Power transfer efficiency in an air-breathing radio frequency ion thruster

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.

Advances in Inductively Coupled Power Transfer Technology for Rail Transit

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.

Cosmic Wireless Power Transfer System and the Equation for Everything E=mc^(2)=vc^(2)/60=a^(3)/T=G(M_(1)+M_(2))/4π^(2)=(KE+PE)/1.0E15=Q=PA|F=λ/hc=1/2q=VI=1/2LI^(2)=1/2CV=I^(2)R=…

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.

多方位无线电能传输耦合机构设计与分析

针对传统的多方位无线电能传输耦合机构常采用xyz正交圆线圈结构,需要3个电源且充电区域受线圈结构限制的问题,提出1种新型多方位无线电能传输耦合机构,该机构由2组8字型线圈和1组圆形线圈组合而成,整体呈现5个不同方位的圆环状,仅需单电源供电。对基于S-S型发射端拓扑进行了改进,通过对电路的操控改变线圈磁场分布,实现了线圈的内、外部电能传输,拓宽了充电区域。基于线圈结构,建立了该耦合机构的数学模型,推导出任意空间位置的互感和效率计算式。通过仿真和试验确定了该耦合机构的最佳工作区域。

Achieving maximum power transfer of inductively coupled wireless power transfer system based on dynamic tuning control

As an emerging research field,inductively coupled wireless power transfer(ICWPT) technology has attracted wide spread attention recently.In this paper,the maximum power transfer performances of four basic topologies labeled as SS,SP,PS and PP are investigated.By modeling the equivalent circuits of these topologies in high frequency(HF),the primary resonance compensation capacitances for maximum power transfer capability are deduced.It is found that these capacitances fluctuate with load resistance change,which is disadvantageous to SP,PS and PP topologies and an obstacle to their practical applications as well.To solve this problem,a phase controlled inductor circuit is proposed.By adjusting the triggering angle,the real-time dynamic tuning control can be achieved to guarantee maximum power transfer.Finally,simulations and experiments show that the proposed method is of great effectiveness and reliability to solve the issue of resonance compensation capacitance fluctuation with load change and to guarantee the flexible applications of all topologies.

基于钳位电路的LCC-S补偿型感应电能传输系统抗偏移方法

在感应电能传输(IPT)系统中,线圈错位难以避免,造成的耦合变化会导致系统的传输功率不稳定。为了保证IPT系统的供电灵活性,系统需具有容忍线圈宽范围偏移的能力。为此,该文借鉴模态切换的思想,提出一种基于钳位电路的LCC-S补偿型IPT系统,用于增强系统抗偏移性。与传统多模态切换的IPT系统相比,该系统中的钳位电路可根据耦合变化自适应地导通或关断,以调节工作模态,从而实现近乎恒定的功率输出,该方法无需耦合识别、输出检测及反馈通信等辅助手段。该文对系统不同工作模态的功率传输特性进行了推导和分析,并结合系统设计相关约束条件,提供一套参数化设计方法。最后设计并搭建一套500 W的实验装置,验证了理论分析的正确性与可行性。实验结果表明,该方法在耦合度为0.205~0.42的情况下,输出功率稳定在470~505 W之间,效率为83.29%~90.21%。

一种感应耦合能量传输系统的软启动控制方法

为解决目前感应耦合能量传输系统启动阶段电流冲击大、启动可靠性较差等问题,提出一种新型软启动控制方法。分析了基于串-串型补偿电路的感应耦合能量传输系统的数学模型,对比分析高频逆变器不同调制占空比与启动特性之间的关系,对系统软启动调节时间长度、占空比调制载波频率等关键参数进行了选取。所提软启动控制方法可较好地抑制启动冲击电流以及软启动调节时间过后的电流振荡现象,并实现高频逆变器在全时间范围内的零电压开关,降低了高频逆变器的开关损耗,进一步提高了系统的安全性和可靠性。基于研制的感应耦合能量传输系统实验样机进行实验,实验结果证明了所提软启动控制方法的有效性。

面向教学的磁耦合谐振式无线电能传输系统研究

围绕电路分析与测量实践教学,研究了一套兼具挑战性和展示度且适合低年级本科生自主探索的无线电能传输系统设计方法。该方法将复杂传输问题进行有效简化,聚焦电路及磁场分析,在各个环节中将理论分析、仿真分析与实验探究相互结合,做到理论结合实际。并开发了一套灵活方便的计算线圈电感工具和电力电子逆变模块,能够较好地满足实际教学的需要,支撑本科生自主设计搭建系统并展开研究。通过该方法和相应研发的工具,学生可自主设计一套兼具挑战性和展示度的无线电能传输系统,有效培养学生的电路分析与设计能力以及解决实际问题的能力。

Design and analysis of an underwater inductive coupling power transfer system for autonomous underwater vehicle docking applications

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.

