A Fuzzy Logical MPPT Control Strategy for PMSG Wind Generation Systems

Making full use of wind power is one of the main purposes of the wind turbine generator control. Conventional hill climbing search (HCS) method can realize the maximum power point tracking (MPPT). However, the step size of HCS method is constant so that it cannot consider both steady-state response and dynamic response. A fuzzy logical control (FLC) algorithm is proposed to solve this problem in this paper, which can track the maximum power point (MPP) quickly and smoothly. To evaluate MPPT algorithms, four performance indices are also proposed in this paper. They are the energy captured by wind turbine, the maximum power-point tracking time when wind speed changes slowly, the fluctuation magnitude of real power during steady state, and the energy captured by wind turbine when wind speed changes fast. Three cases are designed and simulated in MATLAB/Simulink respectively. The comparison of the three MPPT strategies concludes that the proposed fuzzy logical control algorithm is more superior to the conventional HCS algorithms.     

An Improved Control Strategy of Limiting the DC-Link Voltage Fluctuation for a Doubly Fed Induction Wind Generator

The paper presents to develop a new control strategy of limiting the dc-link voltage fluctuation for a back-to-back pulsewidth modulation converter in a doubly fed induction generator (DFIG) for wind turbine systems. The reasons of dc-link voltage fluctuation are analyzed. An improved control strategy with the instantaneous rotor power feedback is proposed to limit the fluctuation range of the dc-link voltage. An experimental rig is set up to valid the proposed strategy, and the dynamic performances of the DFIG are compared with the traditional control method under a constant grid voltage. Furthermore, the capabilities of keeping the dc-link voltage stable are also compared in the ride-through control of DFIG during a three-phase grid fault, by using a developed 2 MW DFIG wind power system model. Both the experimental and simulation results have shown that the proposed control strategy is more effective, and the fluctuation of the dc-link voltage may be successfully limited in a small range under a constant grid voltage and a non-serious grid voltage dip.     

风力发电机、变流器及其低电压穿越概述

风力发电技术发展很快,单机容量不断增大,风电在电网中所占的比重也越来越大。讨论了几种典型的风力发电系统,包括失速型风电系统、双馈和直驱型变速恒频风电系统,并在此基础上,根据齿轮箱结构和发电机不同,讨论了其他类型的风电系统,分析了各自的优缺点。说明了常用的风电变流器拓扑,多电平变流器将得到更多的应用;为适应新的电阚规则对并网风电低电压穿趣与无功支持功能的要求,风电机组必须采取应对措施,对相关技术进行了分析和讨论。从风电系统发电机、变流器和低电压穿越能力等方面进行了论述,并介绍了不同风电公司的相关产品与技术。     

一种基于变速恒频的双馈风力发电MPPT设计

采用双PWM控制型变流器,变速恒频发电技术,变浆距角进行最佳风能追踪(MPPT)控制。分析了如何由绕线式异步电动机参数设计出双馈风力发电最大风能跟踪控制的风力机参数。通过Matlab仿真,分析了风机的切入风速、切出风速、风速过大情况下的变桨距角控制及浆距角随风速减小而自动恢复的最大风能跟踪特性,验证了控制策略的有效性和可行性。     

基于MPPT的变速恒频双馈风力发电系统控制策略

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,本文基于风力机特性和双馈风力发电机的数学模型,提出了一种不依赖于风速测量来实现双馈风力发电系统最大功率点追踪(MPPT)控制的策略。该策略应用定子磁链定向矢量控制技术,对双馈发电机进行有功功率和无功功率的解耦控制,然后通过对发电机输出有功功率进行控制来间接得到与风速相对应的最佳叶尖速比和最优转速,从而实现最大功率点追踪(MPPT)控制。仿真结果证实了基于该方法,双馈风力发电系统在风速变化过程中能自动寻找并追随最大功率点,且控制相对简单,运行可靠,有较高的实用价值。     

Solid State Voltage and Frequency Controller for a Stand Alone Wind Power Generating System

This paper deals with the voltage and frequency controller of a wind turbine driven isolated asynchronous generator. The proposed voltage and frequency controller consists of an insulated gate bipolar junction transistor based voltage source converter along-with battery energy storage system at its dc link. The proposed controller is having bidirectional active and reactive powers flow capability by which it controls the system voltage and frequency with variation of consumer loads and the speed of the wind turbine. It is also having capability of harmonic elimination and load balancing. The proposed electro-mechanical system along with its controller is modeled and simulated in MATLAB using Simulink and power system block-set toolboxes. Performance of the proposed controller is presented to demonstrate voltage and frequency control of a wind turbine driven isolated asynchronous generator along with harmonic elimination and load balancing.     

