Large Scale Systems Theory Research Articles

Active equalization control strategy of Li‐ion battery based on state of charge estimation of an electrochemical‐thermal coupling model

Aiming at solving the problem of poor battery cell consistency caused by excessive decay of cell capacity or increased internal resistance during the operation of lithium-ion battery packs for vehicles, the paper proposes an active equalization control with 12-V power supply as an equalization energy source, which achieves efficient energy replenishment of individual cells with low power. The electrochemical-thermal coupling model of lithium-ion battery is built, and the order reduction of large-scale system theory ensures that the model had higher accuracy and lower amount of calculation, which is suitable for vehicle battery management system (BMS). Then the extended Kalman filter algorithm is used to calculate the real-time state of charge (SOC) of each cell and set as an equalization variable. The equalization simulation circuit is built with MATLAB/Simulink, the experimental platform of active equalization system for battery packs is constructed, and the battery packs are tested for equalization in static state. The simulation and experimental results show that the proposed active equalization control strategy can rapidly improve the voltage inconsistency between single cells, and the energy transfer efficiency can reach about 85% during the equalization process.

Rational allocation of water resources based on ecological groundwater levels:a case study in Jinghui Irrigation District in China

Aimed at the hydrogeological environmental problems caused by over-exploitation and unreasonable utilization of water resources in Jinghui Irrigation District, this paper discusses the ecological groundwater level of the study area and establishes a three-layer optimal allocation model of water resources based on the theory of large scale systems. Then, the genetic algorithm method was employed to optimize the model and obtain the optimal allocation of crop irrigation schedule and water resources under the condition of a 75% assurance rate. Finally, the numerical simulation model of the groundwater was applied to analyze the balance of the groundwater on the basis of the optimal allocation scheme. The results show that the upper limitation of the ecological groundwater in Jinghui Irrigation District ranged from 1.8m to 4.2m, while the lower limitation level ranged from 8m to 28m. By 2020, the condition of the groundwater imbalance that results from adopting the optimal allocation scheme will be much better than that caused by current water utilization scheme. With the exception of only a few areas, the groundwater level in most parts of Jinghui Irrigation District will not exceed the lower limitation of ecological groundwater level.

An overview of transmission theory and techniques of large-scale antenna systems for 5G wireless communications

To meet the future demand for huge traffic volume of wireless data service, the research on the fifth generation (5G) mobile communication systems has been undertaken in recent years. It is expected that the spectral and energy efficiencies in 5G mobile communication systems should be ten-fold higher than the ones in the fourth generation (4G) mobile communication systems. Therefore, it is important to further exploit the potential of spatial multiplexing of multiple antennas. In the last twenty years, multiple-input multiple-output (MIMO) antenna techniques have been considered as the key techniques to increase the capacity of wireless communication systems. When a large-scale antenna array (which is also called massive MIMO) is equipped in a base-station, or a large number of distributed antennas (which is also called large-scale distributed MIMO) are deployed, the spectral and energy efficiencies can be further improved by using spatial domain multiple access. This paper provides an overview of massive MIMO and large-scale distributed MIMO systems, including spectral efficiency analysis, channel state information (CSI) acquisition, wireless transmission technology, and resource allocation.

Order Reduction of Lithium-Ion Battery Model Based on Solid State Diffusion Dynamics via Large Scale Systems Theory

A simple and accurate model is essential for the model-based control design. The 1D electrode-averaged battery model maintains the prediction accuracy and depth of physical interpretations. The most critical and complicated dynamics in the system is solid phase concentration diffusion, which has a direct impact on battery status. The finite difference method based on uneven discretization benefits to reduce the complexity. Then, the simplification theory of large scale systems is applied to retain the dominant variable and make the model more compact. The simplification process meets the requirements of fast computation and retention of electrochemical diffusion dynamics. This approach was experimentally verified under 0.2C to 2Cdischarge tests. The simulation output converges to the real terminal voltage within an error of ±0.1V. The simplified model enjoys advantages including high accuracy, low computational cost, and therefore is suitable for deployment and use in real-time embedded battery management systems (BMSs).

