System Topological Structure Research Articles

A method for simplified modeling and capacity, state of charge, current distribution analysis based on arbitrary topology connection battery pack

To meet the electric energy requirements of electric vehicles (EVs), the battery cells in power battery pack are normally connected in series and parallel. During the process of battery manufacturing and storage, battery parameters of the same batch and type are inconsistent, which may lead to accelerated aging of power batteries. Because of the change of cell-to-cell parameters, varied battery system topology structure will result in different battery pack characteristics. For power battery pack system design and optimization, it is important to understand the relationship among inconsistent parameter distribution, topological connection and battery performance. The traditional bulk model is based on the external characteristics of the battery pack, ignoring the inconsistency of cell-to-cell parameters. In order to investigate the non-uniform characteristics of battery pack, a simplified modeling method for power battery pack is proposed in this paper, which takes into account the parameter inconsistency of the battery pack and is suitable for power batteries with arbitrary topology. Based on the equivalent circuit model (ECM), a parallel model of two-cells is established and extended to the ECM of arbitrary topology structure battery pack. The analytical solution of the battery model is simplified by s-domain analysis and the transformation of current source and voltage source model. Based on the simplified model of battery pack with arbitrary topology, the 104 times Monte Carlo simulations is used to analyze the capacity distribution, state of charge (SOC) difference and maximum current distribution of the battery pack under different topology structures and parameters. The Monte Carlo simulation solves the problem of complex analytical solution of battery system and greatly improves the simulation speed. The results show that the series connection increases the voltage, but it will reduce the capacity. The parallel connection increases the capacity of battery pack, but it will lead to the increase of SOC inconsistency, maximum current and standard deviation of capacity. This paper provides a theoretical basis for reducing the heterogeneity of battery pack and a reference basis for battery manufacturers.

Design and Study of a Series Active Filter for the 10MW-Level High Power and High Stability DC Power Supply

The output power of high stability dc power supply system, which drives the water-cooled magnet of Steady High Magnetic Field Facility (SHMFF), can reach up to tens of megawatt, so that the circuit usually adopts the realization scheme of Silicon-controlled rectifier plus LC filter. For the improvement of magnet current ripple, a novel series active filter (SAPF) is proposed, which adopts high-frequency switching technology and uses a switching power supply instead of a transistor or transformer in the traditional scheme in series at the output of the main power supply. The novel scheme has advantages of lower control complexity and less power loss, and thus higher engineering feasibility. In this paper, the system topology structure, operating principle and control policy are presented at first. Then the key part of the design is discussed, that is, how to accurately extract the output voltage ripple of the main power supply without delay. At last, a small prototype is made to verify the feasibility of the scheme.

Designing the Education Resource Management System Using Apriori Algorithm

Standardization of educational resources and advanced use of appropriate computer knowledge to construct an efficient educational management system is integral for the modern system of education in the age of digitalized education. In the context of this need, this study is aimed at analyzing the Apriori algorithm of education resource management system and its implementation. The Apriori algorithm is analyzed and studied in this paper. Firstly, the background and function of the Apriori algorithm are summarized. Secondly, the content of the Apriori algorithm is introduced in detail. The educational resources managed by this system all follow the Apriori algorithm. It is the most widely used distance education standard at present. In addition, the idea and method of making educational resources in the specification are also expounded. The educational resources made by using this method have higher sharing and reuse. The article analyzes the present situation of the education resource management system, for the insufficiency in its function. The solution for different shortcomings has been dealt with one by one and presented as a grid with an Apriori algorithm for technical support. Moreover, various heterogeneous education resources have been integrated to a unified standardization conforming to the Apriori algorithm. It has been scientifically designed to provide an application platform that can store and manage educational resources efficiently and query educational resources conveniently. The universities can not only effectively manage their own educational resources but also use the resources of other schools, so as to avoid the repeated construction of educational resources. This enables them to achieve the whole Apriori within the scope of resource sharing and reuse. On this basis, this paper gives the system architecture diagram and topological structure diagram of educational resource management system on the Apriori algorithm based, puts forward the design scheme of the system, and describes the system’s technical architecture and functional architecture, respectively.

