This work considers the problem of decentralized control of inverter-based ac micro-grid in different operation modes.The main objectives are to(i)design decentralized frequency and voltage controllers,to gather with ...This work considers the problem of decentralized control of inverter-based ac micro-grid in different operation modes.The main objectives are to(i)design decentralized frequency and voltage controllers,to gather with power sharing,without information exchange between microsources(ii)design passive dynamic controllers which ensure stability of the entire microgrid system(iii)capture nonlinear,interconnected and large-scale dynamic of the micro-grid system with meshed topology as a port-Hamiltonian formulation(iv)expand the property of shifted-energy function in the context of decentralized control of ac micro-grid(v)analysis of system stability in large signal point of view.More precisely,to deal with nonlinear,interconnected and large-scale structure of micro-grid systems,the port-Hamiltonian formulation is used to capture the dynamic of micro-grid components including microsource,distribution line and load dynamics as well as interconnection controllers.Furthermore,to deal with large signal stability problem of the microgrid system in the grid-connected and islanded conditions,the shifted-Hamiltonian energy function is served as a storage function to ensure incremental passivity and stability of the microgrid system.Moreover,it is shown that the aggregating of the microgrid dynamic and the decentralized controller dynamics satisfies the incremental passivity.Finally,the effectiveness of the proposed controllers is evaluated through simulation studies.The different scenarios including grid-connected and islanded modes as well as transition between both modes are simulated.The simulation conforms that the decentralized control dynamics are suited to achieve the desired objective of frequency synchronization,voltage control and power sharing in the grid-connected and islanded modes.The simulation results demonstrate the effectiveness of the proposed control strategy.展开更多
In traditional power systems,besides the conventional power plants that provide the necessary reactive power in transmission system,the shunt capacitors along with the tap changers of transformers are also employed in...In traditional power systems,besides the conventional power plants that provide the necessary reactive power in transmission system,the shunt capacitors along with the tap changers of transformers are also employed in distribution networks.In future years,because of the high number of distributed resources integrated into the distribution networks,it will be essential to schedule complete active-reactive power at distribution level.In this research work,an economic framework based on the active-reactive power bids has been developed for complete active-reactive power dispatch scheduling of smart distribution networks.The economical complete active-reactive power scheduling approach suggested in this study motivates distributed energy resources(DERs)to cooperate in both active power markets and the Volt/Var control scheme.To this end,using DER’s reactive power capability,a generic framework of reactive power offers for DERs is extracted.A 22-bus distribution test system is implemented to verify the impressiveness of the suggested active-reactive power scheduling approach.展开更多
Cancer therapies based on energy conversion,such as photothermal therapy(PTT,light-to-thermal energy conversion)and photodynamic therapy(PDT,light-to-chemical energy conversion)have attracted extensive attention in pr...Cancer therapies based on energy conversion,such as photothermal therapy(PTT,light-to-thermal energy conversion)and photodynamic therapy(PDT,light-to-chemical energy conversion)have attracted extensive attention in preclinical research.However,the PTT-related hyperthermia damage to surrounding tissues and shallow penetration of PDT-applied light prevent further advanced clinical practices.Here,we developed a thermoelectric therapy(TET)based on thermoelectric materials constructed p-n heterojunction(SrTiO_(3)/Cu_(2)Se nanoplates)on the principle of light-thermal-electricity-chemical energy conversion.Upon irradiation and natural cooling-induced the temperature gradient(35-45℃),a self-build-in electric field was constructed and thereby facilitated charges separation in bulk SrTiO_(3)and Cu_(2)Se.Importantly,the contact between SrTiO_(3)(n type)and Cu_(2)Se(p type)constructed another interfacial electric field,further guiding the separated charges to re-locate onto the surfaces of SrTiO_(3)and Cu_(2)Se.The formation of two electric fields minimized probability of charges recombination.Of note,high-performance superoxide radicals and hydroxyl radicals’generation from O_(2)and H_(2)O under catalyzation by separated electrons and holes,led to intracellular ROS burst and cancer cells apoptosis without apparent damage to surrounding tissues.Construction of bulk and interfacial electric fields in heterojunction for improving charges separation and transfer is also expected to provide a robust strategy for diverse applications.展开更多
Reactive Materials(RMs),a new material with structural and energy release characteristics under shockinduced chemical reactions,are promising in extensive applications in national defense and military fields.They can ...Reactive Materials(RMs),a new material with structural and energy release characteristics under shockinduced chemical reactions,are promising in extensive applications in national defense and military fields.They can increase the lethality of warheads due to their dual functionality.This paper focuses on the energy release characteristics of RM casings prepared by alloy melting and casting process under explosive loading.Explosion experiments of RM and conventional 2A12 aluminum alloy casings were conducted in free field to capture the explosive fireballs,temperature distribution,peak overpressure of the air shock wave and the fracture morphology of fragments of reactive material(RM)warhead casings by using high-speed camera,infrared thermal imager temperature and peak overpressure testing and scanning electron microscope.Results showed that an increase of both the fireball temperature and air shock wave were observed in all RM casings compared to conventional 2A12 aluminum ally casings.The RM casings can improve the peak overpressure of the air shock wave under explosion loading,though the results are different with different charge ratios.According to the energy release characteristics of the RM,increasing the thickness of RM casings will increase the peak overpressure of the near-field air shock wave,while reducing the thickness will increase the peak overpressure of the far-field air shock wave.展开更多
