The baseline performance of the latest version （version 2） of an intermediate resolution, stand-alone climate oceanic general circulation model, called LASG/IAP （State Key Laboratory of Numerical Modeling for Atmos...The baseline performance of the latest version （version 2） of an intermediate resolution, stand-alone climate oceanic general circulation model, called LASG/IAP （State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics/Institute of Atmospheric Physics） Climate system Ocean Model （LICOM）, has been evaluated against the observation by using the main metrics from Griffies et al. in 2009. In general, the errors of LICOM2 in the water properties and in the circulation are comparable with the models of Coordinated Ocean-ice Reference Experiments （COREs）. Some common biases are still evident in the present version, such as the cold bias in the eastern Facific cold tongue, the warm biases off the east coast of the basins~ the weak poleward heat transport in the Atlantic, and the relatively large biases in the Arctic Ocean. A unique systematic bias occurs in LICOM2 over the Southern Ocean, compared with CORE models. It seems that this bias may be related to the sea ice process around the Antarctic continent.展开更多
Based on the large-scale penetration of electric vehicles(EV)into the building cluster,a multi-objective optimal strategy considering the coordinated dispatch of EV is proposed,for improving the safe and economical op...Based on the large-scale penetration of electric vehicles(EV)into the building cluster,a multi-objective optimal strategy considering the coordinated dispatch of EV is proposed,for improving the safe and economical operation problems of distribution network.The system power loss and node voltage excursion can be effectively reduced,by taking measures of time-of-use(TOU)price mechanism bonded with the reactive compensation of energy storage devices.Firstly,the coordinate charging/discharging load model for EV has been established,to obtain a narrowed gap between load peak and valley.Next,a multi-objective optimization model of the distribution grid is also defined,and the active power loss and node voltage fluctuation are chosen to be the objective function.For improving the efficiency of optimization process,an advanced genetic algorithm associated with elite preservation policy is used.Finally,reactive compensation capacity supplied by capacitor banks is dynamically determined according to the varying building loads.The proposed strategy is demonstrated on the IEEE 33-node test case,and the simulation results show that the power supply pressure can be obviously relieved by introducing the coordinated charging/discharging behavior of EV;in the meantime,via reasonable planning of the compensation capacitor,the remarkably lower active power loss and voltage excursion can be realized,ensuring the safe and economical operation of the distribution system.展开更多
The observation stations of Northern China are divided into three regions:the arid Northwest China,the Loess Plateau,and the cool Northeast China.The consistencies,differences,and associated mechanisms of land surface...The observation stations of Northern China are divided into three regions:the arid Northwest China,the Loess Plateau,and the cool Northeast China.The consistencies,differences,and associated mechanisms of land surface thermal-hydrologic processes among the three regions were studied based on the normalization of major variables of land surface thermal-hydrologic processes,using data collected during prevailing summer monsoon period(July and August,2008).It is shown that differences of surface thermal-hydrologic processes are remarkable among the three regions because of different impacts of summer monsoon.Especially their soil wet layers occur at different depths,and the average albedo and its diurnal variations are distinctly different.Surface net short-wave radiation in the Loess Plateau is close to that in the cool Northeast China,but its surface net long-wave radiation is close to that in the arid Northwest China.And the ratio of net radiation to global solar radiation in the cool Northeast China is higher than the other two regions,though its temperature is lower.There are obvious regional differences in the ratios of surface sensible and latent heat fluxes to net radiation for the three regions because of distinct contribution of sensible and latent heat fluxesto land surface energy balance.The three regions are markedly different in the ratio of water vapor flux to pan evaporation,but they are consistent in the ratio of water vapor flux to precipitation.These results not only indicate different influences of climate and environmental factors on land surface thermal-hydrologic processes in the three regions,but also show that summer monsoon is important in the formation and variation of the pattern of land surface thermal-hydrologic processes.展开更多
The strict control measures and social lockdowns initiated to combat COVID-19 epidemic have had a notable impact on air pollutant concentrations.According to observation data obtained from the China National Environme...The strict control measures and social lockdowns initiated to combat COVID-19 epidemic have had a notable impact on air pollutant concentrations.According to observation data obtained from the China National Environmental Monitoring Center,compared to levels in 2019,the average concentration of NO_(2) in early 2020 during COVID-19 epidemic has decreased by 53%,50%,and 30%in Wuhan city,Hubei Province(Wuhan excluded),and China(Hubei excluded),respectively.Simultaneously,PM_(2.5) concentration has decreased by 35%,29%,and 19%in Wuhan,Hubei(Wuhan excluded),and China(Hubei excluded),respectively.Less significant declines have also been found for SO_(2) and CO concentrations.We also analyzed the temporal variation and spatial distribution of air pollutant concentrations in China during COVID-19 epidemic.The decreases in PM_(2.5) and NO_(2) concentrations showed relatively consistent temporal variation and spatial distribution.These results support control of NO x to further reduce PM_(2.5) pollution in China.The concurrent decrease in NOx and PM_(2.5) concentrations resulted in an increase of O3 concentrations across China during COVID-19 epidemic,indicating that coordinated control of other pollutants is needed.展开更多
