Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit mission...Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit missions due to its high specific impulse and efficiency. In this paper, the power transfer efficiency of the radio frequency ion thruster with different gas compositions is studied experimentally, which is obtained by measuring the radio frequency power and current of the antenna coil with and without discharge operation. The results show that increasing the turns of antenna coils can effectively improve the radio frequency power transfer efficiency, which is due to the improvement of Q factor. In pure N_2 discharge,with the increase of radio frequency power, the radio frequency power transfer efficiency first rises rapidly and then exhibits a less steep increasing trend. The radio frequency power transfer efficiency increases with the increase of gas pressure at relatively high power, while declines rapidly at relatively low power. In N_(2)/O_(2) discharge, increasing the N_(2) content at high power can improve the radio frequency power transfer efficiency, but the opposite was observed at low power. In order to give a better understanding of these trends, an analytic solution in limit cases is utilized, and a Langmuir probe was employed to measure the electron density. It is found that the evolution of radio frequency power transfer efficiency can be well explained by the variation of plasma resistance, which is related to the electron density and the effective electron collision frequency.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
Along with the prosperous of magnetic coupled inductive power transfer( MCIPT) technology which is widely used in industrial applications such as electric vehicle charging,the topology of double D coils( DD coils) wit...Along with the prosperous of magnetic coupled inductive power transfer( MCIPT) technology which is widely used in industrial applications such as electric vehicle charging,the topology of double D coils( DD coils) with a spatial quadrature Q coil arises with great research interest. The Q coil, however, has been thoroughly studied by adding to the receiving side but seldom to the transmitting side. By using finite element simulation, this paper presents a preliminary study on the effectiveness of Q coil in the transmitting side,and its inner dimension is optimized for optimal compensating the misalignment between the transmitting and receiver sides. Simulation results show that the windings of the Q coil should be placed in the center of the aperture of the DD coils,and these results render a useful guidance for mechanical structural design and circuit controller design of MCIPT.展开更多
Inductively coupled power transfer systems (ICPT) are becoming ubiquitous in industry. Many such systems are excited with single or multi-phase input current. This leads to increased complexity in comparing such syste...Inductively coupled power transfer systems (ICPT) are becoming ubiquitous in industry. Many such systems are excited with single or multi-phase input current. This leads to increased complexity in comparing such systems when solely using the magnetic frequency analysis. This paper utilizes modern finite element method analysis software to propose a novel software methodology for the numerical comparison of single and two phase ICPT systems as demonstrated on a three dimensional (3D) battery charging system. The sinusoidal magnetic frequency response of a single phase system is compared to the magnetic transient response of a multi-phase current system by use of a novel software methodology proposed in this paper. This consists of a transient response analysis to determine compute the resulting magnetic response over the duration of an input current period on the two phase system. The resulting non-sinusoidal response is then integrated over a whole period to extract the root-mean-square value for comparison with that of a single phase system across a 3D cubic power zone.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
