Large-scale new energy grid connection leads to the weakening of the system frequency regulation capability,and the system frequency stability is facing unprecedented challenges.In order to solve rapid frequency fluct...Large-scale new energy grid connection leads to the weakening of the system frequency regulation capability,and the system frequency stability is facing unprecedented challenges.In order to solve rapid frequency fluctuation caused by new energy units,this paper proposes a new energy power system frequency regulation strategy with multiple units including the doubly-fed pumped storage unit(DFPSU).Firstly,based on the model predictive control(MPC)theory,the state space equations are established by considering the operating characteristics of the units and the dynamic behavior of the system;secondly,the proportional-differential control link is introduced to minimize the frequency deviation to further optimize the frequency modulation(FM)output of the DFPSU and inhibit the rapid fluctuation of the frequency;lastly,it is verified on theMatlab/Simulink simulation platform,and the results show that the model predictive control with proportional-differential control link can further release the FM potential of the DFPSU,increase the depth of its FM,effectively reduce the frequency deviation of the system and its rate of change,realize the optimization of the active output of the DFPSU and that of other units,and improve the frequency response capability of the system.展开更多
Controller Link 是 OMRON 推出的一种 FA 网络,能在 PLC、计算机等节点间方便、灵活地发送和接收大容量数据包,且实时性、可靠性较高。本文对 Controller Link 的组网技术进行深入研究,详细介绍了该网络的性能、硬件配置、网络组态、...Controller Link 是 OMRON 推出的一种 FA 网络,能在 PLC、计算机等节点间方便、灵活地发送和接收大容量数据包,且实时性、可靠性较高。本文对 Controller Link 的组网技术进行深入研究,详细介绍了该网络的性能、硬件配置、网络组态、通讯链接和网络监控设计技术。展开更多
This paper presents a control method for the Doubly-fed Induction Generator connected to a dc link through a diode bridge on the stator. In this system, the rotor is fed, at the slip frequency, by a PWM electronic con...This paper presents a control method for the Doubly-fed Induction Generator connected to a dc link through a diode bridge on the stator. In this system, the rotor is fed, at the slip frequency, by a PWM electronic converter and the stator is directly connected to the dc link using a simple diode bridge. The cost of power electronics is reduced in this system when compared with the classic DFIG machine because the system uses less one PWM inverter and additionally it uses a diode bridge. The application in mind is for microgrids. Microgrids need several elements that should work together. The usual way to connect these elements is to use power electronic devices in a common dc link. This paper presents a new form for the DFIG for this application and presents a control system for the inner control loop. Simulation and experimental results show that the system can work acceptably using a stator frequency near the rated frequency of the machine.展开更多
Networking is the important part of the computer networks. Multicasting is also one of the essential areas of networking. In multicasting, sender can send information or data to the group of end receivers in a single ...Networking is the important part of the computer networks. Multicasting is also one of the essential areas of networking. In multicasting, sender can send information or data to the group of end receivers in a single transmission. It is a big issue because of more data demands of receivers which cause the congestion. Multicast is one of the crucial method to avoid congestion and make network perform stably. In this paper, we propose, link utilization algorithm to deal with multicast congestion control. We propose the equation to improve the utilization of the channel or link. The simulation results show that proposed work provide the better throughput of the network with respect to sending rate, queue size, packet loss ratio and time.展开更多
In view of the lack of research on the information model of tufting carpet machine in China,an information modeling method based on Object Linking and Embedding for Process Control Unified Architecture(OPC UA)framewor...In view of the lack of research on the information model of tufting carpet machine in China,an information modeling method based on Object Linking and Embedding for Process Control Unified Architecture(OPC UA)framework was proposed to solve the problem of“information island”caused by the differentiated data interface between heterogeneous equipment and system in tufting carpet machine workshop.This paper established an information model of tufting carpet machine based on analyzing the system architecture,workshop equipment composition and information flow of the workshop,combined with the OPC UA information modeling specification.Subsequently,the OPC UA protocol is used to instantiate and map the information model,and the OPC UA server is developed.Finally,the practicability of tufting carpet machine information model under the OPC UA framework and the feasibility of realizing the information interconnection of heterogeneous devices in the tufting carpet machine digital workshop are verified.On this basis,the cloud and remote access to the underlying device data are realized.The application of this information model and information integration scheme in actual production explores and practices the application of OPC UA technology in the digital workshop of tufting carpet machine.展开更多
The influence of long-range links on spiral waves in an excitable medium has been investigated. Spatiotemporal dynamics in an excitable small-world network transform remarkably when we increase the long-range connecti...The influence of long-range links on spiral waves in an excitable medium has been investigated. Spatiotemporal dynamics in an excitable small-world network transform remarkably when we increase the long-range connection probability P. Spiral waves with few perturbations, broken spiral waves, pseudo spiral turbulence, synchronous oscillations, and homogeneous rest state are discovered under different network structures. Tip number is selected to detect non-equilibrium phase transition between different spatiotemporal patterns. The Kuramoto order parameter is used to identify these patterns and explain the emergence of the rest state. Finally, we use long-range links to successfully control spiral waves and spiral turbulence.展开更多
基金supported by the National Natural Science Foundation of China(Project No.52377082)the Scientific Research Program of Jilin Provincial Department of Education(Project No.JJKH20230123KJ).
