文档介绍：反激变压器设计
参数要求
INPUT MIN 90 VAC INPUT MAX 256 VAC 输入电容CIN=
OUTPUT 1 19 VDC I 4 A
Po 76 W
OUTPUT 2 0 VDC I 0 A
Po 0 W
OUTPUT 3 0 VDC I 0 A
Po 0 W
16 VDC I A
Po W
工作频率Fs 65 KHz Dmax= Ae 170
步骤1 求CORE AP= AW*Ae=(Pt*100000)/(2ΔB*fs*J*Ku)
传递功率Pt = Po /η+Po =
△B = * (390 - 60) = 198mT ≒
J : 电流密度 A / cm2 (300~500)
Ku: 绕组系数 ~
AP= cm4
步骤2 估算临界电流 IOB ( DCM / CCM BOUNDARY )
IOB = 80%*Io(max)
IoB =
步骤3 求匝数比 n
N = [VIN(min) / (Vo + Vf)] * [Dmax / (1-Dmax)]
VIN(min)=
N= * =
步骤4 求CCM / DCM临界状态之副边峰值电流ΔISB.
ΔIsb = 2Iob / (1-Dmax) = A
步骤5 计算次级电感 Ls 及原边电感 Lp.
Ls = (Vo + Vf)(1-Dmax) * Ts / ΔISB =
=
Lp = n2 Ls = uH
步骤6 求CCM时副边峰值电流ΔIsp.
Io(max) = (2ΔIs + ΔISB) * (1- Dmax) / 2
ΔIs = Io(max) / (1-Dmax) - (ΔISB / 2 )
ΔIsp = ΔISB +ΔIs = Io(max) / (1-Dmax) + (ΔISB / 2 )
= A
步骤7 求CCM时原边峰值电流ΔIpp.
ΔIpp = ΔIcp / n = A
步骤8 确定Np、Ns
1> Np Np = Lp * ΔIpp / (ΔB* Ae)=
2> Ns Ns = Np / n =
3>
求每匝伏特数Va Va = (Vo + Vf) / Ns=