Wireless power transfer via inductive link is becoming a popular choice as an alternate powering scheme for biomedical sensor electronics. Spiral printed circuit board (PCB) inductors are gaining attractions for wirel...Wireless power transfer via inductive link is becoming a popular choice as an alternate powering scheme for biomedical sensor electronics. Spiral printed circuit board (PCB) inductors are gaining attractions for wireless power transfer applications due to their various advantages over conventional inductors such as low-cost, batch fabrication, durability, manufacturability on flexible substrates, etc. In this work, design of a multi-spiral stacked solenoidal inductor for biomedical application in 13.56 MHz band is presented. Proposed stacking method enhances the inductance density of the inductor for a given area. This paper reports an optimization technique for design and implementation of the PCB inductors. The proposed scheme shows higher inductance and better figure-of-merit values compared to PCB inductors reported in literature, which are desirable for wireless power transfer system.展开更多
采用多拾取模块并联输出的动态感应电能传输(Inductive power transfer,IPT)系统提高了系统的功率传输能力,适用于长轨式的发射结构,在大功率场合有着广泛的应用前景。但由于拾取模块间参数的微小差异以及模块的动态运行,实际的应用过...采用多拾取模块并联输出的动态感应电能传输(Inductive power transfer,IPT)系统提高了系统的功率传输能力,适用于长轨式的发射结构,在大功率场合有着广泛的应用前景。但由于拾取模块间参数的微小差异以及模块的动态运行,实际的应用过程中会出现拾取模块电流分配不平衡的现象,甚至会导致拾取模块过流损坏。从LCC-S的数学模型出发,推导了拾取模块的输出伏安特性与负载分配特性,分析了不同补偿状态下拾取参数对电流分配的影响,并据此提出一种副边失谐补偿的方案。给出了失谐系数的参数设计方法,利用了对副边参数的调节,实现各个模块的近似均流控制。最后,搭建了一台三个拾取模块并联输出的试验样机,应用所提的失谐补偿方法后,模块间最大电流比例由13.02降低到1.3。试验结果与理论分析一致,证明了所提方案的正确性与有效性。展开更多
为实现感应电能传输(Inductive Power Transfer,IPT)系统在变负载条件下的恒流/恒压高效输出,提出一种基于频率切换的LCC-S型IPT系统参数配置及优化方法。从LCC-S补偿拓扑入手,分别得到系统恒流或恒压零相位角(Zero Phase Angle,ZPA)输...为实现感应电能传输(Inductive Power Transfer,IPT)系统在变负载条件下的恒流/恒压高效输出,提出一种基于频率切换的LCC-S型IPT系统参数配置及优化方法。从LCC-S补偿拓扑入手,分别得到系统恒流或恒压零相位角(Zero Phase Angle,ZPA)输出的条件方程,并推导了电流增益、电压增益与系统参数之间的定量关系;进一步通过定义系统的输出增益比,分析了恒流/恒压模式下输出增益、负载电阻与整体效率的关系;在此基础上,通过选取最佳的输出增益值,使得系统整体效率达到了全局最大化。仿真结果表明,负载电阻在3~300Ω的变化范围内包括恒流/恒压模式切换瞬间都能保持稳定的输出,并且恒流/恒压模式下均能实现ZPA运行,同时系统整体效率都维持在90%以上。展开更多
By representing the Earth as a rotating spherical antenna several historic and scientific breakthroughs are achieved. Visualizing the Sun as a transmitter and the planets as receivers the solar system can be represent...By representing the Earth as a rotating spherical antenna several historic and scientific breakthroughs are achieved. Visualizing the Sun as a transmitter and the planets as receivers the solar system can be represented as a long wave radio system operating at Tremendously Low Frequency (TLF). Results again confirm that the “near-field” is Tesla’s “dynamic gravity”, better known to engineers as dynamic braking or to physicists as centripetal acceleration, or simply (g). Timewave theory is invented, and the relationship of reflected timewaves and time travel explored. A new law of the Sun is proposed as well as the merging of Einstein’s equation with acoustics and cosmic superstring theory. A new law of cosmic efficiency is also proposed that equates vibratory force and pressure with volume acceleration of the solar system. Lorentz force is broken down into centripetal and gravitational waves. Ten-dimensional cosmic superstring theory is espoused versus the aging three-dimensional Maxwellian model. Spherical antenna patterns for planets are presented and flux transfer frequency is calculated using distance to planets as wavelengths. The galactic grid operates at a Schumann Resonance of 7.83 Hz, which is derived from the science of dark energy and dark matter. The Sun and the planets are tuned to transmit and receive electrical power like resonating Tesla coils. The Earth’s stator winding has been modeled as a toroid tesla coil and the armature as a spherical armature. The equation for everything is born.展开更多
