The on-site inspection of high-power DC chargers results in new DC high-current measurement and DC energy traceability system requirements.This paper studies the traceability technology of electric energy value for au...The on-site inspection of high-power DC chargers results in new DC high-current measurement and DC energy traceability system requirements.This paper studies the traceability technology of electric energy value for automotive high-power DC chargers,including:(1)the traceability method of the built-in DC energy meter and shunt of the charger;(2)precision DC high current and small precision DC voltage output and measurement technology.This paper designs a 0.1 mA∼600 A DC high current measurement system and proposes a 0.005 level DC powermeasurement traceability system.The uncertainty evaluation experiment of theDC powermeasurement calibration system and the high-power DC charger’s on-site calibration experiment results verify the method’s effectiveness and feasibility in this paper.The experimental results show that the combined standard uncertainty of the DC power metering verification system can be 0.0451%.展开更多
With a high penetration of Plug-In Electric Vehicles (PEVs) in the electric grid, utilities will have to face the challenges related to them. Considerable research is being done to study and mitigate the impact of PEV...With a high penetration of Plug-In Electric Vehicles (PEVs) in the electric grid, utilities will have to face the challenges related to them. Considerable research is being done to study and mitigate the impact of PEVs on the electric grid and devise methodologies to utilize them for energy storage and distributed generation. In this paper, the impact of PEVs in a smart car park, placed in an unbalanced distribution system, during a Single Line to Ground fault with auto-recloser operation is studied. Level-2, bidirectional battery chargers with Current Controlled and Voltage Controlled Voltage Source Converters are modeled for the battery charging systems of the PEVs. A smart car park, with 16 vehicles connected to each of the three phases is simulated at one of the buses in the IEEE 13 Bus Test Feeder. The impacts observed during the fault are analyzed and a method to mitigate them is suggested.展开更多
The charger of electric vehicle is a power electronic device which consists of rectifying devices and DC-DC converters. This nonlinear diode rectifier circuit has low power factor and high harmonic content. In order t...The charger of electric vehicle is a power electronic device which consists of rectifying devices and DC-DC converters. This nonlinear diode rectifier circuit has low power factor and high harmonic content. In order to improve power factor and reduce the harmonic distortion rate of the AC side current, single-phase non-controlled rectifier charger needs to install the active power factor correction device. A piece of power system analysis software which is called PSCAD is used in modeling of an EV charger which contains Boost-APFC. By means of simulation and analysis, differences of APFC characteristics between the hysteresis current control mode and average current control mode which has an influence on the power grid are compared. The consequence of simulation shows that the two control strategies achieve power factor correction and harmonic reduction requirements;Boost type power conversion circuit employs the average current control mode is better, which has following features: relatively faster settling time of the output voltage, relatively smaller overshoot, lower current harmonic distortion rate on AC side, lower switching frequency and better control effect.展开更多
Integrated battery chargers are highly effective for saving costs and improving the power density of on-board chargers in electric vehicles (EVs), However, achieving torque elimination of the commonly used three-phase...Integrated battery chargers are highly effective for saving costs and improving the power density of on-board chargers in electric vehicles (EVs), However, achieving torque elimination of the commonly used three-phase (3p) motors during the fast-charging process is challenging. In this paper, the general torque cancelation law applied in 3p permanent magnet synchronous motors (PMSMs) and induction motors (IMs) is derived to design high power density integrated fast battery chargers. Two novel integrated systems with fast-charging and vehicle-to-grid (V2G) capabilities are proposed based on this law. The main advantages of the proposed systems are: (1) Two filter inductors are constituted by the stator windings while charging, and only one external inductor and several contactors are supplemented to the motor-drive circuit. Therefore, the proposed integrated systems possess high power density;(2) The 3p open-winding (OW) motor is employed, with no need to modify the propulsion system or redesign the interior structure of the motor;(3) Employing an individual controller for each phase of the inner current loop control, the proposed systems realize unity power factors and low current harmonics in the fast-charging and V2G mode. Simulation and experimental results verify the feasibility of the proposed topologies and control strategies.展开更多