An overview of transmission theory and techniques of large-scale antenna systems for 5G wireless communications

An overview of transmission theory and techniques of large-scale antenna systems for 5G wireless communications

Global optimal control of variable air volume air-conditioning system with iterative learning: an experimental case study

The air-conditioning system in a large commercial or high-rise building is a complex multi-variable system influenced by many factors. The energy saving potential from the optimal operation and control of heating, ventilating, and air-conditioning (HVAC) systems can be large, even when they are properly designed. The ultimate goal of optimization is to use the minimum amount of energy needed to improve system efficiency while meeting comfort requirements. In this study, a multi-zone variable air volume (VAV) and variable water volume (VWV) air-conditioning system is developed. The steady state modes and dynamic models of the HVAC subsystems are constructed. Optimal control based on large scale system theory for system-level energy-saving of HVAC is introduced. Control strategies such as proportional-integral-derivative (PID) controller (gearshift integral PID and self-tuning PID) and iterative learning control (ILC) are studied in the platform to improve the dynamic characteristics. The system performance is improved. An 18.2% energy saving is achieved with the integration of ILC and sequential quadratic programming based on a steady-state hierarchical optimization control scheme.

The Regional Limit of Flood-Bearing Capability: A Theoretical Model and Approaches

A series of interesting questions will be proposed and tried to be answered in this paper such as: Is there a limit of disaster-bearing capability in a region human-environment system (HES) when the system is hit by an extreme flood disaster? If so, what does it mean and how can it be explained? An assumption, naming the regional limit of flood-bearing capability (LFBC), is suggested and proved to respond these questions in this study. The LFBC model consists of three factors, namely, the disaster-causing factor (DCF), disaster-bearing factor (DBF) and disaster-regulating factor (DRF). The DCF can be selected from the cause analysis of flood, the DBF can be extracted from analysis of flood risk and vulnerability, and the DRF is responding to the analysis of flood risk management and measures. The logical relations among the three factors are determined by the analysis of flood inundation-loss models. The limit of disaster-bearing capability in regional HES is introduced by the principles of threshold analysis in terms of large-scale system theory, and can be expressed as the regional inundated depth or the amount of water in a flood. The LFBC model is built up following this idea, and approaches of its application are stated with the support of remote sensing (RS) and geographical information system (GIS). Substantial changes in terms of system succession, such as reservoir resettlement, population migration and land use pattern change, would occur only when extreme flood beyond its limit of disaster-bearing capability in a regional HES. Otherwise, the difference can be use to measures the damage conditions. Combining the occurrence probability of extreme flood, the LFBC model could be used to provide the data support for flood damage assessment, regional disaster control and reduction countermeasures, and regional development planning.

Decomposition–coordination model of reservoir group and flood storage basin for real-time flood control operation

The research of joint optimization operation of complex flood control systems is still in the process of development. This paper introduces a decomposition–coordination model for solving the multi-objective optimization problem for real-time flood control operation in reservoir group and flood storage basin. The multi-objective programming is established for maximum safety of the reservoir group and minimum losses of flood storage basin, according to the real-time flood control requirements. Then, a third-order hierarchical optimization decomposition–coordination model is proposed for solving the multi-objective programming problem, based on the decomposition–coordination principle of large scale system theory. It takes advantage of an objective coordination method and model coordination method to accomplish global optimization and combines progressive optimality algorithm to solve the subsystem local optimization. Finally, the model is applied for simulating the storm flood in July 2007 in the middle reaches of the Huaihe River Basin in China. Results show that the proposed decomposition–coordination model can efficiently calculate the reservoir group optima release strategy and flood storage basin diversion process, and meet the safety discharge at the downstream control section.

Large-scale Systems Control and Complex Networks——Exploration and Thinking

With the rapid development of communication and network technology, more and more complex dynamic networks appear in the fields of social, economic and human s daily life. Network science as a new interdisciplinary subject has gained great achievements in the research on performance characteristic, evolution process and control method of complex dynamic networks. The control theory and methodology of large scale systems, aiming at the behavior analysis,control and optimization for high dimensional dynamic systems, should be able to provide a helpful reference for the study of complex networks. In this paper, against some hotspot problems in the research of complex dynamic networks, we explore the possibility of using the control theory and methodology of large scale systems to solve the structural analysis and control problems of complex networks, analyze the facing difculties and the possible coping ways. For control and optimization of large scale complex dynamic networks, a multi-layer hierarchical structure is proposed which integrates the macroscope analysis methods of network science, the quantitative design methods of control science and the intelligent processing methods of information science.

