The reverse snapback phenomena （RSP） on I-V characteristics of static induction thyristors （SITH） are physically researched. The I-V curves of the power SITH exhibit reverse snapback phenomena, and even turn to th...The reverse snapback phenomena （RSP） on I-V characteristics of static induction thyristors （SITH） are physically researched. The I-V curves of the power SITH exhibit reverse snapback phenomena, and even turn to the conducting-state,when the anode voltage in the forward blocking-state is increased to a critical value. The RSP I-V characteristics of the power SITH are analyzed in terms of operating mechanism, double carrier injection effect, space charge effect, electron-hole plasma in the channel, and the variation in carrier lifetime. The reverse snapback mechanism is theoretically pro- posed and the mathematical expressions to calculate the voltage and current values at the snapback point are presented. The computing results are compared with the experiment values.展开更多
With the aim of sending electric power to autonomous underwater vehicles(AUVs), an automatic wireless power supply system by means of electromagnetic coupler was proposed. An equivalent circuit of the electromagnetic ...With the aim of sending electric power to autonomous underwater vehicles(AUVs), an automatic wireless power supply system by means of electromagnetic coupler was proposed. An equivalent circuit of the electromagnetic coupler with compensating capacitors was presented to analyze the performance of the system.The magnetizing inductance and leakage inductance, which are important for choosing compensating capacitors,were calculated by finite element analysis(FEA) methods. Then the voltage gain, power loss and system efficiency were analyzed to optimize the winding turns. Finally, a phase-shift full bridge zero-voltage-switching converter and an electromagnetic coupler were produced. The experimental results demonstrated that the proposed system has a high voltage gain with small variation and sufficient power feeding.展开更多
Traditional power supply method for moving electric railway vehicles is based on contact type power collection technology.This sometimes cannot meet the requirements of modern rail transportation.A new wireless power ...Traditional power supply method for moving electric railway vehicles is based on contact type power collection technology.This sometimes cannot meet the requirements of modern rail transportation.A new wireless power transfer(WPT)technology can offer significant benefits in modern rail transportation particularly in some stringent environments.This paper reviews the status and the development of rail transit power supply technology,and introduces a new challenging technology--inductive power transfer(IPT)technology for rail transit.Tesla established the underpinning of IPT technology and creatively and significantly demonstrated power transfer by using highly resonant tuned coils long time ago.However,only in recent years the IPT technology has been significantly improved including the transfer air-gap length,transfer efficiency,coupling factor,power transfer capability and so on.This is mainly due to innovative semiconductor switches,higher control frequency,better coil designs and high performance material,new track and vehicle construction techniques.Recent advances in IPT for rail transit and major milestones of the developments are summarized in this paper.Some important technical issues such as coupling coil structures,power supply schemes,segmentation switching techniques for long-distance power supply,and bidirectional IPT systems for braking energy feedback are discussed.展开更多
The pulsed power supply(PPS)is one important component in the electromagnetic launch system.The inductive PPSs have attracted researchers’attentions with the major advantages of high energy storage density(over the c...The pulsed power supply(PPS)is one important component in the electromagnetic launch system.The inductive PPSs have attracted researchers’attentions with the major advantages of high energy storage density(over the capacitive PPSs)as well as simple structure and easy control(over the rotating mechanical PPSs).As for the inductive PPSs,the circuit topology of the basic module will directly determine the comprehensive performance of the whole system.From the perspectives of working principles,strengths,weaknesses,and comprehensive performance,this paper presents a historical and technical review of the major circuit topologies for the inductive PPSs.展开更多
The online detection of metal shaft parameters,such as torque,power and deformation,is widely applied in engineering projects.The power supply of metal shafts is the key to the detection reliability and practicality.H...The online detection of metal shaft parameters,such as torque,power and deformation,is widely applied in engineering projects.The power supply of metal shafts is the key to the detection reliability and practicality.However,traditional slip ring and battery power supply are limited in reliability and service life.In this paper,a side-mounted inductive power supply system for the rotating metal shaft is designed by using a Utype core.The equivalent reluctance and circuit models of the system are analyzed,and the methods of improving the coupling coefficient and transmission efficiency are proposed from theoretical analysis.Through the finite element simulation analysis of the system,the general relationships between the transmission power and efficiency of the system and the number of coil turns,the working frequency and the load are analyzed.The accuracy of theoretical analysis and simulation analysis is verified by the practical power transmission experiments.This paper provides a novel and reliable power supply method for inductive power supply of rotating equipment,and enriches the solutions of rotating power supply.展开更多
