With system parameters falling into a certain area, power system with excitation limits experiences complicated chaotic oscillations which threaten the secure and stable operation of power system. In this paper, to co...With system parameters falling into a certain area, power system with excitation limits experiences complicated chaotic oscillations which threaten the secure and stable operation of power system. In this paper, to control these unwanted chaotic oscillations, a straightforward adaptive chaos controller based on Lyapunov asymptotical stability theory is designed. Since the presented controller does not need to change the controlled system structure and not to use any information of system except the system state variables, the designed controller is simple and desirable. Simulation results show that the proposed control law is very effective. This work is helpful to maintain the power system＇s security operation.展开更多
Suppression of the dynamic oscillations of tie-line power exchanges and frequency in the affected interconnected power systems due to loading-condition changes has been assigned as a prominent duty of automatic genera...Suppression of the dynamic oscillations of tie-line power exchanges and frequency in the affected interconnected power systems due to loading-condition changes has been assigned as a prominent duty of automatic generation control(AGC). To alleviate the system oscillation resulting from such load changes, implementation of flexible AC transmission systems(FACTSs) can be considered as one of the practical and effective solutions. In this paper, a thyristor-controlled series compensator(TCSC), which is one series type of the FACTS family, is used to augment the overall dynamic performance of a multi-area multi-source interconnected power system. To this end, we have used a hierarchical adaptive neuro-fuzzy inference system controller-TCSC(HANFISC-TCSC) to abate the two important issues in multi-area interconnected power systems, i.e., low-frequency oscillations and tie-line power exchange deviations. For this purpose, a multi-objective optimization technique is inevitable. Multi-objective particle swarm optimization(MOPSO) has been chosen for this optimization problem, owing to its high performance in untangling non-linear objectives. The efficiency of the suggested HANFISC-TCSC has been precisely evaluated and compared with that of the conventional MOPSO-TCSC in two different multi-area interconnected power systems, i.e., two-area hydro-thermal-diesel and three-area hydro-thermal power systems. The simulation results obtained from both power systems have transparently certified the high performance of HANFISC-TCSC compared to the conventional MOPSO-TCSC.展开更多
The parameters of power system slowly change with time due to environmental effects or may change rapidly due to faults. It is preferable that the control technique in this system possesses robustness for various faul...The parameters of power system slowly change with time due to environmental effects or may change rapidly due to faults. It is preferable that the control technique in this system possesses robustness for various fault conditions and disturbances. The used flexible alternating current transmission system （FACTS） in this paper is an advanced super-conducting magnetic energy storage （ASMES）. Many control techniques that use ASMES to improve power system stability have been proposed. While fuzzy controller has proven its value in some applications, the researches applying fuzzy controller with ASMES have been actively reported. However, it is sometimes very difficult to specify the rule base for some plants, when the parameters change. To solve this problem, a fuzzy model reference learning controller （FMRLC） is proposed in this paper, which investigates multi-input multi-output FMRLC for time-variant nonlinear system. This control method provides the motivation for adaptive fuzzy control, where the focus is on the automatic online synthesis and tuning of fuzzy controller parameters （i.e., using online data to continually learn the fuzzy controller that will ensure that the performance objectives are met）. Simulation results show that the proposed robust controller is able to work with nonlinear and nonstationary power system （i.e., single machine-infinite bus （SMIB） system）, under various fault conditions and disturbances.展开更多
The problem of robust stabilization for nonlinear systems with partially known uncertainties is considered in this paper. The required information about uncertainties in the system is merely that the uncertainties are...The problem of robust stabilization for nonlinear systems with partially known uncertainties is considered in this paper. The required information about uncertainties in the system is merely that the uncertainties are bounded, but the upper bounds are incompletely known. This paper can be viewed as an extension of the work in reference [1]. To compensate the uncertainties, an adaptive robust controller based on Lyapunov method is proposed and the design algorithm is also suggested. Compared with some previous controllers which can only ensure ultimate uniform boundedness of the systems, the controller given in the paper can make sure that the obtained closed-loop system is asymptotically stable in the large. Simulations show that the method presented is available and effective.展开更多