Control of the Reactive Power Supplied by a WECS Based on an Induction Generator Fed by a Matrix Converter

In this paper, a new control system to regulate the reactive power supplied by a variable-speed wind energy conversion system (WECS), based on an induction generator fed by a matrix converter (MC), is presented. The control system discussed in this paper is based on an input current observer, implemented using an estimation of the modulation matrix, and a nonlinear control loop that regulates the displacement angle at the MC input. The reactive power capability of the proposed system is also investigated. The work presented in this paper demonstrates that, for the proposed WECS, the maximum reactive power supplied to the grid is about 40% of the nominal value. Experimental results obtained from an experimental prototype are presented in this paper. The performance of the system using a wind turbine emulator and typical wind profiles is discussed in this paper.      

Maximum Power Point Tracking in Variable Speed Wind Turbine Based on Permanent Magnet Synchronous Generator Using Maximum Torque Sliding Mode Control Strategy

The present study was carried out in order to track the maximum power point in a variable speed turbine by minimizing electromechanical torque changes using a sliding mode control strategy. In this strategy, first, the rotor speed is set at an optimal point for different wind speeds. As a result of which, the tip speed ratio reaches an optimal point, mechanical power coefficient is maximized, and wind turbine produces its maximum power and mechanical torque. Then, the maximum mechanical torque is tracked using electromechanical torque. In this technique, tracking error integral of maximum mechanical torque, the error, and the derivative of error are used as state variables. During changes in wind speed, sliding mode control is designed to absorb the maximum energy from the wind and minimize the response time of maximum power point tracking (MPPT). In this method, the actual control input signal is formed from a second order integral operation of the original sliding mode control input signal. The result of the second order integral in this model includes control signal integrity, full chattering attenuation, and prevention from large fluctuations in the power generator output. The simulation results, calculated by using MATLAB/m-file software, have shown the effectiveness of the proposed control strategy for wind energy systems based on the permanent magnet synchronous generator (PMSG).     

风力发电机组的电气控制

本文综述风力发电机组的电气控制。在简述风力涡轮机特性的基础上,介绍恒速发电和变速发电的特点和应用场合,重点是基于同步发电机的“直接在线”发电和基于绕线异步机的“双馈”发电系统,以及桨叶倾角控制系统。作为对未来的展望,最后介绍一种新型锥形转子风力发电机组的设想。     

变速恒频双馈风力发电系统仿真研究

阐述变速恒频双馈风力发电系统工作原理,在分析双馈异步发电机的动态数学模型的基础上,介绍了一种基于定子磁链定向的矢量控制方法,实现对电机的有功功率和无功功率的解耦控制,进而实现最大风能追踪。在DFIG转子励磁电源的研究中,重点讨论基于电网电压定向矢量控制技术的网侧变换器的控制方法,以实现网侧变换器交流侧单位功率因数控制和直流环节电压控制。Matlab仿真结果证明了控制策略的正确性和有效性。     

Comparative analysis of maximum power point tracking controller for wind energy system

This paper proposes an adaptive maximum power point tracking (MPPT) control method to achieve the maximum power from the wind turbine (WT) power generation system. The MPPT control method has a vital role to find the maximum power point, and also compute the simulation results in both analysis such as offline using MATLAB/SIMULINK? and online using OPAL-RT simulator. The proposed adaptive perturb and observe (P&;O) algorithm provides better results using the OPAL-RT simulator compared to the P&;O method using MATLAB/SIMULINK?. The power generation through doubly fed induction generator (DFIG) WT system is becoming important day by day throughout the world. The simulation result by OPAL-RT simulator showed that the efficiency of WT-DFIG has been enhanced.     

基于最佳功率给定的永磁直驱同步风力发电系统控制策略研究

直驱型风力发电系统由于不需要增速箱,在风电场中得到广泛的发展和应用.该文研究了发电机和风机的特性分析,提出了基于最佳功率给定的最大风能控制策略,该方法通过对发电机进行闭环控制,使输出功率按照最优功率曲线进行输出,实现最大风能跟踪.并研究了永磁直驱风电系统的双PWM变流器控制策略;搭建了直驱型风电机组整体模型,该系统能够实现并风能最大功率跟踪及并网控制,仿真验证了控制系统的正确性.     

