变速恒频风机双PWM变换器协调控制策略研究

为解决变速恒频风机运行中转子侧功率变化频繁,直流母线电压波动剧烈的问题,对双PWM变换器控制策略进行了研究。结合双馈电机的特点,得出了母线负载电流的计算方法,并分析了负载电流前馈策略的不足。提出了一种基于动态功率前馈的新型协调控制策略,特点在于选择控制电压节点作为前馈补偿点,避免了电流环的迟延,并且将双馈电机动态信息整合进入网侧变换器的控制当中。最后建立双PWM励磁的风电机组模型进行仿真验证,结果表明新策略极大改善了直流母线动态特性,因此降低了对变换器中电解电容容量的要求,提高了机组的可靠性。     

双馈风力发电机有功功率和无功功率的滑模解耦控制

发电机有功功率、无功功率的解耦控制是变速恒频双馈风力发电系统的关键技术。分析了双馈异步发电机的动态数学模型,基于定子磁场定向的矢量控制方案,结合滑模控制与比例积分控制,得到一种有效的双馈风力发电机功率解耦控制策略。应用李雅普诺夫稳定性理论研究系统稳定性,建立了MATLAB/Simulink环境下系统的仿真模型。仿真结果表明,该控制方法能够很好地实现双馈发电机有功功率、无功功率的解耦控制,验证了该控制策略及变速恒频双馈风力发电机系统建模的正确性和有效性。     

Study on Dynamic Participation of Wind Turbines in Automatic Generation Control of Power Systems

This article presents the design of optimal automatic generation control regulators for an interconnected power system incorporating dynamic participation of doubly fed induction generator based wind turbines. Two power system models are identified for the investigations. Power system model 1 is a two-area interconnected power system consisting of identical plants with non-reheat turbines, whereas power system model 2 consists of identical plants with non-reheat turbines and dynamic participation of doubly fed induction generator based wind turbines in both areas. An AC tie-line is used as area interconnection in both power system models. The designed optimal automatic generation control regulators are implemented, and the system dynamic responses for various system states are obtained considering a 1% load disturbance in one of the areas. The pattern of closed-loop eigenvalues is also determined to investigate system stability. From the investigations carried out in the work, it is inferred that the incorporation of doubly fed induction generator based wind turbines in both areas has appreciably improved the dynamic performance of the system under consideration. Moreover, system stability is ensured for both power system models.     

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。     

Stability and nonlinear controller analysis of wind energy conversion system with random wind speed

In the recent years, globally wind energy has played a vital role in renewable sources in order to minimize the environmental consequence on power generation, As a result of this, computer models of wind turbines for power system stability studies have been developed and supplied to the consumer. Therefore, the development of such models is of particular consequence for stability of power system, which has been studied and can be structured and integrated into network simulation software are needed. However, in this contribution a nonlinear control design modeling is required to stabilize and analyze wind energy conversion system (WECS) by regulating the electrical frequency and stator voltage amplitude of the squirrel-cage induction generator (SCIG) at random wind speed approach is presented. A design scheme consists of dynamic wind turbine system and 3-phase SCIG unit. In this research study, we employ a unique technique based on feedback linearization technique through field oriented control concepts. The controllers were designed in simulated software Matlab in order to regulate the SCIG constraints. The validation of the developing system models will be appropriate to provide for large system stability and control.     

Residue Theorem based soft sliding modecontrol for wind power generation systems

This paper proposes a residue theorem based soft sliding mode control strategy for a permanent magnet synchronous generator (PMSG) based wind power generation system (WPGS), to achieve the maximum energy conversion and improved in the system dynamic performance. The main idea is to set a soft dynamic boundary for the controlled variables around a reference point. Thus the controlled variables would lie on a point inside the boundary. The convergence of the operating point is ensured by following the Forward Euler method. The proposed control has been verified via simulation and experiments, compared with conventional sliding mode control (SMC) and proportional integral (PI) control.     

基于PSCAD的双馈感应发电机矢量控制研究

在各种风力发电系统方案中,双馈感应电机（DFIG）变速恒频风力发电系统以其独特的优点逐渐成为当今风力发电的主流。在分析双馈电机的数学模型及原理的基础上,建立了基于定子磁链定向矢量控制的双馈感应电机风力发电系统模型。运用目前国外广泛应用的电力系统计算机辅助设计软件PSCAD/EMTDC对该系统进行仿真研究,并分析风力发电机运行时的动态性能。仿真结果表明,该控制方式实现了定子端口有功功率和无功功率的解耦控制,具有良好的控制效果。     

Dynamic stability study of an isolated wind-diesel hybrid power system with wind power generation using IG,PMIG and PMSG: A comparison

