《反激式变压器设计公式》.xls.xls

Flyback Transformer <40W SVR SET Flyback transformer Design Example> 1. Type Input AC Line Voltage and Frequency Vac= 100 Vac ~ 240 Vac fs= 60 Hz 2. Type Output Power and Efficiency Pout= 40 W η= 80 % Pin= 50 W 3. Type DC link capacitor value and minimum DC link voltage Cin= 100 uF Vmin= 108 V 4. Type SMPS switchiing frequency fsw= 50 kHz 5. Type SMPS Max. Duty Duty_max= 6. Calculated values tsw= 20 us ton_max= 9 us Iin_dc_avg= A Ipk= A 7. If the above Ipk is too high type lower Ipk Ipk_mosfet= A Ipk_ini= A Δ I=1A Lm value Lm= 972 uH :According to the desired operating mode(fig2. A:DCM or M), change the Ipk_mosfet. If you want DCM, increase Ipk_mosfet. : If you M, decrease Ipk_mosfet. core information Acore= 40 ?Δ B= TESLA :Select a core according to the output power from the Core Data Sheet. :ΔB should be less than 50% of Bsat. output voltage and diode forward drop Vo= 12 V V FW = V 11. Calculated values Np= n= Ns= 12. Type number of turns to determine the other outputs Np Turn 61 Turn Vo Ns8 3 Turn V(Vo+V FW ) 4 9 19 23 25 0- 0- *Vo is calculated based on V FW =. 13. Calculated winding diameter. DCM case Iin_rms= A Id_rms= A ? Pout Pin ? fsw tsw 1? max _ max _ Duty tsw ton ?? min __V Pin avg dc Iin? max _ __2 Duty avg dc Iin Ipk ?? sps Ipk Ipk ini Ipk __??I ton Vin Lm ??? max _B Acore ton Vin Np ???? max _ max) _1()( max _ Duty V Vo n Duty Vin n Ns Np??????n Np Ns ? Ipk avg dc Iin__ B A=B=C A=B=C max _ ton max _ Duty tsw AC sps Ipk _ ini Ipk _ fig 1. DC Link Cap Voltage B A=B max _ ton max _ Duty tsw A n(Vo+V FW ) Vmin Vac_pk Vmin fig 3. Transformer Energy fig 2. CCM & DCM fs Cin Pin pk Vac V???? 2_ min 1? Flyback Transformer Awi= mm^2 Awgp= mm Awgs= M case Iin_rms= A Id_rms= A Awi= mm^2 Awgp= mm Awgs=