Curved coils constructed by flexible printed circuit board (PCB) or hand-wound Litz-wire have been steadily becoming popular due to its applicable potential on devices that have a curved body. Inductive Power Transfer...Curved coils constructed by flexible printed circuit board (PCB) or hand-wound Litz-wire have been steadily becoming popular due to its applicable potential on devices that have a curved body. Inductive Power Transfer (IPT) systems based on curved coils and flexible ferrite sheets may provide more flexible charging solutions for various electronic devices such as rice cookers and robot vacuum cleaners. Power repeaters are also used in IPT systems to extend wireless charging range by guiding magnetic fields to the receiving coil. The interaction of these three topics could be inspiring. In this paper, two adjustable power repeaters are applied to an IPT charging system with various curved receiving coils designed for vacuum cleaners. Two power repeaters share the identical structure as the Tx coil and could be rotated to mirror symmetrically. The input and output power are calculated by analyzing the equivalent circuit model. The self-inductance, mutual inductance, and coupling coefficient of the proposed system are obtained via finite element method simulation with variable rotating angles. Three typical IPT designs have also been simulated in ANSYS Maxwell and compared with the proposed magnetic design. The comparison indicates the enhancing feature of the passive power repeaters on coupling performance and the ability to guide the magnetic flux for better magnetic field coupling. Furthermore, two types of co-simulations defined by the power source via Simplorer are conducted to explore how much power could be transferred. The tuned system is shown to be able to provide about 32 W under 100 kHz operating frequency for charging the battery of a robot vacuum cleaner. The results from theoretical calculation and simulation align well with each other.展开更多
In this paper,a novel pulse density modulation(PDM)with semi-bridgeless active rectifier(S-BAR)in inductive power transfer(IPT)system for rail vehicle is proposed.It is to reduce switching losses of the active rectifi...In this paper,a novel pulse density modulation(PDM)with semi-bridgeless active rectifier(S-BAR)in inductive power transfer(IPT)system for rail vehicle is proposed.It is to reduce switching losses of the active rectifier in pickups.In the control method,the insulated-gate bipolar transistors(IGBTs)in the S-BAR are controlled by synchronous PDM signals,so that zero-voltage switching(ZVS)and zero-current switching(ZCS)can be achieved in the whole output power range.The output power is regulated by changing the pulse density(PD)of the S-BAR since the it is almost linear proportional with the PD in high quality factor of pickup side.The communication device between the primary side and pickup side is not necessary anymore.The detailed theoretical analyses of the PDM method are provided,and its advantages are shown in a 7.5kW IPT prototype for rail vehicle.The experimental results are presented to verify the analysis and demonstrate the performance.The overall efficiency of the system by PDM control is 74.2%which is improved by 4%compared with phase shift(PS)control at light load.展开更多
This study responds to global climate concerns by addressing the shift towards sustainable transportation,particularly electric vehicles.Focusing on wireless power transfer to overcome charging infrastructure challeng...This study responds to global climate concerns by addressing the shift towards sustainable transportation,particularly electric vehicles.Focusing on wireless power transfer to overcome charging infrastructure challenges,the research optimizes circular coils for inductive power transfer in electric cars.Utilizing ferrite cores to enhance performance,the study employs ANSYS Electronics Suite R2-202 and the finite element method to analyze circular coils,exploring variations in turns,inner radius,air gap,and misalignment's impact on the coupling coefficient.Introducing ferrite plan cores and boxes,the research finds that ferrite boxes improve coupling efficiency by 50%and electromagnetic field strength by 300%,concentrating the field toward the center.An inequivalent design,enlarging the primary coil,demonstrates significant enhancements,achieving a coupling coefficient increase of 0.183,447 and an electromagnetic field rise of 0.000,40 T.Equivalent coils with ferrite boxes meet a 95%efficiency goal with a strong,narrowed field at a lower cost,while inequivalent coils excel in strengthening and centralizing the field,enhancing misalignment tolerance in distinctive ways.展开更多
Inductive coupled wireless power transfer(WPT)system transfers energy through the magnetic field.The magnetics field distribution of WPT system has significantly influence on the transmission efficiency and misalignme...Inductive coupled wireless power transfer(WPT)system transfers energy through the magnetic field.The magnetics field distribution of WPT system has significantly influence on the transmission efficiency and misalignment tolerance.This study investigates the magnetic field distribution of WPT system and presents a magnetic field distribution analytical model for WPT system.The analytical model is based on Fourier analysis method,and it can be applied in the cases of coil with air core and with Ferrite core.Furthermore,the finite element simulation model and experiment are conducted.The results of analysis,simulation and experiment are in good agreement.展开更多
The analysis of the wind-driven self-excited induction generators （SEIGs） connected to the grid through power converters has been developed in this paper. For this analysis, a method of representing the grid power a...The analysis of the wind-driven self-excited induction generators （SEIGs） connected to the grid through power converters has been developed in this paper. For this analysis, a method of representing the grid power as equivalent load resistance in the steady-state equivalent circuit of SEIG has been formulated. The technique of genetic algorithm （GA） has been adopted for making the analysis of the proposed system simple and straightfor- ward. The control of SEIG is attempted by connecting an uncontrolled diode bridge rectifier （DBR） and a line commutated inverter （LCI） between the generator term- inals and three-phase utility grid. A simple control technique for maximum power point tracking （MPPT） in wind energy conversion systems （WECS）, in which the firing angle of the LCI alone needs to be controlled by sensing the rotor speed of the generator has been proposed. The effectiveness of the proposed method of MPPT and method of analysis of this wind-driven SEIG-converter system connected to the grid through power converters has been demonstrated by experiments and simulation. These experimental and simulated results confirm the usefulness and successful working of the proposed system and its analysis.展开更多
The implementation of a simple power converter for a wound rotor induction generator employing a three phase diode bridge rectifier and a line commutated inverter in the rotor circuit for super synchronous speeds has ...The implementation of a simple power converter for a wound rotor induction generator employing a three phase diode bridge rectifier and a line commutated inverter in the rotor circuit for super synchronous speeds has been proposed. The detailed working of the system in power smoothing mode and maximum power point tracking mode is presented. The current flow in the rotor circuit is controlled （by controlling the firing angle of the line commutated inverter） for controlling the stator power in both the modes. An 8 bit PIC microcontroller has been programmed to vary the firing angle of the line commutated inverter. Experiments have been carried out on a 3- phase, 3.73 kW, 400V, 50Hz, 4-pole, 1500r/rain wound rotor induction generator and the results obtained with the generator supplying power in both the modes are furnished. The complete scheme has been modeled using MATLAB/SIMULINK blocks and a simulation study has been conducted. The experimental waveforms are compared with the simulation results and a very close agreement between them is observed.展开更多