Urbanization is a comprehensive concept, a trinity process that population urbanization, economic urbanization and space urbanization, is based on the interactions and mutual influences among the in which, people are ...Urbanization is a comprehensive concept, a trinity process that population urbanization, economic urbanization and space urbanization, is based on the interactions and mutual influences among the in which, people are the central and leading players in this process, while economic activities serve as the driving force and space is the carrier-the physical or material setting as well as the product. So the coordination among these processes is crucial for a country or region＇s sustainable development. China is experiencing rapid growth of cities and a surge in urban population, with the basic national condition of many people and little land, which calls for a systematic study of the issue of coordinated urbanization from theoretical, methodological and practical perspectives. Based on the concept of urbanization and non-coordination of urbanization, this article built a quantitative method to identify and evaluate the urbanization and non-coordination of urbanization, and made an empirical analysis in China between 2000 and 2008. The results show that the non-coordination overall level of China＇s urbanization declined during the study period, because population urbanization, economic urbanization, and space urbanization exhibited different trajectories of change. This study also reveals that performance assessment system, household registration system, and urban land expropriation system, etc., are the main affecting factors. At the end, we put forward some suggestions to achieve sustainable development of China＇s urbanization from the aspects of improving the local government＇s obiective function, imolementing the urban plalming svstem, enforcing public particination asnects and so on.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
China has made many strides in large-scale development and centralized integration of wind power in recent years.The wind power penetration of some regions has reached a high level,which brings significant challenges ...China has made many strides in large-scale development and centralized integration of wind power in recent years.The wind power penetration of some regions has reached a high level,which brings significant challenges for power system dispatch due to the inherent variability and uncertainty of wind resources.To increase the dispatch capabilities of wind power generation,the spatial smoothing effect among adjacent wind farms needs to be fully utilized.This paper presents the concept of hierarchical coordinated dispatch for wind power based on a new concept of a virtual power generator.The spatial smoothing effect of wind power is analyzed first.Next,the virtual power generator method of a wind farm cluster is defined and established.Then,the hierarchical coordinated dispatch mode is compared with an existing wind power dispatch mode for individual wind farms.Finally,the proposed concept is implemented on a simulation case to demonstrate applicability and effectiveness.展开更多
As more and more distributed renewable energy resources connected to electric power grids,the conventional power system evolves into an integrated energy grid(IEG)in order to satisfy various types of energy demands.Th...As more and more distributed renewable energy resources connected to electric power grids,the conventional power system evolves into an integrated energy grid(IEG)in order to satisfy various types of energy demands.This paper proposes a model of the coordinated scheduling of energy resources(CSoERs)for distributed district heating and cooling systems(DHCs)in an IEG.The model takes into consideration both the dispatchable grid-connected generators and distributed renewable energy resources,such as wind energy,solar energy and natural gas.The objective is to minimize the operation costs in the IEG in order to satisfy not only the electrical loads but also the heating loads and cooling loads.Furthermore,an energy storage system for heating loads and cooling loads is also developed in the DHCs to improve the operation reliability in the distributed DHCs.Detailed simulation studies are carried out to verify the effectiveness of the CSoERs under two different operation scenarios:grid-connected scenario and stand-alone scenario.Simulation results demonstrate that the performance of the CSoERs contributes to significant energy saving and reliability operation in both grid-connected scenario and standalone scenario in the IEG.展开更多
Microgrid is a good option to integrate renewableenergy sources (RES) into power systems. Inorder to deal with the intermittent characteristics of therenewable energy based distributed generation (DG) units,a fuzzy-lo...Microgrid is a good option to integrate renewableenergy sources (RES) into power systems. Inorder to deal with the intermittent characteristics of therenewable energy based distributed generation (DG) units,a fuzzy-logic based coordinated control strategy of a batteryenergy storage system (BESS) and dispatchable DGunits is proposed for the microgrid management system(MMS). In the proposed coordinated control strategy, theBESS is used to minimize active power exchange at thepoint of common coupling of the microgrid for grid-connectedoperation, and is used for frequency control for islandoperation. The efficiency of the proposed controlstrategy was tested by case studies using DIgSILENT/PowerFactroy.展开更多
