The paper addresses the decentralized optimal control and stabilization problems for interconnected systems subject to asymmetric information.Compared with previous work,a closed-loop optimal solution to the control p...The paper addresses the decentralized optimal control and stabilization problems for interconnected systems subject to asymmetric information.Compared with previous work,a closed-loop optimal solution to the control problem and sufficient and necessary conditions for the stabilization problem of the interconnected systems are given for the first time.The main challenge lies in three aspects:Firstly,the asymmetric information results in coupling between control and estimation and failure of the separation principle.Secondly,two extra unknown variables are generated by asymmetric information(different information filtration)when solving forward-backward stochastic difference equations.Thirdly,the existence of additive noise makes the study of mean-square boundedness an obstacle.The adopted technique is proving and assuming the linear form of controllers and establishing the equivalence between the two systems with and without additive noise.A dual-motor parallel drive system is presented to demonstrate the validity of the proposed algorithm.展开更多
The current investigations primarily focus on using advanced suspensions to overcome the tradeo design of ride comfort and handling performance for mining vehicles. It is generally realized by adjusting spring sti nes...The current investigations primarily focus on using advanced suspensions to overcome the tradeo design of ride comfort and handling performance for mining vehicles. It is generally realized by adjusting spring sti ness or damping parameters through active control methods. However, some drawbacks regarding control complexity and uncertain reliability are inevitable for these advanced suspensions. Herein, a novel passive hydraulically interconnected suspension(HIS) system is proposed to achieve an improved ride-handling compromise of mining vehicles. A lumped-mass vehicle model involved with a mechanical–hydraulic coupled system is developed by applying the free-body diagram method. The transfer matrix method is used to derive the impedance of the hydraulic system, and the impedance is integrated to form the equation of motions for a mechanical–hydraulic coupled system. The modal analysis method is employed to obtain the free vibration transmissibilities and force vibration responses under di erent road excitations. A series of frequency characteristic analyses are presented to evaluate the isolation vibration performance between the mining vehicles with the proposed HIS and the conventional suspension. The analysis results prove that the proposed HIS system can e ectively suppress the pitch motion of sprung mass to guarantee the handling performance, and favorably provide soft bounce sti ness to improve the ride comfort. The distribution of dynamic forces between the front and rear wheels is more reasonable, and the vibration decay rate of sprung mass is increased e ectively. This research proposes a new suspension design method that can achieve the enhanced cooperative control of bounce and pitch motion modes to improve the ride comfort and handling performance of mining vehicles as an e ective passive suspension system.展开更多
The paper proposes a novel H∞ load frequency control(LFC) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback(DOF) tracking-regulator cont...The paper proposes a novel H∞ load frequency control(LFC) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback(DOF) tracking-regulator control scheme. To this end, we consider a nonlinear interconnected model for multiarea power systems which also include uncertainties and timevarying communication delays. The design procedure is formulated using semi-definite programming and linear matrix inequality(LMI) method. The solution of the proposed LMIs returns necessary parameters for the tracking controllers such that the impact of model uncertainty and load disturbances are minimized. The proposed controllers are capable of receiving all or part of subsystems information, whereas the outputs of each controller are local. These controllers are designed such that the resilient stability of the overall closed-loop system is guaranteed. Simulation results are provided to verify the effectiveness of the proposed scheme. Simulation results quantify that the distributed(and decentralized) controlled system behaves well in presence of large parameter perturbations and random disturbances on the power system.展开更多
As one of the low-cost energy storage systems,Na-ion batteries(NIBs)have received tremendous attention.However,the performance of current anode materials still cannot meet the requirements of NIBs.In our work,we obtai...As one of the low-cost energy storage systems,Na-ion batteries(NIBs)have received tremendous attention.However,the performance of current anode materials still cannot meet the requirements of NIBs.In our work,we obtain sulfur-doped interconnected carbon microspheres(S-CSs)via a simple hydrothermal method and subsequent sulfurizing treatment.Our S-CSs exhibit an ultrahigh reversible capacity of 520 mAh g^(-1) at 100 mA g^(-1) after 50 cycles and an excellent rate capability of 257 mAh g^(-1),even at a high current density of 2 A g^(-1).The density functional theory calculations demonstrate that sulfur doping in carbon favors the adsorption of Na atom during the sodiation process,which is accountable for the performance enhancement.Furthermore,we also utilize operando Raman spectroscopy to analyze the electrochemical reaction of our S-CSs,which further highlights the sulfur doping in improving Na-ion storage performance.展开更多
