conversion_td5_2.py

Created on December 12, 2023
1.6 KB
Hacheur serie : alim d'un PC

**equations de phases :**
  
0<t<aT
T1 ON D1 OFF
VT1 = 0
VD1 = -Ve
VL1 = Ve - Vs = L(dil/dt)
iT1 = ie
iD1 = 0
iL1 = (Ve-Vs/L1)*t +ILmin = ie

aT < t <T
T1 OFF D1 ON
VT1 = Ve
VD1 = O
VL1 = -Vs = L(dil/dt)
iT1 = 0
iD1 = iL1
iL1 = -Vs/L *(t-aT) +ILmax

**expression de deltaL1**
iL1(t=aT)= Imax
= (Ve-Vs/L1)aT + Ilmin

-> deltaIL1 = IL1max - IL1min
= (Ve-Vs/L1)aT
= (Ve-Vs)a/fL1

**hypotheses de ic(t)**

iL1 = ic + is avec is = IS
donc ic = IL1 - IS

**montrer VT1 = VE - VS**

VE - VT1 - VL1 - VS = 0V

VE - VT1moy - VS = 0V
-> VT1moy = Ve - Vs

**calculer VT1 moy**
VT1 moy = aire VT1 / T
= (Ve(t-aT))/T
= Ve(1-a)

**deduire aVe = Vs**

VT1moy = ve - vs = ve(1-a)
->Ve-Vs = Ve-aVe = Vs = aVe

**calculer le rapport cyclique**

a = Vs/Ve = 1.5/12 = 0.125

**calculer Ismoy**

Ismoy = Vs/R = Ps/Vs 
= 7.5/1.5 = 50A

**deduire IL1moy**

IL1moy = icmoy + ismoy
Ic moy = 0 donc 
IL1moy = Ismoy = 50A

**calculer deltaIL1**

avec L1 = 1 microH

((Ve-Vs)a)/fL1
=(12-1.5*0.125)/(300.10^3*1.10^-6)
= 4.375A

**calculer IL1max et IL1min**

IL1max = IL1moy + (deltaIL1/2)
= 50 + 4.375/2 = 52.1875A
IL1min = IL1moy - (deltaIL1/2)
= 50 - 4.375/2 = 47.8125A

**calculer ondulation deltaS**

avec C = 140 microF

deltaVS = deltaIL1 / 8Cf
= 4.375/ 8*140.10^-6*300.10^3
= 0.013V

**calculer les courants moyens**

Is = IL1moy + IL2moy 
= 2L1moy = 2L2moy
-> IS/2 = 50/2 = 25A

**freq des IL(t)et IC(T)**

fiL1 = fiL2 = fd = 300kHz
fic=fiL=2fiL1=2fiL2=2fd= 600kHz

**intérêts de ces struct**

deltaVS = f(fs) -> fs croissant
et vs decroit si C cte

deltaBS = f(fs) -> fs croissant
et c decroit si Vs cte