Chapter1, Thyristors

Example 1.11.1 : page 1-29

In [1]:
from __future__ import division
#peak reverse recovery current
#given data :
itt=10 # time in micro seconds
qtt=150 #charge in micro colums
prrc=((2*qtt)/itt) #peak reverse recovery current in amperes
print "Peak reverse recovery current = %0.f A" %prrc

Peak reverse recovery current = 30 A

Examples 1.18.1: page 1-44

In [2]:
from __future__ import division
from math import pi, sqrt, cos
#voltage of the capacitor
r=10 #in ohms
l=10 #/inductance in mH
c=10 #capacitance in micro farads
v=100 #in volts
t=((pi)/(sqrt((1/(l*10**-3*c*10**-6))-(r**2/(4*(l*10**-3)**2))))) # time in seconds
vc= v*(1-cos(t/(sqrt(l*10**-3*c*10**-6))*pi/180)) #in volts
print "The capacitor voltage = %0.2f V" %vc
#answer is wrong in the textbook

The capacitor voltage = 0.15 V

Example 1.18.2: page 1-45

In [3]:
from __future__ import division
from math import pi, sqrt, cos
#voltage of the capacitor
r=15 #in ohms
l=12 #/inductance in mH
c=8 #capacitance in micro farads
v=100 #in volts
t=((pi)/(sqrt((1/(l*10**-3*c*10**-6))-(r**2/(4*(l*10**-3)**2))))) # time in seconds
vc= v*(1-cos(t/(sqrt(l*10**-3*c*10**-6))*pi/180)) #in volts
print "The capacitor voltage = %0.2f V" %vc
#this question is not solved in the textbook

The capacitor voltage = 0.16 V

Example 1.20.1: page 1-52

In [4]:
from __future__ import division
#Turn Off Time
#given data :
Vs=200 #in volts
R1=10 # in ohm
R2=R1 
C=5 # in micro-farad
Tc=(R1*C)/1.44 
print "The Circuit Turn Off Time, Tc = %0.2f micro-sec" %Tc

The Circuit Turn Off Time, Tc = 34.72 micro-sec

Example 1.20.2: page 1-52

In [5]:
from __future__ import division
#Peak Current and turn off time
#given data :
Vs=200 #in volts
R1=10 # in ohm
R2=R1 
Vc=200 #in volts
C=10 # in micro-farad
I1=Vs/R1 
I2=(Vs+Vc)/R2 
It1=I1+I2 
print "Peak Current, It1 = %0.2f A " %It1
Tc=(R1*C)/1.44 
print "The Circuit Turn Off Time, Tc = %0.2f micro-sec " %Tc

Peak Current, It1 = 60.00 A 
The Circuit Turn Off Time, Tc = 69.44 micro-sec

Example 1.21.1: page 1-59

In [6]:
from __future__ import division
from math import pi
#L and C
#given data :
V=100 # in volts
Irm=40 # in A
tq=40 # in micro-sec
Del_t=(50/100)*tq # in micro-sec
C=(Irm*(tq+Del_t))/V 
print "Capacitance, C = %0.f micro-farad " %C
L_min=(V/Irm)**2*C 
print "Minimum inductance, L_min = %0.f micro-Henry" %L_min
T=2.5 # assume one cycle period in ms
L_max=((0.01*(T*10**-3)**2)/(pi**2*C*10**-6))*10**6 
print "Maximum inductance, L_max = %0.2f micro-Henry " %L_max

Capacitance, C = 24 micro-farad 
Minimum inductance, L_min = 150 micro-Henry
Maximum inductance, L_max = 263.86 micro-Henry