Wireless sensor networks (WSNs) have the trouble of limited battery power, and wireless charging provides apromising solution to this problem, which is not easily affected by the external environment. In this paper, w...Wireless sensor networks (WSNs) have the trouble of limited battery power, and wireless charging provides apromising solution to this problem, which is not easily affected by the external environment. In this paper, we studythe recharging of sensors in wireless rechargeable sensor networks (WRSNs) by scheduling two mobile chargers(MCs) to collaboratively charge sensors. We first formulate a novel sensor charging scheduling problem with theobjective of maximizing the number of surviving sensors, and further propose a collaborative charging schedulingalgorithm(CCSA) for WRSNs. In the scheme, the sensors are divided into important sensors and ordinary sensors.TwoMCs can adaptively collaboratively charge the sensors based on the energy limit ofMCs and the energy demandof sensors. Finally, we conducted comparative simulations. The simulation results show that the proposed algorithmcan effectively reduce the death rate of the sensor. The proposed algorithm provides a solution to the uncertaintyof node charging tasks and the collaborative challenges posed by multiple MCs in practical scenarios.展开更多
This paper presents a model predictive control(MPC) for off-board plug-in electric vehicle(PEV)chargers with photovoltaic(PV) integration using two-level four-leg inverter topology. The PEV charger is controlled by a ...This paper presents a model predictive control(MPC) for off-board plug-in electric vehicle(PEV)chargers with photovoltaic(PV) integration using two-level four-leg inverter topology. The PEV charger is controlled by a unified controller that incorporates direct power and current MPC to dynamically control decoupled active-reactive power flow in a smart grid environment as well as to control PEV battery charging and discharging reliably. PV power generation with maximum power tracking is seamlessly integrated with the power flow control to provide additional power generation. Fast dynamic response and good steady-state performance under all power flow modes and various environmental conditions are evaluated and analyzed. From the results obtained, the charger demonstrates less than 1.5% total harmonic distortion as well as low active and reactive power ripple of less than 7% and 8% respectively on the grid for all power flow modes. The PEV battery also experiences a low charging and discharging current ripple of less than 2.5%. Therefore,the results indicate the successful implementation of the proposed charger and its control for PV integrated offboard PEV chargers.展开更多
The electric vehicle(EV)charging station is a critical part of the infrastructure for the wide adoption of EVs.Realtime simulation of an EV station plays an essential role in testing its operation under different oper...The electric vehicle(EV)charging station is a critical part of the infrastructure for the wide adoption of EVs.Realtime simulation of an EV station plays an essential role in testing its operation under different operating modes.However,the large numbers of high-frequency power electronic switches contained in EV chargers pose great challenges for real-time simulation.This paper proposes a compact electromagnetic transient program(C-EMTP)algorithm for FPGA-based real-time simulation of an EV station with multiple high-frequency chargers.The C-EMTP algorithm transforms the traditional EMTP algorithm into two parallel sub-tasks only consisting of simple matrix operations,to fully utilize the high parallelism of FPGA.The simulation time step can be greatly reduced compared with that of the traditional EMTP algorithm,and so the simulation accuracy for high-frequency power electronics is improved.The EV chargers can be decoupled with each other and simulated in parallel.A CPU-FPGA-based realtime simulation platform is developed and the proposed simulation of the EV station is implemented.The control strategy is simulated in a CPU with 100μs time-step,while the EV station circuit topology is simulated in a single FPGA with a 250 ns time-step.In the case studies,the EV station consists of a two-level rectifier and five dual-active bridge(DAB)EV chargers.It is tested under different scenarios,and the real-time simulation results are validated using PSCAD/EMTDC.展开更多
The inversion of the particle size distribution from electrical mobility measurements is analyzed. Three different methods are adapted for a dot-matrix approach to the problem, especially for non-square or singular ma...The inversion of the particle size distribution from electrical mobility measurements is analyzed. Three different methods are adapted for a dot-matrix approach to the problem, especially for non-square or singular matrices, and applied to electrical mobility measurements from fixed or scanning voltages. Mul- tiply charged particles, diffusion losses, arbitrary voltage steps and noise were considered, which results in non-adjoining and overlapping transfer functions. The individual contribution of the transfer func- tions in each size interval was geometrically estimated, which requires only its characteristic mobilities. The methodology is applied to mobility measurements from particles charged with unipolar and bipolar chargers. However, the method can be extrapolated to any charging method with a defined charge distribution, and retrieval of the singly charged particle distribution and mean charge from a tandem differential mobility analysis configuration was successfully demonstrated.展开更多
In order to improve the charging efficiency of lead acid battery, shorten the charging time and avoid the battery polarization, a new charging method was put forward. Based on the analyzed results of charging charact...In order to improve the charging efficiency of lead acid battery, shorten the charging time and avoid the battery polarization, a new charging method was put forward. Based on the analyzed results of charging characteristic of lead acid battery, a pulse quick charger is designed to adjust the charging current pulse’s amplitude and pulse width automatically stage by stage according to the measured battery voltage and feedback current. Compared with other kinds of quick chargers, it has such characteristics as shorter charging time, higher charging efficiency and lower temperature increasing during the charging process. As a result, the battery polarization is reduced efficiently.展开更多