Special issue on robust stability and control of large-scale nonlinear systems

In a broad sense, large-scale systems theory is concerned with the analysis and design of often very high-dimensional systems that admit some kind of partition into smaller subsystems. Research in linear large-scale systems analysis and synthesis can be traced back to at least the 1970s. Recently, interest in this subject has been revived by new developments in nonlinear systems and control, which include but are not limited to dissipative systems theory, input-to-state stability, and various Lyapunov and smallgain design schemes. Systems and control theory itself has seen many important advances since the 1970s, including, e.g., concepts like control Lyapunov functions, effective implementations of nonlinear model predictive control, or entire emerging areas like hybrid systems and cooperative multi-agent systems. Naturally, these developments also leap into the area of large-scale systems. It is hence to be expected that the interest in this area will continue to increase, ultimately also due to, e.g., current research efforts in distributed model predictive control, next generation smart electricity grids, incorporating green and renewable energy sources, or bioand neuro-engineering. Many questions are associated with the theory of large-scale systems. A quite central one is about sufficient conditions on interconnections of a number of stable systems such that the composite system is also stable. Another one is how individual

Stability verification for monotone systems using homotopy algorithms

A monotone self-mapping of the nonnegative orthant induces a monotone discrete-time dynamical system which evolves on the same orthant. If with respect to this system the origin is attractive then there must exist points whose image under the monotone map is strictly smaller than the original point, in the component-wise partial ordering. Here it is shown how such points can be found numerically, leading to a recipe to compute order intervals that are contained in the region of attraction and where the monotone map acts essentially as a contraction. An important application is the numerical verification of so-called generalized small-gain conditions that appear in the stability theory of large-scale systems.

Incremental-Dissipativity-Based Synchronization of Interconnected Systems

AbstractIn this paper, the incremental-dissipativity is used to investigate synchronization of a class of dynamical networks from an input-output point of view. The network consists of subsystems described by input-output operators. Firstly, the concept of incremental-passivity is extended to incremental-dissipativity, and it shows that the incremental-dissipativity of the subsystems leads to the dissipativity of a group of virtual systems each of which is related to an individual subsystem. Then the synchronization problem is transformed into the stability problem of a system interconnected by the virtual systems. By utilizing the stability theory of large-scale systems, a sufficient condition is obtained which ensures the input-output synchronization of the network. The counterparts of the main result and the discussion on conditions of the incremental-dissipativity for the subsystems with state space representations are also presented. Finally, an example is given to show the effectiveness of the proposed result.

A Large-Scale Device Collaboration Performance Evaluation Approach Based-on Dynamics

The performance of device collaboration is important in the large-scale device collaboration system, so the large-scale device collaboration performance evaluation is one of the main contents of the large-scale device collaboration research. Aiming at the problem of the large-scale device collaboration performance evaluation, the paper presents a large-scale device collaboration performance evaluation approach based-on dynamical system theory. A dynamics model of the large-scale device collaboration performance evaluation is defined and an evaluation approach is provided. Finally, an application example is given to demonstrate the usage of this approach.

Sample-data Decentralized Reliable H∞ Hyperbolic Control for Uncertain Fuzzy Large-scale Systems with Time-varying Delay

This paper studies the problem of sampled-data reliable H ∞ hyperbolic control for uncertain continuous-time fuzzy large-scale systems with time-varying delay. Firstly, the fuzzy hyperbolic model (FHM) is used to establish the model for certain complex large-scale systems, then according to the Lyapunov direct method and the decentralized control theory of large-scale systems, linear matrixine qualities (LMIs)-based conditions arederived toguarantee the H ∞ performance not only when all control components are operating well, but also in the presence of some possible actuator failures. Moreover, the precise failure parameters of the actuators are not required, and the requirements are only the lower and upper bounds of failure parameters. The conditions are dependent on the upper bound of time-delay, and not dependent on the derivative of time-varying delay. Therefore, the obtained results are less conservative. Finally, two examples are provided to illustrate the design procedure and its effectiveness.