This article considers delay dependent decentralized H∞ filtering for a class of uncertain interconnected systems, where the uncertainties are assumed to be time varying and satisfy the norm-bounded conditions. First...This article considers delay dependent decentralized H∞ filtering for a class of uncertain interconnected systems, where the uncertainties are assumed to be time varying and satisfy the norm-bounded conditions. First, combining the Lyapunov-Krasovskii functional approach and the delay integral inequality of matrices, a sufficient condition of the existence of the robust decentralized H∞ filter is derived, which makes the error systems asymptotically stable and satisfies the H∞ norm of the transfer function from noise input to error output less than the specified up-bound on the basis of the form of uncertainties. Then, the above sufficient condition is transformed to a system of easily solvable LMIs via a series of equivalent transformation. Finally, the numerical simulation shows the efficiency of the main results.展开更多
Hierarchically interconnected porous activated carbon have high specific surface areas, large numbers of dye adsorption sites, and interconnected pores for dye molecule diffusion and transportation. We prepared hierar...Hierarchically interconnected porous activated carbon have high specific surface areas, large numbers of dye adsorption sites, and interconnected pores for dye molecule diffusion and transportation. We prepared hierarchically interconnected porous banana peel activated carbons(BPACs) via a green method involving hydrothermal pretreatment and KOH activation, and systematically tested its methylene blue(MB) adsorption capacity. SEM showed that the BPACs had an interconnected porous structure and high-porosity surface. The Brunauer-Emmett-Teller surface area was 601.21 m^2/g, the adsorption average pore diameter was 2.11 nm, and the total pore volume was 0.32 cm^3/g. The MB adsorption capacity increased with increasing temperature, initial MB concentration, and pH value; it decreased with increasing adsorbent dosage. The adsorption isotherms and kinetic results for MB adsorption on BPACs were best described by the Langmuir adsorption and pseudo-second-order kinetic models, respectively. BPACs have a well-developed hierarchically interconnected porous structure, which increase the MB adsorption capacity and removal efficiency. Systematic MB adsorption tests show that BPAC is a highly efficient and easily available adsorbent.展开更多
This paper is concerned with the decentralized stabilization of continuous and discrete linear interconnected systems with the structural constraints about the interconnection matrices. For the continuous case,the mai...This paper is concerned with the decentralized stabilization of continuous and discrete linear interconnected systems with the structural constraints about the interconnection matrices. For the continuous case,the main improvement in the paper as compared with the corresponding results in the literature is to extend the considered class of systems from S to S (both will be defined in the paper) without resulting in high decentralized gain and difficult numerical computation. The algorithm for obtaining decentralized state feedback control to stable the overall system is presented. The discrete case and some very useful results are discussed as well.展开更多
Security and stability control system(SSCS)in power systems involves collecting information and sending the decision from/to control stations at different layers;the tree structure of the SSCS requires more levels.Fai...Security and stability control system(SSCS)in power systems involves collecting information and sending the decision from/to control stations at different layers;the tree structure of the SSCS requires more levels.Failure of a station or channel can cause all the execution stations(EXs)to be out of control.The randomness of the controllable capacity of the EXs increases the difficulty of the reliability evaluation of the SSCS.In this study,the loop designed SSCS and reliability analysis are examined for the interconnected systems.The uncertainty analysis of the controllable capacity based on the evidence theory for the SSCS is proposed.The bidirectional and loop channels are introduced to reduce the layers and stations of the existing SSCS with tree configuration.The reliability evaluation and sensitivity analysis are proposed to quantify the controllability and vulnerable components for the SSCS in different configurations.By aiming at the randomness of the controllable capacity of the EXs,the uncertainty analysis of the controllable capacity of the SSCS based on the evidence theory is proposed to quantify the probability of the SSCS for balancing the active power deficiency of the grid.展开更多
The European power grid is one of the largest regional interconnected power grids in the world.It realizes a multinational grid operation,which is rare.The total installed capacity of the European power grid is the la...The European power grid is one of the largest regional interconnected power grids in the world.It realizes a multinational grid operation,which is rare.The total installed capacity of the European power grid is the largest throughout the world.In addition,the integration and utilization of renewable energy in this grid is a great benchmark for other countries and can help promote energy transformation and achieve a high proportion of renewable energy consumption.Based on the analysis of the existing status of the European interconnected power grid and the development history of this power grid,this paper summarizes four key development stages of the European power grid.In addition,the characteristics of each stage and the development prospect of the European power grid are analyzed.On this basis,this paper gives suggestions for the development and construction of China’s energy internet;this can provide valuable reference for further studies on China’s energy internet.展开更多