基于多目标优化理论的耦合无关恒压输出型LCC/S补偿感应电能传输系统

基于传统完全谐振参数设计方法的感应电能传输(IPT)系统只有在发射线圈和接收线圈完全耦合时才能表现出最佳性能。实际的IPT系统多为变耦合系统,耦合系数变化可能导致输出电压大范围波动和效率降低等问题。该文提出一种基于多目标优化理论的补偿拓扑参数设计方法,在耦合系数和负载变化的情况下仍然可以获得相对恒定的输出电压且能够高效运行。首先,利用基波近似分析法建立LCC/S补偿IPT系统的系统方程。其次,以补偿参数为优化变量,以减小输出电压波动、提升系统效率为优化目标,以电感最大通过电流、电容最大承受电压和零电压开关为约束条件建立多目标优化模型。然后,利用多目标粒子群优化(MOPSO)算法求解所建立的多目标优化模型,并得到Pareto最优解集。最后,根据实际需要,从Pareto最优解集中选择合适的补偿方案,并进行仿真分析和实验验证。实验结果表明,优化方案的电压波动率(VFR)约为传统方案的45%,且优化方案的最低传输效率(87.5%)仍大于传统方案的最高传输效率(86.3%)。该方法可用于优化满足耦合和负载无关恒定输出、高效率、零电压开关等特性的补偿拓扑。

一种带引导磁芯的齿轮状松耦合变压器

感应耦合式无线电能传输系统中,松耦合变压器的耦合系数是影响系统变换效率的关键因素。为提高其耦合系数,针对普通圆盘型松耦合变压器,基于其磁场仿真结果建立等效的磁路模型并作分析,在此基础上对圆盘形磁芯先后采取挖通孔、加引导磁芯的方法进行优化,并结合多U型磁芯结构提出一种新型齿轮状变压器结构。通过仿真与实验验证了该结构能在降低变压器重量的同时,有效提高其耦合系数,且具有良好的旋转稳定性。

水下单线电能传输机理分析及实验研究

为了实现缆系水下感知平台挂载传感器的低成本、非接触全天候供电,提出了一种以系泊缆和开放海水构成电能传输链路的水下单线电能传输系统。首先从电磁波在系泊缆和海水中的传播机理进行了分析,建立了麦克斯韦方程组并通过分析得到了电磁波束缚在系泊缆表面传播的结论;然后使用Ansys/HFSS软件建立了系泊缆在海水中的模型,仿真得到了电磁场分布情况以及坡印廷矢量分布情况,验证了理论分析的正确性;最后搭建了50 m单线电能传输实验样机,在海水中进行了电能传输实验。实验结果表明,提出的水下单线电能传输系统最高可以实现187 W的电能传输,系统最大效率可达49.2%,证明水下单线电能传输系统具有为缆系水下感知平台挂载传感器非接触供电的可行性。

LCL-S型注入信号式能量与信号共享通道ICPT系统研究

针对感应耦合电能传输(Inductive Coupled Power Transfer,ICPT)系统应用场景中的信号反向传输需求,提出了一种基于LCL-S谐振拓扑的注入信号式ICPT电能信号共享通道系统。运用交流阻抗法对所提出的系统的电能通道与信号通道分别进行了理论分析,建立了数学模型。以负载得到的电压恒定为前提,兼顾信号调制解调结构的影响,分析计算了系统参数,并搭建了MATLAB/Simulink验证模型。仿真结果表明,信号传递电路引入后,负载可以实现恒压,系统能量传输正常,在保证能量传输的情况下,可以实现信号的反向传输。最后按照仿真模型搭建了实际电路,验证了所提出的系统的可行性。

实现3kW功率与50Mb/s速率的电能-数据同步无线传输的解耦设计技术

相较于传统注入式同步无线电能和数据传输(Simultaneous Wireless Power and Data Transfer,SWPDT),“共口径”SWPDT方案具有电能传输功率大、转换效率高、数据传输速率高、可靠性好的优点。针对共口径集成后高压大功率电能传输通道与通信链路强耦合导致通信速率下降乃至失败的问题,结合D型传能松耦合变压器,提出基于耦合电感的双边LCC拓扑、DD型通信线圈及滤波网络协同设计的解耦设计技术,实现传能线圈谐波优化和电能-通信空域解耦,提升了通信链路通带阻抗匹配和带外抑制能力,增强了与传能线圈的频域解耦。分析了功率传输链路和数据传输链路的设计及解耦实现原理,构建了一台270 V输入、270 V/3 kW恒压输出、传能30 mm的SWPDT原理样机。实验结果证明了所提解耦设计技术的可行性和先进性,在实现94.89%电能转换效率的同时可实现50 Mb/s的高速数据同步传输。