Two-stage configuration optimization of a novel standalone renewable integrated energy system coupled with hydrogen refueling

Two-stage optimization framework of a novel hybrid renewable integrated energy system is proposed. Firstly, system topological structure and corresponding behaviors are constructed. In this system, renewable energy and conventional thermal power satisfy electricity, heating and cooling demands of the system, and hydrogen storage subsystem is extended for heavy-load fuel cell vehicle refueling. Next, a multi-objective model is constructed to minimize life-time cost of comprehensive loads (LCCL), energy externality rate (EER), and hydrogen hiatus rate (HHR). As for model solution stage, Kernel functions are applied to create typical day scenarios, which contain uncertain information and profoundly ease computational difficulty. Enhanced particle swarm optimization algorithm based on immune clone concept is applied to search non-inferior solutions. Additionally, preference of decision-makers is expanded in solution selection stage that includes more than objectives in the first stage. In the second stage, best Worst Method and Multi-attributive Border Approximation Area Comparison are applied to determine the optimal alternative that corresponds with subjective preference the best. To validate the model, a case in Datong city, Shanxi province in China is selected to validate the framework. Optimization result shows good performance, with LCCL 2.31 Yuan/kWh, EER 6.66%, and HHR 1.09%. Moreover, scenario analysis shows that 1) preference of decision-makers could dramatically influence the ideal solution; 2) double hydrogen refueling demands could be ensured. 3) solar photovoltaic alone could also support the system in Datong. 4) current carbon trade policy almost does not influence the system.

The energy flow method for modeling and optimization of Organic Rankine Cycle (ORC) systems

This contribution constructs the energy flow model for an ORC system, which synthetically considers fluid characteristics and governing laws of heat transfer and thermodynamic. Then, combined the Kirchhoff’s law with the thermodynamic constraints, a group of mathematical equations is obtained. It not only reveals both system topological structure and the component characteristics, but also connects the system output to the boundary conditions, the structural parameters and the operating parameters. Finally, operation optimizations for a certain ORC system are implemented via Genetic Algorithm (GA). Two sets of Pareto frontiers with different heat source conditions are obtained. The results show that with a 16 K increment of heat source temperature, the net power output and thermal efficiency will increase by 84% and 25%, respectively. In the other hand, the heat source flow rate shows limited impact on optimizations. Besides, design optimizations with the objective of minimizing required total thermal conductance are also conducted. It is concluded that enlarging net power output by 14.9% leads to an increase in the total thermal conductance by 54.3% and a decrease in the corresponding working fluid flow rate by 8.7%. Moreover, the operating parameters related to condenser other than evaporator remarkably influence the optimizations, and the characteristic temperatures vary with different conditions in each optimization. Therefore, the proposed method without fixed PPTD or condensation temperature is more flexible to both modeling and optimization.

Diagnosability of expanded k-ary n-cubes with missing edges under the comparison model

ABSTRACTThe diagnosability of multiprocessor systems is an important research topic. In 2017, Wang et al. extended the k-ary n-cube and defined an expanded k-ary n-cube, which is a system topology structure with good properties. In this paper, we prove that the expanded k-ary n-cube has the strong local diagnosability property for and , and it keeps this strong property even if there exist missing edges in it under the comparison model.

