| | | 应用延时反馈控制电力系统混沌振荡
| | 中国电力论文 摘 要:混沌是非线性系统的中国电力论文固有现象。电力系统是典型的中国电力论文非线性系统,存在着复杂的混沌振荡,它威胁着系统的安全稳定运行。本文利用混沌控制方法之一——延迟反馈法(DFC)控制电力系统混沌振荡,利用Melnikov方法确定延迟时间和反馈系数。数字仿真结果表明,选择适当的延迟时间和反馈系数能够镇定系统的不稳定周期轨道(UPO)、消除混沌,并能使系统从失稳状态进入稳定状态。由于不需要外加参考信号,延迟时间与UPO的周期无关,不必是UPO周期的整数倍,所以该方法简单易行。 关键词:混沌振荡;延迟反馈控制;电力系统稳定性 CONTROLLING POWER SYSTEM CHAOTIC OSCILLATION BY TIME-DELAYED FEEDBACK ABSTRACT: Chaos is an inherent phenomenon of nonlinear systems. Power system is a typical nonlinear system where complicated chaotic oscillations exist and threaten the secure and stable operation of power systems. Here, the power system chaotic oscillation is controlled by one of chaotic control ways, i.e., time-delayed feedback control (DFC), and the delayed time and gain coefficient are determined by Melnikov’s method. Simulation result shows that choosing proper delayed time and gain coefficient the unstable periodic orbits (UPO) of the system can be ballasted and the chaos can be eliminated, and the system can be changed from unstable to stable. Because the additional reference signal is not necessary, the delayed time is not related to the period of UPO and should not be the integral multiple of the period of UPO, so the presented method is simple and easy to apply. KEY WORDS: Chaotic oscillation;Time-delayed feedback control; Power system stability 1 引言 电力系统是典型的非线性系统,具有复杂的动 力学行为,如混沌和分岔,它们对电力系统构成了潜在的威胁,已引起国内外学者的高度重视[1]。 混沌是由确定性非线性系统产生、对初值极为敏感、具有内在随机性和长期预测不可能性的往复非周期运动。随着人们对混沌现象认识的深入,混沌的控制方法应运而生。自从20世纪90年代初出现了混沌控制的OGY(Ott,Grebogi,Yorke)法(参数扰动法)以来,混沌控制受到广泛的关注,相继出现了偶然比例反馈(Occasional Proportional Feedback,OPF)、自适应控制、线性反馈控制、自控制反馈控制等方法 [2]。在这些方法中,由K. Pyragas提出的延迟反馈控制法(Time-delayed Feedback Control,DFC)具有广泛的适应性,它利用简单的反馈来镇定混沌吸引子不稳定的周期轨道(Unstable Periodic Orbits,UPO),既适用于低维系统混沌的控制,也适用于高维系统和无限维延迟微分动力系统混沌的控制,甚至可用于时空混沌的控制[3]。
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