California mandated that 100% of vehicles sold must be electric by 2035. As electric vehicles (EVs) reach a higher penetration of the car sector, cities will need to provide publicly accessible charging stations to me...California mandated that 100% of vehicles sold must be electric by 2035. As electric vehicles (EVs) reach a higher penetration of the car sector, cities will need to provide publicly accessible charging stations to meet the charging demand of people who do not have access to a private charging spot like a personal garage. We have chosen to limit our scope to San Diego County due to its non-trivial size, well-defined shape, and dependence on personal vehicles;this project models 100% of current vehicles as electric, roughly 2.5 million. By planning for the future, our model becomes more useful as well as more equitable. We anticipate that our model will find locations that can service multiple population centers, while also maximizing distance to other stations. Sensitivity analysis and testing of our algorithms are conducted for Coronado Island, an island with 24,697 residents. Our formulation is then scaled to set the parameters for the whole county.展开更多
The large-scale development of electric vehicles(EVs)requires numerous charging stations to serve them,and the charging stations should be reasonably laid out and planned according to the charging demand of electric v...The large-scale development of electric vehicles(EVs)requires numerous charging stations to serve them,and the charging stations should be reasonably laid out and planned according to the charging demand of electric vehicles.Considering the costs of both operators and users,a site selection model for optimal layout planning of charging stations is constructed,and a queuing theory approach is used to determine the charging pile configuration to meet the charging demand in the planning area.To solve the difficulties of particle swarm global optimization search,the improved random drift particle swarm optimization(IRDPSO)and Voronoi diagram are used to jointly solve for the optimal layout of electric vehicles.The final arithmetic analysis verifies the feasibility and practicality of the model and algorithm,and the results show that the total social cost is minimized when the charging station is 9,the location of the charging station is close to the center of gravity and the layout is reasonable.展开更多
As the number of electric vehicles(EVs)continues to grow and the demand for charging infrastructure is also increasing,how to improve the charging infrastructure has become a bottleneck restricting the development of ...As the number of electric vehicles(EVs)continues to grow and the demand for charging infrastructure is also increasing,how to improve the charging infrastructure has become a bottleneck restricting the development of EVs.In other words,reasonably planning the location and capacity of charging stations is important for development of the EV industry and the safe and stable operation of the power system.Considering the construction and maintenance of the charging station,the distribution network loss of the charging station,and the economic loss on the user side of the EV,this paper takes the node and capacity of charging station planning as control variables and the minimum cost of system comprehensive planning as objective function,and thus proposes a location and capacity planning model for the EV charging station.Based on the problems of low efficiency and insufficient global optimization ability of the current algorithm,the simulated annealing immune particle swarm optimization algorithm(SA-IPSO)is adopted in this paper.The simulated annealing algorithm is used in the global update of the particle swarm optimization(PSO),and the immune mechanism is introduced to participate in the iterative update of the particles,so as to improve the speed and efficiency of PSO.Voronoi diagram is used to divide service area of the charging station,and a joint solution process of Voronoi diagram and SA-IPSO is proposed.By example analysis,the results show that the optimal solution corresponding to the optimisation method proposed in this paper has a low overall cost,while the average charging waiting time is only 1.8 min and the charging pile utilisation rate is 75.5%.The simulation comparison verifies that the improved algorithm improves the operational efficiency by 18.1%and basically does not fall into local convergence.展开更多
The demand for fast charging is increasing owing to the rapid expansion of the market for electric vehicles. In addition, the power generation technology for distributed photovoltaic has matured. This paper presents a...The demand for fast charging is increasing owing to the rapid expansion of the market for electric vehicles. In addition, the power generation technology for distributed photovoltaic has matured. This paper presents a design scheme for a fast charging station for electric vehicles equipped with distributed photovoltaic power generation system taking the area with certain conditions in Beijing as an example construction site. The technical indexes and equipment lectotype covering the general framework and subsystems of the charging station are determined by analyzing the charging service demand of fast charging stations. In this study, the layout of the station is developed and the operation benefits of the station is analyzed. The design scheme realizes the design objective of "rationalization, modularization and intelligentization" of the fast charging station and can be used as reference for the construction of a fast charging network in urban area.展开更多
