Multi-agent system (MAS) can provide flexible and intelligent control for micro-grid (MG). In this paper, a new power coordination method of MAS is presented for MG. New way for dispatching controllable generations (...Multi-agent system (MAS) can provide flexible and intelligent control for micro-grid (MG). In this paper, a new power coordination method of MAS is presented for MG. New way for dispatching controllable generations (CGs) and direct cooperation between storages and CGs are designed. Real-time emulations of the coordination, including the usage of both CGs and storages, have been carried out in islanded situation basing on this method, and much higher performance than conventional method is found.展开更多
Given the increasing uncertainties in power supply and load,this paper proposes the concept of power source and grid coordination uniformity planning.In this approach,the standard deviation of the transmission line lo...Given the increasing uncertainties in power supply and load,this paper proposes the concept of power source and grid coordination uniformity planning.In this approach,the standard deviation of the transmission line load rate is considered as the uniformity evaluation index for power source and grid planning.A multi-stage and multi-objective optimization model of the power source and grid expansion planning is established to minimize the comprehensive cost of the entire planning cycle.In this study,the improved particle swarm optimization algorithm and genetic algorithm are combined to solve the model,thus improving the efficiency and accuracy of the solution.The analysis of a simple IEEE Garver’s 6-node system shows that the model and solution method are effective and feasible.Moreover,they are suitable for the coordinated planning of the power source and grid under a diversified nature of power supply and load.展开更多
Lu:If the tense situations in the Middle East and Northeast Asiabecome relaxed,it would certainly exert great influence on world politi-cal pattern.Can non-traditional security solve the contradictions in thetradition...Lu:If the tense situations in the Middle East and Northeast Asiabecome relaxed,it would certainly exert great influence on world politi-cal pattern.Can non-traditional security solve the contradictions in thetraditional security field?Will the major powers continue to cooperate inthe anti-terrorist campaign?All these issues will face challenges展开更多
Modern computer systems are increasingly bounded by the available or permissible power at multiple layers from individual components to data centers.To cope with this reality,it is necessary to understand how power bo...Modern computer systems are increasingly bounded by the available or permissible power at multiple layers from individual components to data centers.To cope with this reality,it is necessary to understand how power bounds im-pact performance,especially for systems built from high-end nodes,each consisting of multiple power hungry components.Because placing an inappropriate power bound on a node or a component can lead to severe performance loss,coordinat-ing power allocation among nodes and components is mandatory to achieve desired performance given a total power bud-get.In this article,we describe the paradigm of power bounded high-performance computing,which considers coordinated power bound assignment to be a key factor in computer system performance analysis and optimization.We apply this paradigm to the problem of power coordination across multiple layers for both CPU and GPU computing.Using several case studies,we demonstrate how the principles of balanced power coordination can be applied and adapted to the inter-play of workloads,hardware technology,and the available total power for performance improvement.展开更多
The dual-mode electro-mechanical transmission(EMT)system is a crucial part of power-split hybrid electric vehicles(HEVs),especially for the heavy HEVs.To improve the precision of the system power distribution and the ...The dual-mode electro-mechanical transmission(EMT)system is a crucial part of power-split hybrid electric vehicles(HEVs),especially for the heavy HEVs.To improve the precision of the system power distribution and the response speed of the electric power supply,a model-based double closed-loop coordinated control strategy is proposed.As the basis of the proposed control strategy,an EMT system model,particularly of an electrical system,is established first.The proposed control strategy includes the power distribution strategy,battery power closed-loop feedback control strategy,and motor coordinated control strategy.To verify the feasibility of the proposed control strategy,simulation and experiment are performed.The results indicate that the proposed control strategy can realize the expected power distribution by coordinating generators and motors and achieve rapid and stable electric power supply.展开更多
