不平衡电网条件下双馈风力发电机预测控制研究

发布时间：2018-05-27 09:03

本文选题：电网电压不平衡 + 双馈感应发电机　；参考：《华北电力大学(北京)》2016年硕士论文

【摘要】：随着风力发电产业的快速发展,风力发电在电力能源结构中所占的比重逐年增长,对电网的影响也愈发明显。在现代风力发电系统中,双馈感应发电机(Doubly-fed Induction Generator, DFIG)的控制需要实现高效率以及高负荷跟踪性能。当电网出现不平衡现象时,会引起发电系统中有功功率,无功功率以及电磁转矩的二倍频脉动振荡现象,严重影响到整个风电系统的安全与稳定。模型预测控制(Model Predictive Control, MPC)则是一种先进的控制策略,在电网不平衡时可以优化双馈发电机的控制操作。它能够直接处理耦合多变量系统,直接考虑对象未来行为特征及输出变量的约束条件,以及对控制律进行最优处理。本文具体分析了电网发生不平衡现象的原因,建立了电网电压不平衡状态下双馈发电机在正转、反转同步速旋转坐标系中的四输入四输出非线性状态空间模型,设计了转子电流不平衡控制方案,推导了转子正、负序电流的计算原则,并构造了相应的非线性模型预测控制器。其中,目标函数综合考虑了功率有效值的跟踪指标以及消除有功功率脉动及无功功率脉动能力的指标。通过控制转子电流的正、负序分量来追踪各变量的参考值,并抑制住功率二倍频脉动。该预测值可通过输入输出反馈线性化(Input-Output Feedback Linearization, IOFL)的策略来计算。最终,仿真实验结果证明了此非线性预测控制器的有效性。
[Abstract]:With the rapid development of wind power generation industry, the proportion of wind power generation in the power energy structure is increasing year by year, and the impact on power grid is becoming more and more obvious. In modern wind power system, Doubly-Federal Induction Generator, DFIG) control of doubly-fed induction generator needs to achieve high efficiency and high load tracking performance. When the power system is unbalanced, it will cause the oscillation of active power, reactive power and electromagnetic torque, which will seriously affect the safety and stability of the whole wind power system. Model predictive control model Predictive Control, MPC) is an advanced control strategy, which can optimize the control operation of doubly-fed generator when the power network is unbalanced. It can directly deal with coupled multivariable systems, directly consider the future behavior characteristics of the object and the constraints of the output variables, as well as the optimal treatment of the control law. In this paper, the causes of power grid unbalance are analyzed in detail, and the nonlinear state space model of four inputs and four outputs of doubly-fed generator in the synchronous rotating coordinate system is established under the condition of voltage unbalance. The control scheme of rotor current imbalance is designed, and the calculation principle of rotor positive and negative sequence current is deduced, and the corresponding nonlinear model predictive controller is constructed. The objective function synthetically considers the tracking index of the effective value of power and the index of eliminating the active power pulsation and reactive power pulsation. The reference values of each variable are tracked by controlling the positive and negative sequence components of the rotor current, and the power double frequency pulsation is suppressed. The predicted value can be calculated by the input and output feedback linearization strategy of input-output Feedback Linearization, IOFL). Finally, the simulation results show the effectiveness of the nonlinear predictive controller.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM315;TP273

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