In this paper, global synchronization is discussed for a general class of delayed neural networks with time-varying and distributed delays. Furthermore, the activation func- tions in the neural networks can be differe...In this paper, global synchronization is discussed for a general class of delayed neural networks with time-varying and distributed delays. Furthermore, the activation func- tions in the neural networks can be different type. Based on the drive-response concept and the Lyapunov stability theorem, some sufficient criteria are obtained to guarantee the global synchronization of the considered models even when input sector nonlinearity caused by physical limitations is presented in response systems. Finally, a typical example is also given to illustrate the effectiveness of the proposed synchronization scheme.展开更多
Based on the quadratic supply rate, the problem of robust dissipative control for a class of uncertain nonlinear system with sector nonlinear input is discussed. The uncertainty is described by bounded norm. It is sho...Based on the quadratic supply rate, the problem of robust dissipative control for a class of uncertain nonlinear system with sector nonlinear input is discussed. The uncertainty is described by bounded norm. It is shown that the robust dissipative control problem can be resolved for all admissible uncertainty, if there exists a storage function such that Hamilton Jacobi inequality holds. When the uncertainties of the system satisfy the matching condition, and input function within the boundedness of the sector, the closed loop system will be stronger dissipativeness, and the controller which we obtained in the paper is more flexible, because it contains an adjustable parameter for some certain range.展开更多
The paper shows that a control strategy with disturbance rejection is able to reduce the control effort to a minimum, ensuring at the same time a desired performance level. The disturbance to be rejected is completely...The paper shows that a control strategy with disturbance rejection is able to reduce the control effort to a minimum, ensuring at the same time a desired performance level. The disturbance to be rejected is completely unknown, except for a sectorial bound. The control unit is endowed with an extended state observer which includes a disturbance dynamics, whose state tracks the unknown disturbance to be rejected. In summary, the novel contributions of the paper are the following. First, we derive a robust stability condition for the proposed control scheme, holding for all the nonlinearities that are bounded by a known （or estimated） maximum slope. Second, we propose a novel approach for designing the observer and state feedback gains, which guarantee robust closed-loop stability. Third, we show that the designed control system yields, with a minimum control effort, the same control performance as a robust state feedback control, which on the contrary may require a larger command activity. Two simulated case studies are presented to show the effectiveness of the proposed approach.展开更多
A nonlinear differential equation system with nonlinearities of a sector type is studied. Using the Lyapunov direct method and the comparison method, conditions are derived under which the zero solution of the system ...A nonlinear differential equation system with nonlinearities of a sector type is studied. Using the Lyapunov direct method and the comparison method, conditions are derived under which the zero solution of the system is stable with respect to all variables and asymptotically stable with respect to a part of variables. Moreover, the impact of nonstationary perturbations with zero mean values on the stability of the zero solution is investigated. In addition, the corresponding time-delay system is considered for which delay-independent partial asymptotic stability conditions are found. Three examples are presented to demonstrate effectiveness of the obtained results.展开更多
为了实现“双碳”战略目标,推动我国能源转型,实现海上风电等大规模新能源的安全可靠送出成为研究关键。柔性低频输电系统通过降低输电频率来提高输送能力并节省经济成本,逐渐成为“新型电力系统”中除传统工频输电和直流输电方式之外...为了实现“双碳”战略目标,推动我国能源转型,实现海上风电等大规模新能源的安全可靠送出成为研究关键。柔性低频输电系统通过降低输电频率来提高输送能力并节省经济成本,逐渐成为“新型电力系统”中除传统工频输电和直流输电方式之外的有益补充。但是,柔性低频输电系统的稳定性问题,尤其是大信号稳定性问题仍是工程实践中的难题。为此,采用Lyapunov直接法对基于模块化多电平矩阵换流器(modular multilevel matrix converter,M3C)的柔性低频输电系统进行了大信号稳定性分析。首先针对系统非线性状态方程阶数较高,导致难以通过经验或者线性系统Jacobian矩阵方法直接构造能量函数的难题,通过扇区非线性方法建立了模糊模型,简洁快速地构建了系统能量函数并计算了大信号稳定吸引域(large signal domain of attraction,LS-DOA)。其次引入多维空间吸引域的映射方法,从频率差异的角度更加直观地揭示了主电路和控制系统等参数对系统大信号稳定性的影响。然后结合线性矩阵不等式(linear matrix inequality,LMI)凸优化理论,分析了系统大信号不稳定的相关机理并给出了高效的镇定策略。最后通过MATLAB/Simulink建立了系统模型,实现了对理论分析的仿真验证,研究结果对柔性低频输电系统的工程实践有一定的参考作用。展开更多
文摘In this paper, global synchronization is discussed for a general class of delayed neural networks with time-varying and distributed delays. Furthermore, the activation func- tions in the neural networks can be different type. Based on the drive-response concept and the Lyapunov stability theorem, some sufficient criteria are obtained to guarantee the global synchronization of the considered models even when input sector nonlinearity caused by physical limitations is presented in response systems. Finally, a typical example is also given to illustrate the effectiveness of the proposed synchronization scheme.
