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
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