With more and more distributed photovoltaic(PV)plants access to the distribution system,whose structure is changing and becoming an active network.The traditional methods of voltage regulation may hardly adapt to this...With more and more distributed photovoltaic(PV)plants access to the distribution system,whose structure is changing and becoming an active network.The traditional methods of voltage regulation may hardly adapt to this new situation.To address this problem,this paper presents a coordinated control method of distributed energy storage systems(DESSs)for voltage regulation in a distribution network.The influence of the voltage caused by the PV plant is analyzed in a simple distribution feeder at first.The voltage regulation areas corresponding to DESSs are divided by calculating and comparing the voltage sensitivity matrix.Then,a coordinated voltage control strategy is proposed for the DESSs.Finally,the simulation results of the IEEE 33-bus radial distribution network verify the effectiveness of the proposed coordinated control method.展开更多
This paper investigates a formation control problem of fixed-wing Unmanned Aerial Vehicle(UAV) swarms. A group-based hierarchical architecture is established among the UAVs, which decomposes all the UAVs into several ...This paper investigates a formation control problem of fixed-wing Unmanned Aerial Vehicle(UAV) swarms. A group-based hierarchical architecture is established among the UAVs, which decomposes all the UAVs into several distinct and non-overlapping groups. In each group, the UAVs form hierarchies with one UAV selected as the group leader. All group leaders execute coordinated path following to cooperatively handle the mission process among different groups, and the remaining followers track their direct leaders to achieve the inner-group coordination. More specifically, for a group leader, a virtual target moving along its desired path is assigned for the UAV, and an updating law is proposed to coordinate all the group leaders’ virtual targets;for a follower UAV, the distributed leader-following formation control law is proposed to make the follower’s heading angle coincide with its direct leader, while keeping the desired relative position with respect to its direct leader. The proposed control law guarantees the globally asymptotic stability of the whole closed-loop swarm system under the control input constraints of fixed-wing UAVs. Theoretical proofs and numerical simulations are provided, which corroborate the effectiveness of the proposed method.展开更多
Eddy Covariance technique(EC) achieves the direct measurement on ecosystem carbon, nitrogen and water fluxes, and it provides scientific data for accurately assessing ecosystem functions in mitigating global climate c...Eddy Covariance technique(EC) achieves the direct measurement on ecosystem carbon, nitrogen and water fluxes, and it provides scientific data for accurately assessing ecosystem functions in mitigating global climate change. This paper briefly reviewed the construction and development of Chinese terrestrial ecosystem flux observation and research network(China FLUX), and systematically introduced the design principle and technology of the terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation system of China FLUX. In addition, this paper summarized the main progress of China FLUX in the ecosystem carbon, nitrogen and water exchange and environmental controlling mechanisms, the spatial pattern of carbon, nitrogen and water fluxes and biogeographical mechanisms, and the regional terrestrial ecosystem carbon budget assessment. Finally, the prospects and emphases of the terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation of China FLUX are put forward to provide theoretical references for the development of flux observation and research in China.展开更多
Decreasing costs and favorable policies have resulted in increased penetration of solar photovoltaic(PV)power generation in distribution networks.As the PV systems penetration is likely to increase in the future,utili...Decreasing costs and favorable policies have resulted in increased penetration of solar photovoltaic(PV)power generation in distribution networks.As the PV systems penetration is likely to increase in the future,utilizing the reactive power capability of PV inverters to mitigate voltage deviations is being promoted.In recent years,droop control of inverter-based distributed energy resources has emerged as an essential tool for use in this study.The participation of PV systems in voltage regulation and its coordination with existing controllers,such as on-load tap changers,is paramount for controlling the voltage within specified limits.In this work,control strategies are presented that can be coordinated with the existing controls in a distributed manner.The effectiveness of the proposed method was demonstrated through simulation results on a distribution system.展开更多
基金Supported by the National Basic Research and Development (973) Program of China (2010CB951904 and 2007CB411806)National Natural Science Foundation of China (41075059 and 41023002)Strategic Priority Research Program of the Chinese Academy of Sciences (XDA05110302)
文摘The baseline performance of the latest version （version 2） of an intermediate resolution, stand-alone climate oceanic general circulation model, called LASG/IAP （State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics/Institute of Atmospheric Physics） Climate system Ocean Model （LICOM）, has been evaluated against the observation by using the main metrics from Griffies et al. in 2009. In general, the errors of LICOM2 in the water properties and in the circulation are comparable with the models of Coordinated Ocean-ice Reference Experiments （COREs）. Some common biases are still evident in the present version, such as the cold bias in the eastern Facific cold tongue, the warm biases off the east coast of the basins~ the weak poleward heat transport in the Atlantic, and the relatively large biases in the Arctic Ocean. A unique systematic bias occurs in LICOM2 over the Southern Ocean, compared with CORE models. It seems that this bias may be related to the sea ice process around the Antarctic continent.