A design for a Li-ion battery charger IC that can operate in a constant current-constant voltage （CC- CV） charge mode is proposed. In the CC-CV charge mode,the charger IC provides a constant charging current at the ...A design for a Li-ion battery charger IC that can operate in a constant current-constant voltage （CC- CV） charge mode is proposed. In the CC-CV charge mode,the charger IC provides a constant charging current at the beginning, and then the charging current begins to decrease before the battery voltage reaches its final value. After the battery voltage reaches its final value and remains constant,the charging current is further reduced. This approach prevents charging the battery with full current near its saturated voltage,which can cause heating. The novel design of the core of the charger IC realizes the proposed CC-CV charge mode. The chip was implemented in a CSMC 0.6μm CMOS mixed signal process. The experimental results verify the realization of the proposed CC- CV charge mode. The voltage of the battery after charging is 4. 1833V.展开更多
In order to design a new type of quick charger for NiMH battery, the new method of pulse charge discharge was adopted after studying the charge process and analyzing the NiMH battery charge characteristics. The charg...In order to design a new type of quick charger for NiMH battery, the new method of pulse charge discharge was adopted after studying the charge process and analyzing the NiMH battery charge characteristics. The charge and discharge experiments were carried out to check feasibility and superiority of the new method. The results indicated that with the discharge pulse added the charger can charge quickly, the battery voltage and temperature can be properly controlled to prevent the battery being destroyed, and the capacity of the NiMH battery is greater than that of the battery without the discharge pulse added.展开更多
Abstract: Demand for green energy is in continuous growth. Wide band efficient wearable systems and antennas are crucial for energy harvesting wearable systems for medical and sport wearable sensors. Small harvesting ...Abstract: Demand for green energy is in continuous growth. Wide band efficient wearable systems and antennas are crucial for energy harvesting wearable systems for medical and sport wearable sensors. Small harvesting antennas suffer from low efficiency. The efficiency of energy harvesting wearable systems may be improved by using active wearable harvesting systems with low power consumption. Amplifiers may be connected to the wearable antenna feed line to increase the system dynamic range. Novel active wearable harvesting systems are presented in this paper. Notch and Slot antennas are low profile and low cost and may be employed in energy harvesting wearable systems. The wearable harvesting system components are assembled on the same PCB. The notch and slot antennas bandwidth is up to 100% for VSWR better than 3:1. The slot antenna gain is around 3 dBi with efficiency higher than 90%. The antennas electrical parameters were computed in vicinity of the human body. The active antenna gain is 24 ± 2.5 dB for frequencies from 200 MHz to 900 MHz. The active antenna gain is 12.5 ± 2.5 dB for frequencies from 1 GHz to 3 GHz. The active slot antenna Noise Figure is 0.5 ± 0.3 dB for frequencies from 200 MHz to 3.3 GHz.展开更多
This paper presents a comprehensive charging operation for an electric-drive-reconfigured onboard charger(EDROC)with active power factor correction(APFC).The charging topology exclusively utilizes the three-phase perm...This paper presents a comprehensive charging operation for an electric-drive-reconfigured onboard charger(EDROC)with active power factor correction(APFC).The charging topology exclusively utilizes the three-phase permanent magnet synchronous motor(PMSM)propulsion system as a three-channel boost-type converter in which only a contactor and a small diode bridge are added.First,the operation scenario of the EDROC is introduced.Second,the relationship between electromagnetic torque and rotor position is investigated.Third,the current ripple cancellation of the EDROC is discussed in detail.Moreover,to implement the single-phase APFC along with charging voltage/current regulation of propulsion battery,control strategies including current balancing and synchronous/interleaving PWM strategies are incorporated.Finally,200W proof-of-concept prototype-based tests are conducted under different operation scenarios.展开更多
A novel 50 kW fast charger was proposed for electric vehicles. The proposed fast charger is divided into two main sections an AC-DC converter performing a PFC function and a DC-DC converter performing a charging funct...A novel 50 kW fast charger was proposed for electric vehicles. The proposed fast charger is divided into two main sections an AC-DC converter performing a PFC function and a DC-DC converter performing a charging function. A transformer including leakage inductances was used in the AC-DC converter in order to obtain isolation and inductance. A series-connection topology was used in the DC-DC converter between the DC-bus and outlet. This topology enables high power conversion efficiency up to 95% for the DC-DC converter. In order to reduce the impact of the 50 kW charging on the AC grid, the proposed fast charger system includes a buffering battery unit between the two main power conversion units. This leads to reductions in the power installation costs of power companies and to improvements in the power quality were verified through simulations and experimental results. on the AC grid. The performances of the proposed fast charger system展开更多