The large-scale utilization and sharing of renewable energy in interconnected systems is crucial for realizing"instrumented,interconnected,and intelligent"power grids.The traditional optimal dispatch method ...The large-scale utilization and sharing of renewable energy in interconnected systems is crucial for realizing"instrumented,interconnected,and intelligent"power grids.The traditional optimal dispatch method can not coordinate the economic benefits of all the stakeholders from multiple regions of the transmission network,comprehensively.Hence,this study proposes a large-scale wind-power coordinated consumption strategy based on the Nash-Q method and establishes an economic dispatch model for interconnected systems considering the uncertainty of wind power,with optimal windpower consumption as the objective for redistributing the shared benefits between regions.Initially,based on the equivalent cost of the interests of stakeholders from different regions,the state decision models are respectively constructed,and the noncooperative game Nash equilibrium model is established.The Q-learning algorithm is then introduced for high-dimension decision variables in the game model,and the dispatch solution methods for interconnected systems are presented,integrating the noncooperative game Nash equilibrium and Q-learning algorithm.Finally,the proposed method is verified through the modified IEEE 39-bus interconnection system,and it is established that this method achieves reasonable distribution of interests between regions and promotes large-scale consumption of wind power.展开更多
We deal with the state consensus problem of a general Linear Interconnected Multi-Agent System (LIMAS) under a time-invariant and directed communication topology. Firstly, we propose a linear consensus protocol in a...We deal with the state consensus problem of a general Linear Interconnected Multi-Agent System (LIMAS) under a time-invariant and directed communication topology. Firstly, we propose a linear consensus protocol in a general form, which consists of state feedback of the agent itself and feedback form of the relative states between the agent and its neighbors. Secondly, a state-linear-transformation is applied to equivalently transform the state consensus problem into a partial stability problem. Based on the partial stability theory, we derive a sufficient and necessary criterion of consensus convergence, which is expressed via the Hurwitz stability of a real matrix constructed from the parameters of the agent models and the protocols, and present an analytical formula of the consensus function. Lastly, we propose a design procedure of the gain matrices in the protocol by solving a bilinear matrix inequality.展开更多
In this paper,a novel finite-time distributed identification method is introduced for nonlinear interconnected systems.A distributed concurrent learning-based discontinuous gradient descent update law is presented to ...In this paper,a novel finite-time distributed identification method is introduced for nonlinear interconnected systems.A distributed concurrent learning-based discontinuous gradient descent update law is presented to learn uncertain interconnected subsystems’dynamics.The concurrent learning approach continually minimizes the identification error for a batch of previously recorded data collected from each subsystem as well as its neighboring subsystems.The state information of neighboring interconnected subsystems is acquired through direct communication.The overall update laws for all subsystems form coupled continuous-time gradient flow dynamics for which finite-time Lyapunov stability analysis is performed.As a byproduct of this Lyapunov analysis,easy-to-check rank conditions on data stored in the distributed memories of subsystems are obtained,under which finite-time stability of the distributed identifier is guaranteed.These rank conditions replace the restrictive persistence of excitation(PE)conditions which are hard and even impossible to achieve and verify for interconnected subsystems.Finally,simulation results verify the effectiveness of the presented distributed method in comparison with the other methods.展开更多
This paper studies the problem of robust H∞ control design for a class of uncertain interconnected systems via state feedback. This class of systems are described by a state space model, which contains unknown nonlin...This paper studies the problem of robust H∞ control design for a class of uncertain interconnected systems via state feedback. This class of systems are described by a state space model, which contains unknown nonlinear interaction and time-varying norm-bounded parametric uncertainties in state equation. Using the Riccati-equation-based approach we design state feedback control laws, which guarantee the decentralized stability with disturbance attenuation for the interconnected uncertain systems. A simple example of an interconnected uncertain linear system is presented to illustrate the results.展开更多
In an integrated refining and petrochemical complex,a centralized utility system(CUS)is introduced to integrate the steam demands of production plants.Besides,two sub-utility systems(SUSs)located inside the alkene and...In an integrated refining and petrochemical complex,a centralized utility system(CUS)is introduced to integrate the steam demands of production plants.Besides,two sub-utility systems(SUSs)located inside the alkene and refinery plants,respectively,can satisfy the shaft demands.It is difficult to determine the steam production of the CUS because the steam demands of the alkene and refinery plants also depend on the design and operation of the SUSs.To explore the complicated interaction between the CUS and SUSs,we proposed a mixed-integer nonlinear programming(MINLP)model for the design and optimization of multiple interconnected utility systems to minimize the total annualized cost(TAC).An extended superstructure was suggested to contain multiple inter-plant connected steam pipe alternatives between the CUS and SUSs.A more accurate model of the complex steam turbine was proposed.Then the proposed MINLP framework is applied to a new integrated refining and petrochemical complex.Two scenarios are investigated in the case study to explore the effect of steam main temperatures on system configurations and operating parameters.By optimizing the main temperatures,a TAC of$2.7 million can be saved.Judging from the results of the two scenarios,the feasibility and effectiveness of the proposed framework for the design and optimization of multiple interconnected utility systems have been demonstrated.展开更多