基金the National Natural Science Foundation of China(6987401569934030)and Foundation of the Education Department of Hubei Province(99A121)
文摘Based on the quadratic supply rate, the problem of robust dissipative control for a class of uncertain nonlinear system with sector nonlinear input is discussed. The uncertainty is described by bounded norm. It is shown that the robust dissipative control problem can be resolved for all admissible uncertainty, if there exists a storage function such that Hamilton Jacobi inequality holds. When the uncertainties of the system satisfy the matching condition, and input function within the boundedness of the sector, the closed loop system will be stronger dissipativeness, and the controller which we obtained in the paper is more flexible, because it contains an adjustable parameter for some certain range.
文摘The paper shows that a control strategy with disturbance rejection is able to reduce the control effort to a minimum, ensuring at the same time a desired performance level. The disturbance to be rejected is completely unknown, except for a sectorial bound. The control unit is endowed with an extended state observer which includes a disturbance dynamics, whose state tracks the unknown disturbance to be rejected. In summary, the novel contributions of the paper are the following. First, we derive a robust stability condition for the proposed control scheme, holding for all the nonlinearities that are bounded by a known （or estimated） maximum slope. Second, we propose a novel approach for designing the observer and state feedback gains, which guarantee robust closed-loop stability. Third, we show that the designed control system yields, with a minimum control effort, the same control performance as a robust state feedback control, which on the contrary may require a larger command activity. Two simulated case studies are presented to show the effectiveness of the proposed approach.
基金was supported by the Saint Petersburg State University(9.42.1045.2016)the Russian Foundation for Basic Research(15-58-53017 and 16-01-00587)the Natural Science Foundation of China(6141101096,61573030,and 61273006)
文摘A nonlinear differential equation system with nonlinearities of a sector type is studied. Using the Lyapunov direct method and the comparison method, conditions are derived under which the zero solution of the system is stable with respect to all variables and asymptotically stable with respect to a part of variables. Moreover, the impact of nonstationary perturbations with zero mean values on the stability of the zero solution is investigated. In addition, the corresponding time-delay system is considered for which delay-independent partial asymptotic stability conditions are found. Three examples are presented to demonstrate effectiveness of the obtained results.
文摘为了实现“双碳”战略目标,推动我国能源转型,实现海上风电等大规模新能源的安全可靠送出成为研究关键。柔性低频输电系统通过降低输电频率来提高输送能力并节省经济成本,逐渐成为“新型电力系统”中除传统工频输电和直流输电方式之外的有益补充。但是,柔性低频输电系统的稳定性问题,尤其是大信号稳定性问题仍是工程实践中的难题。为此,采用Lyapunov直接法对基于模块化多电平矩阵换流器(modular multilevel matrix converter,M3C)的柔性低频输电系统进行了大信号稳定性分析。首先针对系统非线性状态方程阶数较高,导致难以通过经验或者线性系统Jacobian矩阵方法直接构造能量函数的难题,通过扇区非线性方法建立了模糊模型,简洁快速地构建了系统能量函数并计算了大信号稳定吸引域(large signal domain of attraction,LS-DOA)。其次引入多维空间吸引域的映射方法,从频率差异的角度更加直观地揭示了主电路和控制系统等参数对系统大信号稳定性的影响。然后结合线性矩阵不等式(linear matrix inequality,LMI)凸优化理论,分析了系统大信号不稳定的相关机理并给出了高效的镇定策略。最后通过MATLAB/Simulink建立了系统模型,实现了对理论分析的仿真验证,研究结果对柔性低频输电系统的工程实践有一定的参考作用。
