Cuk Converter Design

Discussion in 'The Projects Forum' started by supersculler, Mar 24, 2014.

  1. supersculler

    Thread Starter New Member

    Mar 24, 2014
    1
    0
    I need to design a Cuk converter with the following specs:
    Specification
    • Input Voltage 12V to 24V DC
    • Output Voltage -15V
    • Current Ripple 30%
    • Voltage Ripple 5%

    These are the calculations I have done so far bat am not sure they are correct

    D_min=V_o/(V_o+V_in )=15/(15+12)=0.55

    D_max=V_o/(V_o+V_in )=15/(15+24)=0.38
    Next the current can be calculated using the output power and voltage
    Current input=60W/24V=2.5

    Current output=60W/(-15V)=-4A

    ∆_i1=2.5A/(100%)×(30%)/2=0.375
    ∆_i1=4A/(100%)×(30%)/2=0.6

    Not sure which ∆_i1 I should use 0.375 or 0.6


    T_s=1/100K=10〖×10〗^(-6)

    Load Resistance

    15/4=3.75Ω

    These are all the calculation I done for the Inductors but again am not sure if they are correct I done different ones because I was not sure which values to use.

    L_(1-max)=V_s/∆_i1 DT_s=24/0.375×0.38×10〖×10〗^(-6)=0.2432mH
    L_(2-max)=V_s/∆_i1 DT_s=24/0.375×0.38×10〖×10〗^(-6)=0.2432mH
    L_(2-max)=V_s/∆_i1 DT_s=24/0.6×0.38×10〖×10〗^(-6)=0.152mH

    L_(2-max)=V_s/∆_i1 DT_s=24/0.6×0.55×10〖×10〗^(-6)=0.22mH
    L_(2-max)=V_s/∆_i1 DT_s=24/0.375×0.55×10〖×10〗^(-6)=0.352mH


    Is this C1 calculation correct? And what about C2

    C_1>(D^2 T_s)/2R=(〖0.38〗^2×〖10×10〗^(-6))/(2×6)=0.12μF

    Any help would be greatly appreciated I need to model it in matlab in open loop first then design a closed loop system after.

    Thanks
     
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