For the charging station construction of electric vehicle,location selecting is a key issue.There are two problems in location selection of the electric vehicle charging station.One is determining the location of char...For the charging station construction of electric vehicle,location selecting is a key issue.There are two problems in location selection of the electric vehicle charging station.One is determining the location of charging station;the other is evaluating the location of charging station.To determine the charging station location,an spatial clustering algorithm is proposed and programmed.The example simulation shows the effectiveness of the spatial clustering algorithm.To evaluate the charging station location,a multi-hierarchical fuzzy method is proposed.Based on the location factors of electric vehicle charging station,the hierarchical evaluation structure of electric vehicle charging station location is constructed,including three levels,4first-class factors and 14second-class factors.The fuzzy multi-hierarchical evaluation model and algorithm are built.The analysis results show that the multi-hierarchical fuzzy method can reasonably complete the electric vehicle charging station location evaluation.展开更多
Characters of head of low head pump station and the pump shaft power areanalyzed. Influence of each single factor on pump shaft power is expressed as change of specificshaft power. (non-dimensional) and the probabilit...Characters of head of low head pump station and the pump shaft power areanalyzed. Influence of each single factor on pump shaft power is expressed as change of specificshaft power. (non-dimensional) and the probability density function is determined. Influences ofmultiple factors on pump shaft power are analyzed. Method of calculating none over-loadedprobability of motor by integration by successive reductions is put forward and then relationbetween power spare coefficient and none over-loaded reliability of electric motor is established.Influences of all factors on pump shaft power being considered completely; power spare coefficientsof motor are calculated in three kinds of heads (changing and unchanging), two kinds of dirty-outconditions. Electrical motor power spare coefficients should be chosen as 1.20 approx 1.44, 1.11approx 1.19, 1.09 approx.14 respectively when pump heads are 4, 7, 9.5 m. The results mean much toreasonable choose of electrical motors in large pump stations, increasing reliability of pump unitsand saving equipment investment.展开更多
Considering the additional electric energy generated after the full operation of the underground hydropower station, the electric energy accommodation of the Three Gorges Project (TGP) is reviewed. It is .focused on...Considering the additional electric energy generated after the full operation of the underground hydropower station, the electric energy accommodation of the Three Gorges Project (TGP) is reviewed. It is .focused on the additional electricity accommodation, based on the research at the earl), stage. The electric energ), accommodation solutions ate recommended as that. based on the cost-benefit analysis of the power distribution area, the additional electric energy of the Three Gorges should be given ptqority to meet the needs at the supply end of Hubei and Chongqing. The results of this research has a reference value on the implementation of the Three Gorges electric power accommodation, after the further optimization of the transmission curves in both wet and dry seasons.展开更多
The increasingly large number of electric vehicles(EVs)has resulted in a growing concern for EV charging station load prediction for the purpose of comprehensively evaluating the influence of the charging load on dist...The increasingly large number of electric vehicles(EVs)has resulted in a growing concern for EV charging station load prediction for the purpose of comprehensively evaluating the influence of the charging load on distribution networks.To address this issue,an EV charging station load predictionmethod is proposed in coupled urban transportation and distribution networks.Firstly,a finer dynamic urban transportation network model is formulated considering both nodal and path resistance.Then,a finer EV power consumption model is proposed by considering the influence of traffic congestion and ambient temperature.Thirdly,the Monte Carlo method is applied to predict the distribution of EVcharging station load based on the proposed dynamic urban transportation network model and finer EV power consumption model.Moreover,a dynamic charging pricing scheme for EVs is devised based on the EV charging station load requirements and the maximum thresholds to ensure the security operation of distribution networks.Finally,the validity of the proposed dynamic urban transportation model was verified by accurately estimating five sets of test data on travel time by contrast with the BPR model.The five groups of travel time prediction results showed that the average absolute percentage errors could be improved from 32.87%to 37.21%compared to the BPR model.Additionally,the effectiveness of the proposed EV charging station load prediction method was demonstrated by four case studies in which the prediction of EV charging load was improved from27.2 to 31.49MWh by considering the influence of ambient temperature and speed on power energy consumption.展开更多
The electric vehicle charging station should be allocated based on traffic density, geographical distribution and other factors, and Voronoi diagram is adopted to set the service area of charging station. In combinati...The electric vehicle charging station should be allocated based on traffic density, geographical distribution and other factors, and Voronoi diagram is adopted to set the service area of charging station. In combination with the actual situation of site selection of electric vehicle charging station, the comprehensive benefits index system is established. There are numerous factors influencing the site selection, among which there are uncertainty and fuzziness. The comprehensive evaluation method based on the fuzzy analysis and Analytical Hierarchy Process (AHP) is used to evaluate the comprehensive benefits in the site selection of electric vehicle charging stations, with the consultation of experts. This paper contributes to the best selection of comprehensive benefits and provides the reference for the decision-making of building the electric vehicle charging station. Actual examples show that the method proposed is effective.展开更多