基金Supported by the Program for New Century Excellent Talents in University of China under Grant No.NCET-05-0657(新世纪优秀人才支持计划)the Foundation for Distinguished Young Scientists of Hubei Province of China under Grant No.2006ABB028(湖北省青年杰出人才基金)
文摘This work considers the problem of decentralized control of inverter-based ac micro-grid in different operation modes.The main objectives are to(i)design decentralized frequency and voltage controllers,to gather with power sharing,without information exchange between microsources(ii)design passive dynamic controllers which ensure stability of the entire microgrid system(iii)capture nonlinear,interconnected and large-scale dynamic of the micro-grid system with meshed topology as a port-Hamiltonian formulation(iv)expand the property of shifted-energy function in the context of decentralized control of ac micro-grid(v)analysis of system stability in large signal point of view.More precisely,to deal with nonlinear,interconnected and large-scale structure of micro-grid systems,the port-Hamiltonian formulation is used to capture the dynamic of micro-grid components including microsource,distribution line and load dynamics as well as interconnection controllers.Furthermore,to deal with large signal stability problem of the microgrid system in the grid-connected and islanded conditions,the shifted-Hamiltonian energy function is served as a storage function to ensure incremental passivity and stability of the microgrid system.Moreover,it is shown that the aggregating of the microgrid dynamic and the decentralized controller dynamics satisfies the incremental passivity.Finally,the effectiveness of the proposed controllers is evaluated through simulation studies.The different scenarios including grid-connected and islanded modes as well as transition between both modes are simulated.The simulation conforms that the decentralized control dynamics are suited to achieve the desired objective of frequency synchronization,voltage control and power sharing in the grid-connected and islanded modes.The simulation results demonstrate the effectiveness of the proposed control strategy.
文摘In traditional power systems,besides the conventional power plants that provide the necessary reactive power in transmission system,the shunt capacitors along with the tap changers of transformers are also employed in distribution networks.In future years,because of the high number of distributed resources integrated into the distribution networks,it will be essential to schedule complete active-reactive power at distribution level.In this research work,an economic framework based on the active-reactive power bids has been developed for complete active-reactive power dispatch scheduling of smart distribution networks.The economical complete active-reactive power scheduling approach suggested in this study motivates distributed energy resources(DERs)to cooperate in both active power markets and the Volt/Var control scheme.To this end,using DER’s reactive power capability,a generic framework of reactive power offers for DERs is extracted.A 22-bus distribution test system is implemented to verify the impressiveness of the suggested active-reactive power scheduling approach.
基金supported by the National Natural Science Foundation of China(No.32122044,32071322,32000815)Science,Technology&Innovation Commission of Shenzhen Municipality(No.JCYJ20210324113004010,RCBS20200714114855313).
文摘Cancer therapies based on energy conversion,such as photothermal therapy(PTT,light-to-thermal energy conversion)and photodynamic therapy(PDT,light-to-chemical energy conversion)have attracted extensive attention in preclinical research.However,the PTT-related hyperthermia damage to surrounding tissues and shallow penetration of PDT-applied light prevent further advanced clinical practices.Here,we developed a thermoelectric therapy(TET)based on thermoelectric materials constructed p-n heterojunction(SrTiO_(3)/Cu_(2)Se nanoplates)on the principle of light-thermal-electricity-chemical energy conversion.Upon irradiation and natural cooling-induced the temperature gradient(35-45℃),a self-build-in electric field was constructed and thereby facilitated charges separation in bulk SrTiO_(3)and Cu_(2)Se.Importantly,the contact between SrTiO_(3)(n type)and Cu_(2)Se(p type)constructed another interfacial electric field,further guiding the separated charges to re-locate onto the surfaces of SrTiO_(3)and Cu_(2)Se.The formation of two electric fields minimized probability of charges recombination.Of note,high-performance superoxide radicals and hydroxyl radicals’generation from O_(2)and H_(2)O under catalyzation by separated electrons and holes,led to intracellular ROS burst and cancer cells apoptosis without apparent damage to surrounding tissues.Construction of bulk and interfacial electric fields in heterojunction for improving charges separation and transfer is also expected to provide a robust strategy for diverse applications.
基金the Fundamental Research Funds for the Central Universities(No.30920021108)Open Foundation of Hypervelocity Impact Research Center of CARDC(20200106).
文摘Reactive Materials(RMs),a new material with structural and energy release characteristics under shockinduced chemical reactions,are promising in extensive applications in national defense and military fields.They can increase the lethality of warheads due to their dual functionality.This paper focuses on the energy release characteristics of RM casings prepared by alloy melting and casting process under explosive loading.Explosion experiments of RM and conventional 2A12 aluminum alloy casings were conducted in free field to capture the explosive fireballs,temperature distribution,peak overpressure of the air shock wave and the fracture morphology of fragments of reactive material(RM)warhead casings by using high-speed camera,infrared thermal imager temperature and peak overpressure testing and scanning electron microscope.Results showed that an increase of both the fireball temperature and air shock wave were observed in all RM casings compared to conventional 2A12 aluminum ally casings.The RM casings can improve the peak overpressure of the air shock wave under explosion loading,though the results are different with different charge ratios.According to the energy release characteristics of the RM,increasing the thickness of RM casings will increase the peak overpressure of the near-field air shock wave,while reducing the thickness will increase the peak overpressure of the far-field air shock wave.