This paper focuses on the problem of non-fragile decentralized guaranteed cost control for uncertain neutral large-scale interconnected systems with time-varying delays in state,control input and interconnections.A no...This paper focuses on the problem of non-fragile decentralized guaranteed cost control for uncertain neutral large-scale interconnected systems with time-varying delays in state,control input and interconnections.A novel scheme,viewing the interconnections with time-varying delays as effective information but not disturbances,is developed.Based on Lyapunov stability theory,using various techniques of decomposing and magnifying matrices,a design method of the non-fragile decentralized guaranteed cost controller for unperturbed neutral large-scale interconnected systems is proposed and the guaranteed cost is presented.The further results are derived for the uncertain case from the criterion of unperturbed neutral large-scale interconnected systems.Finally,an illustrative example shows that the results are significantly better than the existing results in the literatures.展开更多
Language and culture are intrinsically interconnected and interactive with each other.On one hand,language is a part of culture and plays a very important role in it:language expresses,embodies and symbolizes cultural...Language and culture are intrinsically interconnected and interactive with each other.On one hand,language is a part of culture and plays a very important role in it:language expresses,embodies and symbolizes cultural reality.On the other,language is influenced and shaped by culture;it reflects culture.This kind of relationship of language and culture is indispensible,which is clearly reflected in and especially ture with their play of roles in communication.Through the overviews of language and culture,and based on the case studies of three types of communication(cross-cultural,intercultural and multicultural communication),this article is aimed at discussing the relationship of language and culture in detail from the perspective of communication,and further explain and prove the importance of language and culture in successful communication.展开更多
A great deal of stabilization criteria has been obtained from study of stabilizing interconnected systems. The results obtained are usually based on continuous systems by state feedback. In this paper, decentralized i...A great deal of stabilization criteria has been obtained from study of stabilizing interconnected systems. The results obtained are usually based on continuous systems by state feedback. In this paper, decentralized impulsive control is presented to stabilize a class of uncertain interconnected systems based on Lyapunov theory. The system under consideration involves parameter uncertainties and unknown nonlinear interactions among subsystems. Some new criteria of stabilization under impulsive control are established. Two numerical examples are offered to prove the effectiveness and practicality of the proposed method.展开更多
For interconnected uncertain systems which are time-varying and assumed to satisfy the matching conditions, a sufficient condition for decentralized stabilization feedback control laws is derived. This condition is ex...For interconnected uncertain systems which are time-varying and assumed to satisfy the matching conditions, a sufficient condition for decentralized stabilization feedback control laws is derived. This condition is expressed as the solvability problem of linear matrix inequalities (LMIs). Based on that, a convex optimization problem with linear matrix inequality (LMI) constraints is formulated to design a decentralized state feedback controI with smaller gain parameters which enables the closed-loop system asymptotically stable.展开更多
The notion of string stability of a countably infinite interconnection of a class of nonlinear system was introduced. Intuitively, string stability implies uniform boundedness of all the stares of the interconnected s...The notion of string stability of a countably infinite interconnection of a class of nonlinear system was introduced. Intuitively, string stability implies uniform boundedness of all the stares of the interconnected system for all time if the initial states of the interconnected system are uniformly bounded. Vector V-function method used to judge the stability is generalized for infinite interconnected system and sufficient conditions which guarantee the asymptotic string stability of a class of interconnected system are given. The stability regions obtained here are much larger than those in previous papers. The method given here overcomes some difficulties to deal with stability of infinite nonlinear interconnected system in previous papers.展开更多
In this paper, we consider the design of interconnected H-infinity feedback control systems with quantized signals. We assume that a decentralized static output feedback has been designed for an interconnected continu...In this paper, we consider the design of interconnected H-infinity feedback control systems with quantized signals. We assume that a decentralized static output feedback has been designed for an interconnected continuous-time LTI system so that the closed-loop system is stable and a desired H-infinity disturbance attenuation level is achieved, and that the subsystems' measurement outputs are quantized before they are passed to the local controller. We propose a local-output-dependent strategy for updating the quantizers' parameters, so that the overall closed-loop system is asymptotically stable and achieves the same H-infinity disturbance attenuation level. Both the pre-designed controllers and the quantizers' parameters are constructed in a decentralized manner, depending on local information.展开更多