The construction of electric vehicle charging station plays an important role in the development of electric vehicles and the promotion of the renewable resource. In the paper, a model to analyze the economic benefit ...The construction of electric vehicle charging station plays an important role in the development of electric vehicles and the promotion of the renewable resource. In the paper, a model to analyze the economic benefit of the charging station is presented, which is based on the break-even theory. Then the threshold price is calculated based on the model according to the construction plans of charging facilities in one district. Finally, the strategy for the development of charging faculties is proposed to improve the health growth of electric automotive industry.展开更多
The magneto-electric dipole antenna is a kind of complementary antenna composed of a planar electric dipole and a shorted patch antenna. It has excellent electrical characteristics including wide impedance bandwidth, ...The magneto-electric dipole antenna is a kind of complementary antenna composed of a planar electric dipole and a shorted patch antenna. It has excellent electrical characteristics including wide impedance bandwidth, low cross-polarization, low back lobe radiation, nearly identical E-plane and H-plane patterns, stable radiation pattern, and steady antenna gain over the operating frequency range. In this paper, the basic characteristics of a linearly polarized magneto-electric dipole antenna are reviewed, and a dual-polarized antenna element based on the magneto-electric dipole is presented. The design of a conical beam wideband antenna with horizontal polarization is also described. These antennas have practical applications in modern 2G, 3G, LTE, WiFi, and WiMax wireless communication systems.展开更多
With the increasing development of EVs, the energy demand from theconventional utility grid increases in proportion. On the other hand, photovoltaic(PV) energy sources can overcome several problems when charging EVs f...With the increasing development of EVs, the energy demand from theconventional utility grid increases in proportion. On the other hand, photovoltaic(PV) energy sources can overcome several problems when charging EVs from theutility grid especially in remote areas. This paper presents an effective photovoltaic stand-alone charging station for EV applications. The proposed charging station incorporates PV array, a lithium-ion battery representing the EV battery, and alead-acid battery representing the energy storage system (ESS). A bidirectionalDC-DC converter is employed for charging/discharging the ESS and a unidirectional DC-DC converter is utilized for charging the EV battery. The proposed controllers achieve maximum power extraction from the PV and regulate the DC-linkvoltage. It also controls the voltage and current levels of both the ESS and the EVduring the charging/discharging process. The study has been applied to two caseswith different power levels. Analysis, simulation, and implementation of the proposed system are presented. A 120 W laboratory prototype is carried out to verifythe system performance, experimentally. Design guides for higher power levelsare proposed to help in choosing the proper parameters of the converters. Boththe simulation and experimental results are matched and verify the highperformance of the proposed system.展开更多
In the paper,an operational program of electric bus charging station is proposed,which is special for "The Construction Project for Expo 2010 Temporary Electric Bus Charging Station".Based on the quick-chang...In the paper,an operational program of electric bus charging station is proposed,which is special for "The Construction Project for Expo 2010 Temporary Electric Bus Charging Station".Based on the quick-change mode,a vehicle operating schedule model has been established to meet the capacity of transport.Then,according to the quantity of passengers and utilization of batteries,a calculative method of parameters,such as the number of spare batteries and bus departure rules,has been provided.Furthermore,optimal simulation software designed for operating process of the charging station has been identified incorporating actual running data from electric buses and monitoring system of the charging station,and the rationality of the design is verified in the preliminary commissioning and the official operation.展开更多
The variations noticed in the atmospheric electric field recorded at Pune (18°32'N, 73°51'E, 559 m ASL), a tropical inland station located in Dcccan Plateau, India, during the period 1930-1987, have ...The variations noticed in the atmospheric electric field recorded at Pune (18°32'N, 73°51'E, 559 m ASL), a tropical inland station located in Dcccan Plateau, India, during the period 1930-1987, have been examined in relation to the variations observed in the Angstrom turbidity coefficient (β) and selected meteorological parameters. The monthly and annual mean values of the atmospheric electric field. Angstrom turbidity coefficient (β), rainfall, temperature and relative humidity for the years 1930-1938, 1957-1958, 1964-1965, 1973-1974 and 1987 were considered in the study.The results of the above study indicated gradual increases in the atmospheric electric field over the period of study (1930-1987) which is statistically significant at less than 5%level. The increases noticed during different periods varied from 30 to 109%. The increase noticed during the period (1930-1938) and (1973-1974) was maximum (109%). The Angstrom turbidity coefficient also showed systematic increases during the period of study, which is consistent. The diurnal curve of the atmospheric electric field at the station by and large, showed a double oscillation, which is generally observed in the conlinental environments.展开更多