Inductive energy storage systems （IES）require opening switches which are technically much more difficult to realize than closing switches. Institute of Advanced Technology （ IAT ） puts forward a meat grinder with ...Inductive energy storage systems （IES）require opening switches which are technically much more difficult to realize than closing switches. Institute of Advanced Technology （ IAT ） puts forward a meat grinder with an inductive pulse power topology called slow transfer of energy through capacitive hybrid （STRETCH）. In this topology, an integrated gate-commutated thyristor （IGCT） is capable of breaking the charging currents on the order of 4 kA, and it may encounter difficulties in expanding to higher energy systems. German-French Institute of Saint Louis （ISL） has developed a high-power opening switch based on standard high-power thyristors by using their so-called inverse current commutation with semiconductor devices （ICCOS） countercurrent commutation principle. Two topologies of the STRETCH meat grinder with ICCOS are analyzed. And they are compared based on the voltage across the main switch, the current multiplication factor and other aspects by u- sing Matlab simulations. The advantages and disadvantages of the two topologies are shown through the comparisons. Therefore a more suitable topology can be chosen for realistic applications accord- ing to their performances.展开更多
This study investigated the inductively coupled plasma etching reactor and RF coils developed by North Microelectronic Corporation. Full three dimensional simulations were made at different discharge conditions. The s...This study investigated the inductively coupled plasma etching reactor and RF coils developed by North Microelectronic Corporation. Full three dimensional simulations were made at different discharge conditions. The simulations examined and compared the distribution and non-uniformity of several plasma parameters at a fixed position upon the wafer at different pressures and coil currents. These parameters included electron density, electron temperature and power deposition. The results demonstrate that the electron density, power deposition and uniformity increase with either higher pressure or stronger coil currents, while the electron temperature decreases at this condition. Coil number increase can reduce the non-uniformity of parameters in the spatial distribution. The linear relationship between power deposition and electron density does not always exist. The comparison between simulation results and experiment results is also presented in the paper.展开更多
A modular-parallel IPT system with multi-inverters is proposed to enhance power capacity and expansibility for primary power equipment.In order to balance the actual output power of each inverter,a control strategy is...A modular-parallel IPT system with multi-inverters is proposed to enhance power capacity and expansibility for primary power equipment.In order to balance the actual output power of each inverter,a control strategy is designed to minimize circulating-current and equalize output current.In the process of circulating current suppression,current could be decoupled into the following two parts through a d-q synchronous rotating frame:virtual active and reactive current.Then,the above two virtual current components can be adjusted by PWM and PPM.A close-loop control method based on master-slave scheme is proposed to improve the scalability for a practical IPT system,and an impedance matching and its ZCS method is proposed to avoid detuning caused by a change of the number of modules.Finally,an IPT experiment platform with 3-parallel modules is established to verify availability of the proposed control methods.As shown in the experiment,circulating current of the prototype can be reduced from 2.6 A to 0.3 A,and the difference of output power of each module is less than 1%when deviation of the input DC voltage,the delay of driving signals,and the resonant inductance is 10%,respectively.The overall efficiency of the modular IPT system is up to 92.5%at 3.3 kW.展开更多
We develop a new kind of underwater inductive coupling power transfer(ICPT)system to evaluate wireless power transfer in autonomous underwater vehicle(AUV)docking applications.Parameters that determine the performance...We develop a new kind of underwater inductive coupling power transfer(ICPT)system to evaluate wireless power transfer in autonomous underwater vehicle(AUV)docking applications.Parameters that determine the performance of the system are systematically analyzed through mathematical methods.A circuit simulation model and a finite element analysis(FEA)simulation model are developed to study the power losses of the system,including copper loss in coils,semiconductor loss in circuits,and eddy current loss in transmission media.The characteristics of the power losses can provide guidelines to improve the efficiency of ICPT systems.Calculation results and simulation results are validated by relevant experiments of the prototype system.The output power of the prototype system is up to 45 W and the efficiency is up to 0.84.The preliminary results indicate that the efficiency will increase as the transmission power is raised by increasing the input voltage.When the output power reaches 500 W,the efficiency is expected to exceed 0.94.The efficiency can be further improved by choosing proper semiconductors and coils.The analysis methods prove effective in predicting the performance of similar ICPT systems and should be useful in designing new systems.展开更多
This paper present a highly-integrated neurostimulator with an on-chip inductive power-recovery fron- tend and high-voltage stimulus generator. In particular, the power-recovery frontend includes a high-voltage full- ...This paper present a highly-integrated neurostimulator with an on-chip inductive power-recovery fron- tend and high-voltage stimulus generator. In particular, the power-recovery frontend includes a high-voltage full- wave rectifier （up to 100 V AC input）, high-voltage series regulators （24/5 V outputs） and a linear regulator （1.8/ 3.3 V output） with bandgap voltage reference. With the high voltage output of the series regulator, the proposed neurostimulator could deliver a considerably large current in high electrode-tissue contact impedance. This neu- rostimulator has been fabricated in a CSMC 1 μm 5/40/700 V BCD＇process and the total silicon area including pads is 5.8 mm2. Preliminary tests are successful as the neurostimulator shows good stability under a 13.56 MHz AC supply. Compared to previously reported works, our design has advantages of a wide induced voltage range （26-100 V）, high output voltage （up to 24 V） and high-level integration, which are suitable for implantable neu- rostimulators.展开更多
