# 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)

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