Survivability Evaluation Method for Cascading Failure of Electric Cyber Physical System Considering Load Optimal Allocation

The scale of the electric cyber physical system (ECPS) is continuously extending, and the existing cascade failure models ignore both the information flow and power flow transferring characteristics and also lack effective survivability analysis. In this paper, the quantitative evaluation method for cascading failure of ECPS survivability considering optimal load allocation is proposed. Firstly, according to the system topological structure and correlation, the degree-betweenness weighted correlation matrix of ECPS is established by defining the degree function as well as the electric betweenness, and the formal representation of coupled ECPS network model is realized. Secondly, based on the structural connectivity change and risk propagation range of ECPS cascade failure, the survivability evaluation model is designed by taking into account the constraints such as node load capacity limitation, information flow optimal allocation strategy, power flow optimization equation, and system safety operation. Finally, the firefly algorithm with chaotic Lévy flight is proposed to solve the evaluation model efficiently. The case study vividly shows that the evaluation method can effectively quantify the survivability of ECPS and thus enhance the evaluation efficiency of large-scale coupled systems.

Alleviating congestion of hybrid urban grid by VSC‐control and AC‐line switching

As electricity load in large cities overgrows these years, mainly due to the increasing penetration of electric vehicles, the urban transmission networks are subject to the high risk of congestion because of insufficient planning. Reconfigure the high-voltage distribution network (HVDN) is an efficient way to mitigate the urban congestion. However, the discrete load transfer amount is not precise that might cause load curtailment, and the computation burden is also heavy when the system scale is enormous. In recent years, the emergence of voltage source converter (VSC) as the core components of DC transmission technique provides a new control measurement featuring fast and flexible. Nevertheless, its adjusting capacity is limited and subject to the system topological structure. Thus this paper proposed a coordinative control model that combines the load transfer capability of the HVDN and flexible and precise control of VSC to alleviate the urban transmission congestion. Numerical results showed that the congestion lines could be efficiently relieved thus defer further investment in the transmission network.

Electrical LeaderRank method for node importance evaluation of power grids considering uncertainties of renewable energy

Node importance evaluation of power grids plays an important role in the safe operation and planning of power systems. This paper proposes an electrical LeaderRank (ELR) method to identify the important nodes in complex power grids, considering the renewable energy uncertainties, system topological structure, transmission power flow and the loss of loads caused by cascading failures. The proposed method uses an ELR value function to represent the importance of a system node, which can be derived iteratively from the weighted distribution strategy of its in-linked nodes. Furthermore, the uncertainties of wind and solar energy generation are modelled as interval numbers, and the interval power flow calculation is employed to obtain the interval power in transmission lines, direct adjacent matrix, and finally the interval ELR values. The performance of ELR method has been fully tested and benchmarked on the IEEE 118-bus power system and the Western Liaoning Power Grid of China. Comparative results on four performance criteria have not only demonstrated the validity and superiority of the proposed method, but also confirmed its capability to cope with the node importance evaluation of practical power grids.

Dynamical analysis and circuit implementation of a DC/DC single-stage boost converter with memristance load

The DC/DC boost converter can exhibit nonlinear phenomena like chaos and periodic motion, which are influenced by system parameters, topological structure, load and pulse period. In this paper, we mainly investigate these phenomena in a DC/DC single-stage current-mode-controlled boost converter. This study focuses on the nonlinear dynamics when the load is memristance. Two independent nonlinear models are derived when the switch S is closed and open, respectively, and the bifurcation behaviors of the boost converter are investigated. By adjusting the bifurcation parameters, i.e., the pulse period T, chaos and periodic motion occur. Finally, an experimental circuit is presented to implement the DC/DC boost converter system with a memristance load, and the experimental results agreed well with the numerical results.

Robustness of road systems to extreme flooding: using elements of GIS, travel demand, and network science

The main objective of this article is to study the robustness of road networks to extreme flooding events that can negatively affect entire regional systems in a relatively unpredictable way. Here, we adopt a deterministic approach to simulate extreme flooding events in two cities, New York City and Chicago, by removing entire sections of road systems using U.S. FEMA floodplains. We then measure changes in the number of real trips that can be completed (using travel demand data), Geographical Information Systems properties, and network topological indicators. We notably measure and discuss how betweenness centrality is being redistributed after flooding. Broadly, robustness in spatial systems like road networks is dependent on many factors, including system size (number of nodes and links) and topological structure of the network. Expectedly, robustness also depends on geography, and cities that are naturally more at risk will tend to be less robust, and therefore the notion of robustness rapidly becomes sensitive to individual contexts.