基金supported by Natural Science Foundation of Hunan Province(2017JJ5044).
文摘Based on the large-scale penetration of electric vehicles(EV)into the building cluster,a multi-objective optimal strategy considering the coordinated dispatch of EV is proposed,for improving the safe and economical operation problems of distribution network.The system power loss and node voltage excursion can be effectively reduced,by taking measures of time-of-use(TOU)price mechanism bonded with the reactive compensation of energy storage devices.Firstly,the coordinate charging/discharging load model for EV has been established,to obtain a narrowed gap between load peak and valley.Next,a multi-objective optimization model of the distribution grid is also defined,and the active power loss and node voltage fluctuation are chosen to be the objective function.For improving the efficiency of optimization process,an advanced genetic algorithm associated with elite preservation policy is used.Finally,reactive compensation capacity supplied by capacitor banks is dynamically determined according to the varying building loads.The proposed strategy is demonstrated on the IEEE 33-node test case,and the simulation results show that the power supply pressure can be obviously relieved by introducing the coordinated charging/discharging behavior of EV;in the meantime,via reasonable planning of the compensation capacitor,the remarkably lower active power loss and voltage excursion can be realized,ensuring the safe and economical operation of the distribution system.
基金supported by State Key Program of National Natural Science Foundation of China (Grant No. 40830957)Public Welfare Research Project of China (Grant No. GYHY200806021)
文摘The observation stations of Northern China are divided into three regions:the arid Northwest China,the Loess Plateau,and the cool Northeast China.The consistencies,differences,and associated mechanisms of land surface thermal-hydrologic processes among the three regions were studied based on the normalization of major variables of land surface thermal-hydrologic processes,using data collected during prevailing summer monsoon period(July and August,2008).It is shown that differences of surface thermal-hydrologic processes are remarkable among the three regions because of different impacts of summer monsoon.Especially their soil wet layers occur at different depths,and the average albedo and its diurnal variations are distinctly different.Surface net short-wave radiation in the Loess Plateau is close to that in the cool Northeast China,but its surface net long-wave radiation is close to that in the arid Northwest China.And the ratio of net radiation to global solar radiation in the cool Northeast China is higher than the other two regions,though its temperature is lower.There are obvious regional differences in the ratios of surface sensible and latent heat fluxes to net radiation for the three regions because of distinct contribution of sensible and latent heat fluxesto land surface energy balance.The three regions are markedly different in the ratio of water vapor flux to pan evaporation,but they are consistent in the ratio of water vapor flux to precipitation.These results not only indicate different influences of climate and environmental factors on land surface thermal-hydrologic processes in the three regions,but also show that summer monsoon is important in the formation and variation of the pattern of land surface thermal-hydrologic processes.