Electric propulsion is used for all electric propulsion satellites to perform the orbit transfer,attitude control and station-keeping tasks. Generally electric propulsion subsystem contains 4 thrusters. But if one thr...Electric propulsion is used for all electric propulsion satellites to perform the orbit transfer,attitude control and station-keeping tasks. Generally electric propulsion subsystem contains 4 thrusters. But if one thruster fails in the beginning of satellite lifetime,other thrusters will undertake all the firing tasks. The firing time will be 2 to 3 times of thrusters without failure. Thus it may go beyond the allow ed lifetime of thruster. This paper puts forward two thruster redundancy configuration solutions with 6 thrusters to solve this problem. Two layout configurations and their corresponding station-keeping strategies are simulated and compared. The results show that the maximum firing time of both layout configurations can meet the lifetime limitation. This solution is a good reference for all electric propulsion satellites design.展开更多
Applications of electric vehicles need to build a large number of charging stations. The electric vehicle charging stations communicate with the grid. In V2G (vehicle to grid) mode, electric vehicles can be used as ...Applications of electric vehicles need to build a large number of charging stations. The electric vehicle charging stations communicate with the grid. In V2G (vehicle to grid) mode, electric vehicles can be used as energy storage units and transfer power to the grid. The electric vehicles charge at night to reduce the cost and the grid load, simultaneously to fill the valley. When grid load increases, electric vehicles' batteries discharge to the grid to improve the stability of the grid. As distributed storage units, electric vehicles are important components of the smart grid. In this paper, the three-phase PWM (pulse width modulation) rectifier used for smart charging and discharging system of electric vehicles are analyzed and designed. This paper includes the principle of PWM rectifier-inverter and direct current control strategy. Also, the SVPWM (space vector pulse width modulation) and system design of three-phase PWM rectifiers are analyzed. A 10 kW prototype is developed. Simulation and experiment results show that the three-phase PWM rectifiers reach the unit power factor. From the experimental results, PWM rectifier implements the sinusoidal grid current and achieves the unit power factor.展开更多
In east Europe and north Asia the majority of nuclear power-stations (NPS) as well as large hydro-electric (HES) and thermal electric stations (TES) are located within the north Eurasian lithosphere plate, which is ch...In east Europe and north Asia the majority of nuclear power-stations (NPS) as well as large hydro-electric (HES) and thermal electric stations (TES) are located within the north Eurasian lithosphere plate, which is characterized by the low seismicity and weak modern tectonic activity besides the different exogenetic processes. Some operating and projected NPS are relatively near to zones of the moderate seismicity in the Kaliningrad Region of northwest Russia and in south Ukraine. HES and TES in Baltic, Byelorussia and Ukraine are in the same position. Zones of more intensive seismicity and existence of active faults include NPS, HEP and TEP in the Urals, the Kola Peninsula, south Siberia, Transbaikal and Far East regions of Russia. Some of these stations are situated within crust blocks in transit zones, which separate main lithosphere plates and are characterized by increased tectonic mobility. The electric power-stations are most danger in the transit zones between north Eurasian, Arabian and Indian lithosphere plates, where collision processes have yet not stopped. This concerns electric stations in central Asia and Caucasus including NPS in Armenia. Seven schemes of the seismic energy distribution are composed for different parts of east Europe and north Asia. The location of nuclear and main other electric power-stations on them makes it possible to form a correct estimate of negative consequences connected with the up-to-date inner-continental tectonic activity.展开更多
Solar power is mostly influenced by solar irradiation,weather conditions,solar array mismatches and partial shading conditions.Therefore,before installing solar arrays,it is necessary to simulate and determine the pos...Solar power is mostly influenced by solar irradiation,weather conditions,solar array mismatches and partial shading conditions.Therefore,before installing solar arrays,it is necessary to simulate and determine the possible power generated.Maximum power point tracking is needed in order to make sure that,at any time,the maximum power will be extracted from the photovoltaic system.However,maximum power point tracking is not a suitable solution for mismatches and partial shading conditions.To overcome the drawbacks of maximum power point tracking due to mismatches and shadows,distributed maximum power point tracking is util-ized in this paper.The solar farm can be distributed in different ways,including one DC-DC converter per group of modules or per module.In this paper,distributed maximum power point tracking per module is implemented,which has the highest efficiency.This technology is applied to electric vehicles(EVs)that can be charged with a Level 3 charging station in<1 hour.However,the problem is that charging an EV in<1 hour puts a lot of stress on the power grid,and there is not always enough peak power reserve in the existing power grid to charge EVs at that rate.Therefore,a Level 3(fast DC)EV charging station using a solar farm by implementing distributed maximum power point tracking is utilized to address this issue.Finally,the simulation result is reported using MATLAB®,LTSPICE and the System Advisor Model.Simulation results show that the proposed 1-MW solar system will provide 5 MWh of power each day,which is enough to fully charge~120 EVs each day.Additionally,the use of the proposed photovoltaic system benefits the environment by removing a huge amount of greenhouse gases and hazardous pollutants.For example,instead of supplying EVs with power from coal-fired power plants,1989 pounds of CO_(2) will be eliminated from the air per hour.展开更多