The efficiency of inductive power links driven by Class-E amplifiers may deteriorate due to variation in the coupling coefficient when the relative position of the radio frequency (RF) coils changes.To solve this prob...The efficiency of inductive power links driven by Class-E amplifiers may deteriorate due to variation in the coupling coefficient when the relative position of the radio frequency (RF) coils changes.To solve this problem,a new design methodology of power links is presented in this paper.The aim of the new design is to use the feedback signal,which is a phase difference between the driving signal and the output current of the Class-E amplifier,to adjust the duty cycle and angular frequency of the driving signal to maintain the optimum state of the inductive power link,and to adjust the supply voltage to keep the output power constant when the coupling coefficient of the RF coils changes.The parameter adjustments with respect to the coupling coefficient and the feedback signal are derived from the design equation of the inductive power link.To validate the feedback control rules,a prototype of the inductive power link was constructed,and its performance validated with the coupling coefficient set at 0.2 and a duty cycle of 0.5.The experimental results showed that,by adjusting the duty cycle,the angular frequency,and the supply voltage,the power link can be kept in optimal operation with a constant output power when the coupling coefficient changes from 0.2 to 0.1 to 0.25.展开更多
This paper presents a P-Q coordination based highvoltage ride through(HVRT) control strategy for doubly fed induction generators(DFIGs) based on a combined Q-V control and P-V de-loading control. The active/reactive p...This paper presents a P-Q coordination based highvoltage ride through(HVRT) control strategy for doubly fed induction generators(DFIGs) based on a combined Q-V control and P-V de-loading control. The active/reactive power injection effect of DFIG on transient overvoltage is firstly analyzed and the reactive power capacity evaluation of DFIG considering its de-loading operation is then conducted. In the proposed strategy, the reactive power limit of DFIG can be flexibly extended during the transient process in coordination with its active power adjustment. As a result, the transient overvoltage caused by DC bipolar block can be effectively suppressed. Moreover, key outer loop parameters such as Q-V control coefficient and deloading coefficient can be determined based on the voltage level of point of common coupling(PCC) and the available power capacity of DFIG. Finally, case studies based on MATLAB/Simulink simulation are used to verify the effectiveness of the proposed control strategy.展开更多
Inductive power transfer system can generate eddy current when operating in seawater medium. On the one hand, it can cause eddy current loss, and reduce operating efficiency of the system. On the other hand, it can ch...Inductive power transfer system can generate eddy current when operating in seawater medium. On the one hand, it can cause eddy current loss, and reduce operating efficiency of the system. On the other hand, it can change parameters of the system and increase difficulty of system design. To grasp the influence mechanism of seawater on the inductive power transfer system,firstly, an equivalent circuit model of double-sided inductor-capacitor-capacitor(LCC) inductive power transfer system in seawater environment was established based on loosely-coupled transformer model of eddy current. Then, based on Maxwell’s equations, the distribution function of the magnetic field and electric current density along radium direction of the coupling coils in seawater medium was obtained by analytical calculation. Besides, in combination with Biot-Savart law, expression of the eddy current loss in transfer direction was derived, and based on which expression of the equivalent of the eddy current loss on the coupling coils was got. Thus the equivalent resistance of the eddy current on the coupling coils in a seawater environment could be predicated, and the optimal operating frequency of the inductive power transfer system could be further optimized. Finally, a prototype of inductive power transfer system was established, which gave the experimental results, and verified the correctness of theoretical analysis, and the experiments showed that: in air medium, the transfer distance was 100 mm, the transfer power was 3.3 k W, and the transfer efficiency was 92.6%;while, in seawater medium, the transfer efficiency was 87%. Eddy current losses mainly caused the reduction in efficiency, and the experimental results of eddy current loss were consistent with the simulation results.展开更多
We show that resonant tunneling of electromagnetic （EM） fields can occur through a six-layer structure con- sisting of two pairs of bilayer slabs： one＇being an epsilon-negative layer and the other being a mu-negat...We show that resonant tunneling of electromagnetic （EM） fields can occur through a six-layer structure con- sisting of two pairs of bilayer slabs： one＇being an epsilon-negative layer and the other being a mu-negative layer with a double-positive （DPS） medium and air. This type of tunneling is accompanied by high-magnetic field. The Poynting vector distributions and the material dissipation are studied. Our results demonstrate that the EM field in the structure is controlled flexibly by single-negative media and DPS slab. Therefore, this structure has potential applications in wireless energy transfer.展开更多
文摘The reverse snapback phenomena （RSP） on I-V characteristics of static induction thyristors （SITH） are physically researched. The I-V curves of the power SITH exhibit reverse snapback phenomena, and even turn to the conducting-state,when the anode voltage in the forward blocking-state is increased to a critical value. The RSP I-V characteristics of the power SITH are analyzed in terms of operating mechanism, double carrier injection effect, space charge effect, electron-hole plasma in the channel, and the variation in carrier lifetime. The reverse snapback mechanism is theoretically pro- posed and the mathematical expressions to calculate the voltage and current values at the snapback point are presented. The computing results are compared with the experiment values.
