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双馈风电机组参与电力系统频率调节的综合控制方法研究
Research on the Integrated Control Method of Doubly-fed Induction Generator Participating in Power System Frequency Regulation
【作者】 陈斌；
【导师】 康积涛；
【作者基本信息】 西南交通大学 ， 电气工程， 2018， 硕士
【摘要】 随着传统能源的枯竭和环境污染的加剧,风力发电正在快速发展,风电的并网容量也在逐渐增大。双馈异步风力发电机(Doubly-Fed Induction Generator,DFIG)作为风力发电的主流机型,其转子侧经变换器接入电网导致转子转速与电网频率解耦控制,大量的DFIG并网时将导致系统的调频能力减弱,而且风能的不稳定性也会影响DFIG并网系统的稳定性。因此,研究DFIG参与电网的调频控制方法,以及与传统同步发电机协调调频的控制策略变得尤为重要和紧迫。本文以DFIG并网系统为研究基础,对DFIG的调频控制方法及其与飞轮储能装置、同步发电机综合调频的控制策略进行了相应研究。本文将超速减载控制与转子惯性控制结合对DFIG进行协调控制,利用超速减载控制为DFIG提供调频备用容量,转子惯性控制响应系统频率的变化,使DFIG具备良好的调频能力。通过理论推导得出了协调控制中下垂系数、惯量系数的整定公式,改进并设计了一种变参数整定的协调控制方法,使DFIG参与系统调频时能响应风速的变化调整其调频出力。对风速进行分段研究,结合变参数整定的协调控制与变桨距技术,制定了多风速段下DFIG参与系统一次调频的控制策略,并在MATLAB/Simulink仿真平台中搭建4机2区域系统模型进行了仿真验证。仿真结果表明变参数整定的协调控制方法能够响应风速的变化并很好地参与系统频率的调节,而且多风速段下DFIG参与系统一次调频的控制策略能够提升DFIG的调频效果。为了改善风能的不稳定导致DFIG输出功率波动的问题,搭建了DFIG-飞轮储能系统,利用飞轮储能装置的充放电过程来平滑DFIG输出功率的波动,辅助参与系统频率的调节,并设计了不同风速下飞轮储能装置调频容量需求的计算方法。为了配合同步发电机的调频能力,理论分析了DFIG并网系统的调频特性,制定了DFIG并网系统下的综合调频控制策略,并在MATLAB/Simulink仿真平台中搭建4机2区域系统模型进行了仿真验证。仿真结果表明,飞轮储能装置能改善DFIG输出功率的不稳定并能参与系统调频,而且DFIG并网系统下的综合调频控制策略能够减小同步发电机的调频压力,减小弃风,调频效果良好。
【Abstract】 With the depletion of traditional energy sources and the intensification of environmental pollution,wind power generation is rapidly developing,and the grid-connected capacity of wind power is also gradually increasing.Doubly-Fed Induction Generator(DFIG)is the mainstream model of wind power generation.The rotor side is connected to the grid by the converter,which results in the decoupling control of the rotor speed and the grid frequency.When a large number of DFIG are connected to the grid,it will lead to the frequency modulation capability of the system is weakened,and wind energy instability also affects the stability of the DFIG grid-connected system.Therefore,it is very important and urgent to study the frequency modulation control method of DFIG participating in the power grid and the control strategy of coordinate frequency modulation with traditional synchronous generator.Based on the research of DFIG grid-connected system,this paper researches the frequency modulation control method of DFIG and the control strategy of integrated frequency modulation of flywheel energy storage device and synchronous generator.This paper combines the speeding load shedding control with the rotor inertial control to coordinate the control of the DFIG.The speeding load shedding control is used to provide the DFIG with the frequency modulation reserve capacity.The rotor inertial control response system frequency changes make the DFIG have good frequency modulation capability.The derivation formulas for the droop coefficient and inertia coefficient in the coordinated control are obtained through theoretical derivation,and a coordinated control method for variable parameter tuning is improved and designed so that the DFIG can adjust its frequency output in response to the change of wind speed when it participates in system frequency modulation.A segmented study of wind speed,combined with coordinated control of variable parameter setting and variable pitch technology,developed a control strategy for DFIG participating in system frequency tuning at multiple wind speeds,and built a 4-machine 2-area system model in the MATLAB/Simulink simulation platform.The simulation results show that the coordinated control method for variable parameter tuning can respond to the change of wind speed and participate in the adjustment of the system frequency.Moreover,the control strategy of DFIG participating in the first frequency modulation of the system at multiple wind speeds can improve the frequency regulation effect of DFIG.In order to improve the instability of wind power caused by the fluctuation of DFIG output power,a DFIG-flywheel energy storage system was built to use the charging and discharging process of the flywheel energy storage device to smooth the fluctuation of DFIG output power,assist in the regulation of the system frequency,and designed calculating method of frequency modulation capacity of flywheel energy storage device under different wind speeds.In order to match the frequency modulation capability of the synchronous generator,theoretically analyzed the frequency modulation characteristics of the DFIG grid-connected system,developed a comprehensive frequency modulation control strategy based on the DFIG grid-connected system,and built a 4-machine 2-area system model in the MATLAB/Simulink simulation platform.The simulation results show that the flywheel energy storage device can improve the instability of the DFIG output power and participate in the system frequency modulation.Moreover,the integrated frequency modulation control strategy under the DFIG grid-connection system can reduce the frequency modulation pressure of the synchronous generator,reduce the wind rejection,and the frequency modulation effect is well.