感应电能传输(inductive power transfer,IPT)系统中需要引入谐振补偿网络来消除电路中的无功损耗,而固定参数下的谐振补偿网络往往只能实现恒压或者恒流源输出,输出类型单一且不具有可控性。为解决这一问题,将常用的LCC型拓扑改进为LCC...感应电能传输(inductive power transfer,IPT)系统中需要引入谐振补偿网络来消除电路中的无功损耗,而固定参数下的谐振补偿网络往往只能实现恒压或者恒流源输出,输出类型单一且不具有可控性。为解决这一问题,将常用的LCC型拓扑改进为LCCC型拓扑,并建立数学模型分析该拓扑的电路特性;其次,利用高频开关电容变换器取代单一的补偿电容,实现输出电压调节,并分析多阶受控开关电容(switch-controlled capacitor,SCC)变换器电路的工作原理以及开关管的移相调制条件;最后通过仿真和实验验证该IPT系统的可行性与有效性。仿真和实验结果表明:所构建的三SCC结构的LCCC-S型IPT系统具有软开关特性,控制方式简单;在不同负载和互感的条件下,可定向调节输出电压;在松耦合系数较低的情况下,系统的仿真效率平均为91.51%(最高为92.96%),实验效率平均为80.6%(最高为83.43%);调节过程中可以使IPT系统始终处于弱感性状态,保证了IPT系统在实现输出调整的同时依然具有较低的无功损耗。展开更多
传统的感应电能传输(inductive power transfer,IPT)系统采用单相全桥谐振逆变器,由于受到功率器件的容量限制,IPT系统的输出功率较低。为实现IPT系统大功率输出,构建了基于阶梯波移相合成方法的级联型多电平逆变器的IPT系统,并详细分...传统的感应电能传输(inductive power transfer,IPT)系统采用单相全桥谐振逆变器,由于受到功率器件的容量限制,IPT系统的输出功率较低。为实现IPT系统大功率输出,构建了基于阶梯波移相合成方法的级联型多电平逆变器的IPT系统,并详细分析其工作原理和功率自平衡特性。在此基础上,建立谐波消除方程,得到移相角与脉宽的显式解,从而避免求解高次超越方程。在消除3次谐波的基础上,通过改变移相角与脉宽,不需增加DC-DC环节便能实现IPT系统输出功率的连续调节。仿真和实验验证了IPT系统的级联型逆变器输出功率为1.6 kW时,每个全桥单元的输出功率约为800 W,且级联逆变器的输出电压的3次谐波被完全消除,同时能连续调节IPT系统的功率。这种基于阶梯波移相合成方法的级联型多电平逆变器可望在大功率IPT系统中得到应用。展开更多
为了简化感应电能传输(inductive power transfer,IPT)电池充电系统原边与副边电路的设计和控制复杂性,该文提出通过在原边电路加入一个附加电容和一个半导体开关的方法实现对电池恒流恒压切换充电,无需调节逆变器直流输入电压、原边移...为了简化感应电能传输(inductive power transfer,IPT)电池充电系统原边与副边电路的设计和控制复杂性,该文提出通过在原边电路加入一个附加电容和一个半导体开关的方法实现对电池恒流恒压切换充电,无需调节逆变器直流输入电压、原边移相控制及副边加入调压电路。恒流模式时,配置的补偿电容完全补偿原边线圈;恒压模式时,只需一个开关切出或者切入附加电容。该方法只需简单的通信(用于充电模式切换),没有复杂的控制策略,结构简单,成本低。实验表明,所提出方法输出的恒流和恒压随着电池等效负载电阻改变而轻微变化,但结果仍然满足电池充电要求。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12005031 and 12275041)the Natural Science Fund from the Interdisciplinary Project of Dalian University(Grant No.DLUXK-2023-QN-001)。
文摘Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit missions due to its high specific impulse and efficiency. In this paper, the power transfer efficiency of the radio frequency ion thruster with different gas compositions is studied experimentally, which is obtained by measuring the radio frequency power and current of the antenna coil with and without discharge operation. The results show that increasing the turns of antenna coils can effectively improve the radio frequency power transfer efficiency, which is due to the improvement of Q factor. In pure N_2 discharge,with the increase of radio frequency power, the radio frequency power transfer efficiency first rises rapidly and then exhibits a less steep increasing trend. The radio frequency power transfer efficiency increases with the increase of gas pressure at relatively high power, while declines rapidly at relatively low power. In N_(2)/O_(2) discharge, increasing the N_(2) content at high power can improve the radio frequency power transfer efficiency, but the opposite was observed at low power. In order to give a better understanding of these trends, an analytic solution in limit cases is utilized, and a Langmuir probe was employed to measure the electron density. It is found that the evolution of radio frequency power transfer efficiency can be well explained by the variation of plasma resistance, which is related to the electron density and the effective electron collision frequency.