基金the National High Technology Research and Development Program(863) of China(No.2012AA8094033)
文摘With the aim of sending electric power to autonomous underwater vehicles(AUVs), an automatic wireless power supply system by means of electromagnetic coupler was proposed. An equivalent circuit of the electromagnetic coupler with compensating capacitors was presented to analyze the performance of the system.The magnetizing inductance and leakage inductance, which are important for choosing compensating capacitors,were calculated by finite element analysis(FEA) methods. Then the voltage gain, power loss and system efficiency were analyzed to optimize the winding turns. Finally, a phase-shift full bridge zero-voltage-switching converter and an electromagnetic coupler were produced. The experimental results demonstrated that the proposed system has a high voltage gain with small variation and sufficient power feeding.
基金This work was supported in part by the National Key R&D Program of China under Grant 2017YFB1201003.
文摘Traditional power supply method for moving electric railway vehicles is based on contact type power collection technology.This sometimes cannot meet the requirements of modern rail transportation.A new wireless power transfer(WPT)technology can offer significant benefits in modern rail transportation particularly in some stringent environments.This paper reviews the status and the development of rail transit power supply technology,and introduces a new challenging technology--inductive power transfer(IPT)technology for rail transit.Tesla established the underpinning of IPT technology and creatively and significantly demonstrated power transfer by using highly resonant tuned coils long time ago.However,only in recent years the IPT technology has been significantly improved including the transfer air-gap length,transfer efficiency,coupling factor,power transfer capability and so on.This is mainly due to innovative semiconductor switches,higher control frequency,better coil designs and high performance material,new track and vehicle construction techniques.Recent advances in IPT for rail transit and major milestones of the developments are summarized in this paper.Some important technical issues such as coupling coil structures,power supply schemes,segmentation switching techniques for long-distance power supply,and bidirectional IPT systems for braking energy feedback are discussed.
基金This work was supported in part by the National Natural Science Foundation of China under Grant 50877039in part by the Tsinghua University Initiative Scientific Research Program under Grant No.20121087927(Corresponding author:Xinjie Yu).
文摘The pulsed power supply(PPS)is one important component in the electromagnetic launch system.The inductive PPSs have attracted researchers’attentions with the major advantages of high energy storage density(over the capacitive PPSs)as well as simple structure and easy control(over the rotating mechanical PPSs).As for the inductive PPSs,the circuit topology of the basic module will directly determine the comprehensive performance of the whole system.From the perspectives of working principles,strengths,weaknesses,and comprehensive performance,this paper presents a historical and technical review of the major circuit topologies for the inductive PPSs.
基金the National Natural Science Foundation of China(No.51475306)。
文摘The online detection of metal shaft parameters,such as torque,power and deformation,is widely applied in engineering projects.The power supply of metal shafts is the key to the detection reliability and practicality.However,traditional slip ring and battery power supply are limited in reliability and service life.In this paper,a side-mounted inductive power supply system for the rotating metal shaft is designed by using a Utype core.The equivalent reluctance and circuit models of the system are analyzed,and the methods of improving the coupling coefficient and transmission efficiency are proposed from theoretical analysis.Through the finite element simulation analysis of the system,the general relationships between the transmission power and efficiency of the system and the number of coil turns,the working frequency and the load are analyzed.The accuracy of theoretical analysis and simulation analysis is verified by the practical power transmission experiments.This paper provides a novel and reliable power supply method for inductive power supply of rotating equipment,and enriches the solutions of rotating power supply.