基金the National Natural Science Foundation of China(No.41877304)the National Key R&D Program of China(No.2018YFC0506901)the Youth Innovation Promotion Association,CAS(Nos.2018060 and 2018055)。
文摘The strict control measures and social lockdowns initiated to combat COVID-19 epidemic have had a notable impact on air pollutant concentrations.According to observation data obtained from the China National Environmental Monitoring Center,compared to levels in 2019,the average concentration of NO_(2) in early 2020 during COVID-19 epidemic has decreased by 53%,50%,and 30%in Wuhan city,Hubei Province(Wuhan excluded),and China(Hubei excluded),respectively.Simultaneously,PM_(2.5) concentration has decreased by 35%,29%,and 19%in Wuhan,Hubei(Wuhan excluded),and China(Hubei excluded),respectively.Less significant declines have also been found for SO_(2) and CO concentrations.We also analyzed the temporal variation and spatial distribution of air pollutant concentrations in China during COVID-19 epidemic.The decreases in PM_(2.5) and NO_(2) concentrations showed relatively consistent temporal variation and spatial distribution.These results support control of NO x to further reduce PM_(2.5) pollution in China.The concurrent decrease in NOx and PM_(2.5) concentrations resulted in an increase of O3 concentrations across China during COVID-19 epidemic,indicating that coordinated control of other pollutants is needed.
基金Under the auspices of National Natural Science Foundation of China(No.41071109)Fundamental Research Funds for the Central University(No.10SSXT137)
文摘Urbanization is a comprehensive concept, a trinity process that population urbanization, economic urbanization and space urbanization, is based on the interactions and mutual influences among the in which, people are the central and leading players in this process, while economic activities serve as the driving force and space is the carrier-the physical or material setting as well as the product. So the coordination among these processes is crucial for a country or region＇s sustainable development. China is experiencing rapid growth of cities and a surge in urban population, with the basic national condition of many people and little land, which calls for a systematic study of the issue of coordinated urbanization from theoretical, methodological and practical perspectives. Based on the concept of urbanization and non-coordination of urbanization, this article built a quantitative method to identify and evaluate the urbanization and non-coordination of urbanization, and made an empirical analysis in China between 2000 and 2008. The results show that the non-coordination overall level of China＇s urbanization declined during the study period, because population urbanization, economic urbanization, and space urbanization exhibited different trajectories of change. This study also reveals that performance assessment system, household registration system, and urban land expropriation system, etc., are the main affecting factors. At the end, we put forward some suggestions to achieve sustainable development of China＇s urbanization from the aspects of improving the local government＇s obiective function, imolementing the urban plalming svstem, enforcing public particination asnects and so on.
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 in part by Chinese National Key Technologies R&D Program(2013BAA01B03)National Natural Science Foundation of China(51190101)industrial project of State Grid Corporation of China(No.NY71-13-043).
文摘China has made many strides in large-scale development and centralized integration of wind power in recent years.The wind power penetration of some regions has reached a high level,which brings significant challenges for power system dispatch due to the inherent variability and uncertainty of wind resources.To increase the dispatch capabilities of wind power generation,the spatial smoothing effect among adjacent wind farms needs to be fully utilized.This paper presents the concept of hierarchical coordinated dispatch for wind power based on a new concept of a virtual power generator.The spatial smoothing effect of wind power is analyzed first.Next,the virtual power generator method of a wind farm cluster is defined and established.Then,the hierarchical coordinated dispatch mode is compared with an existing wind power dispatch mode for individual wind farms.Finally,the proposed concept is implemented on a simulation case to demonstrate applicability and effectiveness.
基金supported by the State Key Program of National Natural Science of China(Grant No.51437006)Guangdong Innovative Research Team Program(No.201001 NO 104744201).
文摘As more and more distributed renewable energy resources connected to electric power grids,the conventional power system evolves into an integrated energy grid(IEG)in order to satisfy various types of energy demands.This paper proposes a model of the coordinated scheduling of energy resources(CSoERs)for distributed district heating and cooling systems(DHCs)in an IEG.The model takes into consideration both the dispatchable grid-connected generators and distributed renewable energy resources,such as wind energy,solar energy and natural gas.The objective is to minimize the operation costs in the IEG in order to satisfy not only the electrical loads but also the heating loads and cooling loads.Furthermore,an energy storage system for heating loads and cooling loads is also developed in the DHCs to improve the operation reliability in the distributed DHCs.Detailed simulation studies are carried out to verify the effectiveness of the CSoERs under two different operation scenarios:grid-connected scenario and stand-alone scenario.Simulation results demonstrate that the performance of the CSoERs contributes to significant energy saving and reliability operation in both grid-connected scenario and standalone scenario in the IEG.
基金The authors from Technical University of Denmark are grateful to Sino-Danish Education and Research Centre(SDC)for the financial support to the PhD project of‘Coordinated Control of Wind Power Plants and Energy Storage Systems’.