Utilizing the feature of quick response of HVDC to improve the performance of AC/DC system has become the emphasis to be researched.This paper intro-duces firstly the principle of the robust adaptive control of nonlin...Utilizing the feature of quick response of HVDC to improve the performance of AC/DC system has become the emphasis to be researched.This paper intro-duces firstly the principle of the robust adaptive control of nonlinear systems with unmodeled dynamics,then devel-oped the robust adaptive additional control of HVDC with unmodeled dynamics of generator in order to improve sta-bility of power system.The additional control of HVDC with unmodeled dynamics only uses the local signals and its design is simple,furthermore it can obviously improve the stability of power system in different operational conditions.Experimental results using the presented concepts obtained on single machine infinite bus model are also included.These results prove the efficiency of the control scheme.The design process of controller provided a new idea to design controller by use of simplified model.展开更多
This paper provides an OpenMP-based parallel Very Dishonest Newton(VDHN) algorithm with variable step size,running transient stability simulations(TSA) on multi-core computers.Under the framework of simultaneous solut...This paper provides an OpenMP-based parallel Very Dishonest Newton(VDHN) algorithm with variable step size,running transient stability simulations(TSA) on multi-core computers.Under the framework of simultaneous solution method of TSA,the step-size control strategy is used according to the local truncation error theory firstly.Then,computation of the generation units,which is the most time-consuming part of the simulation,is dynamically dispatched to several cores using an α dynamic scheduling scheme to obtain workload balancing based on OpenMP.Due to the convergence of Newton-type iterations,an adaptive Jacobian update control strategy is applied to reduce the sequential part of the simulation and the overhead generated by OpenMP.Several large scale test cases verify the validity and practicability of the proposed parallel algorithm,showing that the proposed approach achieves high speed-up and a considerable reduction in parallel overheads.展开更多
This paper introduces a new adaptive neural network-based sliding mode control of rotary inverted pendulum system(RIPS)subject to model uncertainties and disturbances.First,the sliding mode control is designed using t...This paper introduces a new adaptive neural network-based sliding mode control of rotary inverted pendulum system(RIPS)subject to model uncertainties and disturbances.First,the sliding mode control is designed using the double power rate reaching law.Second,an adaptive neural network(ANN)is exploited to deal with model uncertainties and disturbances.The weight matrices of the neural network are adaptively tuned.In the proposed control method the exact dynamic model of the RIPS is not required due to the exploitation of the universal property of the neural network.Moreover,the implementation of a double power-reaching law can greatly suppress the undesirable chattering.The convergence and stability analysis is validated using Lyapunov stability theory.Finally,the robustness and excellence of the proposed control strategy are verified by comparing the system performance with the existing SMC method and improved super-twisting SMC method.展开更多
A micro-extended-analog-computer （uEAC） is developed on the basis of Rubel＇ s extended analog computer（EAC） model. Through the uEAC mathematical model, the resistance properties of the conductive sheet, several f...A micro-extended-analog-computer （uEAC） is developed on the basis of Rubel＇ s extended analog computer（EAC） model. Through the uEAC mathematical model, the resistance properties of the conductive sheet, several feedback uEAC models, and a more flexible uEAC cell structure with a multi-level hierarchy are discussed. Futhermore, for the dynamic uEAC array with a linear Lukasiewicz function, a nonlinear differential equation description is presented, and then a sufficient global asymptotic stability condition is derived by utilizing a Lyapunov function and a Lipchitz function. Finally, comparative simulations for a cam servo mechanism system are conducted to verify the capability of the uEAC array as an adaptive controller.展开更多
针对网络化电力系统在分布式拒绝服务(Distributed Denial of Service,DDoS)攻击与控制器增益偏差并存导致的频率调节退化问题,提出一种将非脆弱比例积分(Non-fragile Proportional Integral,NFPI)与Q-learning自适应采样结合的采样数...针对网络化电力系统在分布式拒绝服务(Distributed Denial of Service,DDoS)攻击与控制器增益偏差并存导致的频率调节退化问题,提出一种将非脆弱比例积分(Non-fragile Proportional Integral,NFPI)与Q-learning自适应采样结合的采样数据负荷频率控制(Load Frequency Control,LFC)框架。采用伯努利随机门控刻画由DDoS引发的指令丢失与阻塞,构建含状态、采样保持与能量积分项的Lyapunov-Krasovskii泛函,并配合线性矩阵不等式(Linear Matrix Inequalities,LMIs)给出H_(∞)稳定性判据与控制器综合。同时以频差和攻击指示等构成学习状态,将候选采样间隔离散为动作空间并设计兼顾误差与通信代价的回报函数以在线优化采样策略。仿真表明,在较高攻击概率下该方案仍能实现频率快速且近乎无过冲的收敛,并在保持可比稳态精度的前提下显著减少采样与控制更新,从而在增益不确定与对抗性丢包并存时兼顾鲁棒性与通信效率,适于现代网络化电力系统部署。展开更多