文摘Curved coils constructed by flexible printed circuit board (PCB) or hand-wound Litz-wire have been steadily becoming popular due to its applicable potential on devices that have a curved body. Inductive Power Transfer (IPT) systems based on curved coils and flexible ferrite sheets may provide more flexible charging solutions for various electronic devices such as rice cookers and robot vacuum cleaners. Power repeaters are also used in IPT systems to extend wireless charging range by guiding magnetic fields to the receiving coil. The interaction of these three topics could be inspiring. In this paper, two adjustable power repeaters are applied to an IPT charging system with various curved receiving coils designed for vacuum cleaners. Two power repeaters share the identical structure as the Tx coil and could be rotated to mirror symmetrically. The input and output power are calculated by analyzing the equivalent circuit model. The self-inductance, mutual inductance, and coupling coefficient of the proposed system are obtained via finite element method simulation with variable rotating angles. Three typical IPT designs have also been simulated in ANSYS Maxwell and compared with the proposed magnetic design. The comparison indicates the enhancing feature of the passive power repeaters on coupling performance and the ability to guide the magnetic flux for better magnetic field coupling. Furthermore, two types of co-simulations defined by the power source via Simplorer are conducted to explore how much power could be transferred. The tuned system is shown to be able to provide about 32 W under 100 kHz operating frequency for charging the battery of a robot vacuum cleaner. The results from theoretical calculation and simulation align well with each other.
文摘In this paper,a novel pulse density modulation(PDM)with semi-bridgeless active rectifier(S-BAR)in inductive power transfer(IPT)system for rail vehicle is proposed.It is to reduce switching losses of the active rectifier in pickups.In the control method,the insulated-gate bipolar transistors(IGBTs)in the S-BAR are controlled by synchronous PDM signals,so that zero-voltage switching(ZVS)and zero-current switching(ZCS)can be achieved in the whole output power range.The output power is regulated by changing the pulse density(PD)of the S-BAR since the it is almost linear proportional with the PD in high quality factor of pickup side.The communication device between the primary side and pickup side is not necessary anymore.The detailed theoretical analyses of the PDM method are provided,and its advantages are shown in a 7.5kW IPT prototype for rail vehicle.The experimental results are presented to verify the analysis and demonstrate the performance.The overall efficiency of the system by PDM control is 74.2%which is improved by 4%compared with phase shift(PS)control at light load.
基金supported by the German Academic Exchange Service(DAAD)and the Federal Ministry for Economic Cooperation and Development(BMZ),Germany,within the framework of the REMO project(Renewable Energy-based E-Mobility in Higher Education),Grant Number:57545562.
文摘This study responds to global climate concerns by addressing the shift towards sustainable transportation,particularly electric vehicles.Focusing on wireless power transfer to overcome charging infrastructure challenges,the research optimizes circular coils for inductive power transfer in electric cars.Utilizing ferrite cores to enhance performance,the study employs ANSYS Electronics Suite R2-202 and the finite element method to analyze circular coils,exploring variations in turns,inner radius,air gap,and misalignment's impact on the coupling coefficient.Introducing ferrite plan cores and boxes,the research finds that ferrite boxes improve coupling efficiency by 50%and electromagnetic field strength by 300%,concentrating the field toward the center.An inequivalent design,enlarging the primary coil,demonstrates significant enhancements,achieving a coupling coefficient increase of 0.183,447 and an electromagnetic field rise of 0.000,40 T.Equivalent coils with ferrite boxes meet a 95%efficiency goal with a strong,narrowed field at a lower cost,while inequivalent coils excel in strengthening and centralizing the field,enhancing misalignment tolerance in distinctive ways.
基金supported by Beijing Nova Program(Grant No.20220484153).
文摘Inductive coupled wireless power transfer(WPT)system transfers energy through the magnetic field.The magnetics field distribution of WPT system has significantly influence on the transmission efficiency and misalignment tolerance.This study investigates the magnetic field distribution of WPT system and presents a magnetic field distribution analytical model for WPT system.The analytical model is based on Fourier analysis method,and it can be applied in the cases of coil with air core and with Ferrite core.Furthermore,the finite element simulation model and experiment are conducted.The results of analysis,simulation and experiment are in good agreement.
文摘The analysis of the wind-driven self-excited induction generators （SEIGs） connected to the grid through power converters has been developed in this paper. For this analysis, a method of representing the grid power as equivalent load resistance in the steady-state equivalent circuit of SEIG has been formulated. The technique of genetic algorithm （GA） has been adopted for making the analysis of the proposed system simple and straightfor- ward. The control of SEIG is attempted by connecting an uncontrolled diode bridge rectifier （DBR） and a line commutated inverter （LCI） between the generator term- inals and three-phase utility grid. A simple control technique for maximum power point tracking （MPPT） in wind energy conversion systems （WECS）, in which the firing angle of the LCI alone needs to be controlled by sensing the rotor speed of the generator has been proposed. The effectiveness of the proposed method of MPPT and method of analysis of this wind-driven SEIG-converter system connected to the grid through power converters has been demonstrated by experiments and simulation. These experimental and simulated results confirm the usefulness and successful working of the proposed system and its analysis.