This article gives an overview of the main passive solutions and active techniques, based on AC switches to limit inrush currents in medium power AC-DC converters （up to 3.7 kW） for electric vehicle charging systems...This article gives an overview of the main passive solutions and active techniques, based on AC switches to limit inrush currents in medium power AC-DC converters （up to 3.7 kW） for electric vehicle charging systems. In particular, a strategy, based on SCR （silicon controlled rectifier） phase, shift control in a mixed rectifier bridge with diodes and thyristors, is proposed. The challenge is to help designers optimize the triggering delay of SCRs to both limit the peak value of inrush current spikes and optimize the charge duration of the DC-link capacitor. A mathematical model （Mathcad engineering tool） has been defined to point out, the interest of a variable triggering delay to control SCRs to meet the expectations described previously. Experimental measurements using an industrial evaluation board of the AC-DC converter demonstrate the robustness of the method.展开更多
Compared with the traditional techniques of forest fires detection,wireless sensor network(WSN)is a very promising green technology in detecting efficiently the wildfires.However,the power constraint of sensor nodes i...Compared with the traditional techniques of forest fires detection,wireless sensor network(WSN)is a very promising green technology in detecting efficiently the wildfires.However,the power constraint of sensor nodes is one of the main design limitations of WSNs,which leads to limited operation time of nodes and late fire detection.In the past years,wireless power transfer(WPT)technology has been known as a proper solution to prolong the operation time of sensor nodes.In WPT-based mechanisms,wireless mobile chargers(WMC)are utilized to recharge the batteries of sensor nodes wirelessly.Likewise,the energy of WMC is provided using energy-harvesting or energy-scavenging techniques with employing huge,and expensive devices.However,the high price of energy-harvesting devices hinders the use of this technology in large and dense networks,as such networks require multiple WMCs to improve the quality of service to the sensor nodes.To solve this problem,multiple power banks can be employed instead of utilizing WMCs.Furthermore,the long waiting time of critical sensor nodes located outside the charging range of the energy transmitters is another limitation of the previous works.However,the sensor nodes are equipped with radio frequency(RF)technology,which allows them to exchange energy wirelessly.Consequently,critical sensor nodes located outside the charging range of the WMC can easily receive energy from neighboring nodes.Therefore,in this paper,an energy-efficient and cost-effective wireless power transmission(ECWPT)scheme is presented to improve the network lifetime and performance in forest fire detection-based systems.Simulation results exhibit that ECWPT scheme achieves improved network performance in terms of computational time(12.6%);network throughput(60.7%);data delivery ratio(20.9%);and network overhead(35%)as compared to previous related schemes.In conclusion,the proposed scheme significantly improves network energy efficiency for WSN.展开更多
In this paper, we tested the entire charging process of a single off-board charger in one charging station in Beijing. Among the testing data, we chose the typical power quality parameters and compared them with natio...In this paper, we tested the entire charging process of a single off-board charger in one charging station in Beijing. Among the testing data, we chose the typical power quality parameters and compared them with national standard. Then we drew conclusions as follows: 1) Electric vehicle battery is the capacitive load. It can export reactive power when charging. 2) In the charging process of the off-board charger, indicators of voltage deviation, frequency deviation, power factor, and voltage distortion rate are qualified. 3) Off-board charger produces odd harmonics in the charging process, and with increasing harmonic order, harmonic content reduces. There is a certain amount of high-order harmonic in off-board charger, mainly distributing around 6650 kHz. 4) Generated harmonics of the actual device, the harmonic is mainly reflected in the current, voltage, only a small distortion.展开更多
The Battery Charger Specification presents solution for rechargeable batteries used in portable electronic equipment such as laptop computer systems, cellular telephones and video cameras and the demands for low cost ...The Battery Charger Specification presents solution for rechargeable batteries used in portable electronic equipment such as laptop computer systems, cellular telephones and video cameras and the demands for low cost battery chargers are rising these days without give attention for the performance. The goal of the paper was combining high efficiency and versatility with low-cost design and this paper includes the design of the snubber cell, and the components of the current/voltage control charge method. This charger applies a relatively constant current and constant voltage to the battery indefinitely regardless of the AC input rang voltage all the equations described in this paper. The design of prototype converter is verified through an experimental result.展开更多