This paper presents a comparative study of reactive power control for isolated wind-diesel hybrid power system in three different cases with wind power generation by induction generator (IG), permanent-magnet induction generator (PMIG) and permanent-magnet synchronous generator. The synchronous generator (SG) is used with diesel engine set. A mathematical model of the system based on small signal analysis, is developed considering reactive power flow balance equations. The variable reactive power needed by the system is provided by a static synchronous compensator (STATCOM) when wind power generation is done by IG and PMIG. When permanent-magnet synchronous generator (PMSG) is used for wind power generation, the variable reactive power demand is fulfilled by a voltage source converter (VSC) which is on the load side. A new mathematical approximation model for VSC connected with PMSG is proposed such that the voltage source converter fulfills the increased reactive power requirement of load and also increases its active power equal to the increased input wind power. Proportional and integral (PI) gains of the STATCOM and VSC controllers are optimized using integral square error criterion (ISE). The dynamic responses of the system for small (1%) step increase in load reactive power with and without 1% step increase in input wind power are shown. The paper also shows the dynamic responses of the system for random step change in load reactive power plus random step change in input wind power. The MATLAB/SIMULINK environment is used for simulation.     

风力发电机组动态模型研究

该文针对基于双馈感应发电机的变速风力发电机组轴系的特点，用等效集中质量法和动力学方程建立了其包含机械传动链动态的轴系模型，与发电机动态方程组成8阶微分方程组。该8阶模型同时考虑了风力发电机组的机械和电气动态特性，弥补了现有各种模型过于简化的不足。并与不考虑机械动态的简化模型进行了仿真结果的对比。采用该模型可以更加有效地进行风力发电系统控制系统的设计，以及分析机组在各种运行工况下的动态行为。     

A Study of Hydrogen Generation with Doubly‐Fed Adjustable Speed Wind Generator

This paper presents a combination system for wind power generation and hydrogen generation. In the proposed system, a doubly‐fed synchronous generator (DFSG) is used as an adjustable speed wind generator, and an electrolyzer is connected to its terminals for hydrogen generation, which is controlled by power electronic converters. The output power from the wind generator is smoothed and supplied to the power system as well as to the electrolyzer to generate hydrogen under cooperative control between the wind generator and the electrolyzer. The performance of the proposed system is investigated by simulation analyses, in which simulations are performed using PSCAD/EMTDC. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(3): 27–36, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21003     

风电机组对电力系统暂态稳定性影响分析

风电机组作为环境友好型发电的最大来源在电网中的规模日益扩大,必将影响电力系统的稳定性。文章首先对比了恒速异步(CSWT),双馈变速(DFIG)及直驱同步(DDSG)等市场上广为应用的三种风电机组的结构,分析了各个机组的降阶数学模型;通过一款基于Matlab的电力系统分析工具箱PSAT研究了不同故障持续时间下的风电机组暂态稳定性和系统暂态稳定性,对三种机组及其系统的暂态稳定性进行了分析对比;最后讨论了风力发电机组参数对机组暂态稳定性的影响,得知,发电机参数Rr的增加和Xr、Xs的减小有利于恒速风电机组暂态稳定性的提高,Xm、Rs对机组暂态稳定性影响不明显。     

电池储能系统用于改善并网风电场电能质量和稳定性的研究

建立了基于等效电路的电池储能系统和基于异步发电机风力发电系统的整体动态数学模型,设计了相应的控制策略,并以随机风和电网大扰动为例,采用电池储能系统对并网风电场的电能质量和稳定性问题进行仿真。结果表明采用该控制策略的电池储能系统可很好地改善并网风电场的电能质量和稳定性。     

双馈式风力发电系统的机电暂态建模与运行分析

为了准确分析双馈式风力发电系统及其在电网中的运行特性,建立了该系统的机电暂态模型。应用机理建模方法建立了风力机、机械转动装置和双馈异步发电机等双馈式风力发电系统各组件的数学模型和桨距角控制模型。基于电磁暂态模型结合机电运行特性建立了转子侧和网侧的变流器控制系统模型。在此基础上,在PSASP7.0建模系统中构建了完整的双馈式风力发电系统的UD模型。将该UD模型应用于含双馈式风力发电的单机无穷大系统中,对风速变化和电网故障等情形进行了仿真分析,结果表明所建模型能正确反映系统的机电暂态特性和运行特性。     

