平面变压器3D仿真资料
采用COMSOL软件，对平面变压器的仿真过程进行叙述，让大家了解平面变压器的仿真流程，是个很好的指导教材Solved with COMSOL Multiphysics 5.0Results and discussionThe magnetostatic analysis yields an inductance of 0. 1l mH and a dc resistance of0. 29 mQ2. Figure 2 shows the magnetic flux density norm and the electric potentialdistributionvolume: Coil potentiaL()Volume: Magnetic flux density norm (t▲0.07▲2.88×10-42.51.50.03050.01V656×107v0igure 2: Magnetic flux density norm and electric potential distribution for themagnetostatic analysisIn the static (DC) limit, the potential drop along the winding is purely resistive andcould in principle be computed separately and before the magnetic flux density iscomputed. When increasing the frequency, inductive effects start to limit the currentand skin effect makes it increasingly difficult to resolve the current distribution in thewinding. At sufficiently high frequency, the current is mainly flowing in a thin layernear the conductor surface. When increasing the frequency further. capacitive effectscome into play and current is flowing across the winding as displacement currentdensity. When going through the resonance frequency, the device goes from behavingas an inductor to become predominantly capacitive. At the self resonance, the resistivelosses peak due to the large internal currents Figure 4 shows the surface current3 MODELING OF A 3D INDUCTORSolved with COMSOL Multiphysics 5.0distribution atl MHz. Typical for high frequency the currents are displaced towardsthe edges of the conductor.freq(1)=1.0000E6_Surfaee: Surface-current density norm (A/)▲18618Q16010￥1.02Figure 3: Surface current density at I MHz (below the resonance frequency)Figure 4 shows how the resistive part of the coil impedance peaks at the resonancefrequency near 6MHz whereas Figure 5 shows how the reactive part of the coiimpedance changes sign and goes from inductive to capacitive when passing throughthe resonance4 MODELING OFA3DINDUCTORSolved with COMSOL Multiphysics 5.0Global: Lumped port impedance(Q2)d port impedance7.5G6.583275655545352510.10.20.30.40.509igure 4: Real part of the electric potential distribution5 MODELING OF A INDUCTORSolved with COMSOL Multiphysics 5.0Global: Lumped port impedance(Q2)35000Lumped port impedance200001000050000500010000-1500020000250000.10.20.30.40.50.60.70.809Figure 5: The reactive part of the coil impedance changes sign hen passing through theresonance frequency, going from inductive to capacitiveModel library path: ACDC_Module/Inductive_ Devices_and_coils/inductor 3dFrom the file menu. choose newNEWI In the new window click model wizardMODEL WIZARDI In the model wizard window click 3D2 In the Select physics tree, select AC/DC> Magnetic Fields(mf)3 Click Add4 Click StudyMODELING OF A3D NDUCTORSolved with COMSOL Multiphysics 5.05 In the Select study tree, select Preset Studies>StationaryGEOMETRYThe main geometry is imported from file. Air domains are typically not part of a