The coke plant of a steel plant corresponds to the area that transforms a blend of coal into coke for using in blast furnace and steam to power plant. The coking plant of ThyssenKrupp CSA uses the heat recovery techno...The coke plant of a steel plant corresponds to the area that transforms a blend of coal into coke for using in blast furnace and steam to power plant. The coking plant of ThyssenKrupp CSA uses the heat recovery technology with stamping charger for stamping and preparation a blend of coals for charging and coking. Stamping technology adds several benefits to the process, such as increased density, homogeneity and alignment of the coal cake charged into the oven, as well as provides better control of the coking process, improves parameters of coke quality and allows coal blending with lower coking power, thereby reducing the production cost of coke and power generation. Through the automation of stamping charger, it is possible to evaluate and calculate the stamped coal density charged and the productivity gains this system provides.展开更多
文摘The on-site inspection of high-power DC chargers results in new DC high-current measurement and DC energy traceability system requirements.This paper studies the traceability technology of electric energy value for automotive high-power DC chargers,including:(1)the traceability method of the built-in DC energy meter and shunt of the charger;(2)precision DC high current and small precision DC voltage output and measurement technology.This paper designs a 0.1 mA∼600 A DC high current measurement system and proposes a 0.005 level DC powermeasurement traceability system.The uncertainty evaluation experiment of theDC powermeasurement calibration system and the high-power DC charger’s on-site calibration experiment results verify the method’s effectiveness and feasibility in this paper.The experimental results show that the combined standard uncertainty of the DC power metering verification system can be 0.0451%.
文摘With a high penetration of Plug-In Electric Vehicles (PEVs) in the electric grid, utilities will have to face the challenges related to them. Considerable research is being done to study and mitigate the impact of PEVs on the electric grid and devise methodologies to utilize them for energy storage and distributed generation. In this paper, the impact of PEVs in a smart car park, placed in an unbalanced distribution system, during a Single Line to Ground fault with auto-recloser operation is studied. Level-2, bidirectional battery chargers with Current Controlled and Voltage Controlled Voltage Source Converters are modeled for the battery charging systems of the PEVs. A smart car park, with 16 vehicles connected to each of the three phases is simulated at one of the buses in the IEEE 13 Bus Test Feeder. The impacts observed during the fault are analyzed and a method to mitigate them is suggested.
文摘The charger of electric vehicle is a power electronic device which consists of rectifying devices and DC-DC converters. This nonlinear diode rectifier circuit has low power factor and high harmonic content. In order to improve power factor and reduce the harmonic distortion rate of the AC side current, single-phase non-controlled rectifier charger needs to install the active power factor correction device. A piece of power system analysis software which is called PSCAD is used in modeling of an EV charger which contains Boost-APFC. By means of simulation and analysis, differences of APFC characteristics between the hysteresis current control mode and average current control mode which has an influence on the power grid are compared. The consequence of simulation shows that the two control strategies achieve power factor correction and harmonic reduction requirements;Boost type power conversion circuit employs the average current control mode is better, which has following features: relatively faster settling time of the output voltage, relatively smaller overshoot, lower current harmonic distortion rate on AC side, lower switching frequency and better control effect.
基金supported by the Guangdong Provincial Natural Science Research Team Project(2017B030312001).
文摘Integrated battery chargers are highly effective for saving costs and improving the power density of on-board chargers in electric vehicles (EVs), However, achieving torque elimination of the commonly used three-phase (3p) motors during the fast-charging process is challenging. In this paper, the general torque cancelation law applied in 3p permanent magnet synchronous motors (PMSMs) and induction motors (IMs) is derived to design high power density integrated fast battery chargers. Two novel integrated systems with fast-charging and vehicle-to-grid (V2G) capabilities are proposed based on this law. The main advantages of the proposed systems are: (1) Two filter inductors are constituted by the stator windings while charging, and only one external inductor and several contactors are supplemented to the motor-drive circuit. Therefore, the proposed integrated systems possess high power density;(2) The 3p open-winding (OW) motor is employed, with no need to modify the propulsion system or redesign the interior structure of the motor;(3) Employing an individual controller for each phase of the inner current loop control, the proposed systems realize unity power factors and low current harmonics in the fast-charging and V2G mode. Simulation and experimental results verify the feasibility of the proposed topologies and control strategies.