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Sichuan International Exchange of Science and Technology Cooperation and Research Program,China(No.2015HH0010)
文摘Along with the prosperous of magnetic coupled inductive power transfer( MCIPT) technology which is widely used in industrial applications such as electric vehicle charging,the topology of double D coils( DD coils) with a spatial quadrature Q coil arises with great research interest. The Q coil, however, has been thoroughly studied by adding to the receiving side but seldom to the transmitting side. By using finite element simulation, this paper presents a preliminary study on the effectiveness of Q coil in the transmitting side,and its inner dimension is optimized for optimal compensating the misalignment between the transmitting and receiver sides. Simulation results show that the windings of the Q coil should be placed in the center of the aperture of the DD coils,and these results render a useful guidance for mechanical structural design and circuit controller design of MCIPT.
文摘Inductively coupled power transfer systems (ICPT) are becoming ubiquitous in industry. Many such systems are excited with single or multi-phase input current. This leads to increased complexity in comparing such systems when solely using the magnetic frequency analysis. This paper utilizes modern finite element method analysis software to propose a novel software methodology for the numerical comparison of single and two phase ICPT systems as demonstrated on a three dimensional (3D) battery charging system. The sinusoidal magnetic frequency response of a single phase system is compared to the magnetic transient response of a multi-phase current system by use of a novel software methodology proposed in this paper. This consists of a transient response analysis to determine compute the resulting magnetic response over the duration of an input current period on the two phase system. The resulting non-sinusoidal response is then integrated over a whole period to extract the root-mean-square value for comparison with that of a single phase system across a 3D cubic power zone.
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.
文摘Wireless power transfer via inductive link is becoming a popular choice as an alternate powering scheme for biomedical sensor electronics. Spiral printed circuit board (PCB) inductors are gaining attractions for wireless power transfer applications due to their various advantages over conventional inductors such as low-cost, batch fabrication, durability, manufacturability on flexible substrates, etc. In this work, design of a multi-spiral stacked solenoidal inductor for biomedical application in 13.56 MHz band is presented. Proposed stacking method enhances the inductance density of the inductor for a given area. This paper reports an optimization technique for design and implementation of the PCB inductors. The proposed scheme shows higher inductance and better figure-of-merit values compared to PCB inductors reported in literature, which are desirable for wireless power transfer system.
