率点跟踪控制策略与一种变桨距控制策略。当风速波动时,发电机转子转速的参考值将根据风电机组运行状态的不同选择不同的计算方式,使得风力机功率系数最大或稳定在额定转速不超速。而桨距角的大小将根据发电机的输出功率变化,当输出功率小于额定值时保持为0,大于额定值时增大使得输出功率稳定在额定值附近。最大功率点跟踪控制系统及桨距角控制系统都以发电机的输出功率大小作为控制方式的切换条件,无需复杂的切换规则。在Matlab/Simulink仿真平台上全风速范围内的风电机组的运行结果验证了所提出的控制策略的正确性与有效性。     

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.     

A study of generator system selection for large wind turbine generator system

This paper focuses on selection of wind turbine generation systems that include generators, converters, and gears. We study three systems: a permanent magnet generator (PMG) system, a doubly‐fed generator (DFG) system, and a synchronous generator (SYG) system in terms of the system efficiencies and running costs. The system efficiencies and running costs are calculated by considering the relationship between wind power and wind conditions. According to these results, the one‐step gear PMG system is the best choice for a large wind turbine system. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(1): 51–57, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20506     

直驱式永磁同步风力发电机性能研究

通过等效磁路法设计了额定功率1.5MW的直驱式永磁风力发电机;为了深入研究额定功率1.5MW的直驱式永磁风力发电机的运行特性,采用场路结合法分析了永磁风力发电机在空载、额定负载和短路情况下的运行特点,并验证了所设计永磁风力发电机的可行性;在此基础上,将极孤系数、负载变化对永磁同步发电机输出功率的影响进行了仿真;对比研究了每极每相槽数对永磁同步发电机性能的影响.结果表明:极槽匹配对直驱式风力永磁发电机性能有很大影响;通过合理选择极数、槽数以及极弧系数,可以减少输出电压谐波分量的影响,降低永磁材料的使用,节省成本,有助于直驱式风力永磁发电机获得良好的性能.     

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     

Effective MPPT technique and robust power control of the PMSG wind turbine

Wind generator performance improvement requires sophisticated and robust control techniques to overcome various constraints and achieve optimal aerodynamic energy conversion. Because of the continuously changing nature of the wind, the output power of a wind energy conversion system (WECS) can be maximized if the wind rotor is driven at an optimal rotational speed for a particular wind speed. This is achieved with a maximum power point tracking (MPPT) controller. Over the years, a variety of MPPT studies have been made, but very few provide guidelines to single out the most suited MPPT technique. In this paper, a comprehensive comparison of the four most used schemes has been made in relation to a permanent magnet synchronous generator (PMSG) wind turbine system. These techniques can be classified into various categories. The obtained results show clearly the superiority of the fuzzy logic control (FLC) technique. Using this MPPT approach, the generated power by the turbine is considered to be, in terms of power control, an auxiliary source feeding a grid. To achieve smooth regulation of the active and reactive power exchange between the PMSG and the grid, direct power control, using space vector modulation DPC‐SVM strategy combined with sliding mode control (SMC) is applied in the grid‐side converter. Simulation results show the efficiency and reliability of the control strategy proposed in this paper. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

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.     

新型直驱永磁风力发电机电磁场数值分析

以新型直驱永磁风力发电机为研究对象,在完成采用XLPE高压电缆作为定子绕组的1.5 MW/10.5kV内转子新型直驱永磁风力发电机电磁设计的基础上,在Ansoft Maxwell环境下建立发电机二维模型,对发电机各个工况下的电磁场进行有限元仿真与分析,包括静态空载、额定负载、不对称短路故障情况,对发电机永磁体在出线端突然三相短路时受冲击电流影响是否会发生局部失磁进行分析,验证新型永磁风力发电机电磁设计的可行性。结果表明,新型风力发电机与传统永磁风力发电机电磁场分布规律一致,且其额定电压高,绕组电流密度较小,额定负载与单相短路情况下永磁体磁场受电枢磁场影响较小,铜耗和铁耗也较小,同时在极端短路情况下永磁体局部不会出现永久性退磁,设计方案可行。     

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.     

直驱永磁风电机组LVRT模型参数的整定方法与实测验证

针对直驱永磁风电机组,提出低电压穿越(LVRT)模型参数的整定方法。基于直驱永磁风电机组的通用模型结构,计算各参数的轨迹灵敏度,获得LVRT模型的关键参数。指出由于参数的非线性特性,现有的基于轨迹灵敏度的参数辨识方法难以适用。为此,提出将参数调整与参数优化相结合的参数整定方法。以某直驱永磁风电机组为例,基于实测数据进行了参数整定及模型验证,并进行了其他扰动场景下的适应性分析,结果验证了所提方法的可行性和有效性。     

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).     

