DC-DC Forward convertor

Discussion in 'Homework Help' started by saturnsakini, Sep 9, 2015.

  1. saturnsakini

    Thread Starter New Member

    Jul 10, 2015
    8
    0
    Hello everybody,

    I wanna design to a forward convertor with these spec;

    Input Voltage= 50 to 150 V
    Input Power= 75 W
    i desired to efficency 0.8
    so my output power= 60 W @12V, @5Amper
    f=50kHz
    there is my calculations for turn ratio and output inductor;
    calculating

    and i used turn ratio 1.5/1

    Vout=dutycycle*inputvoltage*ratio of transformer
    12=duty*150*1.5 @150V minimum duty cycle=0.053

    question 1) why my output voltage and current aren't proper my calculatings
    question 2) why input current flow from input voltage source is too high

    my LTspice model and output waves in attachments;
    forfor.PNG forfor.PNG
     
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