基金supported by the National Natural Science Foundation of China(62273213,62073199,62103241)Natural Science Foundation of Shandong Province for Innovation and Development Joint Funds(ZR2022LZH001)+4 种基金Natural Science Foundation of Shandong Province(ZR2020MF095,ZR2021QF107)Taishan Scholarship Construction Engineeringthe Original Exploratory Program Project of National Natural Science Foundation of China(62250056)Major Basic Research of Natural Science Foundation of Shandong Province(ZR2021ZD14)High-level Talent Team Project of Qingdao West Coast New Area(RCTD-JC-2019-05)。
文摘The paper addresses the decentralized optimal control and stabilization problems for interconnected systems subject to asymmetric information.Compared with previous work,a closed-loop optimal solution to the control problem and sufficient and necessary conditions for the stabilization problem of the interconnected systems are given for the first time.The main challenge lies in three aspects:Firstly,the asymmetric information results in coupling between control and estimation and failure of the separation principle.Secondly,two extra unknown variables are generated by asymmetric information(different information filtration)when solving forward-backward stochastic difference equations.Thirdly,the existence of additive noise makes the study of mean-square boundedness an obstacle.The adopted technique is proving and assuming the linear form of controllers and establishing the equivalence between the two systems with and without additive noise.A dual-motor parallel drive system is presented to demonstrate the validity of the proposed algorithm.
基金Supported by National Natural Science Foundation of China(Grant Nos.51805155,51675152)Foundation for Innovative Research Groups of National Natural Science Foundation of China(Grant No.51621004)Open Fund in the State Key Laboratory of Advanced Design and Manufacture for Vehicle Body(Grant No.71575005)
文摘The current investigations primarily focus on using advanced suspensions to overcome the tradeo design of ride comfort and handling performance for mining vehicles. It is generally realized by adjusting spring sti ness or damping parameters through active control methods. However, some drawbacks regarding control complexity and uncertain reliability are inevitable for these advanced suspensions. Herein, a novel passive hydraulically interconnected suspension(HIS) system is proposed to achieve an improved ride-handling compromise of mining vehicles. A lumped-mass vehicle model involved with a mechanical–hydraulic coupled system is developed by applying the free-body diagram method. The transfer matrix method is used to derive the impedance of the hydraulic system, and the impedance is integrated to form the equation of motions for a mechanical–hydraulic coupled system. The modal analysis method is employed to obtain the free vibration transmissibilities and force vibration responses under di erent road excitations. A series of frequency characteristic analyses are presented to evaluate the isolation vibration performance between the mining vehicles with the proposed HIS and the conventional suspension. The analysis results prove that the proposed HIS system can e ectively suppress the pitch motion of sprung mass to guarantee the handling performance, and favorably provide soft bounce sti ness to improve the ride comfort. The distribution of dynamic forces between the front and rear wheels is more reasonable, and the vibration decay rate of sprung mass is increased e ectively. This research proposes a new suspension design method that can achieve the enhanced cooperative control of bounce and pitch motion modes to improve the ride comfort and handling performance of mining vehicles as an e ective passive suspension system.
文摘The paper proposes a novel H∞ load frequency control(LFC) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback(DOF) tracking-regulator control scheme. To this end, we consider a nonlinear interconnected model for multiarea power systems which also include uncertainties and timevarying communication delays. The design procedure is formulated using semi-definite programming and linear matrix inequality(LMI) method. The solution of the proposed LMIs returns necessary parameters for the tracking controllers such that the impact of model uncertainty and load disturbances are minimized. The proposed controllers are capable of receiving all or part of subsystems information, whereas the outputs of each controller are local. These controllers are designed such that the resilient stability of the overall closed-loop system is guaranteed. Simulation results are provided to verify the effectiveness of the proposed scheme. Simulation results quantify that the distributed(and decentralized) controlled system behaves well in presence of large parameter perturbations and random disturbances on the power system.
基金Fundamental Research Funds for the Central Universities,Grant/Award Number:21617330National Natural Science Foundation of China,Grant/Award Numbers:21703081,51702056,51772135Ministry of Education of the People's Republic of China,Grant/Award Number:6141A02022516。
文摘As one of the low-cost energy storage systems,Na-ion batteries(NIBs)have received tremendous attention.However,the performance of current anode materials still cannot meet the requirements of NIBs.In our work,we obtain sulfur-doped interconnected carbon microspheres(S-CSs)via a simple hydrothermal method and subsequent sulfurizing treatment.Our S-CSs exhibit an ultrahigh reversible capacity of 520 mAh g^(-1) at 100 mA g^(-1) after 50 cycles and an excellent rate capability of 257 mAh g^(-1),even at a high current density of 2 A g^(-1).The density functional theory calculations demonstrate that sulfur doping in carbon favors the adsorption of Na atom during the sodiation process,which is accountable for the performance enhancement.Furthermore,we also utilize operando Raman spectroscopy to analyze the electrochemical reaction of our S-CSs,which further highlights the sulfur doping in improving Na-ion storage performance.