双馈风力发电系统低电压穿越的建模与控制

为提高双馈感应风力发电机组并网的运行稳定性,研究电网故障下双馈风电机组的运行特性,使发电机在电网故障时仍能保持不间断的运行。本文主要研究了基于Orowbar保护控制的低电压穿越运行的控制策略,通过Orowbar保护电路来限制电压跌落时转子回路的最大电流,并通过仿真分析了电压跌落的程度和旁路电阻的取值对控制的影响。仿真结果验证了在电网电压骤降下Crowbar保护电路的有效性,可实现双馈风力发电机不间断的运行。     

基于垂直轴双馈风力发电系统的仿真研究

以垂直轴风轮（VAWT）和双馈感应发电机（DFIG）为研究对象,建立了包括风力机模型、传动系统模型和双馈电机模型的垂直轴双馈风力发电系统的数学模型及结构,采用双馈电机定子磁链定向前馈解耦控制,使得电机的有功分量和无功分量可以分别得到控制。运用Matlab/Simulink建立了系统仿真模型,对定子磁链定向前馈解耦控制策...     

New Fuzzy Control Strategies Applied to the DFIG Converter in Wind Generation Systems

This paper presents new fuzzy control strategies which may be applied to the converter connected to the rotor of doubly fed induction generators (DFIG) composing a variable speed wind generation system connected to a real electrical grid. The fuzzy control proposed strategies are of the type supervised “look-up-table”. The performance of these intelligent controllers are compare with the fixed parameters PI controllers for fault ocurrence in the power system. The fuzzy controllers are supposed to better the transient performance of the electrical power system as compared with the conventional PI controllers. The obtained results from simulation studies have of the fuzzy controllers. To formulate the simulation studies an equivalent mathematical model of a significant number of wind turbines was implemented using the MATLABTM software packcage.     

双馈风力发电系统功率控制的相关问题研究

针对目前在风电系统最大风能捕获控制策略中应用较为广泛的功率控制方法,本文首先分析了当前此法中有关反馈量的选取所存在的误区,并通过仿真验证了理论分析结果。在此基础上,结合双馈风电系统的慢动态模型,通过对其功率控制的稳定性分析,给出了系统的闭环稳定性条件,结果表明,闭环系统的稳定性取决于控制器的参数以及系统的工作点。     

供变速风机使用的电力电子变流器

在风力发电系统中变速驱动方式的引入给系统带来了许多好处，但是变速风力发电机产生的电能与电网要求的标准不相适应，必须在发电机和电网之间安装电力电子变流器，才有可能将风力能源送入电网。文章主要介绍了在变速风力发电系统中使用的几种不同电力电子变流器的拓扑结构和它们在其它系统中的应用及目前的发展情况。     

An intelligent maximum power extraction algorithm for inverter-based variable speed wind turbine systems

This paper focuses on the development of maximum wind power extraction algorithms for inverter-based variable speed wind power generation systems. A review of existing maximum wind power extraction algorithms is presented in this paper, based on which an intelligent maximum power extraction algorithm is developed by the authors to improve the system performance and to facilitate the control implementation. As an integral part of the max-power extraction algorithm, advanced hill-climb searching method has been developed to take into account the wind turbine inertia. The intelligent memory method with an on-line training process is described in this paper. The developed maximum wind power extraction algorithm has the capability of providing initial power demand based on error driven control, searching for the maximum wind turbine power at variable wind speeds, constructing an intelligent memory, and applying the intelligent memory data to control the inverter for maximum wind power extraction, without the need for either knowledge of wind turbine characteristics or the measurements of mechanical quantities such as wind speed and turbine rotor speed. System simulation results and test results have confirmed the functionality and performance of this method.     

风电系统中发电机励磁控制系统的研究

论文介绍了风电系统中双馈风力发电机（DFIG）的工作原理,论文中所提出的双馈风力发电系统主要采用了双PWM换流器结构的交流励磁系统。并运用矢量控制的控制策略对网侧变换器和励磁侧变换器进行控制。并通过Matlab软件构建了最大风能追踪的仿真模型对其进行仿真,仿真表明论文中所提出的控制策略能够实现现风力发电系统的最大风能追...     

A New Interconnecting Method for Wind Turbine/Generators in a Wind Farm and Basic Performances of the Integrated System

A new interconnecting method for a cluster of wind turbine/generators is proposed, and some examples of the basic characteristics of the integrated system are shown. This method can be achieved with a wind turbine generating system using a shaft generator system. A group of wind turbine/generators can be interconnected easily with the proposed method, and high reliability and electric output power with high quality are also expected. Moreover, since this method enables transmission of the generated power through a long-distance dc transmission line, the optimum site for wind turbines can be selected so as to acquire the maximum wind energy.