Charging infrastructure supports the rapid development of China's new energy vehicle industry.It not only plays a decisive role in providing accessible and convenient services for electric vehicle(EV)users but als...Charging infrastructure supports the rapid development of China's new energy vehicle industry.It not only plays a decisive role in providing accessible and convenient services for electric vehicle(EV)users but also,in one of the seven new infrastructure areas,plays an important role in stabilizing growth and unleashing economic potential during the new coronavirus(COVID-19)pandemic,impacting China's economy.In this study,the system dynamics model was used to predict the development of the EV industry and the demand for charging infrastructure,while considering the influence of policy,increase in EV mileage,and consumer purchase intention index.Furthermore,using the matching of EVs and charging infrastructure in Beijing and policy oriented sensitivity analysis,a simulation of the construction of battery swap taxis and power stations under three policy scenarios was conducted.This research shows that with policies implemented to support charging infrastructure and swapping compatible taxis,Beijing can achieve its goal of replacing all EVs with fast-swap batteries and fast-charging functions within three years.展开更多
文摘California mandated that 100% of vehicles sold must be electric by 2035. As electric vehicles (EVs) reach a higher penetration of the car sector, cities will need to provide publicly accessible charging stations to meet the charging demand of people who do not have access to a private charging spot like a personal garage. We have chosen to limit our scope to San Diego County due to its non-trivial size, well-defined shape, and dependence on personal vehicles;this project models 100% of current vehicles as electric, roughly 2.5 million. By planning for the future, our model becomes more useful as well as more equitable. We anticipate that our model will find locations that can service multiple population centers, while also maximizing distance to other stations. Sensitivity analysis and testing of our algorithms are conducted for Coronado Island, an island with 24,697 residents. Our formulation is then scaled to set the parameters for the whole county.
基金the National Social Science Foundation of China(No.18AJL014)。
文摘The large-scale development of electric vehicles(EVs)requires numerous charging stations to serve them,and the charging stations should be reasonably laid out and planned according to the charging demand of electric vehicles.Considering the costs of both operators and users,a site selection model for optimal layout planning of charging stations is constructed,and a queuing theory approach is used to determine the charging pile configuration to meet the charging demand in the planning area.To solve the difficulties of particle swarm global optimization search,the improved random drift particle swarm optimization(IRDPSO)and Voronoi diagram are used to jointly solve for the optimal layout of electric vehicles.The final arithmetic analysis verifies the feasibility and practicality of the model and algorithm,and the results show that the total social cost is minimized when the charging station is 9,the location of the charging station is close to the center of gravity and the layout is reasonable.
基金Key R&D Program of Tianjin,China(No.20YFYSGX00060).
文摘As the number of electric vehicles(EVs)continues to grow and the demand for charging infrastructure is also increasing,how to improve the charging infrastructure has become a bottleneck restricting the development of EVs.In other words,reasonably planning the location and capacity of charging stations is important for development of the EV industry and the safe and stable operation of the power system.Considering the construction and maintenance of the charging station,the distribution network loss of the charging station,and the economic loss on the user side of the EV,this paper takes the node and capacity of charging station planning as control variables and the minimum cost of system comprehensive planning as objective function,and thus proposes a location and capacity planning model for the EV charging station.Based on the problems of low efficiency and insufficient global optimization ability of the current algorithm,the simulated annealing immune particle swarm optimization algorithm(SA-IPSO)is adopted in this paper.The simulated annealing algorithm is used in the global update of the particle swarm optimization(PSO),and the immune mechanism is introduced to participate in the iterative update of the particles,so as to improve the speed and efficiency of PSO.Voronoi diagram is used to divide service area of the charging station,and a joint solution process of Voronoi diagram and SA-IPSO is proposed.By example analysis,the results show that the optimal solution corresponding to the optimisation method proposed in this paper has a low overall cost,while the average charging waiting time is only 1.8 min and the charging pile utilisation rate is 75.5%.The simulation comparison verifies that the improved algorithm improves the operational efficiency by 18.1%and basically does not fall into local convergence.
基金supported by National Key Research and Development Program of China–Comprehensive Demonstration Project of Smart Grid Supporting Lowcarbon Winter Olympics(No.2016YFB0900500)
文摘The demand for fast charging is increasing owing to the rapid expansion of the market for electric vehicles. In addition, the power generation technology for distributed photovoltaic has matured. This paper presents a design scheme for a fast charging station for electric vehicles equipped with distributed photovoltaic power generation system taking the area with certain conditions in Beijing as an example construction site. The technical indexes and equipment lectotype covering the general framework and subsystems of the charging station are determined by analyzing the charging service demand of fast charging stations. In this study, the layout of the station is developed and the operation benefits of the station is analyzed. The design scheme realizes the design objective of "rationalization, modularization and intelligentization" of the fast charging station and can be used as reference for the construction of a fast charging network in urban area.