基金the National Natural Science Foundation of China (60634020)the Hunan Provincial Natural Science Foundation of China (07JJ6138)+1 种基金the Postdoctoral Science Foundation of China (20060390883)the China Ph.D. Discipline Special Foundation (20050533028).
文摘This article considers delay dependent decentralized H∞ filtering for a class of uncertain interconnected systems, where the uncertainties are assumed to be time varying and satisfy the norm-bounded conditions. First, combining the Lyapunov-Krasovskii functional approach and the delay integral inequality of matrices, a sufficient condition of the existence of the robust decentralized H∞ filter is derived, which makes the error systems asymptotically stable and satisfies the H∞ norm of the transfer function from noise input to error output less than the specified up-bound on the basis of the form of uncertainties. Then, the above sufficient condition is transformed to a system of easily solvable LMIs via a series of equivalent transformation. Finally, the numerical simulation shows the efficiency of the main results.
基金Funded by the Project of Scientific Research Staring Foundation of Huaqiao University(11BS214)the Cultivate Project of National Natural Science Foundation of Huaqiao University(JBZR1214)the Educational research project for Young and middle-aged Teachers of Fujian Province(JAT160031)
文摘Hierarchically interconnected porous activated carbon have high specific surface areas, large numbers of dye adsorption sites, and interconnected pores for dye molecule diffusion and transportation. We prepared hierarchically interconnected porous banana peel activated carbons(BPACs) via a green method involving hydrothermal pretreatment and KOH activation, and systematically tested its methylene blue(MB) adsorption capacity. SEM showed that the BPACs had an interconnected porous structure and high-porosity surface. The Brunauer-Emmett-Teller surface area was 601.21 m^2/g, the adsorption average pore diameter was 2.11 nm, and the total pore volume was 0.32 cm^3/g. The MB adsorption capacity increased with increasing temperature, initial MB concentration, and pH value; it decreased with increasing adsorbent dosage. The adsorption isotherms and kinetic results for MB adsorption on BPACs were best described by the Langmuir adsorption and pseudo-second-order kinetic models, respectively. BPACs have a well-developed hierarchically interconnected porous structure, which increase the MB adsorption capacity and removal efficiency. Systematic MB adsorption tests show that BPAC is a highly efficient and easily available adsorbent.
基金National Natural Science Foundation of China(1 970 1 0 2 2 )
文摘This paper is concerned with the decentralized stabilization of continuous and discrete linear interconnected systems with the structural constraints about the interconnection matrices. For the continuous case,the main improvement in the paper as compared with the corresponding results in the literature is to extend the considered class of systems from S to S (both will be defined in the paper) without resulting in high decentralized gain and difficult numerical computation. The algorithm for obtaining decentralized state feedback control to stable the overall system is presented. The discrete case and some very useful results are discussed as well.
基金supported by Science and Technology Project of SGCC“Research on Flat Architecture and Implementation Technology of Security and Stability Control System in Ultra Large Power Grid”(52170221000U).
文摘Security and stability control system(SSCS)in power systems involves collecting information and sending the decision from/to control stations at different layers;the tree structure of the SSCS requires more levels.Failure of a station or channel can cause all the execution stations(EXs)to be out of control.The randomness of the controllable capacity of the EXs increases the difficulty of the reliability evaluation of the SSCS.In this study,the loop designed SSCS and reliability analysis are examined for the interconnected systems.The uncertainty analysis of the controllable capacity based on the evidence theory for the SSCS is proposed.The bidirectional and loop channels are introduced to reduce the layers and stations of the existing SSCS with tree configuration.The reliability evaluation and sensitivity analysis are proposed to quantify the controllability and vulnerable components for the SSCS in different configurations.By aiming at the randomness of the controllable capacity of the EXs,the uncertainty analysis of the controllable capacity of the SSCS based on the evidence theory is proposed to quantify the probability of the SSCS for balancing the active power deficiency of the grid.