直驱永磁风力发电系统仿真与优化控制

分析了直驱永磁风力发电系统的基本原理及各模块的控制策略,在Matlab/Simulink中搭建风电系统及其控制器的仿真模型,仿真验证了模型的正确性。在发电机精确模型的基础上,忽略发电机定子暂态得到实用模型,并对两种模型的适用性进行讨论。仿真分析表明:当分析发电机本身的动态问题时,可采用精确模型;当进行并网计算时,实用模型和精确模型均可以准确描述。最后利用粒子群算法对直驱永磁风力发电系统中的控制器参数进行优化,提高了系统的动态特性,实验结果验证了该直驱永磁风力发电系统控制器参数优化方法的有效性和可行性。     

Jointly improving energy efficiency and smoothing power oscillations of integrated offshore wind and photovoltaic power: a deep reinforcement learning approach

This paper proposes a novel deep reinforcement learning (DRL) control strategy for an integrated ofshore wind and photovoltaic (PV) power system for improving power generation efciency while simultaneously damping oscillations. A variable-speed ofshore wind turbine (OWT) with electrical torque control is used in the integrated ofshore power system whose dynamic models are detailed. By considering the control system as a partially-observable Markov decision process, an actor-critic architecture model-free DRL algorithm, namely, deep deterministic policy gradient, is adopted and implemented to explore and learn the optimal multi-objective control policy. The potential and efectiveness of the integrated power system are evaluated. The results imply that an OWT can respond quickly to sudden changes of the infow wind conditions to maximize total power generation. Signifcant oscillations in the overall power output can also be well suppressed by regulating the generator torque, which further indicates that complementary operation of ofshore wind and PV power can be achieved.     

双馈异步风力发电机组运行特性仿真分析

在分析双馈异步风力发电机组整体模型结构的基础上,引入了交流励磁变速恒频风力发电系统中基于定子磁链定向和定子电压定向的矢量变换控制技术,针对双馈风力发电机的变速恒频、最大风能捕获和有功无功解耦运行的需求,建立基于PSCAD/EMTDC软件的双馈异步风力发电机组仿真模型.仿真结果验证了模型在实现追踪最大风能的变化和有功、无功解耦控制功能上的有效性.     

Real power and frequency control of a small isolated power system

This paper describes the dynamic analysis of a small isolated power system comprising a wind turbine generator and a diesel generator. The analysis is carried out in time domain considering simplified models of the system components by taking into account the wind turbine pitch controller and the diesel engine speed governor. Wind disturbance model consisting components of gusting of wind, rapid ramp changes and random noise. The wind generator is always operated with its rated power and the additional power required by the load is supplied by the diesel generator. For better dynamic performances of wind–diesel system under wind and load disturbance conditions, two control schemes are used. In the first case, a proportional–integral (P–I) controller and in the second case a proportional–integral–derivative (P–I–D) controller are used. Gain parameters of these controllers are optimized using genetic algorithm (GA) and Particle swarm optimization (PSO) considering two different objective functions and the results are compared. The sensitivity analysis of the wind diesel system is carried out for parameter uncertainties and the stability of the system is analyzed using D-stability criterion. Analysis is also carried out to examine the effect of power injection to a 69 bus radial distribution network by wind–diesel isolated system.     

无源高阶终端滑模控制双馈风力发电系统

为了简化双馈风力发电系统模型并且使得系统具有抗干扰的特性,依据无源性理论和滑模控制理论从能量和鲁棒性的角度研究了变速恒频双馈风力发电系统.首先建立了基于Euler La-grange (EL)方程的双馈风电系统数学模型,使得双馈风电系统分解为电气和机械两个无源子系统的反馈互联.在设计控制器时只需考虑电气子系统,而机械子系统是一个能量耗散系统,通过选择适合的参数可以保证稳定,因此简化了控制算法.针对速度环响应速度慢,鲁棒性差的问题设计了高阶非奇异滑模速度控制器.仿真结果表明了所提控制算法简单有效,能够保证风力发电系统输出恒定频率的同时,电机转速也能快速的跟踪参考转速,提高了整个系统的动静态性能.     

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。     

Sliding mode control of a dual-stator induction generator for wind energy conversion systems

This paper presents a sliding mode control (SMC) associated to the field oriented control (FOC) of a dual-stator induction generator (DSIG) based wind energy conversion systems (WECSs). The DSIG has two sets of stator three-phase windings spatially shifted by 30 electrical degrees. The study of operation of the wind turbine leads us to two essential cases: optimization of the power for wind speeds lower than the nominal speed of the turbine and limitation of the power for higher speeds. Conventional electrical grid connected WECS present interesting control demands, due to the intrinsic nonlinear characteristic of wind mills and electric generators. The SMC is a robust nonlinear algorithm which uses discontinuous control to force the system states trajectories to join some specified sliding surface, it has been widely used for its robustness to model parameter uncertainties and external disturbances, is studied. In order to verify the validity of the proposed method, a dynamic model of the proposed system has been simulated, to demonstrate its performance.