基于松耦合变压器的无线电能传输技术研究

电能的无线传输一直是研究的热点。然而受限于安全和技术因素,以微波、激光为载体的无线输电手段现阶段很难获得大规模应用,所以基于感应耦合的无线电能传输技术是目前最容易实现的无线输电手段,而松耦合变压器是特定环境中效率最高的无线输电手段。通过理论推导与软件仿真相结合的方式,研究了影响松耦合变压器系统电能传输效率的主要因素,并利用ANSYS有限元软件对不同类型的铁心结构的松耦合变压器的传输效率进行了仿真计算。

一对轴向互耦线圈的耦合系数讨论及基于此的线圈设计方法

在感应电能传输(Inductive Power Transfer,IPT)中,耦合线圈是必不可少的器件。对于一对耦合线圈而言,耦合系数(k)是表征它们耦合程度的关键参量,通过对耦合系数进行优化可以有效地提升感应电能传输系统的效率。提出了一种通用的设计方案来提高一对轴向放置的平面圆形线圈的耦合系数。耦合系数首先通过丝电流法计算得到,基于此分析并归纳了三条为一对轴向平面圆形线圈尺寸设计的规则。第一条规则,一对垂直放置的满布互耦线圈当它们的外径和传输距离给定时,总可以取得最大耦合系数;其次,当其中一个线圈的空心率给定时,另一线圈的空心率不宜选取过大,否则耦合系数将会快速衰减;第三条,为了取得最优耦合系数,一对互耦线圈的的尺寸往往不同,并同时给出了一个经验公式,用于在一定距离下,当一个线圈的外径一定时来确定另一线圈的外径。

海流冲击对IPT系统互感系数及传输性能影响研究

海洋复杂的洋流运动冲击会使耦合器初级侧、次级侧线圈相对位置发生变化,导致初级侧线圈与次级侧线圈互感发生变化,对感应电能传输(IPT)系统的传输性能造成影响。研究了海流冲击下IPT系统耦合线圈错位对传输性能的影响,建立了IPT系统耦合线圈的有限元模型,通过实验验证了在一侧耦合线圈发生横向、轴向及有角度的偏转时IPT系统的输出电压、电流以及输出功率、传输效率的变化。

无接触电能传输技术的研究进展

无接触电能传输技术具有广泛的应用前景。目前主要的无接触电能传输方式有远场辐射、电磁共振和电磁感应直接耦合三种。远场辐射采取微波或激光来传递能量,频率最高,传输距离最远,效率也较低。电磁共振采用频率为MHz范围的谐振频率实现电能在波长范围内的中等距离高效率传输。基于电磁感应原理的电能传输技术相对比较成熟,频率较低,传输距离相对很小,传输效率较高。本文主要分析了这三种电能传输方式的特点及国内外研究现状,给出了该技术的应用前景及存在问题,也展示了一些研究结果。

感应耦合电能传输系统互感耦合参数的分析与优化

针对感应耦合电能传输(inductively coupled power transfer,ICPT)系统能效(传输功率和效率)优化问题,分析了互感耦合参数对4种典型拓扑结构ICPT系统能效的影响,并优化互感以提高系统的功率传输能力,同时,对优化得到的互感耦合参数的适用条件给出了限制;此外,针对原边采用串联补偿拓扑结构的ICPT系统在最大功率传输条件下,系统效率偏低的现象,提出一种新的系统综合评价指标。在满足系统输出功率的基础上,该指标综合考虑了系统效率、成本和可靠性等其他因素。通过在该指标下对系统的互感耦合参数进行优化,在满足功率传输的基础上,实现了ICPT系统的全局最优设计。最后,通过仿真和实验研究,证明了理论分析的正确性。

非接触感应电能传输系统松耦合变压器参数设计

松耦合变压器是非接触感应电能传输系统中的关键部分。在简要介绍松耦合变压器的基本结构和工作原理的基础上,提出了松耦合变压器的互感等效电路模型。根据松耦合变压器的特点,分析了铁芯材料、绕组位置、气隙大小对变压器耦合系数的影响。同时,针对原、副边漏感的特性,进一步讨论了变压器原、副边电路补偿问题。最后给出了非接触感应电能传输系统中松耦合变压器的耦合系数、网络补偿等几个重要参数的设计方案。