CaDgeometry so they usually have to be added later. For convenience three additionaldomains have been defined in the CAd file. These are used to define a narrow feed gapwhere an excitation can be appliedport l(impl)I On the model toolbar, click Import2 In the Settings window for Import, locate the Import section3 Click Browse4 Browse to the models model library folder and double-click the filenductor 3d. mphbinSphere /(sphl)I On the Geometry toolbar, click Sphere2 In the Settings window for Sphere, locate the Size section3 In the Radius text field, type 0.2ick to expand the Layers section. In the table, enter the following settingsLayer nameThickness(m)ayer0.055 Click the Build All Objects buttonForm Union(fin)i On the Geometry toolbar, click Build AllClick the Zoom Extents button on the Graphics toolbar7 MODELING OF A 3D INDUCTORSolved with COMSOL Multiphysics 5.03 Click the Wireframe Rendering button on the Graphics toolbarThe geometry should now look as in the figure below0.1-0.10.20.0.0.1y0.0.2Next, define selections to be used when setting up materials and physics Start bdefining the domain group for the inductor winding and continue by adding otheruseful selectionsDEFINITIONSExplicitI On the Definitions toolbar, click Explicit2 In the Settings window for Explicit, in the Label text field, type Winding3 Select Domains 7,8 and 14 onlyI On the Definitions toolbar, click Explicit2 In the Settings window for Explicit, in the Label text field, type Gap3 Select domain 9 onlI On the Definitions toolbar, click Explicit8 MODELING OF A3DINDUCTORSolved with COMSOL Multiphysics 5.02 In the Settings window for Explicit, in the Label text field, type core3 Select Domain 6 onlyExplicit 4I On the Definitions toolbar, click Explicit2 In the Settings window for Explicit, in the Label text field, type InfiniteElements3 Select Domains 1-4 and 10-13 onlyExplicit 5I On the Definitions toolbar, click Explicit2 In the Settings window for Explicit, in the Label text field, type Non-conducting3 Select Domains 1-6 and 9-13 onlyI On the Definitions toolbar, click Explicit2 In the Settings window for Explicit, in the Label text field, type Non-conductingwithout Ie3 Select Domains 5, 6, and 9 only.Infinite Element Domain /(iel)Use infinite elements to emulate an infinite open space surrounding the inductorI On the definitions toolbar click Infinite element domain2 In the Settings window for Infinite Element Domain, locate the Domain Selectionsection3 From the Selection list. choose Infinite Elements4 Locate the Geometry section From the Type list, choose SphericalNext define the material settingsADD MATERIALI On the Model toolbar, click Add Material to open the add Material window2 Go to the Add material window3 In the tree, select AC/DC>Copper.4 Click Add to Component in the window toolbar9 MODELING OF A 3D INDUCTORSolved with COMSOL Multiphysics 5.0MATERIALSCopper(mat/)I In the Model Builder window, under