Project 1
1). Buck CCM
Vin = 40-50 V, Vo = 30V, P = 500W, fs = 50kHz
The design procedure is as follows
Duty cycle `D = (Vo)/(Vi) = 30/40 = 0.75`
Inductor current `IL = Io = (Po)/(Vo)= 500/30 = 16.67A`
`DeltaIL = 10%*IL = 0.1*16.67 = 1.67A`
Load Resistance `R = (Vo^2)/(P)= 30^2/500 = 1.8 ohm`
Inductor `L = ((Vo)/(fs*DeltaIL))*(1-D) = ((30)/(50*10^3))*(1-0.75) = 89.82uH`
Output Capacitor `Co = (1-D)/(8*L*fs^2*(DeltaVo)/(Vo)) = (1-0.75)/(8*89.82*10^-6*(50*10^3)^2*0.01) = 13.92uF`
Simulation of BUCK CCM
Simulation Results:
The input voltage is(40-50)V and the output voltage obtained is 30V in aclosed loop Buck CCM. The zoomed out and Zoomed in figures are shown below
2). Boost CCM
Vin = 20-30 V, Vo = 40V, P = 600W, fs = 30kHz
Design procedure is as follows
Duty cycle `(Vo)/(Vi) = 1/(1-D)`
`D = 1-20/40 = 0.5`
Load resistance `Ro = (Vo^2)/P = 40^2/600 = 2.67 ohm`
Inductor current `IL = (Vi)/((1-D)^2*Ro) = 20/((1-0.5)^2*2.67) = 29.96A`
`Delta IL = 20%IL = 0.2*29.96 = 5.99A`
Inductor `L = (Vi)/(fs*DeltaIL)*D =20/(30*10^3*5.99)*0.5=55.625 uH`
Output Capacitor `Co =D/(R*fs*(DeltaVo)/(Vo)) =0.5/(2.67*30*10^3*0.1) = 62.42uF`
Simulation Results:
The input voltage is(20-30)V and the output voltage obtained is 40V in a closed loop Boost CCM. The zoomed out and Zoomed in figures are shown below
3) SEPIC CCM converter
Vin = 30-60 V, Vo = 45V, P = 1kW, fs = 300kHz
Design procedure:
Duty cycle calculation: `(Vo)/(Vi) = D/(1-D)`
`D/(1-D) = 45/30`
`D = 0.6`
Load Resistance`R = (Vo)^2/P = 45^2/1000 = 2.025`
Ripple currrents:
`IL1 = ((Vo)/R)*D/(1-D)= (45/2.025)*(0.6/1-0.6) = 33.33A`
`IL2 = Io = (Vo)/R = 45/2.025 = 22.22A`
Inductors LI and L2:
`L1=(Vi*D)/(fs*DeltaIL1) = (30*0.6)/(300*10^3*0.1*33.33) = 18uH`
`L2=(Vi*D)/(fs*DeltaIL2) = (30*0.6)/(300*10^3*0.1*22.22) = 27uH`
Capacitors C1 and C2:
`C1=C2 = (D)/(R*fs*((DeltaVo)/(Vo)))= 0.6/(2.025*300*10^3*0.01) = 98.76uF`
Simulation Results:
The input voltage is(30-60)V and the output voltage obtained is 45V in a closed loop SEPIC Converter. The zoomed out and Zoomed in figures are shown below