文摘Large-scale new energy grid connection leads to the weakening of the system frequency regulation capability,and the system frequency stability is facing unprecedented challenges.In order to solve rapid frequency fluctuation caused by new energy units,this paper proposes a new energy power system frequency regulation strategy with multiple units including the doubly-fed pumped storage unit(DFPSU).Firstly,based on the model predictive control(MPC)theory,the state space equations are established by considering the operating characteristics of the units and the dynamic behavior of the system;secondly,the proportional-differential control link is introduced to minimize the frequency deviation to further optimize the frequency modulation(FM)output of the DFPSU and inhibit the rapid fluctuation of the frequency;lastly,it is verified on theMatlab/Simulink simulation platform,and the results show that the model predictive control with proportional-differential control link can further release the FM potential of the DFPSU,increase the depth of its FM,effectively reduce the frequency deviation of the system and its rate of change,realize the optimization of the active output of the DFPSU and that of other units,and improve the frequency response capability of the system.
文摘This paper presents a control method for the Doubly-fed Induction Generator connected to a dc link through a diode bridge on the stator. In this system, the rotor is fed, at the slip frequency, by a PWM electronic converter and the stator is directly connected to the dc link using a simple diode bridge. The cost of power electronics is reduced in this system when compared with the classic DFIG machine because the system uses less one PWM inverter and additionally it uses a diode bridge. The application in mind is for microgrids. Microgrids need several elements that should work together. The usual way to connect these elements is to use power electronic devices in a common dc link. This paper presents a new form for the DFIG for this application and presents a control system for the inner control loop. Simulation and experimental results show that the system can work acceptably using a stator frequency near the rated frequency of the machine.
文摘Networking is the important part of the computer networks. Multicasting is also one of the essential areas of networking. In multicasting, sender can send information or data to the group of end receivers in a single transmission. It is a big issue because of more data demands of receivers which cause the congestion. Multicast is one of the crucial method to avoid congestion and make network perform stably. In this paper, we propose, link utilization algorithm to deal with multicast congestion control. We propose the equation to improve the utilization of the channel or link. The simulation results show that proposed work provide the better throughput of the network with respect to sending rate, queue size, packet loss ratio and time.
文摘In view of the lack of research on the information model of tufting carpet machine in China,an information modeling method based on Object Linking and Embedding for Process Control Unified Architecture(OPC UA)framework was proposed to solve the problem of“information island”caused by the differentiated data interface between heterogeneous equipment and system in tufting carpet machine workshop.This paper established an information model of tufting carpet machine based on analyzing the system architecture,workshop equipment composition and information flow of the workshop,combined with the OPC UA information modeling specification.Subsequently,the OPC UA protocol is used to instantiate and map the information model,and the OPC UA server is developed.Finally,the practicability of tufting carpet machine information model under the OPC UA framework and the feasibility of realizing the information interconnection of heterogeneous devices in the tufting carpet machine digital workshop are verified.On this basis,the cloud and remote access to the underlying device data are realized.The application of this information model and information integration scheme in actual production explores and practices the application of OPC UA technology in the digital workshop of tufting carpet machine.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11105003)the Science Foundation of the Education Bureau of Shaanxi Province of China (Grant No. 11JK0544)
文摘The influence of long-range links on spiral waves in an excitable medium has been investigated. Spatiotemporal dynamics in an excitable small-world network transform remarkably when we increase the long-range connection probability P. Spiral waves with few perturbations, broken spiral waves, pseudo spiral turbulence, synchronous oscillations, and homogeneous rest state are discovered under different network structures. Tip number is selected to detect non-equilibrium phase transition between different spatiotemporal patterns. The Kuramoto order parameter is used to identify these patterns and explain the emergence of the rest state. Finally, we use long-range links to successfully control spiral waves and spiral turbulence.