First, a three-tier coordinated scheduling system consisting of a distribution network dispatch layer, a microgrid centralized control layer, and local control layer in the energy internet is proposed. The multi-time ...First, a three-tier coordinated scheduling system consisting of a distribution network dispatch layer, a microgrid centralized control layer, and local control layer in the energy internet is proposed. The multi-time scale optimal scheduling of the microgrid based on Model Predictive Control（MPC） is then studied, and the optimized genetic algorithm and the microgrid multi-time rolling optimization strategy are used to optimize the datahead scheduling phase and the intra-day optimization phase. Next, based on the three-tier coordinated scheduling architecture, the operation loss model of the distribution network is solved using the improved branch current forward-generation method and the genetic algorithm. The optimal scheduling of the distribution network layer is then completed. Finally, the simulation examples are used to compare and verify the validity of the method.展开更多
In the Internet of Things（IoT）, various battery-powered wireless devices are connected to collect and exchange data, and typical traffic is periodic and heterogeneous. Polling with power management is a very promisi...In the Internet of Things（IoT）, various battery-powered wireless devices are connected to collect and exchange data, and typical traffic is periodic and heterogeneous. Polling with power management is a very promising technique that can be used for communication among these devices in the IoT. In this paper, we propose a novel and scalable model to study the delay and the power consumption performance for polling schemes with power management under heterogeneous settings（particularly the heterogeneous sleeping interval）. In our model,by introducing the concept of virtual polling interval, we successfully convert the considered energy-efficient polling scheme into an equivalent purely-limited vacation system. Thus, we can easily evaluate the mean and variance of the delay and the power consumption by applying existing queueing formulae, without developing a new theoretical model as required in previous works. Extensive simulations show that our analytical results are very accurate for both homogeneous and heterogeneous settings.展开更多
In the existing multi-period robust optimization methods for the optimal power flow in radial distribution systems,the capability of distributed generators(DGs)to regulate the reactive power,the operation costs of the...In the existing multi-period robust optimization methods for the optimal power flow in radial distribution systems,the capability of distributed generators(DGs)to regulate the reactive power,the operation costs of the regulation equipment,and the current of the shunt capacitor of the cables are not considered.In this paper,a multi-period two-stage robust scheduling strategy that aims to minimize the total cost of the power supply is developed.This strategy considers the time-ofuse price,the capability of the DGs to regulate the active and reactive power,the action costs of the regulation equipment,and the current of the shunt capacitors of the cables in a radial distribution system.Furthermore,the numbers of variables and constraints in the first-stage model remain constant during the iteration to enhance the computation efficiency.To solve the second-stage model,only the model of each period needs to be solved.Then,their objective values are accumulated,revealing that the computation rate using the proposed method is much higher than that of existing methods.The effectiveness of the proposed method is validated by actual 4-bus,IEEE 33-bus,and PG 69-bus distribution systems.展开更多
The coordinated control of multiple-sources including wind,photovoltaic(PV)and storage brings new challenges to traditional dispatch and control technologies.This paper firstly introduces a framework of wind,PV and st...The coordinated control of multiple-sources including wind,photovoltaic(PV)and storage brings new challenges to traditional dispatch and control technologies.This paper firstly introduces a framework of wind,PV and storage co-generation monitoring system.Then,key technologies of co-generation monitoring system including day-ahead optimal dispatching,active power coordinated control and reactive power and voltage control are proposed.The framework and the techniques described in this paper have been applied in the National Wind,Photovoltaic,Storage and Transmission Demonstration Project of China,and their validity have been tested and verified.展开更多
The current planning system in China lacks coordination, which is a crucial issue to be explored to fully implement the multi-plan integration. Mianzhu is an example that is officially named as one of the pilot cities...The current planning system in China lacks coordination, which is a crucial issue to be explored to fully implement the multi-plan integration. Mianzhu is an example that is officially named as one of the pilot cities for multi-plan integration on the county level. The paper firstly analyzes the problems associated with multi-plan integration in Mianzhu, including the indeterminate hierarchy of the planning system, the disunity of technical standards, problems regarding spatial order, coordination and division of powers and functions, and the intensive utilization of spatial resources, the lack of a coordination mechanism, and low participation of experts and the public. Secondly, by learning from Germany's spatial planning, and also practical experiences of pilot cities for multi-plan integration in China, this paper creatively brings in the connotation of multi-plan integration on the county level, and further proposes a power division based on three-level planning system and three kinds of space, the reinforcement of a spatial order, intensive spatial utilization, and a planning coordination mechanism, hoping to provide reference to other cities.展开更多