文摘采用多拾取模块并联输出的动态感应电能传输(Inductive power transfer,IPT)系统提高了系统的功率传输能力,适用于长轨式的发射结构,在大功率场合有着广泛的应用前景。但由于拾取模块间参数的微小差异以及模块的动态运行,实际的应用过程中会出现拾取模块电流分配不平衡的现象,甚至会导致拾取模块过流损坏。从LCC-S的数学模型出发,推导了拾取模块的输出伏安特性与负载分配特性,分析了不同补偿状态下拾取参数对电流分配的影响,并据此提出一种副边失谐补偿的方案。给出了失谐系数的参数设计方法,利用了对副边参数的调节,实现各个模块的近似均流控制。最后,搭建了一台三个拾取模块并联输出的试验样机,应用所提的失谐补偿方法后,模块间最大电流比例由13.02降低到1.3。试验结果与理论分析一致,证明了所提方案的正确性与有效性。
文摘为实现感应电能传输(Inductive Power Transfer,IPT)系统在变负载条件下的恒流/恒压高效输出,提出一种基于频率切换的LCC-S型IPT系统参数配置及优化方法。从LCC-S补偿拓扑入手,分别得到系统恒流或恒压零相位角(Zero Phase Angle,ZPA)输出的条件方程,并推导了电流增益、电压增益与系统参数之间的定量关系;进一步通过定义系统的输出增益比,分析了恒流/恒压模式下输出增益、负载电阻与整体效率的关系;在此基础上,通过选取最佳的输出增益值,使得系统整体效率达到了全局最大化。仿真结果表明,负载电阻在3~300Ω的变化范围内包括恒流/恒压模式切换瞬间都能保持稳定的输出,并且恒流/恒压模式下均能实现ZPA运行,同时系统整体效率都维持在90%以上。
文摘By representing the Earth as a rotating spherical antenna several historic and scientific breakthroughs are achieved. Visualizing the Sun as a transmitter and the planets as receivers the solar system can be represented as a long wave radio system operating at Tremendously Low Frequency (TLF). Results again confirm that the “near-field” is Tesla’s “dynamic gravity”, better known to engineers as dynamic braking or to physicists as centripetal acceleration, or simply (g). Timewave theory is invented, and the relationship of reflected timewaves and time travel explored. A new law of the Sun is proposed as well as the merging of Einstein’s equation with acoustics and cosmic superstring theory. A new law of cosmic efficiency is also proposed that equates vibratory force and pressure with volume acceleration of the solar system. Lorentz force is broken down into centripetal and gravitational waves. Ten-dimensional cosmic superstring theory is espoused versus the aging three-dimensional Maxwellian model. Spherical antenna patterns for planets are presented and flux transfer frequency is calculated using distance to planets as wavelengths. The galactic grid operates at a Schumann Resonance of 7.83 Hz, which is derived from the science of dark energy and dark matter. The Sun and the planets are tuned to transmit and receive electrical power like resonating Tesla coils. The Earth’s stator winding has been modeled as a toroid tesla coil and the armature as a spherical armature. The equation for everything is born.
文摘感应电能传输(inductive power transfer,IPT)系统中需要引入谐振补偿网络来消除电路中的无功损耗,而固定参数下的谐振补偿网络往往只能实现恒压或者恒流源输出,输出类型单一且不具有可控性。为解决这一问题,将常用的LCC型拓扑改进为LCCC型拓扑,并建立数学模型分析该拓扑的电路特性;其次,利用高频开关电容变换器取代单一的补偿电容,实现输出电压调节,并分析多阶受控开关电容(switch-controlled capacitor,SCC)变换器电路的工作原理以及开关管的移相调制条件;最后通过仿真和实验验证该IPT系统的可行性与有效性。仿真和实验结果表明:所构建的三SCC结构的LCCC-S型IPT系统具有软开关特性,控制方式简单;在不同负载和互感的条件下,可定向调节输出电压;在松耦合系数较低的情况下,系统的仿真效率平均为91.51%(最高为92.96%),实验效率平均为80.6%(最高为83.43%);调节过程中可以使IPT系统始终处于弱感性状态,保证了IPT系统在实现输出调整的同时依然具有较低的无功损耗。
文摘传统的感应电能传输(inductive power transfer,IPT)系统采用单相全桥谐振逆变器,由于受到功率器件的容量限制,IPT系统的输出功率较低。为实现IPT系统大功率输出,构建了基于阶梯波移相合成方法的级联型多电平逆变器的IPT系统,并详细分析其工作原理和功率自平衡特性。在此基础上,建立谐波消除方程,得到移相角与脉宽的显式解,从而避免求解高次超越方程。在消除3次谐波的基础上,通过改变移相角与脉宽,不需增加DC-DC环节便能实现IPT系统输出功率的连续调节。仿真和实验验证了IPT系统的级联型逆变器输出功率为1.6 kW时,每个全桥单元的输出功率约为800 W,且级联逆变器的输出电压的3次谐波被完全消除,同时能连续调节IPT系统的功率。这种基于阶梯波移相合成方法的级联型多电平逆变器可望在大功率IPT系统中得到应用。
文摘为了简化感应电能传输(inductive power transfer,IPT)电池充电系统原边与副边电路的设计和控制复杂性,该文提出通过在原边电路加入一个附加电容和一个半导体开关的方法实现对电池恒流恒压切换充电,无需调节逆变器直流输入电压、原边移相控制及副边加入调压电路。恒流模式时,配置的补偿电容完全补偿原边线圈;恒压模式时,只需一个开关切出或者切入附加电容。该方法只需简单的通信(用于充电模式切换),没有复杂的控制策略,结构简单,成本低。实验表明,所提出方法输出的恒流和恒压随着电池等效负载电阻改变而轻微变化,但结果仍然满足电池充电要求。