Research on the performance of multifunctional distributed optical fiber sensing system based on the combination of Brillouin optical time-domain analysis and phase-sensitive optical time-domain reflectometer

There are many similarities between Brillouin optical time-domain analysis and phase-sensitive optical time-domain reflectometer in system topological structure. A multifunctional distributed optical fiber sensing system based on their similarities and the combination of their topological structure is presented. The system can monitor strain and temperature, as well as detect and locate the intrusions or disturbances along the sensing fiber. Suppose that X is the width of the optical pulse incident into the sensing fiber with the unit of nanosecond and Y is the minimum detectable distance with the unit of meter between two intrusions that are being detected simultaneously. The experiment results show that y changes linearly with x according to the equation: y=0.103x−0.452. By optimizing device parameters of the system, strain measurement accuracy of 3.17 μϵ and the temperature measurement accuracy of 0.45°C have been realized when the optical pulse width is 30 ns. On the other hand, two intrusions have been detected and located simultaneously with this multifunctional system. The results show that the pulse width and the minimum distance between two intrusions (Lmin) have a linear relationship. The theoretical analyses and the experiment results show it is applicable to use this multifunctional system for strain and temperature monitoring, and intrusion detecting.

Parameter estimation and topology identification of uncertain general fractional-order complex dynamical networks with time delay

Complex networks have attracted much attention from various fields of sciences and engineering in recent years. However, many complex networks have various uncertain information, such as unknown or uncertain system parameters and topological structure, which greatly affects the system dynamics. Thus, the parameter estimation and structure identification problem has theoretical and practical importance for uncertain complex dynamical networks. This paper investigates identification of unknown system parameters and network topologies in uncertain fractional-order complex network with time delays (including coupling delay and node delay). Based on the stability theorem of fractional-order differential system and the adaptive control technique, a novel and general method is proposed to address this challenge. Finally two representative examples are given to verify the effectiveness of the proposed approach.

Remote Monitoring System of an Agricultural Tillage Machine Based on an Embedded ARM Technology Wireless Sensor

To solve the problems of monitoring system topology structure and joint ductility, as well as to improve the efficiency of agricultural planting, this study presents a greenhouse-monitoring system based on the advanced RISC machine (ARM) wireless sensor network. The design schemes of the hardware and software of the network nodes are presented, and the process of a ZigBee network coordinator is elucidated. The system uses ARM to control the wireless transceiver module for data transmission and reception as well to collect data through an inter-integrated circuit bus. The working-state data of the seeding machine are transmitted to the monitoring platform through the ZigBee network, which can achieve real-time data view. Test results show that the system has the advantages of a simple structure, a flexible node, and low power consumption. The effective monitoring of the agricultural seeding machine in a wireless environment is realized. This system can quickly monitor the agricultural seeding machine while working, and the data center allows reading the data for remote viewing and analysis. This system can also effectively reduce the workload of farmers, improve the efficiency of field sowing, and promote the rapid development of modern agriculture.

Finite-time synchronization and identification of complex delayed networks with Markovian jumping parameters and stochastic perturbations

In this paper, the finite-time synchronization and identification for the uncertain system parameters and topological structure of complex delayed networks with Markovian jumping parameters and stochastic perturbations is studied. On the strength of finite time stability theorem and appropriate stochastic Lyapunov–Krasovskii functional under the Itô’s formula, some sufficient conditions are obtained to assurance that the complex delayed networks with Markovian switching dynamic behavior can be identified the uncertain parameters and topological structure matrix in finite time under stochastic perturbations. In addition, three numerical simulations of different situation and dimension are presented to illustrate the effectiveness and feasibility of the theoretical results.