The aim of this paper is the formulation of the finite element method in polar coordinates to solve transient heat conduction problems. It is hard to find in the literature a formulation of the finite element method(F...The aim of this paper is the formulation of the finite element method in polar coordinates to solve transient heat conduction problems. It is hard to find in the literature a formulation of the finite element method(FEM) in polar or cylindrical coordinates for the solution of heat transfer problems. This document shows how to apply the most often used boundary conditions. The global equation system is solved by the Crank-Nicolson method. The proposed algorithm is verified in three numerical tests. In the first example, the obtained transient temperature distribution is compared with the temperature obtained from the presented analytical solution. In the second numerical example, the variable boundary condition is assumed. In the last numerical example the component with the shape different than cylindrical is used. All examples show that the introduction of the polar coordinate system gives better results than in the Cartesian coordinate system. The finite element method formulation in polar coordinates is valuable since it provides a higher accuracy of the calculations without compacting the mesh in cylindrical or similar to tubular components. The proposed method can be applied for circular elements such as boiler drums, outlet headers, flux tubes. This algorithm can be useful during the solution of inverse problems, which do not allow for high density grid. This method can calculate the temperature distribution in the bodies of different properties in the circumferential and the radial direction. The presented algorithm can be developed for other coordinate systems. The examples demonstrate a good accuracy and stability of the proposed method.展开更多
Coordinated multi-point transmission and reception （CoMP） for single user, named as SU-CoMP, is considered as an efficient approach to mitigate inter-cell interference in orthogonal frequency division multiple acce...Coordinated multi-point transmission and reception （CoMP） for single user, named as SU-CoMP, is considered as an efficient approach to mitigate inter-cell interference in orthogonal frequency division multiple access （OFDMA） systems. Two prevalent approaches in SU-CoMP are coordinated scheduling （CS） and joint processing （JP）. Although JP in SU-CoMP has been proved to achieve a great link performance improvement for the cell-edge user, efficient resource allocation （RA） on the system level is quite needed. However, so far limited work has been done considering JP, and most existing schemes achieved the improvement of cell-edge performance at cost of the cell-average performance degradation compared to the single cell RA. In this paper, a two-phase strategy is proposed for SU-CoMP networks. CS and JP are combined to improve both cell-edge and cell-average performance. Compared to the single cell RA, simulation results demonstrate that, the proposed strategy leads to both higher cell-average and cell-edge throughput.展开更多
文摘Multi-agent system (MAS) can provide flexible and intelligent control for micro-grid (MG). In this paper, a new power coordination method of MAS is presented for MG. New way for dispatching controllable generations (CGs) and direct cooperation between storages and CGs are designed. Real-time emulations of the coordination, including the usage of both CGs and storages, have been carried out in islanded situation basing on this method, and much higher performance than conventional method is found.
基金supported by Theoretical study of power system synergistic dispatch National Science Foundation of China(51477091).
文摘Given the increasing uncertainties in power supply and load,this paper proposes the concept of power source and grid coordination uniformity planning.In this approach,the standard deviation of the transmission line load rate is considered as the uniformity evaluation index for power source and grid planning.A multi-stage and multi-objective optimization model of the power source and grid expansion planning is established to minimize the comprehensive cost of the entire planning cycle.In this study,the improved particle swarm optimization algorithm and genetic algorithm are combined to solve the model,thus improving the efficiency and accuracy of the solution.The analysis of a simple IEEE Garver’s 6-node system shows that the model and solution method are effective and feasible.Moreover,they are suitable for the coordinated planning of the power source and grid under a diversified nature of power supply and load.
文摘Lu:If the tense situations in the Middle East and Northeast Asiabecome relaxed,it would certainly exert great influence on world politi-cal pattern.Can non-traditional security solve the contradictions in thetraditional security field?Will the major powers continue to cooperate inthe anti-terrorist campaign?All these issues will face challenges
基金supported in part by the U.S.National Science Foundation under Grant Nos.CCF-1551511 and CNS-1551262.