基金funded by the State Grid Science and Technology Research Program:“Research on coordination development mode and reliability evaluation of source,network,load and storage considering the safety requirements(No.B3440818K005)”
文摘The European power grid is one of the largest regional interconnected power grids in the world.It realizes a multinational grid operation,which is rare.The total installed capacity of the European power grid is the largest throughout the world.In addition,the integration and utilization of renewable energy in this grid is a great benchmark for other countries and can help promote energy transformation and achieve a high proportion of renewable energy consumption.Based on the analysis of the existing status of the European interconnected power grid and the development history of this power grid,this paper summarizes four key development stages of the European power grid.In addition,the characteristics of each stage and the development prospect of the European power grid are analyzed.On this basis,this paper gives suggestions for the development and construction of China’s energy internet;this can provide valuable reference for further studies on China’s energy internet.
基金supported by the Fundamental Research Funds For the Central Universities(No.2017MS093)
文摘The large-scale utilization and sharing of renewable energy in interconnected systems is crucial for realizing"instrumented,interconnected,and intelligent"power grids.The traditional optimal dispatch method can not coordinate the economic benefits of all the stakeholders from multiple regions of the transmission network,comprehensively.Hence,this study proposes a large-scale wind-power coordinated consumption strategy based on the Nash-Q method and establishes an economic dispatch model for interconnected systems considering the uncertainty of wind power,with optimal windpower consumption as the objective for redistributing the shared benefits between regions.Initially,based on the equivalent cost of the interests of stakeholders from different regions,the state decision models are respectively constructed,and the noncooperative game Nash equilibrium model is established.The Q-learning algorithm is then introduced for high-dimension decision variables in the game model,and the dispatch solution methods for interconnected systems are presented,integrating the noncooperative game Nash equilibrium and Q-learning algorithm.Finally,the proposed method is verified through the modified IEEE 39-bus interconnection system,and it is established that this method achieves reasonable distribution of interests between regions and promotes large-scale consumption of wind power.
基金supported in part by NSF of China(61273006 and 6141101096)High Technology Research and Development Program of China(863Program)(2011AA110301)+2 种基金Specialized Research Fund for the Doctoral Program of Higher Education of China(20111103110017)St.Petersburg State University(9.38.674.2013)the Russian Foundation for Basic Research(13-01-00376-a and 15-58-53017)
文摘We deal with the state consensus problem of a general Linear Interconnected Multi-Agent System (LIMAS) under a time-invariant and directed communication topology. Firstly, we propose a linear consensus protocol in a general form, which consists of state feedback of the agent itself and feedback form of the relative states between the agent and its neighbors. Secondly, a state-linear-transformation is applied to equivalently transform the state consensus problem into a partial stability problem. Based on the partial stability theory, we derive a sufficient and necessary criterion of consensus convergence, which is expressed via the Hurwitz stability of a real matrix constructed from the parameters of the agent models and the protocols, and present an analytical formula of the consensus function. Lastly, we propose a design procedure of the gain matrices in the protocol by solving a bilinear matrix inequality.
基金This work was partially supported by the European Union’s Horizon 2020 research and innovation programme(739551)(KIOS CoE)from the Republic of Cyprus through the Directorate General for European Programmes,Coordination and Development.
文摘In this paper,a novel finite-time distributed identification method is introduced for nonlinear interconnected systems.A distributed concurrent learning-based discontinuous gradient descent update law is presented to learn uncertain interconnected subsystems’dynamics.The concurrent learning approach continually minimizes the identification error for a batch of previously recorded data collected from each subsystem as well as its neighboring subsystems.The state information of neighboring interconnected subsystems is acquired through direct communication.The overall update laws for all subsystems form coupled continuous-time gradient flow dynamics for which finite-time Lyapunov stability analysis is performed.As a byproduct of this Lyapunov analysis,easy-to-check rank conditions on data stored in the distributed memories of subsystems are obtained,under which finite-time stability of the distributed identifier is guaranteed.These rank conditions replace the restrictive persistence of excitation(PE)conditions which are hard and even impossible to achieve and verify for interconnected subsystems.Finally,simulation results verify the effectiveness of the presented distributed method in comparison with the other methods.
文摘This paper studies the problem of robust H∞ control design for a class of uncertain interconnected systems via state feedback. This class of systems are described by a state space model, which contains unknown nonlinear interaction and time-varying norm-bounded parametric uncertainties in state equation. Using the Riccati-equation-based approach we design state feedback control laws, which guarantee the decentralized stability with disturbance attenuation for the interconnected uncertain systems. A simple example of an interconnected uncertain linear system is presented to illustrate the results.