基金Hubei Provincial Natural Science Foundation of China under Grant No.2017CKB893Wuhan Polytechnic University Reform Subsidy Project Grant No.03220153.
文摘Wireless sensor networks (WSNs) have the trouble of limited battery power, and wireless charging provides apromising solution to this problem, which is not easily affected by the external environment. In this paper, we studythe recharging of sensors in wireless rechargeable sensor networks (WRSNs) by scheduling two mobile chargers(MCs) to collaboratively charge sensors. We first formulate a novel sensor charging scheduling problem with theobjective of maximizing the number of surviving sensors, and further propose a collaborative charging schedulingalgorithm(CCSA) for WRSNs. In the scheme, the sensors are divided into important sensors and ordinary sensors.TwoMCs can adaptively collaboratively charge the sensors based on the energy limit ofMCs and the energy demandof sensors. Finally, we conducted comparative simulations. The simulation results show that the proposed algorithmcan effectively reduce the death rate of the sensor. The proposed algorithm provides a solution to the uncertaintyof node charging tasks and the collaborative challenges posed by multiple MCs in practical scenarios.
基金supported by Malaysian Ministry of Higher Education(MOHE)(No.FRGS/1/2015/TK10/USMC/03/1)
文摘This paper presents a model predictive control(MPC) for off-board plug-in electric vehicle(PEV)chargers with photovoltaic(PV) integration using two-level four-leg inverter topology. The PEV charger is controlled by a unified controller that incorporates direct power and current MPC to dynamically control decoupled active-reactive power flow in a smart grid environment as well as to control PEV battery charging and discharging reliably. PV power generation with maximum power tracking is seamlessly integrated with the power flow control to provide additional power generation. Fast dynamic response and good steady-state performance under all power flow modes and various environmental conditions are evaluated and analyzed. From the results obtained, the charger demonstrates less than 1.5% total harmonic distortion as well as low active and reactive power ripple of less than 7% and 8% respectively on the grid for all power flow modes. The PEV battery also experiences a low charging and discharging current ripple of less than 2.5%. Therefore,the results indicate the successful implementation of the proposed charger and its control for PV integrated offboard PEV chargers.
基金supported by China Postdoctoral Science Foundation(BX20200221,2020 M671122)National Key Research and Development Program of China(2019YFE012784)National Natural Science Foundation of China(51877133).
文摘The electric vehicle(EV)charging station is a critical part of the infrastructure for the wide adoption of EVs.Realtime simulation of an EV station plays an essential role in testing its operation under different operating modes.However,the large numbers of high-frequency power electronic switches contained in EV chargers pose great challenges for real-time simulation.This paper proposes a compact electromagnetic transient program(C-EMTP)algorithm for FPGA-based real-time simulation of an EV station with multiple high-frequency chargers.The C-EMTP algorithm transforms the traditional EMTP algorithm into two parallel sub-tasks only consisting of simple matrix operations,to fully utilize the high parallelism of FPGA.The simulation time step can be greatly reduced compared with that of the traditional EMTP algorithm,and so the simulation accuracy for high-frequency power electronics is improved.The EV chargers can be decoupled with each other and simulated in parallel.A CPU-FPGA-based realtime simulation platform is developed and the proposed simulation of the EV station is implemented.The control strategy is simulated in a CPU with 100μs time-step,while the EV station circuit topology is simulated in a single FPGA with a 250 ns time-step.In the case studies,the EV station consists of a two-level rectifier and five dual-active bridge(DAB)EV chargers.It is tested under different scenarios,and the real-time simulation results are validated using PSCAD/EMTDC.
基金support under the project MEC05CGL2005-05244/CLI and grant BES-2006-12469supported by the Deutsche Forschungsgemeinschaft(DFG) in the framework of the joint research program "Multiparameter Characterization of Particle-based Functional Materials by Innovative Online Measurement Technology" (PAK688)
文摘The inversion of the particle size distribution from electrical mobility measurements is analyzed. Three different methods are adapted for a dot-matrix approach to the problem, especially for non-square or singular matrices, and applied to electrical mobility measurements from fixed or scanning voltages. Mul- tiply charged particles, diffusion losses, arbitrary voltage steps and noise were considered, which results in non-adjoining and overlapping transfer functions. The individual contribution of the transfer func- tions in each size interval was geometrically estimated, which requires only its characteristic mobilities. The methodology is applied to mobility measurements from particles charged with unipolar and bipolar chargers. However, the method can be extrapolated to any charging method with a defined charge distribution, and retrieval of the singly charged particle distribution and mean charge from a tandem differential mobility analysis configuration was successfully demonstrated.
