确定coreAP值.决定core规格型号.doc

確定core AP值.決定core規格型號. AP=AW×Ae=(Ps×104)/(2×ΔB×fs×J×Ku) Ps : 變壓器傳遞視在功率 ( W ) Ps=Po/η+Po (正激式) Ps=294/0.8+294＝661.5W J : 電流密度 ( A ) .取400 A/cm2 Ku: 銅窗占用系數. 取0.2 AP=(661.5×104)/(2×0.20×60×103×400×0.2)≈3.4453 cm2 選用CORE ER42/15 PC40．其參數為: AP=4.3262 cm4 Ae=194 mm2 Aw=223mm2 Ve=19163mm3 AL=4690±25% Pt=433 W (100KHz 25℃) 計算Np Ns. (1). 計算匝比 n = Np / Ns 設 Dmax = 0.4 n = Np / Ns = Vi / Vo = [Vin(min) ×Dmax] / (Vo+Vf) Vf :二极管正向壓降 取1V Vin(min)=180×0.9×√2-20=209 VDC Vin(max)=260×√2=370 VDC n=(209*0.4)/(13.8+0.7)=5.766 取5.5 CHECK Dmax Dmax=n(Vo+Vf)/Vin(min)= 5.5 (13.8+1)/209=0.3868≈0.387 Dmin=n(Vo+Vf)/Vin(max)= 5.5 (13.8+1) /370=0.218 (2). 計算Np Np =Vin(min) ×ton/(ΔB×Ae) Ton：MOS管导通时间 ton= Dmax/ fs＝0.387/60×103＝6.33uS Np = (209×6.33)/( 0.20×194)=34.1 取34TS (3). 計算Ns Ns = Np / n = 34÷5.5＝6.18 取整为6 TS (4). CHECK Np （以Ns驗算Np) Np = Ns×n = 6×5 .5= 33TS 取 Np = 33TS (5).確定NR NR = Np = 33TS (6). CHECK ΔB之選擇合理性. ΔB=[Vin(min) ×Dmax×Ts] / (Np×Ae) = (209×6.33)/ (33×194)=0.2067T 計算线径： (1). 求初級線徑dwp： Ip = Pi / VL = Po / (η×Dmax×VIN) =294/(0.80×0.38×209) = 4.63 A Iprms= Ip×√D =4.63 ×√0.38 = 2.854A Awp = I/J = 2.854/5 = 0.571mm2 dwp=√(4Awp/π)＝√(4×0.571/3.14)= 0.853mm Φ0.9mm orΦ0.55mm×4 (2). 求NR繞組線徑dwR. NR = 33TS L = N2×AL L = 332×4690×0.75 = 3.83mH Im = Vin(min) ×ton / L = (209×6.33) / (3.83×103) ≈ 0.345A AWN = 0.345 / 5 = 0.0691mm2 dwN=√(4×0.0691/3.14) = 0.235mm 取Φ0.28mm (3). 求繞組Ns之線徑dws Isrms=16×√0.35=9.47A (设计输出电流最大为16A) Aws= I / J＝9.47÷5＝1.9 mm2 查ER42/15 BOBBIN幅寬27.5mm±0.3mm.考虑扣除挡墙約6mm,則有 27.5 - 6=21.5mm之可繞寬度,預留適當空間(1.5mm) ， W＝20mm 則: dws=√(4Aws/π)＝√(4×1.9/3.14)= 1.56mm 选用Φ0.40mm×16 计算副边输出储能电感的感量 Lo=Vo×(1-Dmin)÷(0.2×Io×Fs) =13.7×（1-0.218）÷（0.2×20×60