电网阻抗自适应的风电变流器稳定控制方法研究

发布时间：2018-05-25 21:10

本文选题：并网逆变器 + 电网阻抗　；参考：《上海电机学院》2017年硕士论文

【摘要】：随着传统非可再生能源总量不断减少和环境污染等问题的日益加剧,促使了以风能、太阳能等为代表的可再生能源的研发和利用。风电变流器是风力发电机所发电能并入电网的必经环节,但在连接变流器与电网的输电网络中存在的电网阻抗会影响到变流器的稳定控制,因此,需要对考虑电网阻抗时维持风电变流器稳定控制的方法进行研究,主要内容为:(1)在建立三相带LCL滤波的并网逆变器数学模型基础上,分析了两相静止坐标系下的并网逆变器控制系统,推导了并网逆变器控制系统中电流环的开环传递函数,利用MATLAB仿真分析加入电网阻抗前后控制系统的稳定性。(2)在注入非特征谐波、利用系统固有谐波以及基于复数滤波器的测量原理的基础上,研究了一种改进的注入非特征谐波测量阻抗的方法,并在MATLAB/SIMULINK中搭建仿真模型,仿真验证了该方法可以实现电网阻抗的测量。(3)在考虑电网阻抗时,分析三相并网逆变系统中控制参数的设计过程,得出了控制参数与电网阻抗的关系表达式,仿真验证表明,适应阻抗变化的控制参数起到维持控制系统稳定的作用。(4)基于控制参数与电网阻抗的关系,设计了电网阻抗自适应的并网逆变系统控制结构,并在MATLAB/SIMULINK中搭建仿真模型,仿真结果表明,与控制参数不随阻抗变化时相比,根据电网阻抗的变化来调节系统控制参数,可以较好的维持三相并网逆变系统的稳定。
[Abstract]:With the decrease of the total amount of traditional non-renewable energy and the worsening of environmental pollution, the research and development and utilization of renewable energy, such as wind energy and solar energy, have been promoted. Wind power converter is a necessary link for wind power generation to merge into the power grid. However, the network impedance existing in the transmission network connecting the converter and the power grid will affect the stability control of the converter. It is necessary to study the method of maintaining the stability control of wind converter when considering the impedance of power network. The main content is: 1) based on the mathematical model of three-phase grid-connected inverter with LCL filter, The control system of grid-connected inverter in two-phase static coordinate system is analyzed, and the open-loop transfer function of current loop in grid-connected inverter control system is derived. MATLAB simulation is used to analyze the stability of the control system before and after adding impedance to the power network. Based on the injection of non-characteristic harmonics, the inherent harmonics of the system and the measurement principle based on complex filter, the stability of the control system is analyzed. An improved method for measuring impedance by injecting non-characteristic harmonics is studied, and a simulation model is built in MATLAB/SIMULINK. The simulation results show that the method can be used to measure the impedance of power network. The design process of control parameters in three-phase grid-connected inverter system is analyzed, and the relationship between control parameters and grid impedance is obtained. The simulation results show that, Based on the relation between control parameters and grid impedance, the control structure of grid impedance adaptive grid-connected inverter system is designed, and the simulation model is built in MATLAB/SIMULINK. The simulation results show that the stability of the three-phase grid-connected inverter system can be maintained better by adjusting the control parameters according to the change of the impedance of the power network than when the control parameters do not change with the impedance.
【学位授予单位】：上海电机学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46

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