Component I(comp l)>Materials click Copper(matD)2 In the Settings window for Material, locate the Geometric Entity Selection section3 From the Selection list, choose windingADD MATERIALI Go to the Add Material window2 In the tree. select built-In>Air3 Click Add to Component in the window toolbarMATERIALSAir(mat2I In the Model Builder window, under Component I(comp l)>Materials click Air(mat2)2 In the Settings window for Material, locate the Geometric Entity Selection section3 From the Selection list, choose Non-conductingThe core material is not part of the material library so it is entered as a user-definedmateriaMaterial 3(mat3)I In the Model Builder window, right-click Materials and choose Blank Material2 In the Settings window for Material, in the Label text field, type Core3 Locate the geometric Entity Selection section4 From the selection list choose Core5 Locate the Material Contents section. In the table, enter the following settingsPropertName Value Unit Property groupElectrical conductivity sigma0S/IBasicRelative permittivity epsilonrBasicRelative permeability mur1e3Basic6 On the model toolbar. click Add Material to close the Add Material windowMAGNETIC FIELDS (MF)Select Domains 1-8 and 10-14 only0MODELING OF A 3D INDUCTOR
- 2020-12-10下载
- 积分：1
MIMO技术原理及应用
PPT内容 pdf 现代通信先进技术MIMO技术原理及应用。MMO系统模型(1)MIMO系统模型(2)■M根发送天线发射的倌号矢量为■N根接收天线上引入的噪声矢量为N根接收天线HM根发送天线(n的每一个分量都是独立同发布的复高斯随机过程)■接攻信号可以表示为r= hs+n〔其中图MIM0系统框图MIMo系统模型(3)MIMO信道模型(1)■独立同分布的复高斯信道为n,表示第j根发送天线到第根接收天线幼冲击响应函数;且都是独立司分布的复机变量,实部和虚部都是高斯随机变量h注:这样的独立高斯信道,一般用于描述较强的散射环境,可以认为是比较理想的信道MIMO信道模型(2)MIMO信道模型(3)■带有相关性的信道模型主散射休>天线之间的间距入射波的到达角入射波的角度扩展接收端多輸入多输出系天线结构示意图MIMO信道模型(4)MIMo信道模型(5)■ nokia空间相关MMo信道模型■每一条路径接收角(A0A)和发送角(AOD)定研究的MHMo信道模型假定在远场区有很少的空间义为关于天线阵列和主要反射体位置的量。独立的主反射体,一个主反射体有一条主要路径■由于本地散射,每一条路径P都会有角度扩展a9),这条路径含有大量的引入波,这些波是由接收机使信号延时几乎相同的时间,但会随AOA的变化:和发射机附近的当地散射体的结构引起的g)=∑)∑yMIMo信道模型(6)MIMo信道模型(7)表示有L个本地散射体。同理定义发送端有当地散射的角度扩展(φ)假设接收天线在发送天线的远区场内。因此式中可假定接收天线接收的是平面波。通过天线阵列,平面波的传播在不同的天线环境下产生时延^。不同天线的波前到达的很小的时间延式中d“是两个邻近的天线的距离,几是通信系統的载迟导致接收天线的相移Φ波波长MIM信道模型(8)MIMO信道模型(9)≯阵列的传播向量包括关于第一个天线的这些■同样,在发送端相移。对于具有相同天线间隔d的线性阵列,向量a。可表示为Oo,uit. d sin o.接收端的相关矩阵为MIMo信道模型(10)MIMo信道模型(11)■发送端的天线之间的相关矩阵Noka空间相关MMO信道的仿真用生成单天线快衰落的方法,生成互相独立的列向量R1=∑ana3)用上述方法分別计算接收天线和发送天线的相关矩阵Rx、RR计算接收天线和发送天线的相关矩阵的Kronecker积,得到总的相关矩阵RNuMIMo信道模型(12)MIM◎信道 Shannon容量(1)Nokia空间相关MMO信道的仿真(续■基于前面所述的信道模型,根据信息论的结论,此将总的相关矩阵进行 Cholesky分解,得到矩阵MIMO系统能达到的系统 Shannon容量为Nx MNC=log;deo+fH”)bsH计算列向量hx=[h,h2,…,hw丁和矩阵其中du)表示取方阵的行列式,是NxN单位矩阵,p为每根CMww的乘积,得到列向量hMN接收天线的信噪比,∥表示信道矩阵的共轭转置■由于信道矩阵H是随机的,上式的容量也是一个随机变量将列向量h进行分段,得到矩阵hM,即为空间相关的MMO信道MIMo信道 Shannon容量(2)MIM信道 Shannon容量(3)■在理想情况下,即MMO信道可以等效为最大数目的独C=log, I/eI立、等增益、并行的子信道时,得到最大的 Shannon容量(为保证系统性能比较是在相同条件下,将发射功率Roll Lahs Tewchaui n AR s, UTs归一化;每根发送天线的发射功率与1/M成比例)当信道列矢量互相正交时可以达到的容量aCaloyM log,(C=Logo/.5以看出,对于采用多天线发送和接收技术的系统,理想情况下的信道容量将随着发射天线的数目成线性増长这就为MIMO的高速数据速率传输奠定了理论基础。MIM信道 Shannon容量(4)MIM信道 Shannon容量(5)■当接收天线和发送天线数目都为8根,且平均H吧M=信噪比为20旧B时,链路容量可以高达42b/s/HzDm5■在大信噪比下,仅仅在链路的一端采用多天线,比两端都采用多天线所取得的容量要小。