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1.
利用PSASP软件的UPI接口程序模块．在PSASP中建立了双馈风电机组模型,以两个实际的地区电网为例,研究双馈风电机组接入地区电网后对电网电压的影响,结果表明：双馈风电机组提高了地区电网的静态电压水平：双馈风电机组在故障后能够减少系统所需的无功储备,从而有利于地区电网的电压稳定;风速的波动对地区电网的电压有影响,但一般不会影响其暂态稳定性。 相似文献
2.
目前,撬棒(crowbar)保护技术是双馈风电机组实现故障穿越的有效手段之一,但其最大的问题是,保护投入期间,双馈风电机组(doubly fed induction generator,DFIG)处于失控状态,不利于系统稳定。因此,利用定子撬棒方案代替传统撬棒保护已得到广泛关注。然而,仅仅采用定子撬棒的方法,并不能保证直流母线电压在限值之内,为此,提出定子撬棒和直流侧卸荷电路协调的故障穿越方案来解决该问题。首先分析定子串电阻对转子电流故障影响的理论基础,之后,确定和优化所串电阻的大小,分析说明该故障穿越方案的基本工作原理,并利用PSCAD/EMTDC专业仿真软件,验证所提方案的有效性和可行性。 相似文献
3.
着重研究双馈感应电机在电网电压不平衡条件下的不间断运行控制问题。利用对称分量法将三相不对称向量分解成正序、负序、零序分量给出的电网电压不平衡情况下的双馈感应电机数学模型,使用非线性自适应控制技术综合设计了电机转子电压的鲁棒自适应控制器。理论分析和仿真研究表明,即使在系统参数和外部干扰存在的情况下,设计的控制器仍可以保证：系统安全可靠的运行、最大风能跟踪、输出恒压恒频的电流以及电网电压不平衡情况下的电机不间断运行。 相似文献
4.
当电网电压跌落时,风电机组须维持一定时间与电网连接而不解列,并且能提供无功以支持电网电压的恢复,即具有低电压穿越能力,而双馈风电机组低电压穿越能力最弱。分析建立了双馈风力发电机组的模型,通过使用MATLAB/SIMULINK仿真,来研究它的LVRT性能,及影响它LVRT性能的因素,探讨它的改进方案。 相似文献
5.
The objective of this paper is to propose a simple approach to solve the steady state of a wind turbine (WT) equipped with a doubly fed induction generator (DFIG), which can be used to initialize dynamic studies of the machine. The idea is to model the rotor‐side converter (RSC) as a constant current source connected to the rotor of the DFIG. The resulting equivalent circuit consists of a voltage source in series with a reactance, which makes it possible to obtain simple phasor expressions that can be used to obtain the Park components of the variables. The proposed method is compared with the traditional Newton–Raphson algorithm, showing that it is easier and faster to implement, as it makes use of the phasor expressions and it does not require an iterative process to obtain the final solution. Finally, the results of the proposed method are used to simulate a 2‐MW DFIG‐based WT under three‐phase faults, considering three different WT‐operating points. In these simulations, the idea of constant rotor current is extrapolated to the entire event. The simulated results show that both current at torque peaks are reduced. The analytical study and the simulations have been carried out in Matlab ?. 相似文献
6.
通过研究已有的风力发电机空载并网控制的文献,指出定子磁链并网控制策略的不足之处,提出了电网电压并网控制策略,同时通过试验设计了并网前相位与相序的检测方法。通过仿真发现,在此控制策略下,双馈风力发电机定子侧的电压在频率、幅值、相位上接近电网电压,达到了无冲击并网的目的,验证了此控制策略的正确性和有效性,是空载并网方式的一种理想的控制策略。 相似文献
7.
风力发电厂系统的完整模型建模,阶数太高,不适合全系统在线安全分析和稳定裕度计算。提出一种风电场双馈感应发电机(DFIG)动态等值技术,即将风力发电厂中的多台DFIG发电单元等值聚合为一个发电单元,对发电单元的聚合包括风力涡轮机的聚合、双馈感应发电机聚合以及电能传输和收集系统的聚合。保留了在不同的风速下,被聚合的发电单元的主要的动态性能。聚合模型应用在电力系统在线仿真中,优化了在线分析计算时间,提高了在线计算的精确性。等值前后发电单元具有相同的模型结构。通过仿真研究,验证了动态等值方法的正确性。 相似文献
8.