文摘The implementation of a simple power converter for a wound rotor induction generator employing a three phase diode bridge rectifier and a line commutated inverter in the rotor circuit for super synchronous speeds has been proposed. The detailed working of the system in power smoothing mode and maximum power point tracking mode is presented. The current flow in the rotor circuit is controlled （by controlling the firing angle of the line commutated inverter） for controlling the stator power in both the modes. An 8 bit PIC microcontroller has been programmed to vary the firing angle of the line commutated inverter. Experiments have been carried out on a 3- phase, 3.73 kW, 400V, 50Hz, 4-pole, 1500r/rain wound rotor induction generator and the results obtained with the generator supplying power in both the modes are furnished. The complete scheme has been modeled using MATLAB/SIMULINK blocks and a simulation study has been conducted. The experimental waveforms are compared with the simulation results and a very close agreement between them is observed.
文摘Inductive energy storage systems （IES）require opening switches which are technically much more difficult to realize than closing switches. Institute of Advanced Technology （ IAT ） puts forward a meat grinder with an inductive pulse power topology called slow transfer of energy through capacitive hybrid （STRETCH）. In this topology, an integrated gate-commutated thyristor （IGCT） is capable of breaking the charging currents on the order of 4 kA, and it may encounter difficulties in expanding to higher energy systems. German-French Institute of Saint Louis （ISL） has developed a high-power opening switch based on standard high-power thyristors by using their so-called inverse current commutation with semiconductor devices （ICCOS） countercurrent commutation principle. Two topologies of the STRETCH meat grinder with ICCOS are analyzed. And they are compared based on the voltage across the main switch, the current multiplication factor and other aspects by u- sing Matlab simulations. The advantages and disadvantages of the two topologies are shown through the comparisons. Therefore a more suitable topology can be chosen for realistic applications accord- ing to their performances.
基金supported by North Microelectronic Corporation (NMC).
文摘This study investigated the inductively coupled plasma etching reactor and RF coils developed by North Microelectronic Corporation. Full three dimensional simulations were made at different discharge conditions. The simulations examined and compared the distribution and non-uniformity of several plasma parameters at a fixed position upon the wafer at different pressures and coil currents. These parameters included electron density, electron temperature and power deposition. The results demonstrate that the electron density, power deposition and uniformity increase with either higher pressure or stronger coil currents, while the electron temperature decreases at this condition. Coil number increase can reduce the non-uniformity of parameters in the spatial distribution. The linear relationship between power deposition and electron density does not always exist. The comparison between simulation results and experiment results is also presented in the paper.
文摘A modular-parallel IPT system with multi-inverters is proposed to enhance power capacity and expansibility for primary power equipment.In order to balance the actual output power of each inverter,a control strategy is designed to minimize circulating-current and equalize output current.In the process of circulating current suppression,current could be decoupled into the following two parts through a d-q synchronous rotating frame:virtual active and reactive current.Then,the above two virtual current components can be adjusted by PWM and PPM.A close-loop control method based on master-slave scheme is proposed to improve the scalability for a practical IPT system,and an impedance matching and its ZCS method is proposed to avoid detuning caused by a change of the number of modules.Finally,an IPT experiment platform with 3-parallel modules is established to verify availability of the proposed control methods.As shown in the experiment,circulating current of the prototype can be reduced from 2.6 A to 0.3 A,and the difference of output power of each module is less than 1%when deviation of the input DC voltage,the delay of driving signals,and the resonant inductance is 10%,respectively.The overall efficiency of the modular IPT system is up to 92.5%at 3.3 kW.
基金Project supported by the National High-Tech R&D Program of China(No.2013AA09A414)the National Natural Science Foundation of China(No.51221004)the Interdisciplinary Research Foundation of Zhejiang University(No.2012HY003A)
文摘We develop a new kind of underwater inductive coupling power transfer(ICPT)system to evaluate wireless power transfer in autonomous underwater vehicle(AUV)docking applications.Parameters that determine the performance of the system are systematically analyzed through mathematical methods.A circuit simulation model and a finite element analysis(FEA)simulation model are developed to study the power losses of the system,including copper loss in coils,semiconductor loss in circuits,and eddy current loss in transmission media.The characteristics of the power losses can provide guidelines to improve the efficiency of ICPT systems.Calculation results and simulation results are validated by relevant experiments of the prototype system.The output power of the prototype system is up to 45 W and the efficiency is up to 0.84.The preliminary results indicate that the efficiency will increase as the transmission power is raised by increasing the input voltage.When the output power reaches 500 W,the efficiency is expected to exceed 0.94.The efficiency can be further improved by choosing proper semiconductors and coils.The analysis methods prove effective in predicting the performance of similar ICPT systems and should be useful in designing new systems.