Purpose-The purpose of this paper is to address the problem of control in a typical chaotic power system.Chaotic oscillations cannot only extremely endanger the stabilization of the power system but they can also not ...Purpose-The purpose of this paper is to address the problem of control in a typical chaotic power system.Chaotic oscillations cannot only extremely endanger the stabilization of the power system but they can also not be controlled by adding the traditional controllers.So,the sliding mode control based on a fuzzy supervisor can sufficiently ensure perfect tracking and controlling in the presence of uncertainties.Closed-loop stability is proved using the Lyapunov stability theory.The simulation results show the effectiveness of the proposed method in damping chaotic oscillations of the power system,eliminating control signal chattering and also show less control effort in comparison with the methods considered in previous literatures.Design/methodology/approach-The sliding mode control based on a fuzzy supervisor can sufficiently ensure perfect tracking and controlling in the presence of uncertainties.Closed-loop stability is proved using the Lyapunov stability theory.Findings-Closed-loop stability is proved using the Lyapunov stability theory.The simulation results show the effectiveness of the proposed method in damping chaotic oscillations of power system,eliminating control signal chattering and also less control effort in comparison with the methods considered in previous literatures.Originality/value-Main contributions of the paper are as follows:the chaotic behavior of power systems with two uncertainty parameters and tracking reference signal for the control of generator angle and the controller signal are discussed;designing sliding mode control based on a fuzzy supervisor in order to practically implement for the first time;while the generator speed is constant,the proposed controller will enable the power system to go in any desired trajectory for generator angle at first time;stability of the closed-loop sliding mode control based on the fuzzy supervisor system is proved using the Lyapunov stability theory;simulation of the proposed controller shows that the chattering is low control signal.展开更多
In this paper, a new approach is successfully addressed to design the state-feedback adaptive stabilizing control law for a class of high-order nonlinear systems in triangular form and with unknown and nonidentical co...In this paper, a new approach is successfully addressed to design the state-feedback adaptive stabilizing control law for a class of high-order nonlinear systems in triangular form and with unknown and nonidentical control coefficients, whose stabilizing control has been investigated recently under the knowledge that the lower bounds of the control coefficients are exactly known. In the present paper, without any knowledge of the lower bounds of the control coefficients, based on the adaptive technique and appropriately choosing design parameters, we give the recursive design procedure of the stabilizing control law by utilizing the approach of adding a power integrator together with tuning functions. The state-feedback adaptive control law designed not only preserves the equilibrium at the origin, but also guarantees the global asymptotic stability of the closed-loop states and the uniform boundedness of all the other closed-loop signals.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 70571017）.
文摘With system parameters falling into a certain area, power system with excitation limits experiences complicated chaotic oscillations which threaten the secure and stable operation of power system. In this paper, to control these unwanted chaotic oscillations, a straightforward adaptive chaos controller based on Lyapunov asymptotical stability theory is designed. Since the presented controller does not need to change the controlled system structure and not to use any information of system except the system state variables, the designed controller is simple and desirable. Simulation results show that the proposed control law is very effective. This work is helpful to maintain the power system＇s security operation.
文摘Suppression of the dynamic oscillations of tie-line power exchanges and frequency in the affected interconnected power systems due to loading-condition changes has been assigned as a prominent duty of automatic generation control(AGC). To alleviate the system oscillation resulting from such load changes, implementation of flexible AC transmission systems(FACTSs) can be considered as one of the practical and effective solutions. In this paper, a thyristor-controlled series compensator(TCSC), which is one series type of the FACTS family, is used to augment the overall dynamic performance of a multi-area multi-source interconnected power system. To this end, we have used a hierarchical adaptive neuro-fuzzy inference system controller-TCSC(HANFISC-TCSC) to abate the two important issues in multi-area interconnected power systems, i.e., low-frequency oscillations and tie-line power exchange deviations. For this purpose, a multi-objective optimization technique is inevitable. Multi-objective particle swarm optimization(MOPSO) has been chosen for this optimization problem, owing to its high performance in untangling non-linear objectives. The efficiency of the suggested HANFISC-TCSC has been precisely evaluated and compared with that of the conventional MOPSO-TCSC in two different multi-area interconnected power systems, i.e., two-area hydro-thermal-diesel and three-area hydro-thermal power systems. The simulation results obtained from both power systems have transparently certified the high performance of HANFISC-TCSC compared to the conventional MOPSO-TCSC.