For the representation of wind farms in transient stability studies of electrical power systems, reduced models based on aggregating identical wind turbines are commonly used. In the case of a wind farm with different wind turbines coupled to the same grid connection point, it is usual to aggregate identical wind turbines operating in similar conditions into an equivalent one. However, in the existing literature, there are not any references to the aggregation of different wind turbines (same wind turbine technology but different rated power or components) into a single one. This paper presents a comparative study of four reduced models for aggregating different DFIG wind turbines, experiencing different incoming winds, into an equivalent model. The first of them is the classical clustering model, in which each equivalent model experiences an equivalent wind. The other reduced models have the same equivalent generation system but different equivalent mechanical systems. Thus, the second and third ones are compound models with a clustering aggregated mechanical system and individual simplified models, respectively, to approximate the individual mechanical power according to the incoming wind speeds. The fourth is a mixed model that uses an equivalent wind speed, which is applied to an equivalent mechanical system (equivalent rotor and drive train) in order to approximate the mechanical power of the aggregated wind turbines. The equivalent models are validated by means of comparison with the complete model of the wind farm when simulated under wind fluctuations and grid disturbances. Finally, recommendations with regard to the applicability of models are established. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
9.
In this paper, double PWM converter AC excitation system of the variable speed constant frequency doubly fed induction generator (DFIG) for wind power generation is taken as the research object. At present, most vector control systems of rotor-side PWM converter adopt feedforward compensation to realize the purpose of power decoupling control. The decoupling effect is greatly affected by the power changes. A power decoupling control strategy based on auto-disturbance rejection control (ADRC) is proposed. The decoupling control between active power and reactive power is realized by observing the coupling term and the total disturbance of the d-axis and q-axis components of the stator current and the stator voltage with the extended state observer and compensating. Simulation analysis and experimental test show that, on the basis of vector transformation, the rotor-side PWM converter power decoupling control based on ADRC has a small overshoot and fast dynamic response when tracking the change of wind turbine input power, which can achieve the decoupling control between active power and reactive power well. The system has strong robustness and adaptability. 相似文献
10.
双馈感应风力发电机的无源性控制方法研究 总被引：1，自引：0，他引：1
基于双馈感应风力发电机Euler-Lagrange系统模型,设计了本质上是非线性反馈的无源性控制(PBC)策略,实现了负载转矩时变未知情形下磁链、转速的渐近跟踪控制.针对实际运行时风力发电机参数具有不确定性的问题,将PBC方法与自适应控制相结合,不仅可实现电机参数摄动时期望电流轨迹的准确跟踪,并可有效抑制由电阻、电感变化引起的跟踪误差.该方法从能量角度分析风力发电控制系统,确定不必抵消的"无功力",设计全局定义的控制律,具有形式简单、无奇异点、鲁棒性好等特点.基于dSPACE 的实验结果证明了该控制策略的有效性. 相似文献
11.
Frequency regulation in a generation mix having large wind power penetration is a critical issue, as wind units isolate from the grid during disturbances with advanced power electronics controllers and reduce equivalent system inertia. Thus, it is important that wind turbines also contribute to system frequency control. This paper examines the dynamic contribution of doubly fed induction generator (DFIG)-based wind turbine in system frequency regulation. The modified inertial support scheme is proposed which helps the DFIG to provide the short term transient active power support to the grid during transients and arrests the fall in frequency. The frequency deviation is considered by the controller to provide the inertial control. An additional reference power output is used which helps the DFIG to release kinetic energy stored in rotating masses of the turbine. The optimal speed control parameters have been used for the DFIG to increases its participation in frequency control. The simulations carried out in a two-area interconnected power system demonstrate the contribution of the DFIG in load frequency control. 相似文献
12.
13.
Due to several factors, wind energy becomes an essential type of electricity generation. The share of this type of energy in the network is becoming increasingly important. The objective of this work is to present the modeling and control strategy of a grid connected wind power generation scheme using a doubly fed induction generator (DFIG) driven by the rotor. This paper is to present the complete modeling and simulation of a wind turbine driven DFIG in the second mode of operating (the wind turbine pitch control is deactivated). It will introduce the vector control, which makes it possible to control independently the active and reactive power exchanged between the stator of the generator and the grid, based on vector control concept (with stator flux or voltage orientation) with classical PI controllers. Various simulation tests are conducted to observe the system behavior and evaluate the performance of the control for some optimization criteria (energy efficiency and the robustness of the control). It is also interesting to play on the quality of electric power by controlling the reactive power exchanged with the grid, which will facilitate making a local correction of power factor. 相似文献
14.