文摘In an integrated refining and petrochemical complex,a centralized utility system(CUS)is introduced to integrate the steam demands of production plants.Besides,two sub-utility systems(SUSs)located inside the alkene and refinery plants,respectively,can satisfy the shaft demands.It is difficult to determine the steam production of the CUS because the steam demands of the alkene and refinery plants also depend on the design and operation of the SUSs.To explore the complicated interaction between the CUS and SUSs,we proposed a mixed-integer nonlinear programming(MINLP)model for the design and optimization of multiple interconnected utility systems to minimize the total annualized cost(TAC).An extended superstructure was suggested to contain multiple inter-plant connected steam pipe alternatives between the CUS and SUSs.A more accurate model of the complex steam turbine was proposed.Then the proposed MINLP framework is applied to a new integrated refining and petrochemical complex.Two scenarios are investigated in the case study to explore the effect of steam main temperatures on system configurations and operating parameters.By optimizing the main temperatures,a TAC of$2.7 million can be saved.Judging from the results of the two scenarios,the feasibility and effectiveness of the proposed framework for the design and optimization of multiple interconnected utility systems have been demonstrated.
基金supported by the National Natural Science Foundation of China(6057401160972164+1 种基金60904101)the Scientific Research Fund of Liaoning Provincial Education Department(2009A544)
文摘This paper focuses on the problem of non-fragile decentralized guaranteed cost control for uncertain neutral large-scale interconnected systems with time-varying delays in state,control input and interconnections.A novel scheme,viewing the interconnections with time-varying delays as effective information but not disturbances,is developed.Based on Lyapunov stability theory,using various techniques of decomposing and magnifying matrices,a design method of the non-fragile decentralized guaranteed cost controller for unperturbed neutral large-scale interconnected systems is proposed and the guaranteed cost is presented.The further results are derived for the uncertain case from the criterion of unperturbed neutral large-scale interconnected systems.Finally,an illustrative example shows that the results are significantly better than the existing results in the literatures.
文摘Language and culture are intrinsically interconnected and interactive with each other.On one hand,language is a part of culture and plays a very important role in it:language expresses,embodies and symbolizes cultural reality.On the other,language is influenced and shaped by culture;it reflects culture.This kind of relationship of language and culture is indispensible,which is clearly reflected in and especially ture with their play of roles in communication.Through the overviews of language and culture,and based on the case studies of three types of communication(cross-cultural,intercultural and multicultural communication),this article is aimed at discussing the relationship of language and culture in detail from the perspective of communication,and further explain and prove the importance of language and culture in successful communication.
文摘A great deal of stabilization criteria has been obtained from study of stabilizing interconnected systems. The results obtained are usually based on continuous systems by state feedback. In this paper, decentralized impulsive control is presented to stabilize a class of uncertain interconnected systems based on Lyapunov theory. The system under consideration involves parameter uncertainties and unknown nonlinear interactions among subsystems. Some new criteria of stabilization under impulsive control are established. Two numerical examples are offered to prove the effectiveness and practicality of the proposed method.
文摘For interconnected uncertain systems which are time-varying and assumed to satisfy the matching conditions, a sufficient condition for decentralized stabilization feedback control laws is derived. This condition is expressed as the solvability problem of linear matrix inequalities (LMIs). Based on that, a convex optimization problem with linear matrix inequality (LMI) constraints is formulated to design a decentralized state feedback controI with smaller gain parameters which enables the closed-loop system asymptotically stable.
文摘The notion of string stability of a countably infinite interconnection of a class of nonlinear system was introduced. Intuitively, string stability implies uniform boundedness of all the stares of the interconnected system for all time if the initial states of the interconnected system are uniformly bounded. Vector V-function method used to judge the stability is generalized for infinite interconnected system and sufficient conditions which guarantee the asymptotic string stability of a class of interconnected system are given. The stability regions obtained here are much larger than those in previous papers. The method given here overcomes some difficulties to deal with stability of infinite nonlinear interconnected system in previous papers.
基金supported by the Japan Ministry of Education,Sciences and Culture under Grant-in-Aid for Scientific Research(C)(No.21560471)
文摘In this paper, we consider the design of interconnected H-infinity feedback control systems with quantized signals. We assume that a decentralized static output feedback has been designed for an interconnected continuous-time LTI system so that the closed-loop system is stable and a desired H-infinity disturbance attenuation level is achieved, and that the subsystems' measurement outputs are quantized before they are passed to the local controller. We propose a local-output-dependent strategy for updating the quantizers' parameters, so that the overall closed-loop system is asymptotically stable and achieves the same H-infinity disturbance attenuation level. Both the pre-designed controllers and the quantizers' parameters are constructed in a decentralized manner, depending on local information.