文摘The parameters of power system slowly change with time due to environmental effects or may change rapidly due to faults. It is preferable that the control technique in this system possesses robustness for various fault conditions and disturbances. The used flexible alternating current transmission system （FACTS） in this paper is an advanced super-conducting magnetic energy storage （ASMES）. Many control techniques that use ASMES to improve power system stability have been proposed. While fuzzy controller has proven its value in some applications, the researches applying fuzzy controller with ASMES have been actively reported. However, it is sometimes very difficult to specify the rule base for some plants, when the parameters change. To solve this problem, a fuzzy model reference learning controller （FMRLC） is proposed in this paper, which investigates multi-input multi-output FMRLC for time-variant nonlinear system. This control method provides the motivation for adaptive fuzzy control, where the focus is on the automatic online synthesis and tuning of fuzzy controller parameters （i.e., using online data to continually learn the fuzzy controller that will ensure that the performance objectives are met）. Simulation results show that the proposed robust controller is able to work with nonlinear and nonstationary power system （i.e., single machine-infinite bus （SMIB） system）, under various fault conditions and disturbances.
文摘The problem of robust stabilization for nonlinear systems with partially known uncertainties is considered in this paper. The required information about uncertainties in the system is merely that the uncertainties are bounded, but the upper bounds are incompletely known. This paper can be viewed as an extension of the work in reference [1]. To compensate the uncertainties, an adaptive robust controller based on Lyapunov method is proposed and the design algorithm is also suggested. Compared with some previous controllers which can only ensure ultimate uniform boundedness of the systems, the controller given in the paper can make sure that the obtained closed-loop system is asymptotically stable in the large. Simulations show that the method presented is available and effective.
基金supported by the National Key Basic Research Special Found(No.2004CB217907)National Natural Science Foundation of China(No.50595412,No.50577044)Xu-ji Electric Power Science and Technology Found.
文摘Utilizing the feature of quick response of HVDC to improve the performance of AC/DC system has become the emphasis to be researched.This paper intro-duces firstly the principle of the robust adaptive control of nonlinear systems with unmodeled dynamics,then devel-oped the robust adaptive additional control of HVDC with unmodeled dynamics of generator in order to improve sta-bility of power system.The additional control of HVDC with unmodeled dynamics only uses the local signals and its design is simple,furthermore it can obviously improve the stability of power system in different operational conditions.Experimental results using the presented concepts obtained on single machine infinite bus model are also included.These results prove the efficiency of the control scheme.The design process of controller provided a new idea to design controller by use of simplified model.
基金supported by the National Natural Science Foundation of China (Grant No. 2012CB215106)the National Basic Research Program of China ("973" Program) (Grant No. 50977082)
文摘This paper provides an OpenMP-based parallel Very Dishonest Newton(VDHN) algorithm with variable step size,running transient stability simulations(TSA) on multi-core computers.Under the framework of simultaneous solution method of TSA,the step-size control strategy is used according to the local truncation error theory firstly.Then,computation of the generation units,which is the most time-consuming part of the simulation,is dynamically dispatched to several cores using an α dynamic scheduling scheme to obtain workload balancing based on OpenMP.Due to the convergence of Newton-type iterations,an adaptive Jacobian update control strategy is applied to reduce the sequential part of the simulation and the overhead generated by OpenMP.Several large scale test cases verify the validity and practicability of the proposed parallel algorithm,showing that the proposed approach achieves high speed-up and a considerable reduction in parallel overheads.
文摘This paper introduces a new adaptive neural network-based sliding mode control of rotary inverted pendulum system(RIPS)subject to model uncertainties and disturbances.First,the sliding mode control is designed using the double power rate reaching law.Second,an adaptive neural network(ANN)is exploited to deal with model uncertainties and disturbances.The weight matrices of the neural network are adaptively tuned.In the proposed control method the exact dynamic model of the RIPS is not required due to the exploitation of the universal property of the neural network.Moreover,the implementation of a double power-reaching law can greatly suppress the undesirable chattering.The convergence and stability analysis is validated using Lyapunov stability theory.Finally,the robustness and excellence of the proposed control strategy are verified by comparing the system performance with the existing SMC method and improved super-twisting SMC method.