基金supported by the National Natural Science Foundation of China(No.51575047)
文摘For the charging station construction of electric vehicle,location selecting is a key issue.There are two problems in location selection of the electric vehicle charging station.One is determining the location of charging station;the other is evaluating the location of charging station.To determine the charging station location,an spatial clustering algorithm is proposed and programmed.The example simulation shows the effectiveness of the spatial clustering algorithm.To evaluate the charging station location,a multi-hierarchical fuzzy method is proposed.Based on the location factors of electric vehicle charging station,the hierarchical evaluation structure of electric vehicle charging station location is constructed,including three levels,4first-class factors and 14second-class factors.The fuzzy multi-hierarchical evaluation model and algorithm are built.The analysis results show that the multi-hierarchical fuzzy method can reasonably complete the electric vehicle charging station location evaluation.
文摘Characters of head of low head pump station and the pump shaft power areanalyzed. Influence of each single factor on pump shaft power is expressed as change of specificshaft power. (non-dimensional) and the probability density function is determined. Influences ofmultiple factors on pump shaft power are analyzed. Method of calculating none over-loadedprobability of motor by integration by successive reductions is put forward and then relationbetween power spare coefficient and none over-loaded reliability of electric motor is established.Influences of all factors on pump shaft power being considered completely; power spare coefficientsof motor are calculated in three kinds of heads (changing and unchanging), two kinds of dirty-outconditions. Electrical motor power spare coefficients should be chosen as 1.20 approx 1.44, 1.11approx 1.19, 1.09 approx.14 respectively when pump heads are 4, 7, 9.5 m. The results mean much toreasonable choose of electrical motors in large pump stations, increasing reliability of pump unitsand saving equipment investment.
文摘Considering the additional electric energy generated after the full operation of the underground hydropower station, the electric energy accommodation of the Three Gorges Project (TGP) is reviewed. It is .focused on the additional electricity accommodation, based on the research at the earl), stage. The electric energ), accommodation solutions ate recommended as that. based on the cost-benefit analysis of the power distribution area, the additional electric energy of the Three Gorges should be given ptqority to meet the needs at the supply end of Hubei and Chongqing. The results of this research has a reference value on the implementation of the Three Gorges electric power accommodation, after the further optimization of the transmission curves in both wet and dry seasons.
基金supported by the National Natural Science Foundation of China(No.U22B20105).
文摘The increasingly large number of electric vehicles(EVs)has resulted in a growing concern for EV charging station load prediction for the purpose of comprehensively evaluating the influence of the charging load on distribution networks.To address this issue,an EV charging station load predictionmethod is proposed in coupled urban transportation and distribution networks.Firstly,a finer dynamic urban transportation network model is formulated considering both nodal and path resistance.Then,a finer EV power consumption model is proposed by considering the influence of traffic congestion and ambient temperature.Thirdly,the Monte Carlo method is applied to predict the distribution of EVcharging station load based on the proposed dynamic urban transportation network model and finer EV power consumption model.Moreover,a dynamic charging pricing scheme for EVs is devised based on the EV charging station load requirements and the maximum thresholds to ensure the security operation of distribution networks.Finally,the validity of the proposed dynamic urban transportation model was verified by accurately estimating five sets of test data on travel time by contrast with the BPR model.The five groups of travel time prediction results showed that the average absolute percentage errors could be improved from 32.87%to 37.21%compared to the BPR model.Additionally,the effectiveness of the proposed EV charging station load prediction method was demonstrated by four case studies in which the prediction of EV charging load was improved from27.2 to 31.49MWh by considering the influence of ambient temperature and speed on power energy consumption.
文摘The electric vehicle charging station should be allocated based on traffic density, geographical distribution and other factors, and Voronoi diagram is adopted to set the service area of charging station. In combination with the actual situation of site selection of electric vehicle charging station, the comprehensive benefits index system is established. There are numerous factors influencing the site selection, among which there are uncertainty and fuzziness. The comprehensive evaluation method based on the fuzzy analysis and Analytical Hierarchy Process (AHP) is used to evaluate the comprehensive benefits in the site selection of electric vehicle charging stations, with the consultation of experts. This paper contributes to the best selection of comprehensive benefits and provides the reference for the decision-making of building the electric vehicle charging station. Actual examples show that the method proposed is effective.
