5V2A高頻變壓器設計及參數(shù)

5V,2A反激式電源變壓器設計要求:VinAC=85V~265Vf=50/60HzVout=5V+5%Iout=2A紋波電壓=20mvVbias=22V, 0.1A (偏置線圈電壓取22V,100mV)η=0.8-0.85fs=60KHz計算過程:設工作模式為DCMPout=5*2=10WPin =Pout/η=10/0.8=12.5WVinDCminVinDCmax

=85*=265*

-30(直流紋波電壓)=90V22=375V22Dmax=0.45:Vn(Vout

inDCmin

*DmaxD

90*0.45

12.91813

VdVL

)*(1

max

)

0.5

0.2)*(1

0.45)VL0.2V.初級峰值電流計算:Ip

2PoutV *DinDCmin

max

2*10

0.494A初級電感量計算:D *V 0.45*90Lp max inDCmin 621*106H621uHfs*Ip 132*103*0.494變壓器磁芯選擇EFD20,參數(shù)如下:Ae=28.5mm2 AL=1200+30%-20%nH/N2 Le=45.49mm Cl=1.59mm-1 Aw=50.05mm2 Ap=1426.425mm4初級繞組,次級繞組及偏置繞組匝數(shù)計算:Np

Ip*Lp*1040.494*621*106*104

53.8254(匝)Bw*Ae 0.2*0.285Ns

N

4.155(匝)pn 13p(V V )*Ns (220.7)*5Nb

b bdV V Vout d

19.9120匝50.50.2LpH;T;Aecm2;Vb為偏置繞組電壓Vbias=22V;Vbd0.7V.氣隙長度計算:Lg

0.4Np2*Ae*108

0.4*3.14*542*0.285*108

0.0168cm0.168mm

Lp 621*106Lg單位為cm;Lp單位為H;重核算占空比Dmin,Dmax及最大磁通密度Bmax:inDCmin(1).當輸入電壓為最低時:V =90VinDCmin(V V V)*n (50.50.2)*13dDmax(Vd

out

outVd

LL

VinDCmin

0.2)*1390

0.4515inDCmax(2).當輸入電壓為最高時:V =375VinDCmax(V V V)*n (50.50.2)*13(3).Bmax

out

outVd

d LV)*nVL inDCmax

0.2)*13

375

0.1649

Lp*Ip

*100

621*0.494*1001993Guass3000Guass

Np*Ae 54*0.285Lp單位為uH; Ip單位為A; Np單位為N(匝);Ae單位為cm2.繞組線徑計算及窗口占有率:fsdfs

66.1

66.1

0.182mm,2d=0.364mm132*103132*103Ip=0.494A,Dmax0.45Dmax0.45

0.331ARMS=Ip*

=0.494*

=0.331A,Aw

4A/mm2

0.0827mm2,查表承受=肌膚深度),包括皮膜最0.402mmWa=54*0.4022=8.7266mm2.次級繞組線徑計算:IIo=2A, Aw=0.1257mm2的導線,I其裸銅線徑為0.4mm,承受0.5/0.1257=40.456mm.Wa=5*4*0.4562=4.1587mm2.偏置繞組線徑計算:Io=0.1A,IRM=Io=0.1A,Aw=0.1A/4=0.025m2Aw=0.0254mm2的導線,0.18mm<0.364mm0.226mm.占有Wa=20*0.2262=1.0215mm2.=8.7266+4.1587+1.0215=13.9068mm2.占總窗口面積=(E-D)*F=50.05mm227.8%.結構設計:EFD2013.5mm,10.5mm.如下圖示:13.5/0.402=33.5,54230,240.402mm.13.5/0.456=29.6,510.456mm.13.5/0.226=59.7,2010.226mm.使用順序繞法,繞組排列如下:繞組總厚度=0.6+0.402+0.402+0.226+0.456=2.836mm<磁芯窗口寬度=(E-D)/2=(15.4-8.9)/2=3.25mm.估算損耗及溫升:各繞組之線長:依照平均匝長=2舌寬+2疊厚+4窗寬,得:Np1 =2*(8.9+3.6)+4*(0.6+0.201)=28.204mmNp2 =2*(8.9+3.6)+4*(0.6+0.201*2+0.15)=29.608mmNb=2*(8.9+3.6)+4*(0.6+0.201*2+0.15*2+0.113)=30.66mmNs=2*(8.9+3.6)+4*(0.6+0.201*2+0.15*4+0.113+0.228)=31.572mm即NpL=30*28.204+24*29.608=1556.712mm=155.6712cmNpNbL=20*30.66=613.2mm=61.32cmNbNsL=5*31.572=157.86mm=15.786cmNs查線阻表可知:0.402mmWIRE R=0.00259Ω/cm@100℃DC0.456mmWIRE R=0.00198Ω/cm@100℃DC0.226mmWIRE R=0.01001Ω/cm@100℃R =1.4*R@100℃

DC@20℃初級,次級各電流值:求次級各電流值,Io=2A.

Io

2 3.636A

pa2.6922.69222

1Dmax 0.45(1D(1Dmax)*I2spa

(10.45)*(10.45)*3.6362I2s I2s Io2rmsac

1.79A求初級各電流值:

3.636

0.279Apa n 13初級直流有效電流:Ip

rms

pa

0.279*0.450.125A初級溝通有效電流:Ip ac

*I2pDDmax

0.45*0.2790.186A求各繞組交,直流電阻:

=(L*R)/2=(155.6712*0.00259)/2=0.2023ΩDC Np DCRp=1.6*Rp=0.321Ωac DC次級:Rs=