conversion_thytistors.py

Created by famille-bvc

Created on November 14, 2023

2.8 KB


4 types de conv statiques :

cvs DC/DC = hacheur (chopper)
cvs AC/DC = redresseur (rectifier
cvs DC/AC = onduleur (inverter)
cvs AC/AC = gradateur (dimmer)

*****************

3 regles d'interconnexions
des sources :

Source de tension peut pas etre
court circuite, mais elle peut 
etre ouverte

Source de courant peut pas etre
ouverte sauf si i(t)= 0A, mais
elle peut etre court circuite

Seules deux sources de nature
differente peuvent etre co entres
elles 

*****************

3 fonctions assures par les
elements reactions du cvs
statique :

stokage, transfert d'energie
et filtrage 

*****************

2 configurations possibles de 
cvs statiques :

2 sources de nature diff 
= cvs statique a liaison direct 

2 sources de meme nature 
= cvs statique a liaison indirect

/////////////////////////////////

PD2 a thysistors = 4 thysistors 

Le thysustor -> 1er interrupteur
semi conducteur commande utulise
en EP

comporte en plus de l'anode A et
la cathode K, une gachette G 
permettant le controle de la 
fermeture 

 TH devient ON si Va > Va 
 + impulsion gachette (alpha)
 
 TH OFF si Im = 0 
 
Fonctionnement :

phase 1 -> α<0<π+α
TH1 TH4 ON
TH2 TH3 OFF 

phase 2 -> π+α<0<2π+α
TH2 TH3 ON
TH1 TH4 OFF

Equations :
  
  phase 1
VS = VE 
VTH VTH4 = 0 
ITH2 ITH3 = 0 
ITH1 = IS
IE = IS 

  phase 2
VS = -VE
VTH1 = VE
VTH2 VTH3 = 0 
ITH1 ITH4 = 0 
IE = -IS

**********

TRACAGE :

Ne pas oublier le decalage α
0 à x => α sur le schema

états :

   TH1,TH4       TH1,TH4
          TH2,TH3       TH2,TH3

Tracer ie(t):
^ 
|
|  _______       _______
|  |     |       |     |      |
---x--------------------------->
|__|     |_______|     |______|
|
|

Tracer is(t) => long trait is:
+ tracer Vs(t)
^   _     _     _     _
|  / \   / \   / \   / \
is |  \  |  \  |  \  |  \
|  |   \ |   \ |   \ |   \
---x--------------------------->
|\ |    \|    \|    \|    \
| \|     |     |     |     |
|

Tracer ith1(t):
^ 
|
|  _______       _______
|  |     |       |     |      
---x     ---------     -------->
|
|

Tracer Vth1
^
|
| /|            /|
|/ |           / |
-  x------    /  -------    --->
|        |   /         |   /
|        \__/          \__/
|

***********

Vs moy = 1/π *integ(α,π+α, Vs dθ)

  2sqrt(2)
= -------- V cos α
     π

caracteristique de Vs moy :
  
part de 2sqrt(2)/π
(redresseur)
passe par 90
(onduleur)
fini à -2sqrt(2)/π

=> Is toujours positif

**********
amorçage nominal, αn :
  
           π Vn
cos αn = ---------
         2sqrt(2)V
         
puissance active cote DC, PDC :
  
PDC = Vn * In

expression analytique PDC / PAC:
  
K parfait = pas de perte du cvs
=> PDC = PAC

            2sqrt(2)
PDC = PAC = -------- V Is cos α
               π
               
express analytique P react, Qac:
  
QAC = (2sqrt2/π) V Is sin α

val numerique =>

α = 0deg => Qac = 0^VAR
α = ...deg => appliquer form

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