文摘In order to improve the charging efficiency of lead acid battery, shorten the charging time and avoid the battery polarization, a new charging method was put forward. Based on the analyzed results of charging characteristic of lead acid battery, a pulse quick charger is designed to adjust the charging current pulse’s amplitude and pulse width automatically stage by stage according to the measured battery voltage and feedback current. Compared with other kinds of quick chargers, it has such characteristics as shorter charging time, higher charging efficiency and lower temperature increasing during the charging process. As a result, the battery polarization is reduced efficiently.
文摘A design for a Li-ion battery charger IC that can operate in a constant current-constant voltage （CC- CV） charge mode is proposed. In the CC-CV charge mode,the charger IC provides a constant charging current at the beginning, and then the charging current begins to decrease before the battery voltage reaches its final value. After the battery voltage reaches its final value and remains constant,the charging current is further reduced. This approach prevents charging the battery with full current near its saturated voltage,which can cause heating. The novel design of the core of the charger IC realizes the proposed CC-CV charge mode. The chip was implemented in a CSMC 0.6μm CMOS mixed signal process. The experimental results verify the realization of the proposed CC- CV charge mode. The voltage of the battery after charging is 4. 1833V.
文摘In order to design a new type of quick charger for NiMH battery, the new method of pulse charge discharge was adopted after studying the charge process and analyzing the NiMH battery charge characteristics. The charge and discharge experiments were carried out to check feasibility and superiority of the new method. The results indicated that with the discharge pulse added the charger can charge quickly, the battery voltage and temperature can be properly controlled to prevent the battery being destroyed, and the capacity of the NiMH battery is greater than that of the battery without the discharge pulse added.
文摘Abstract: Demand for green energy is in continuous growth. Wide band efficient wearable systems and antennas are crucial for energy harvesting wearable systems for medical and sport wearable sensors. Small harvesting antennas suffer from low efficiency. The efficiency of energy harvesting wearable systems may be improved by using active wearable harvesting systems with low power consumption. Amplifiers may be connected to the wearable antenna feed line to increase the system dynamic range. Novel active wearable harvesting systems are presented in this paper. Notch and Slot antennas are low profile and low cost and may be employed in energy harvesting wearable systems. The wearable harvesting system components are assembled on the same PCB. The notch and slot antennas bandwidth is up to 100% for VSWR better than 3:1. The slot antenna gain is around 3 dBi with efficiency higher than 90%. The antennas electrical parameters were computed in vicinity of the human body. The active antenna gain is 24 ± 2.5 dB for frequencies from 200 MHz to 900 MHz. The active antenna gain is 12.5 ± 2.5 dB for frequencies from 1 GHz to 3 GHz. The active slot antenna Noise Figure is 0.5 ± 0.3 dB for frequencies from 200 MHz to 3.3 GHz.
基金This work was supported in part by the National Natural Science Foundation of China(51807098,61673226)and the Six Talent Peaks Project in Jiangsu Province(2015-JY-028).
文摘This paper presents a comprehensive charging operation for an electric-drive-reconfigured onboard charger(EDROC)with active power factor correction(APFC).The charging topology exclusively utilizes the three-phase permanent magnet synchronous motor(PMSM)propulsion system as a three-channel boost-type converter in which only a contactor and a small diode bridge are added.First,the operation scenario of the EDROC is introduced.Second,the relationship between electromagnetic torque and rotor position is investigated.Third,the current ripple cancellation of the EDROC is discussed in detail.Moreover,to implement the single-phase APFC along with charging voltage/current regulation of propulsion battery,control strategies including current balancing and synchronous/interleaving PWM strategies are incorporated.Finally,200W proof-of-concept prototype-based tests are conducted under different operation scenarios.