文摘The construction of electric vehicle charging station plays an important role in the development of electric vehicles and the promotion of the renewable resource. In the paper, a model to analyze the economic benefit of the charging station is presented, which is based on the break-even theory. Then the threshold price is calculated based on the model according to the construction plans of charging facilities in one district. Finally, the strategy for the development of charging faculties is proposed to improve the health growth of electric automotive industry.
文摘The magneto-electric dipole antenna is a kind of complementary antenna composed of a planar electric dipole and a shorted patch antenna. It has excellent electrical characteristics including wide impedance bandwidth, low cross-polarization, low back lobe radiation, nearly identical E-plane and H-plane patterns, stable radiation pattern, and steady antenna gain over the operating frequency range. In this paper, the basic characteristics of a linearly polarized magneto-electric dipole antenna are reviewed, and a dual-polarized antenna element based on the magneto-electric dipole is presented. The design of a conical beam wideband antenna with horizontal polarization is also described. These antennas have practical applications in modern 2G, 3G, LTE, WiFi, and WiMax wireless communication systems.
基金funded by the Deanship of Scientific Research,Taif University,KSA(Research project number 1-441-99).
文摘With the increasing development of EVs, the energy demand from theconventional utility grid increases in proportion. On the other hand, photovoltaic(PV) energy sources can overcome several problems when charging EVs from theutility grid especially in remote areas. This paper presents an effective photovoltaic stand-alone charging station for EV applications. The proposed charging station incorporates PV array, a lithium-ion battery representing the EV battery, and alead-acid battery representing the energy storage system (ESS). A bidirectionalDC-DC converter is employed for charging/discharging the ESS and a unidirectional DC-DC converter is utilized for charging the EV battery. The proposed controllers achieve maximum power extraction from the PV and regulate the DC-linkvoltage. It also controls the voltage and current levels of both the ESS and the EVduring the charging/discharging process. The study has been applied to two caseswith different power levels. Analysis, simulation, and implementation of the proposed system are presented. A 120 W laboratory prototype is carried out to verifythe system performance, experimentally. Design guides for higher power levelsare proposed to help in choosing the proper parameters of the converters. Boththe simulation and experimental results are matched and verify the highperformance of the proposed system.
基金Supported by the National High Technology Research and Development Programme of China(No.2011AA05A108)the National NaturalScience Foundation of China(No.71041025)
文摘In the paper,an operational program of electric bus charging station is proposed,which is special for "The Construction Project for Expo 2010 Temporary Electric Bus Charging Station".Based on the quick-change mode,a vehicle operating schedule model has been established to meet the capacity of transport.Then,according to the quantity of passengers and utilization of batteries,a calculative method of parameters,such as the number of spare batteries and bus departure rules,has been provided.Furthermore,optimal simulation software designed for operating process of the charging station has been identified incorporating actual running data from electric buses and monitoring system of the charging station,and the rationality of the design is verified in the preliminary commissioning and the official operation.
文摘The variations noticed in the atmospheric electric field recorded at Pune (18°32'N, 73°51'E, 559 m ASL), a tropical inland station located in Dcccan Plateau, India, during the period 1930-1987, have been examined in relation to the variations observed in the Angstrom turbidity coefficient (β) and selected meteorological parameters. The monthly and annual mean values of the atmospheric electric field. Angstrom turbidity coefficient (β), rainfall, temperature and relative humidity for the years 1930-1938, 1957-1958, 1964-1965, 1973-1974 and 1987 were considered in the study.The results of the above study indicated gradual increases in the atmospheric electric field over the period of study (1930-1987) which is statistically significant at less than 5%level. The increases noticed during different periods varied from 30 to 109%. The increase noticed during the period (1930-1938) and (1973-1974) was maximum (109%). The Angstrom turbidity coefficient also showed systematic increases during the period of study, which is consistent. The diurnal curve of the atmospheric electric field at the station by and large, showed a double oscillation, which is generally observed in the conlinental environments.
文摘Electric propulsion is used for all electric propulsion satellites to perform the orbit transfer,attitude control and station-keeping tasks. Generally electric propulsion subsystem contains 4 thrusters. But if one thruster fails in the beginning of satellite lifetime,other thrusters will undertake all the firing tasks. The firing time will be 2 to 3 times of thrusters without failure. Thus it may go beyond the allow ed lifetime of thruster. This paper puts forward two thruster redundancy configuration solutions with 6 thrusters to solve this problem. Two layout configurations and their corresponding station-keeping strategies are simulated and compared. The results show that the maximum firing time of both layout configurations can meet the lifetime limitation. This solution is a good reference for all electric propulsion satellites design.
