1、Modeling Resonant Coupled Wireless Power Transfer System谐振耦合式无线电力传输系统建模This example shows how to create and analyze resonant coupling type wireless power transfer(WPT) system with emphasis on concepts such as resonant mode, coupling effect, and magnetic field pattern. The analysis is based on a 2-el
2、ement system of spiral resonators.这个例子显示了如何创建和分析谐振耦合式无线电力传输系统（WPT）的概念如谐振模式，强调耦合效应和磁场模式。 此分析是基于两螺旋谐振器系统。This example requires the following product:这个例子需要以下产品：Partial Differential Equation ToolboxDesign Frequency and System Parameters 设计频率和系统参数Choose the design frequency to be 30MHz. This is a popula
3、r frequency for compact WPT system design. Also specify the frequency for broadband analysis, and the points in space to plot near fields.选择的设计频率为 30MHz。这是便携式 WPT 系统设计的一个流行的频率。还指定了宽带分析的频率，和在附近的空间中的点 。fc=30e6;fcmin = 28e6;fcmax = 31e6;fband1 = 27e6:1e6:fcmin;fband2 = fcmin:0.25e6:fcmax;fband3 = fcmax
4、:1e6:32e6;freq = unique(fband1 fband2 fband3);pt=linspace(-0.3,0.3,61);X,Y,Z=meshgrid(pt,0,pt);field_p=X(:);Y(:);Z(:);The Spiral Resonator 螺旋谐振器The spiral is a very popular geometry in resonant coupling type wireless power transfer system for its compact size and highly confined magnetic field. We w
5、ill use such a spiral as the fundamental element in this example.螺旋是一种非常流行的几何形状在谐振耦合型无线功率传输系统，其紧凑的尺寸和高度密闭的磁场。我们会使用这样一个螺旋的基本元素在这个例子中。Create Spiral Geometry The spiral is defined by its inner and outer radius, and number of turns. Express the geometry by its boundary points, then import its boundary p
6、oints into pdetool. The mesh is generated in pdetool and exported. The mesh is described by points and triangles.创建螺旋几何形状的螺旋是由它的内部和外部半径定义，和数量的圈数。由边界点的几何表达，那么进口边界点为有效。网格产生有效和出口。网格是由点和三角形描述的。Rin=0.05;Rout=0.15;N=6.25;p,t=createSpiral(Rin,Rout,N);Create custom antenna Use customAntennaMesh to import th
7、e mesh. The feed is created at the inner circle of the spiral mesh. This structure is now ready for analysis.创建自定义的天线，使用 customAntennaMesh 输入网格。反馈是在螺旋网格的内圆上创建的。这种结构现在已经准备好进行分析。spiralobj=customAntennaMesh(p,t);spiralobj.Tilt=90;spiralobj.TiltAxis=Y;createFeed(spiralobj,0.0525 0.0025,0.0675 0.0025);Re
8、sonance Frequency and Mode 谐振频率和模式It is important to find the resonant frequency of the designed spiral geometry. A good way to find the resonant frequency is to study the impedance of the spiral resonantor. Since the spiral is a magnetic resonator, a lorentz shaped reactance is expected and observe
9、d in the calculated impedance result.重要的是要找到所设计的螺旋几何的谐振频率。找到谐振频率的好方法是研究螺旋谐振器的阻抗。由于螺旋是一个磁电磁谐振腔，洛伦兹形电抗预计和计算的阻抗结果观察。figure;impedance(spiralobj,freq);Since the spiral is a magnetic resonator, the dominant field component of this resonance is the magnetic field. A strongly localized magnetic field is obs
10、erved when the near field is plotted.由于螺旋是一个磁谐振器，这种共振的占主导地位的磁场分量是磁场。 绘制近场时，观察到一个强局部磁场。figure;EHfields(spiralobj,fc,field_p,ViewField,H,ScaleFields,0 5);Create Spiral to Spiral Power Transfer System 创建螺旋到螺旋动力传输系统The complete wireless power transfer system is composed of two parts: the transmitter(Tx)
11、 and receiver(Rx). Choose identical resonators for both transmitter and receiver to maximize the transfer efficiency. Here, the wirelesspower transfer system is modeled as a linear array.完整的无线电力传输系统是由两部分组成：发射机（Tx）和接收机（RX）。选择发射器和接收器的最大传输效率相同的谐振器效率。这里的无线电能传输系统建模为一个线性阵列。wptsys=linearArray(Element,spira