基金Project supported by Changwon National University in 2011-2012
文摘A novel 50 kW fast charger was proposed for electric vehicles. The proposed fast charger is divided into two main sections an AC-DC converter performing a PFC function and a DC-DC converter performing a charging function. A transformer including leakage inductances was used in the AC-DC converter in order to obtain isolation and inductance. A series-connection topology was used in the DC-DC converter between the DC-bus and outlet. This topology enables high power conversion efficiency up to 95% for the DC-DC converter. In order to reduce the impact of the 50 kW charging on the AC grid, the proposed fast charger system includes a buffering battery unit between the two main power conversion units. This leads to reductions in the power installation costs of power companies and to improvements in the power quality were verified through simulations and experimental results. on the AC grid. The performances of the proposed fast charger system
文摘This article gives an overview of the main passive solutions and active techniques, based on AC switches to limit inrush currents in medium power AC-DC converters （up to 3.7 kW） for electric vehicle charging systems. In particular, a strategy, based on SCR （silicon controlled rectifier） phase, shift control in a mixed rectifier bridge with diodes and thyristors, is proposed. The challenge is to help designers optimize the triggering delay of SCRs to both limit the peak value of inrush current spikes and optimize the charge duration of the DC-link capacitor. A mathematical model （Mathcad engineering tool） has been defined to point out, the interest of a variable triggering delay to control SCRs to meet the expectations described previously. Experimental measurements using an industrial evaluation board of the AC-DC converter demonstrate the robustness of the method.
文摘Compared with the traditional techniques of forest fires detection,wireless sensor network(WSN)is a very promising green technology in detecting efficiently the wildfires.However,the power constraint of sensor nodes is one of the main design limitations of WSNs,which leads to limited operation time of nodes and late fire detection.In the past years,wireless power transfer(WPT)technology has been known as a proper solution to prolong the operation time of sensor nodes.In WPT-based mechanisms,wireless mobile chargers(WMC)are utilized to recharge the batteries of sensor nodes wirelessly.Likewise,the energy of WMC is provided using energy-harvesting or energy-scavenging techniques with employing huge,and expensive devices.However,the high price of energy-harvesting devices hinders the use of this technology in large and dense networks,as such networks require multiple WMCs to improve the quality of service to the sensor nodes.To solve this problem,multiple power banks can be employed instead of utilizing WMCs.Furthermore,the long waiting time of critical sensor nodes located outside the charging range of the energy transmitters is another limitation of the previous works.However,the sensor nodes are equipped with radio frequency(RF)technology,which allows them to exchange energy wirelessly.Consequently,critical sensor nodes located outside the charging range of the WMC can easily receive energy from neighboring nodes.Therefore,in this paper,an energy-efficient and cost-effective wireless power transmission(ECWPT)scheme is presented to improve the network lifetime and performance in forest fire detection-based systems.Simulation results exhibit that ECWPT scheme achieves improved network performance in terms of computational time(12.6%);network throughput(60.7%);data delivery ratio(20.9%);and network overhead(35%)as compared to previous related schemes.In conclusion,the proposed scheme significantly improves network energy efficiency for WSN.
文摘In this paper, we tested the entire charging process of a single off-board charger in one charging station in Beijing. Among the testing data, we chose the typical power quality parameters and compared them with national standard. Then we drew conclusions as follows: 1) Electric vehicle battery is the capacitive load. It can export reactive power when charging. 2) In the charging process of the off-board charger, indicators of voltage deviation, frequency deviation, power factor, and voltage distortion rate are qualified. 3) Off-board charger produces odd harmonics in the charging process, and with increasing harmonic order, harmonic content reduces. There is a certain amount of high-order harmonic in off-board charger, mainly distributing around 6650 kHz. 4) Generated harmonics of the actual device, the harmonic is mainly reflected in the current, voltage, only a small distortion.
文摘The Battery Charger Specification presents solution for rechargeable batteries used in portable electronic equipment such as laptop computer systems, cellular telephones and video cameras and the demands for low cost battery chargers are rising these days without give attention for the performance. The goal of the paper was combining high efficiency and versatility with low-cost design and this paper includes the design of the snubber cell, and the components of the current/voltage control charge method. This charger applies a relatively constant current and constant voltage to the battery indefinitely regardless of the AC input rang voltage all the equations described in this paper. The design of prototype converter is verified through an experimental result.
文摘The coke plant of a steel plant corresponds to the area that transforms a blend of coal into coke for using in blast furnace and steam to power plant. The coking plant of ThyssenKrupp CSA uses the heat recovery technology with stamping charger for stamping and preparation a blend of coals for charging and coking. Stamping technology adds several benefits to the process, such as increased density, homogeneity and alignment of the coal cake charged into the oven, as well as provides better control of the coking process, improves parameters of coke quality and allows coal blending with lower coking power, thereby reducing the production cost of coke and power generation. Through the automation of stamping charger, it is possible to evaluate and calculate the stamped coal density charged and the productivity gains this system provides.