例如,N=M=2在大信噪比下的容量比N=4,M=1的容量要大图二不同天线数目下, Shann。n容量与SNR曲线MIMo系统的实现接收分集(1)■接收分集■采用一个发送天线,多个接收天线的分集方式,■发送分集能够抗衰落和抗噪声■分层空时结构r=hs+n■空时编码■空时扩频其中■正交发送分集r=r2…y■空时发送分集Th, h,,hy j接收分集(2)接收分集(3)■最大比合并算法(MRc■容量为s=[h,,,+h1…hn=(h2+h2+,+h(+h1nhC-log(+p∑■分集增益为h2+1hP+,+h16发送分集(1)发送分集(2)■采用多个发送天线,一个接收天线的分集方式,能够抗衰落■如果和接收分集保持相同的总的发送功率,则每个发送天线的发送功率为发送分集的1MC=log(1-(p/M∑h■分集增益为(内2+h2F÷.+h)/M发送分集(3)发送分集(5)■上面的发送分集方案是在发送端不知道信道信息的情况下得到的性能,如果发送端准确地知道信道的信息,可以获得与接收分集相同的性S能,下面以2个天线的情况为例加以说明。√h22+|h22■对发送的信息进行预处理,令h2发送分集(6)发送分集(7)■则■系统增益为r= hs+nh2+1h2+.+h2h *s,+h,.s+n■容量为hIh,.s+nN4P+1212°h1P+1h2PC=log(+*∑2)2+|h2*s+n分层空时结构(1)分层空时结构(2)■为了充分利用MMO的信道容量,G. OSchin提出■将信源数据分为多个数据子流,分别经过多个信道编了分层空时结构( BLAST: Bel-laboratories码器编码,或不经过信道编码,直接送入调制映射器Layered Space-Time进行信号映射。输出的多路调制信号进行空间域和时间域的信号构造(对角结构、垂直结构等)后,再由■ BLAST的优点是真正意义上实现了高数据通信多个发射天线发射出去.经无线信道传播后,由多个因为它在多条并行信道里发送的是独立的、没有冗余接收天线接收。在接收机中经空时检测、解调、译码,的信息流,所以它的传输速率将远大于利用传统技术得到判决数据。所得到的传输速率分层空时结构(3)分层空时结构(4)■特点高散射高信噪比T开环系统,因为 BLAST的发射机不需要信道的data ende信息,只需在接收端进行信道预澳Fig 1 V-BLASTHigh-lerei syster dagra:m分层空时结构(5)分层空时结构(6)■发送端将单个用户的数据部变并到多个发送天线上,同时l D-BLAST( Diagonal Bell Laboratories Layered的、并行的发送这些数据,利用多输入和多输出方式在同Space-Time)技术是一种在接收端和发送端均使频率上传输并行信息流。如果信道是多径散射环境足够用多天线矩阵,并运用一种较好的钟层编码的结构,强,在接攻端可以采用 BLAST算法,恢复出原始信号码块在空时结构中分散在对角线在独立的瑞利散射环境中,这种处理技术理论上以使容量与发送天线数目成线而且接近于■ BLAST根据构造方式的不同,可以分为对角结构(D-Shannon容量极限的90%,但是这种算法较复杂BLAST: Diagonal BLAST)和垂直结构( V-BLAST实现较困难Vertical blast)。■ V-BLAST( Vertical BLAST)是一种简化的BLAST检测算法,也就是码块垂直分散在每根天线上在室肉慢表环境中其频谱效率可以达到40bits/Hz。8分层空时结构(7)分层空时结构(8)对角结构的检测也是对角线进行处理的。比如现在需要如图三阶示,设发送天线数检测第1路数据,a3:图中对角线(蓝色)以上部为M=5,5路数括流在5根天线上循环发,比如对于第1分(红色)都是未检测数据,对角线以下部分(绿色)路,第1个数据a在天熊1都是已测数据。对于数据干扰抵消法将巳检测的时间t泼送,第2个数据在b1,c1,d1,e1抵消,再进行检测;对于数据2,用干扰天线2上时间发送,5个时抵消法将已检测的b:;2d抵消,再用干扰置零法将未控间段完成一个循环测的巳2消除,再进行检测,依此类推。分层空时结构(9)分层空时结构(10)■发射机采用循环变动的结构;就避免了某一路数据因为信道条件的不好,而导致连续的误码,从如图四所示,设发射天线数而影响整个接收机的性能.D- BLAST能够达到为M5,5路数据流分別在5根天线上并行发送,第Shannon容量的90%,其运算极其复杂;所以贝路的数据恒在天线1尔实验室又进一步提出了 V-BLAST算法上发送:第二路的数据也恒在天线2上发送;等等依次类推分层空时结构(11)分层空时结构(12)广在检测时间!1的数据时,先计算出信道转移炬阵■ V-BLAST迫零算法的伪逆,取出其中模数最小的行向量,亦即对应于最大信噪比■迫零(ZF)矢量(w:i=1,2…,M)的数椐,假设为C1,用干扰置零法将术检测的a1hd,消除从而进行C1的检测,检测后的C1应在总的接收信号去掉它的影响,并且在信道转移矩阵中去掉相应的列向量,生成新的信7(H);=道矩阵;再计算此信道粳阵的伪逆,依此类推其中(为H的第j列,d为 Kronecker delta函数,迫零炬阵HH(伪逆)分层空时结构(13)分层空时结构(14)≯假设发送信号向量为a=(x1,42…,ax),对应的N维摄■V- BLAST迫零加干扰消除算法向量为由矩阵理论可知,矩阵H的列数越少,迫零失量的模越小所以性能越好y=Wr=(H"H)H"(Ha+v)=a+H"H"*v分层空时结构(15)分层空时结构(16)V- BLAST加干扰消除检测算法是一个循环过程,包括优化排序方法■以下是一个循环递归过程的选取W;=(G,)rGI=H=(HH)H(ZF这样就判决出了一个信号.然后把它的影响从接收信号中减去,并去掉k,= arg min (G;lI信道转移矩阵肀相应的列,得到新的转移矩降,并确定新竹伪迸阵,确定耕的判决顺序注:1k1,k为检测过程的排序2k1为追零矩阵G1中具有最小模值的行向k:= argmin(G21),‖表示H中去掉的量第《列后卓伪逆分层空时结构(17)分层空时结构(18)a的第k个成分检测后的SNR为■最小均方误差(MMSE)算法H*=( I+H"H)H在栓测过程中,不同的推序会产生不同的P1:例如M=3的系统,一般来说,先检测1和先检测2,所褥的■只是迫零矢量变化,不能严格迫零,但是使总的嗓声加干是不一样的。假没的所有成分均采用相同的消除方法:则扰的方差最小。信噪比内最小的成分将决定系純的误码率性能。因此,该系统中我们可以采用一种最小信噪比最大亿的概念。在榍环检测过程中,每一步我们都选择最好的,从这种将最小信嗅比最大化的意义上来说,就可以萩得最优化排序510
- 2021-05-06下载
- 积分：1