12、lobj spiralobj);wptsys.ElementSpacing=Rout*2;figure;show(wptsys);Variation of System Efficiency with Transfer Distance系统效率随传输距离的变化One way to evaluate the efficiency of the system is by studying the S21 parameter. As presented in 1, the system efficiency changes rapidly with operating frequency and t
13、he coupling strength between the transmitter and receiver resonator. Peak efficiency occurs when the system is operating at its resonant frequency, and the two resonators are strongly coupled. The results for s-parameter analysis has been precomputed and stored in a MAT-file.评估系统的效率的一个方法是研究的 S21 参数。
14、在 1 中，系统的效率迅速变化与工作频率和耦合强度之间发射机和接收机谐振器。峰值效率发生时，该系统是在其谐振频率工作，和两个谐振器的强耦合。参数分析结果已预先计算并存储在一个 mat 文件。load arraysparamfigure;rfplot(sparam,2,1,abs);Critical Coupled Point 临界耦合点The coupling between two spirals increases with decreasing distance between two resonators. This trend is approximately proportiona
15、l to . Therefore, the system efficiency increases with shortertransfer distance till it reaches the critical coupled regime 1. When the two spirals are over coupled, exceeding the critical coupled threshold, system efficiency remains at its peak, as shown in Fig.3 in1. We observe this critical coupl
16、ing point and over coupling effect during modeling the system. Perform a parameteric study of the system s-parameters as a function of the transfer distance. 双螺旋线的增加与减少之间的距离两谐振器之间的耦合。这种趋势是 近似成正比。因此，系统效率随shortertransfer 距离直到它达到临界耦合机制 1 。当两螺线是耦合的，超过临界耦合阈值，系统效率保持在峰值，如图 3 所示的 1 。我们观察到这个关键的耦合点和超耦合效应建模过程中
17、的系统。执行系统的 S 参数，一个参数化的研究的一个 转移 距离函数。The transfer distance is varied by changing the ElementSpacing. It is varied from half of spiral dimension to one and half times of the spiral dimension, which is twice of the spirals outer radius. The frequency range is expanded and set from 25 MHz to 36 MHz.传输距离是
18、通过改变 elementspacing 变化。它是从螺旋尺寸的一半变化到一个和半倍的螺旋尺寸，这是螺旋的外半径的两倍。 他的频率范围扩大，并设置从 25 兆赫至 36 兆赫。freq=(25:0.1:36)*1e6;dist=Rout*2*(0.5:0.1:1.5);load(wptData.mat);s21_dist=zeros(length(dist),length(freq);for i=1:length(dist)s21_dist(i,:)=rfparam(sparam_dist(i),2,1);endfigure;X,Y=meshgrid(freq/1e6,dist);surf(X,
19、Y,abs(s21_dist),EdgeColor,none);view(150,20);shading(gca,interp);axis tight;xlabel(Frequency MHz);ylabel(Distance m);zlabel(S_21 Magnitude);Coupling Mode between Two Spiral Resonator双螺旋谐振腔的耦合模The dominant energy exchange mechanism between the two spiral resonators is through the magnetic field. Stro
20、ng magnetic fields are present between the two spirals at the resonant frequency.两个螺旋谐振器之间的占主导地位的能量交换机制是通过磁场。强磁场存在于两个在谐振频率螺旋。wptsys.ElementSpacing=Rout*2;figure;EHfields(wptsys,fc,field_p,ViewField,H,ScaleFields,0 5);view(0,0);ConclusionThe results obtained for the wireless power transfer system mat
21、ch well with the results published in 1.所获得的无线功率传输系统的结果相匹配，以及与在 1 发表的结果。(见下文)References1 A. P. Sample, D. T. Meyer, and J. R. Smith, “Analysis, Experimental Results, and Range Adaptation of Magnetically Coupled Resonators for Wirelss Power Transfer“, IEEE Transations on Industrial Electronics, pp.54
22、4-554, 58, 2, 2011. 1 A. P. Sample，D. T. Meyer，J. R. Smith，”分析，实验结果，和无线电力传输的“磁耦合谐振器系列改编，IEEE 工业电子交易电子、pp.544-554，58，2 ，2011 。Magnetically coupled resonant structures offer a unique set of benefits as well as design challenges when used for wireless power transfer. One of the remarkable results is th