基金Supported by the National Natural Science Foundation of China(61433003,61273150)Beijing Higher Education Young Elite Teacher Project
文摘A micro-extended-analog-computer （uEAC） is developed on the basis of Rubel＇ s extended analog computer（EAC） model. Through the uEAC mathematical model, the resistance properties of the conductive sheet, several feedback uEAC models, and a more flexible uEAC cell structure with a multi-level hierarchy are discussed. Futhermore, for the dynamic uEAC array with a linear Lukasiewicz function, a nonlinear differential equation description is presented, and then a sufficient global asymptotic stability condition is derived by utilizing a Lyapunov function and a Lipchitz function. Finally, comparative simulations for a cam servo mechanism system are conducted to verify the capability of the uEAC array as an adaptive controller.
文摘针对网络化电力系统在分布式拒绝服务(Distributed Denial of Service,DDoS)攻击与控制器增益偏差并存导致的频率调节退化问题,提出一种将非脆弱比例积分(Non-fragile Proportional Integral,NFPI)与Q-learning自适应采样结合的采样数据负荷频率控制(Load Frequency Control,LFC)框架。采用伯努利随机门控刻画由DDoS引发的指令丢失与阻塞,构建含状态、采样保持与能量积分项的Lyapunov-Krasovskii泛函,并配合线性矩阵不等式(Linear Matrix Inequalities,LMIs)给出H_(∞)稳定性判据与控制器综合。同时以频差和攻击指示等构成学习状态,将候选采样间隔离散为动作空间并设计兼顾误差与通信代价的回报函数以在线优化采样策略。仿真表明,在较高攻击概率下该方案仍能实现频率快速且近乎无过冲的收敛,并在保持可比稳态精度的前提下显著减少采样与控制更新,从而在增益不确定与对抗性丢包并存时兼顾鲁棒性与通信效率,适于现代网络化电力系统部署。
文摘Purpose-The purpose of this paper is to address the problem of control in a typical chaotic power system.Chaotic oscillations cannot only extremely endanger the stabilization of the power system but they can also not be controlled by adding the traditional controllers.So,the sliding mode control based on a fuzzy supervisor can sufficiently ensure perfect tracking and controlling in the presence of uncertainties.Closed-loop stability is proved using the Lyapunov stability theory.The simulation results show the effectiveness of the proposed method in damping chaotic oscillations of the power system,eliminating control signal chattering and also show less control effort in comparison with the methods considered in previous literatures.Design/methodology/approach-The sliding mode control based on a fuzzy supervisor can sufficiently ensure perfect tracking and controlling in the presence of uncertainties.Closed-loop stability is proved using the Lyapunov stability theory.Findings-Closed-loop stability is proved using the Lyapunov stability theory.The simulation results show the effectiveness of the proposed method in damping chaotic oscillations of power system,eliminating control signal chattering and also less control effort in comparison with the methods considered in previous literatures.Originality/value-Main contributions of the paper are as follows:the chaotic behavior of power systems with two uncertainty parameters and tracking reference signal for the control of generator angle and the controller signal are discussed;designing sliding mode control based on a fuzzy supervisor in order to practically implement for the first time;while the generator speed is constant,the proposed controller will enable the power system to go in any desired trajectory for generator angle at first time;stability of the closed-loop sliding mode control based on the fuzzy supervisor system is proved using the Lyapunov stability theory;simulation of the proposed controller shows that the chattering is low control signal.
基金The work is supported by the National Natural Science Foundation of China under Grants No.60304002 No.60674036the Science and Technical Development Plan of Shandong Province under Grant No.2004GG4204014.
文摘In this paper, a new approach is successfully addressed to design the state-feedback adaptive stabilizing control law for a class of high-order nonlinear systems in triangular form and with unknown and nonidentical control coefficients, whose stabilizing control has been investigated recently under the knowledge that the lower bounds of the control coefficients are exactly known. In the present paper, without any knowledge of the lower bounds of the control coefficients, based on the adaptive technique and appropriately choosing design parameters, we give the recursive design procedure of the stabilizing control law by utilizing the approach of adding a power integrator together with tuning functions. The state-feedback adaptive control law designed not only preserves the equilibrium at the origin, but also guarantees the global asymptotic stability of the closed-loop states and the uniform boundedness of all the other closed-loop signals.