提出了不平衡电网电压下双馈发电机的控制策略,并建立了双馈发电机在正、反旋转坐标系下的数学模型。在此基础上推导和分析了电网电压不平衡条件下双馈发电机输出的瞬时有功、无功功率的组成。提出了4种可供选择的不平衡电压控制方案,并给出了不同控制目标下转子的正、负序电流目标值的计算原则。通过MATLAB/SIMULINK仿真验证了控制方案的有效性。 相似文献
15.
A doubly fed induction generator (DFIG) wind turbine depends on the control of the system at both generator and turbine levels, and the operation of the turbine is affected by the electrical characteristics of the generator and the aerodynamic characteristics of the turbine blades. This paper presents a DFIG energy extraction and control study by combining the two characteristics together in one integrative environment to examine various factors that are critical for an optimal DFIG system design. The generator characteristics are examined for different d‐q control conditions, and the extracted power characteristics of the turbine blades versus generator slip are presented. Then, the two characteristics are analyzed in a joint environment. An integrative study is conducted to examine a variety of parametric data simultaneously for DFIG maximum wind power extraction evaluation. A close‐loop transient simulation using SimPowerSystem is developed to validate the effectiveness of steady‐state results and to further investigate the wind energy extraction and speed control in a feedback control environment. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
16.
The aim of this study is to provide a simplified model of a variable‐speed wind turbine (VSWT) with the technology of a doubly fed induction generator (DFIG), which operates under faulty grid conditions. A simplified model is proposed, which consists of a set of electrical and mechanical equations that can be easily modeled as simplistic electrical circuits. It makes it an excellent tool to achieve fault ride‐through capability of grid‐connected VSWT with DFIGs. Both symmetrical and unsymmetrical grid faults, which cause symmetrical and unsymmetrical voltage sags, have been applied to the system in order to validate the model. The proposed simplified model has been compared with the traditional full‐order model under multiple sags (different durations and depths), and the results reveal that both models present similar accuracy. As the idea is to reduce the computational time required to simulate the machine behavior under faulty grid conditions, the proposed model becomes suitable for that purpose. The analytical study has been validated by simulations carried out with MATLAB . 相似文献
17.
This paper investigates virtual inertia control of doubly fed induction generator (DFIG)‐based wind turbines to provide dynamic frequency support in the event of sudden power change. The relationships among DFIGs' virtual inertia, rotor speed and network frequency variation are analysed, and a novel virtual inertia control strategy is proposed. The proposed control strategy shifts the maximum power point tracking (MPPT) curve to the virtual inertia control curves according to the frequency deviation so as to release the ‘hidden’ kinetic energy and provide dynamic frequency support to the grid. The calculation of the virtual inertia and its control curves are also presented. Compared with a PD regulator‐based inertial controller, the proposed virtual inertia control scheme not only provides fast inertial response in the event of sudden power change but also achieves a smoother recovery to the MPPT operation. A four‐machine system with 30% of wind penetration is simulated to validate the proposed control strategy. Simulation results show that DFIG‐based wind farms can provide rapid response to the frequency deviation using the proposed control strategy. Therefore, the dynamic frequency response of the power grid with high wind power penetration can be significantly improved. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
18.
矩阵式变换器励磁的双馈风力发电机系统 总被引：8，自引：0，他引：8
该文建立了基于双馈电机的变速恒频风力发电系统模型。该系统采用矩阵式变换器作为交流励磁电源，利用定子磁场定向的矢量变换控制实现有功功率和无功功率的独立调节，采用最佳风能控制策略，使系统能够在不同风速下跟踪最大风能曲线，实现风能的有效利用。仿真结果展现了系统的优良特性，在一定程度上验证了该方案的正确性和有效性。 相似文献
19.
This paper proposes a novel control strategy for doubly fed induction generator (DFIG)‐based wind energy conversion system to investigate the potential of enhancing the stability of wind energy transmission system, a synchronous generator weakly integrated to a power system with a DFIG‐based wind farm. The proposed approach uses state feedback to exactly linearize the nonlinear wind energy transmission system from control actions (active power and reactive power control order of DFIG) to selected outputs (power angle and voltage behind transient resistance of synchronous generator) at first. Then, on account of the linearized subsystem, the stability enhancement controller is designed based on linear quadratic regulator algorithm to contribute adequate damping characteristics to oscillations of the synchronous generator system under various operation points. The proposed control strategy successfully deals with the nonlinear behaviors exist from the inputs to outputs and improve the robustness with respect to the variation of system operation points. Furthermore, not only the rotor angle stability but also the voltage stability is enhanced by using the proposed control strategy. The simulation results carried on the studied system verify the effectiveness of the proposed control strategy of wind energy conversion system for system stability enhancement and the robustness against various system operation points. 相似文献