23、e existence of the magic regime, where efficiency remains nearly constant over distance, as long as the receiver is within the operating range of the transmitter. This is not the case for conventional far-field and near-field wireless power systems, whose efficiencies decline sharply with range. The
24、 work in this paper provides a deeper understanding of the underlying principles of coupled magnetic resonance, as well as a simple circuit model of the system. A derivation of the transfer function of this model reveals which concepts play a critical role in system performance: frequency splitting,
25、 operating range, and impedance matching. In order to accurately characterize the wireless power system, measurement techniques that use a network analyzer for circuit parameter extraction have been implemented. Excellent agreement between the circuit model and measurements has been demonstrated, wi
26、th a coefficient of determination of 0.9875. Lastly, the issue of receiver alignment sensitivity is addressed with an adaptive tuning algorithm. We demonstrate that for any receiver position and/or orientation, a frequency can be identified that maximizes power transfer efficiency. Additionally, a t
27、racking algorithm allows for the peak efficiency to be maintained as the receiver is moved in space.磁耦合的谐振结构提供了一个独特的好处，以及设计的挑战时，用于无线功率传输。其中一个显著的结果就是“魔术”的存在政权，在那里效率保持几乎恒定的距离，只要接收器是在发射机的工作范围内。这不是传统的远场和近场的情况下无线电力系统，其效率急剧下降的范围内。本文的工作提供了一个更深入的了解耦合磁共振的基本原则，以及系统的一个简单的电路模型。这个模型的传递函数的推导揭示了概念在系统性能中起着至关重要的作用：频
28、率分裂，工作范围，和 I 阻抗匹配。为了准确地描述的无线电力系统，测量技术，使用网络分析仪的电路参数提取已实施。优秀的电路模型和测量之间的协议已被证明，与一个系数的测定 0.9875。最后，接收器对准灵敏度的问题是解决与一个适应调整算法。我们表明，对于任何接收器的位置和/或方向，可以确定一个频率，最大限度地提高功率传输效率。此外，跟踪算法允许当接收机在空间移动时保持峰值效率。One compelling usage scenario is a workspace where devices such as laptops, cells phones, and USB peripherals a
29、re seamlessly powered and recharged as easily as data is transmitted through the air. As a final demonstration of the potential of this type of wireless power system, Fig.15 shows a laptop being continuously powered via the magnetically coupled resonators. Here the laptop battery has been removed an
30、d the wireless power system is providing all the power needed for operation. The signal generator, amplifier, and directional coupler can be seeing in the background (top left corner) and are controlled by a computer. The amplifier dives the same 28 cm transmit loop and 59 cm transmit coil from the
31、early experiments. The receiver is placed 0.7 meters for the transmitters and consists of a smaller 28 cm coil and a 30 cm loop, seen in the foreground. A simple bridge rectifier is used to provide DC power to the modified laptop power brick. In this demonstration removed battery is visible place ne
32、xt to the laptop (lower right). The RF amplifier output to DC laptop input efficiency is 50% (which includes the efficiency of the non-optimized rectifier and power brick)一个引人注目的使用场景是一个工作区设备如笔记本电脑，手机，和 USB 外设供电和充电的无缝数据是通过空气传播一样容易。作为最后演示了这种无线电力系统的潜力，显示笔记本电脑不断的动力通过磁耦合谐振器。这里的笔记本电脑电池删除和无线电力系统提供的所有运行所需的电源。信号发生器，放大器和定向耦合器可以看到在背景（左上角）和一个由计算机重新控制。放大器跳水相同的 28 厘米的发射回路和 59 厘米的发射线圈从早期的实验。接收器放置 0.7 米的发射器和由一个较小的 28 厘米的线圈和一个30 厘米的循环，在前景中看到。一个简单的桥式整流器是用来提供直流电源的修改后的笔记本电脑电源砖。在这个演示中移除电池自旁边的笔记本电脑（右下）。射频放大器的输出到直流笔记本电脑的输入效率为 50%（其中包括效率的非优化整流器和电源砖）