Underwater acoustic sensor array based on variable sampling rates and high precision synchronization

The performance of traditional underwater acoustic sensor array is limited in actual operation because of the single sampling rate and synchronization errors caused by the distribution of different hydrophones. To overcome these problems, a high precision synchronization method is presented. Firstly on the basis of the previous system, the function of variable sampling rate is accomplished by using a new system topology structure and an improved phase-locked loop (PLL). Secondly, fast resynchronization under sampling rates conversion is achieved by a novel resynchronization method. Thirdly, the ignored synchronization errors are compensated by embedding different delays to different hydrophones. Finally, related experiments verified the performance of the presented method.

THEORETICAL BASES OF CREATION OF DISTRIBUTED AUTOMATION SYSTEM AND CRITICALITY ASSESSMENT OF THE OBJECTS OF ITS STRUCTURE

The article analyzes the problem of choosing a rational variant of the distributed automated system, quality indicators, based on which selection is appropriate are justified and given. Formulation of the problem of synthesis of distributed AS is conducted. There are three levels: functional management tasks, elements of a topological structure, organizational structures, synthesis tasks are combined into two groups - the synthesis of topological and functional structures. A task sequence and steps of synthesis of AS structures were formed and an approach to synthesis of rational variant of the AS was arranged, based on the integrated use of fuzzy-targeted and cognitive models. Set of interrelated models and algorithms and schemes of their interaction in the synthesis of a system-topological and functional structure of the system is shown. The article also deals with the classification of objects of distributed AS in order to identify critical objects in the topological structure using the methods of cluster analysis. Indicators for the classification of a large AS knots were found. Models and methods, proposed in the article, can be used as a theoretical basis for the design of distributed automation systems.

RFID-enabled real-time manufacturing operation management system for the assembly process of mechanical products

In real discrete manufacturing industry, task urgency, plan variation and other uncertainties make it difficult to communicate process information. The information gap between the enterprise man- agement level and the process control level in workshop cause low productivity, unsmooth process flow, uncontrollable Work In Process (WIP) quantity and overstocked products. Aiming at this problem, a new RFID-enabled real-time manufacturing operation management system (RT-MOMS) is designed in this paper. In this system, RFID tags are used to mark assembly resources and monitor their status, RFID technology is employed to collect the real-time production information (e.g. equipment, material, WIP, operator, etc.), which can enhance the visibility, track ability and traceability of items of interest. Work- station and zone controller are united via the system integration interface to guarantee the information communication. Meanwhile, intelligent manufacturing resource is introduced to achieve the logical inte- gration of management operation system and the real-time visual management during the assembly process. The interaction process among RT-MOMS, system topology structure and main functional modules are also addressed. The result of RT-MOMS system's application on XinRui automotive gearbox assembly line shows that the proposed system can improve the productivity and quality and promote the application of RFID technology.

Research on Pipeline Gas Application System

This paper studied the traditional supervisory control and data acquisition and investigates what is the most important in pipeline gas management system. Then a novel scheme is proposed for remote control interface on pipeline gas providing management. This scheme introduced GPRS and internet network technology to the traditional supervisory control and data acquisition. The details of System topological structure is given and Remote control interface structure are listed. At last, the system performance is analyzed and the results indicate that pipeline gas management system using remote control interface has the excellent protection performance and operability of RCI. It can meet the demand of intelligent home and intelligent building.

Application of Cloud Storage in the Data Bank of Teaching Resources of Plane Design Specialty

Cloud storage is a new type of concept of digital information storage. In view of its advantages in distributed storage, collaborative storage, dynamic allocation storage space, smooth migration and backup, on the basis of the introduction of related concepts and unique advantages of cloud storage, the present essay introduced cloud storage into the data bank of plane design materials, and constructed a scheme of cloud storage of the data bank of the plane design materials from the three aspects of system structure, topological structure and function module.