文摘Modern computer systems are increasingly bounded by the available or permissible power at multiple layers from individual components to data centers.To cope with this reality,it is necessary to understand how power bounds im-pact performance,especially for systems built from high-end nodes,each consisting of multiple power hungry components.Because placing an inappropriate power bound on a node or a component can lead to severe performance loss,coordinat-ing power allocation among nodes and components is mandatory to achieve desired performance given a total power bud-get.In this article,we describe the paradigm of power bounded high-performance computing,which considers coordinated power bound assignment to be a key factor in computer system performance analysis and optimization.We apply this paradigm to the problem of power coordination across multiple layers for both CPU and GPU computing.Using several case studies,we demonstrate how the principles of balanced power coordination can be applied and adapted to the inter-play of workloads,hardware technology,and the available total power for performance improvement.
基金The authors are grateful for the financial support from the National Natural Science Foundation of China(Grant Nos.51705480,No.51575043,Nos.51975048,U1564210,and U1764257).
文摘The dual-mode electro-mechanical transmission(EMT)system is a crucial part of power-split hybrid electric vehicles(HEVs),especially for the heavy HEVs.To improve the precision of the system power distribution and the response speed of the electric power supply,a model-based double closed-loop coordinated control strategy is proposed.As the basis of the proposed control strategy,an EMT system model,particularly of an electrical system,is established first.The proposed control strategy includes the power distribution strategy,battery power closed-loop feedback control strategy,and motor coordinated control strategy.To verify the feasibility of the proposed control strategy,simulation and experiment are performed.The results indicate that the proposed control strategy can realize the expected power distribution by coordinating generators and motors and achieve rapid and stable electric power supply.
基金supported by Beijing Municipal Science Technology commission research(No.Z171100000317003)
文摘First, a three-tier coordinated scheduling system consisting of a distribution network dispatch layer, a microgrid centralized control layer, and local control layer in the energy internet is proposed. The multi-time scale optimal scheduling of the microgrid based on Model Predictive Control（MPC） is then studied, and the optimized genetic algorithm and the microgrid multi-time rolling optimization strategy are used to optimize the datahead scheduling phase and the intra-day optimization phase. Next, based on the three-tier coordinated scheduling architecture, the operation loss model of the distribution network is solved using the improved branch current forward-generation method and the genetic algorithm. The optimal scheduling of the distribution network layer is then completed. Finally, the simulation examples are used to compare and verify the validity of the method.
基金supported by Macao FDCT-MOST grant 001/2015/AMJ, Macao FDCT grants 013/2014/A1 and 005/2016/A1the National Natural Science Foundation of China (Nos. 61373027 and 61672321)the Natural Science Foundation of Shandong Province (No. ZR2012FM023)
文摘In the Internet of Things（IoT）, various battery-powered wireless devices are connected to collect and exchange data, and typical traffic is periodic and heterogeneous. Polling with power management is a very promising technique that can be used for communication among these devices in the IoT. In this paper, we propose a novel and scalable model to study the delay and the power consumption performance for polling schemes with power management under heterogeneous settings（particularly the heterogeneous sleeping interval）. In our model,by introducing the concept of virtual polling interval, we successfully convert the considered energy-efficient polling scheme into an equivalent purely-limited vacation system. Thus, we can easily evaluate the mean and variance of the delay and the power consumption by applying existing queueing formulae, without developing a new theoretical model as required in previous works. Extensive simulations show that our analytical results are very accurate for both homogeneous and heterogeneous settings.
基金supported in part by the Fundamental Research Funds for the Central Universities of China(No.PA2021GDSK0083)in part by the State Key Program of National Natural Science of China(No.51637004)in part by the National Key Research and Development Plan“Important Scientific Instruments and Equipment Development”(No.2016YFF0102200)。
文摘In the existing multi-period robust optimization methods for the optimal power flow in radial distribution systems,the capability of distributed generators(DGs)to regulate the reactive power,the operation costs of the regulation equipment,and the current of the shunt capacitor of the cables are not considered.In this paper,a multi-period two-stage robust scheduling strategy that aims to minimize the total cost of the power supply is developed.This strategy considers the time-ofuse price,the capability of the DGs to regulate the active and reactive power,the action costs of the regulation equipment,and the current of the shunt capacitors of the cables in a radial distribution system.Furthermore,the numbers of variables and constraints in the first-stage model remain constant during the iteration to enhance the computation efficiency.To solve the second-stage model,only the model of each period needs to be solved.Then,their objective values are accumulated,revealing that the computation rate using the proposed method is much higher than that of existing methods.The effectiveness of the proposed method is validated by actual 4-bus,IEEE 33-bus,and PG 69-bus distribution systems.