Delay-dependent robust and reliable [formula omitted] fuzzy hyperbolic decentralized control for uncertain nonlinear interconnected systems

This paper develops the delay-dependent robust and reliable H ∞ fuzzy hyperbolic control for nonlinear large-scale interconnected systems with parameter uncertainties. Firstly, the modeling method of fuzzy hyperbolic model (FHM) is given for the general large-scale interconnected systems. The main advantages of using FHM over T–S fuzzy model are that neither premise structure identification nor completeness design of premise variables space is needed. Therefore the required computational effort is less than that of using T–S fuzzy model, especially when a lot of fuzzy rules are needed to model complex nonlinear systems. Then according to the Lyapunov direct method and the decentralized control theory of large-scale interconnected systems, linear matrix inequality (LMI)-based conditions with some free weighting matrices are derived, which guarantee the closed-loop interconnected systems to be robustly stable with the H ∞ performance even in the presence of some possible actuator failures. Moreover, precise failure parameters of actuators are not required, and the only requirements are the lower and upper bounds of failure parameters. The restriction that the derivative of the time-varying delay is smaller than one is removed. Therefore, the results obtained are less conservative. Three simulation examples are provided to show the effectiveness of the proposed approach.

Multidisciplinary Design-Optimization Methods for Aircrafts using Large-Scale System Theory

Abstract The relationship between multidisciplinary design optimization (MDO) for aircrafts and the large-scale system theory was expatiated. Using the large-scale system theory, the system was decomposed gradually based on the different classification standards and the system characteristics. At the same time, the MDO methods for aircrafts were classified according to the decomposition-coordination method of the large-scale system theory. The theory background and applicable range of each algorithm were elucidated. Aircraft design system is a typical engineering large-scale system, and the basic of MDO for aircrafts is the large-scale system theory. Therefore, the large-scale system theory and MDO for aircrafts should be studied simultaneously to improve the MDO.

Modeling research on manufacturing execution system based on large-scale system cybernetics

A cybernetics model of manufacturing execution system (MES CM) was proposed and studied from the viewpoint of cybernetics. Combining with the features of manufacturing system, the MES CM was modeled by “generalized modeling” method that is discussed in large-scale system theory. The mathematical model of MES CM was constructed by the generalized operator model, and the main characteristics of MES CM were analyzed.

Semi-active Suspension and Its Control System Based on Large Scale System Theory

The mathematic model of whole vehicle semi-active suspension system is built on the basis of large-scale system theory. The fuzzy controller of time-delay semi-active suspension of the subsystems of suspension system is designed.By using the large-scale system hierarchical control theory,integrated control of vehicle suspension system is realized,the dynamic performance of vehicle is analyzed,and on the basis of simulation computer,road test of actual vehicle is carried out.The results show that the large-scale system hierarchical control system can improve the stability of control system,which opens a new way for the research of semi-active suspension and its control system.

Modelling and Operation Optimization and Flow Control of Large Scale Water Injection Systems

Abstract This paper presents a new method for modelling and operation optimization of large scale water injection systems. Systems of tms Kma usually consist of a great number of water injection stations.pipelines.valves.pipe fittings,and water injection wells, and is a multi-source multi-sink nonlinear time-vaiying system with thousands of vanables. A properly simplified and sufficiently accurate mathematical model lias been made by both the analytical method and the system identification method. A new operation optimization method has been developed for this system by the large scale system theory and the dynamic programming method To solve this optimization problem.the concept of pressure valley in hydrodynamic system is presented for the first time in this paper. The water uniection system is divided into a senes of subsystems according to pressure valleys It has been proved 1 that system optimization on the whole is equivalent to optimization of every subsystem in it if coupling variables of the subsvstems have the values resulting from the optimized system. Thus, rhe system optimization problem is decomposed into a senes of subsystem optimization problems. The above modelling method and operation optimization procedures are programmed in a software package. This package has been applied to an oilfield in Daqing Electnc power consumption for water injection decreased by 3- 10%,and waterflood efficiency improved.

Konstruktivismus und die Traditionen der Historik

The present article undertakes a systematic exposition of three divergent domains, ranging from core topics of radical constructivism up to current options of the historical sciences. In the first part, a constructivist explication of various concepts is performed which centres around notions like memory, remembering, time or communication. In a second step, a brief review is presented on major perspectives with respect to the philosophy of history, starting from the unexpectedly modern views within the enlightenment period and leading to the objective approaches of German historicism and, finally, to the current postobjectivist traditions. In a final section, two radically different options for contemporary historical sciences are outlined, namely, first, a literary departure of historiography and, second, a new orientation of the historical sciences as a theory of large-scale dynamical systems.