基金Project supported by the National Natural Science Foundation of China(Nos.61076023,61178051)the National Basic Research Program of China(No.2011CB933203)the High-Tech-Program of China(No.2012AA030308)
文摘This paper present a highly-integrated neurostimulator with an on-chip inductive power-recovery fron- tend and high-voltage stimulus generator. In particular, the power-recovery frontend includes a high-voltage full- wave rectifier （up to 100 V AC input）, high-voltage series regulators （24/5 V outputs） and a linear regulator （1.8/ 3.3 V output） with bandgap voltage reference. With the high voltage output of the series regulator, the proposed neurostimulator could deliver a considerably large current in high electrode-tissue contact impedance. This neu- rostimulator has been fabricated in a CSMC 1 μm 5/40/700 V BCD＇process and the total silicon area including pads is 5.8 mm2. Preliminary tests are successful as the neurostimulator shows good stability under a 13.56 MHz AC supply. Compared to previously reported works, our design has advantages of a wide induced voltage range （26-100 V）, high output voltage （up to 24 V） and high-level integration, which are suitable for implantable neu- rostimulators.
基金Project (No.60271031) supported by the National Natural Science Foundation of China
文摘The efficiency of inductive power links driven by Class-E amplifiers may deteriorate due to variation in the coupling coefficient when the relative position of the radio frequency (RF) coils changes.To solve this problem,a new design methodology of power links is presented in this paper.The aim of the new design is to use the feedback signal,which is a phase difference between the driving signal and the output current of the Class-E amplifier,to adjust the duty cycle and angular frequency of the driving signal to maintain the optimum state of the inductive power link,and to adjust the supply voltage to keep the output power constant when the coupling coefficient of the RF coils changes.The parameter adjustments with respect to the coupling coefficient and the feedback signal are derived from the design equation of the inductive power link.To validate the feedback control rules,a prototype of the inductive power link was constructed,and its performance validated with the coupling coefficient set at 0.2 and a duty cycle of 0.5.The experimental results showed that,by adjusting the duty cycle,the angular frequency,and the supply voltage,the power link can be kept in optimal operation with a constant output power when the coupling coefficient changes from 0.2 to 0.1 to 0.25.
基金jointly supported by the National Natural Science Foundation of China (No.51677165,No.51837004)the National Key R&D Program of China (No.2017YFB0902000)。
文摘This paper presents a P-Q coordination based highvoltage ride through(HVRT) control strategy for doubly fed induction generators(DFIGs) based on a combined Q-V control and P-V de-loading control. The active/reactive power injection effect of DFIG on transient overvoltage is firstly analyzed and the reactive power capacity evaluation of DFIG considering its de-loading operation is then conducted. In the proposed strategy, the reactive power limit of DFIG can be flexibly extended during the transient process in coordination with its active power adjustment. As a result, the transient overvoltage caused by DC bipolar block can be effectively suppressed. Moreover, key outer loop parameters such as Q-V control coefficient and deloading coefficient can be determined based on the voltage level of point of common coupling(PCC) and the available power capacity of DFIG. Finally, case studies based on MATLAB/Simulink simulation are used to verify the effectiveness of the proposed control strategy.
基金supported by the Youth Program of National Natural Science Foundation of China(Grant No.52007195)Group Project in Hubei Province Natural Science Foundation of Innovation(Grant No.2018CFA008)+1 种基金General Program in Hubei Province Natural Science Foundation(Grant No.2019CFB608)the Major Projects of Military Logistics Research(Grant No.BHJ18C007)。
文摘Inductive power transfer system can generate eddy current when operating in seawater medium. On the one hand, it can cause eddy current loss, and reduce operating efficiency of the system. On the other hand, it can change parameters of the system and increase difficulty of system design. To grasp the influence mechanism of seawater on the inductive power transfer system,firstly, an equivalent circuit model of double-sided inductor-capacitor-capacitor(LCC) inductive power transfer system in seawater environment was established based on loosely-coupled transformer model of eddy current. Then, based on Maxwell’s equations, the distribution function of the magnetic field and electric current density along radium direction of the coupling coils in seawater medium was obtained by analytical calculation. Besides, in combination with Biot-Savart law, expression of the eddy current loss in transfer direction was derived, and based on which expression of the equivalent of the eddy current loss on the coupling coils was got. Thus the equivalent resistance of the eddy current on the coupling coils in a seawater environment could be predicated, and the optimal operating frequency of the inductive power transfer system could be further optimized. Finally, a prototype of inductive power transfer system was established, which gave the experimental results, and verified the correctness of theoretical analysis, and the experiments showed that: in air medium, the transfer distance was 100 mm, the transfer power was 3.3 k W, and the transfer efficiency was 92.6%;while, in seawater medium, the transfer efficiency was 87%. Eddy current losses mainly caused the reduction in efficiency, and the experimental results of eddy current loss were consistent with the simulation results.
基金supported by the National Natural Science Foundation of China under Grant No.11274225
文摘We show that resonant tunneling of electromagnetic （EM） fields can occur through a six-layer structure con- sisting of two pairs of bilayer slabs： one＇being an epsilon-negative layer and the other being a mu-negative layer with a double-positive （DPS） medium and air. This type of tunneling is accompanied by high-magnetic field. The Poynting vector distributions and the material dissipation are studied. Our results demonstrate that the EM field in the structure is controlled flexibly by single-negative media and DPS slab. Therefore, this structure has potential applications in wireless energy transfer.