文摘Microgrid is a good option to integrate renewableenergy sources (RES) into power systems. Inorder to deal with the intermittent characteristics of therenewable energy based distributed generation (DG) units,a fuzzy-logic based coordinated control strategy of a batteryenergy storage system (BESS) and dispatchable DGunits is proposed for the microgrid management system(MMS). In the proposed coordinated control strategy, theBESS is used to minimize active power exchange at thepoint of common coupling of the microgrid for grid-connectedoperation, and is used for frequency control for islandoperation. The efficiency of the proposed controlstrategy was tested by case studies using DIgSILENT/PowerFactroy.
基金This paper is supported by The National Key Research and Development Plan,Energy Storage Technology of 10MW Level Redox Battery,2017YFB0903504。
文摘With more and more distributed photovoltaic(PV)plants access to the distribution system,whose structure is changing and becoming an active network.The traditional methods of voltage regulation may hardly adapt to this new situation.To address this problem,this paper presents a coordinated control method of distributed energy storage systems(DESSs)for voltage regulation in a distribution network.The influence of the voltage caused by the PV plant is analyzed in a simple distribution feeder at first.The voltage regulation areas corresponding to DESSs are divided by calculating and comparing the voltage sensitivity matrix.Then,a coordinated voltage control strategy is proposed for the DESSs.Finally,the simulation results of the IEEE 33-bus radial distribution network verify the effectiveness of the proposed coordinated control method.
基金supported in part by National Natural Science Foundation of China (Nos. 61973309, 61801494 and61702528)in part by Hunan Provincial Innovation Foundation for Postgraduate,China (No. CX2017B014)。
文摘This paper investigates a formation control problem of fixed-wing Unmanned Aerial Vehicle(UAV) swarms. A group-based hierarchical architecture is established among the UAVs, which decomposes all the UAVs into several distinct and non-overlapping groups. In each group, the UAVs form hierarchies with one UAV selected as the group leader. All group leaders execute coordinated path following to cooperatively handle the mission process among different groups, and the remaining followers track their direct leaders to achieve the inner-group coordination. More specifically, for a group leader, a virtual target moving along its desired path is assigned for the UAV, and an updating law is proposed to coordinate all the group leaders’ virtual targets;for a follower UAV, the distributed leader-following formation control law is proposed to make the follower’s heading angle coincide with its direct leader, while keeping the desired relative position with respect to its direct leader. The proposed control law guarantees the globally asymptotic stability of the whole closed-loop swarm system under the control input constraints of fixed-wing UAVs. Theoretical proofs and numerical simulations are provided, which corroborate the effectiveness of the proposed method.
基金Science and Technology Service Network Initiative of CAS,No.KFJ-SW-STS-169National Natural Science Foundation of China,No.31420103917
文摘Eddy Covariance technique(EC) achieves the direct measurement on ecosystem carbon, nitrogen and water fluxes, and it provides scientific data for accurately assessing ecosystem functions in mitigating global climate change. This paper briefly reviewed the construction and development of Chinese terrestrial ecosystem flux observation and research network(China FLUX), and systematically introduced the design principle and technology of the terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation system of China FLUX. In addition, this paper summarized the main progress of China FLUX in the ecosystem carbon, nitrogen and water exchange and environmental controlling mechanisms, the spatial pattern of carbon, nitrogen and water fluxes and biogeographical mechanisms, and the regional terrestrial ecosystem carbon budget assessment. Finally, the prospects and emphases of the terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation of China FLUX are put forward to provide theoretical references for the development of flux observation and research in China.
基金by a project under the scheme entitled“Developing Policies&Adaptation Strategies to Climate Change in the Baltic Sea Region”(ASTRA),Project No.ASTRA6-4(2014-2020.4.01.16-0032).
文摘Decreasing costs and favorable policies have resulted in increased penetration of solar photovoltaic(PV)power generation in distribution networks.As the PV systems penetration is likely to increase in the future,utilizing the reactive power capability of PV inverters to mitigate voltage deviations is being promoted.In recent years,droop control of inverter-based distributed energy resources has emerged as an essential tool for use in this study.The participation of PV systems in voltage regulation and its coordination with existing controllers,such as on-load tap changers,is paramount for controlling the voltage within specified limits.In this work,control strategies are presented that can be coordinated with the existing controls in a distributed manner.The effectiveness of the proposed method was demonstrated through simulation results on a distribution system.