文摘The coordinated control of multiple-sources including wind,photovoltaic(PV)and storage brings new challenges to traditional dispatch and control technologies.This paper firstly introduces a framework of wind,PV and storage co-generation monitoring system.Then,key technologies of co-generation monitoring system including day-ahead optimal dispatching,active power coordinated control and reactive power and voltage control are proposed.The framework and the techniques described in this paper have been applied in the National Wind,Photovoltaic,Storage and Transmission Demonstration Project of China,and their validity have been tested and verified.
基金supported by the Science and Technology Projects for People of Chengdu Municipal Science and Technology Bureau(2015-HM01-00356-SF)Sichuan Tourism Development and Research Center Project(LYC15-14)Project of Resource-Based Urban Development Research Center(ZYZXYB-1506)
文摘The current planning system in China lacks coordination, which is a crucial issue to be explored to fully implement the multi-plan integration. Mianzhu is an example that is officially named as one of the pilot cities for multi-plan integration on the county level. The paper firstly analyzes the problems associated with multi-plan integration in Mianzhu, including the indeterminate hierarchy of the planning system, the disunity of technical standards, problems regarding spatial order, coordination and division of powers and functions, and the intensive utilization of spatial resources, the lack of a coordination mechanism, and low participation of experts and the public. Secondly, by learning from Germany's spatial planning, and also practical experiences of pilot cities for multi-plan integration in China, this paper creatively brings in the connotation of multi-plan integration on the county level, and further proposes a power division based on three-level planning system and three kinds of space, the reinforcement of a spatial order, intensive spatial utilization, and a planning coordination mechanism, hoping to provide reference to other cities.
文摘The aim of this paper is the formulation of the finite element method in polar coordinates to solve transient heat conduction problems. It is hard to find in the literature a formulation of the finite element method(FEM) in polar or cylindrical coordinates for the solution of heat transfer problems. This document shows how to apply the most often used boundary conditions. The global equation system is solved by the Crank-Nicolson method. The proposed algorithm is verified in three numerical tests. In the first example, the obtained transient temperature distribution is compared with the temperature obtained from the presented analytical solution. In the second numerical example, the variable boundary condition is assumed. In the last numerical example the component with the shape different than cylindrical is used. All examples show that the introduction of the polar coordinate system gives better results than in the Cartesian coordinate system. The finite element method formulation in polar coordinates is valuable since it provides a higher accuracy of the calculations without compacting the mesh in cylindrical or similar to tubular components. The proposed method can be applied for circular elements such as boiler drums, outlet headers, flux tubes. This algorithm can be useful during the solution of inverse problems, which do not allow for high density grid. This method can calculate the temperature distribution in the bodies of different properties in the circumferential and the radial direction. The presented algorithm can be developed for other coordinate systems. The examples demonstrate a good accuracy and stability of the proposed method.
基金supported by the National Natural Science Foundation of China (61001116)State Emphasis Special Project 2009ZX03003-011-02+1 种基金the Hi-Tech Research and Development Program of China (2009AA011506)International Scientific and Technological Cooperation Program (2010DFA11060)
文摘Coordinated multi-point transmission and reception （CoMP） for single user, named as SU-CoMP, is considered as an efficient approach to mitigate inter-cell interference in orthogonal frequency division multiple access （OFDMA） systems. Two prevalent approaches in SU-CoMP are coordinated scheduling （CS） and joint processing （JP）. Although JP in SU-CoMP has been proved to achieve a great link performance improvement for the cell-edge user, efficient resource allocation （RA） on the system level is quite needed. However, so far limited work has been done considering JP, and most existing schemes achieved the improvement of cell-edge performance at cost of the cell-average performance degradation compared to the single cell RA. In this paper, a two-phase strategy is proposed for SU-CoMP networks. CS and JP are combined to improve both cell-edge and cell-average performance. Compared to the single cell RA, simulation results demonstrate that, the proposed strategy leads to both higher cell-average and cell-edge throughput.