Review of DFIG wind turbine impact on power system dynamic performances

Recently, the variable‐speed wind turbine with doubly fed induction generator (DFIG ) has drawn significant attention because of its many advantages such as small power converter rating, the ability to control the output power, etc. Nevertheless, the large penetration of DFIG wind turbines may affect the power system dynamics. This paper provides a general review of the DFIG wind turbine's impact on power system dynamic performances such as frequency stability, transient stability, small‐signal stability, and voltage stability. Besides, ancillary services from the DFIG wind turbine for the power grid, such as frequency support, reactive power, and voltage support, are explained. Especially, the survey emphasizes power oscillation damping methods by the DFIG wind turbine. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

风速突变工况下永磁风力发电机静态偏心磁场分析

为了研究风速突然变化对永磁风力发电机主轴的电磁力作用,特别是在已发生一定的主轴偏心的情况下风速突变对主轴的影响,利用数学表达式和仿真对气隙磁场进行了计算和分析。根据发电机气隙偏心故障时气隙磁场变化的特点,计算气隙磁导和磁场密度,并利用ANSOFT MAXWELL软件建立永磁风力发电机的二维模型,分析电流变化引起的电磁力及其对主轴的作用。仿真结果表明:风速突变引起的电流变化影响永磁风力发电机气隙磁密。转子偏心使发电机转子产生沿偏心方向的磁拉力,风速突变时转子收到的不平衡磁拉力比正常风速运行更大。     

直驱式永磁同步风力发电机稳态模型与最大功率跟踪控制

针对直驱式永磁同步风力发电系统最大功率点跟踪问题,通过风力机、永磁同步发电机、三相不控整流桥、DC-DC变换器等的等效电路分析,建立了系统的稳态数学模型,推导出交流侧电功率的计算、最大功率点的捕获与直流电压等的相关计算公式,进而采用功率信号反馈(PSF)算法实现最大功率点跟踪(MPPT)控制,然后在Matlab/Sim...     

带感应耦合器的永磁同步风力发电系统建模与分析

对一种新型风力发电系统——带感应耦合器的永磁同步风力发电系统进行了研究.建立了自然风、风力涡轮机、感应耦合器及永磁同步发电机的数学模型和仿真模型.建立基于传递函数的系统整体动态仿真模型,并将其作为分析研究系统动态特性的工具.对阵风和涡轮机转矩产生7.5Hz波动条件下,有和无感应耦合器两种情况下永磁同步风力发电机的特性进行对比分析.讨论了感应耦合器的等效电阻对系统特性的影响.研究结果表明,引入感应耦合器有效削弱了干扰对系统的影响,降低了电压闪变程度,改善了风速变化或涡轮转矩波动时系统运行不稳定的情况.另外,耦合器等效电阻的减小可减小其运行的转差率,提高系统效率,但稳定性有所下降.     

一种新型永磁同步风力发电系统的研究

为了提高风力发电能量转换效率以及降低成本,提出了一种新型的永磁同步电机变速恒频风力发电系统结构,并根据风力机特性,设计了一种最大功率点跟踪算法。该系统主电路由直流变换器及网侧SAPWM变换器构成,分析了这两部分的工作原理。根据实际条件提出了一种风力机定性模拟方法,在此基础上对整个系统进行了实验分析。实验结果表明,本系统能够较好地实现最大功率点跟踪以及高质量单位功率因数能量馈送。     

单相双半波可控整流稳压发电装置的研究

采用高磁性永磁材料和对发电装置的优化设计，研发出单相双半波可控整流稳压式电子稳压器，提高了低转速时的输出电压。主电路利用两只可控硅实现稳压直流输出，取代了硅整流发电机的6只整流管组成的整流桥和电子调节器，集稳压、整流于一体，电能消耗少，发电效率高，解决了汽车用永磁发电机在变转速变负载工况下输出电压保持稳定的问题。     

真驱永磁同步风力发电机组低电压穿越控制策略

分析直驱永磁同步风力发电机组（DDPMSG）在电网故障情况下的低电压运行特性,提出一种综合控制策略．包括通过变桨距控制实现最大风能追踪：控制发电机电磁功率以控制直流链及电网侧逆变器的功率;利用发电机侧功率控制网侧变流器的电流,实现直流链电压的稳定,以提高直驱永磁同步风力发电机组的低电压穿越能力,维持所并电网的运行稳定性。运用仿真分析软件PSCAD／EMTDC建立DDPMSG及其控制策略的仿真模型,仿真结果验证了所提策略的有效性和可行性。     

A calculation method of the total efficiency of wind generators

The spread of wind energy converters is progressing in recent years and its capacity is becoming larger and larger. In order to capture more energy from the wind, it is important to analyze loss characteristics of wind generators for the operating speed which is determined dependent on the wind speed. This paper presents a method to evaluate various losses in a wind generator as a function of wind speed, which is based on steady‐state analysis and thus the calculations can be performed quickly. By using the proposed method, wind turbine power, generator output, various losses, and the total energy efficiency are calculated for three types of wind speed data which are represented by a Weibull function. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(3): 52–62, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20426 Copyright © 2006 Wiley Periodicals, Inc.     

直驱永磁同步风力发电机组低电压穿越控制策略

分析直驱永磁同步风力发电机组(DDPMSG)在电网故障情况下的低电压运行特性,提出一种综合控制策略,包括通过变桨距控制实现最大风能追踪;控制发电机电磁功率以控制直流链及电网侧逆变器的功率;利用发电机侧功率控制网侧变流器的电流,实现直流链电压的稳定,以提高直驱永磁同步风力发电机组的低电压穿越能力,维持所并电网的运行稳定性。运用仿真分析软件PSCAD/EMTDC建立DDPMSG及其控制策略的仿真模型,仿真结果验证了所提策略的有效性和可行性。