文摘Applications of electric vehicles need to build a large number of charging stations. The electric vehicle charging stations communicate with the grid. In V2G (vehicle to grid) mode, electric vehicles can be used as energy storage units and transfer power to the grid. The electric vehicles charge at night to reduce the cost and the grid load, simultaneously to fill the valley. When grid load increases, electric vehicles' batteries discharge to the grid to improve the stability of the grid. As distributed storage units, electric vehicles are important components of the smart grid. In this paper, the three-phase PWM (pulse width modulation) rectifier used for smart charging and discharging system of electric vehicles are analyzed and designed. This paper includes the principle of PWM rectifier-inverter and direct current control strategy. Also, the SVPWM (space vector pulse width modulation) and system design of three-phase PWM rectifiers are analyzed. A 10 kW prototype is developed. Simulation and experiment results show that the three-phase PWM rectifiers reach the unit power factor. From the experimental results, PWM rectifier implements the sinusoidal grid current and achieves the unit power factor.
文摘In east Europe and north Asia the majority of nuclear power-stations (NPS) as well as large hydro-electric (HES) and thermal electric stations (TES) are located within the north Eurasian lithosphere plate, which is characterized by the low seismicity and weak modern tectonic activity besides the different exogenetic processes. Some operating and projected NPS are relatively near to zones of the moderate seismicity in the Kaliningrad Region of northwest Russia and in south Ukraine. HES and TES in Baltic, Byelorussia and Ukraine are in the same position. Zones of more intensive seismicity and existence of active faults include NPS, HEP and TEP in the Urals, the Kola Peninsula, south Siberia, Transbaikal and Far East regions of Russia. Some of these stations are situated within crust blocks in transit zones, which separate main lithosphere plates and are characterized by increased tectonic mobility. The electric power-stations are most danger in the transit zones between north Eurasian, Arabian and Indian lithosphere plates, where collision processes have yet not stopped. This concerns electric stations in central Asia and Caucasus including NPS in Armenia. Seven schemes of the seismic energy distribution are composed for different parts of east Europe and north Asia. The location of nuclear and main other electric power-stations on them makes it possible to form a correct estimate of negative consequences connected with the up-to-date inner-continental tectonic activity.
基金support of the National Science Foundation(NSF)under Award Number:2115427 is gratefully acknowledged.SRS RN:Sustainable Transportation Electrification for an Equitable and Resilient Society(STEERS).
文摘Solar power is mostly influenced by solar irradiation,weather conditions,solar array mismatches and partial shading conditions.Therefore,before installing solar arrays,it is necessary to simulate and determine the possible power generated.Maximum power point tracking is needed in order to make sure that,at any time,the maximum power will be extracted from the photovoltaic system.However,maximum power point tracking is not a suitable solution for mismatches and partial shading conditions.To overcome the drawbacks of maximum power point tracking due to mismatches and shadows,distributed maximum power point tracking is util-ized in this paper.The solar farm can be distributed in different ways,including one DC-DC converter per group of modules or per module.In this paper,distributed maximum power point tracking per module is implemented,which has the highest efficiency.This technology is applied to electric vehicles(EVs)that can be charged with a Level 3 charging station in<1 hour.However,the problem is that charging an EV in<1 hour puts a lot of stress on the power grid,and there is not always enough peak power reserve in the existing power grid to charge EVs at that rate.Therefore,a Level 3(fast DC)EV charging station using a solar farm by implementing distributed maximum power point tracking is utilized to address this issue.Finally,the simulation result is reported using MATLAB®,LTSPICE and the System Advisor Model.Simulation results show that the proposed 1-MW solar system will provide 5 MWh of power each day,which is enough to fully charge~120 EVs each day.Additionally,the use of the proposed photovoltaic system benefits the environment by removing a huge amount of greenhouse gases and hazardous pollutants.For example,instead of supplying EVs with power from coal-fired power plants,1989 pounds of CO_(2) will be eliminated from the air per hour.
基金This research was funded by the National Social Science Fund of China[Grant number.16AGL004].
文摘Charging infrastructure supports the rapid development of China's new energy vehicle industry.It not only plays a decisive role in providing accessible and convenient services for electric vehicle(EV)users but also,in one of the seven new infrastructure areas,plays an important role in stabilizing growth and unleashing economic potential during the new coronavirus(COVID-19)pandemic,impacting China's economy.In this study,the system dynamics model was used to predict the development of the EV industry and the demand for charging infrastructure,while considering the influence of policy,increase in EV mileage,and consumer purchase intention index.Furthermore,using the matching of EVs and charging infrastructure in Beijing and policy oriented sensitivity analysis,a simulation of the construction of battery swap taxis and power stations under three policy scenarios was conducted.This research shows that with policies implemented to support charging infrastructure and swapping compatible taxis,Beijing can achieve its goal of replacing all EVs with fast-swap batteries and fast-charging functions within three years.