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{
"metadata": {
"name": ""
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 02 : Power Semiconductor Diodes and Transistors"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.1, Page No 21"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#initialisation of variables\n",
"B=40.0\n",
"R_c=10 #ohm\n",
"V_cc=130.0 #V\n",
"V_B=10.0 #V\n",
"V_CES=1.0 #V\n",
"V_BES=1.5 #V\n",
"\n",
"#Calculations\n",
"I_CS=(V_cc-V_CES)/R_c #A\n",
"I_BS=I_CS/B #A\n",
"R_B1=(V_B-V_BES)/I_BS\n",
"P_T1=V_BES*I_BS+V_CES*I_CS\n",
"ODF=5\n",
"I_B=ODF*I_BS\n",
"R_B2=(V_B-V_BES)/I_B\n",
"P_T2=V_BES*I_B+V_CES*I_CS\n",
"B_f=I_CS/I_B\n",
"\n",
"#Results\n",
"print(\"value of R_B in saturated state= %.2f ohm\" %R_B1)\n",
"print(\"Power loss in transistor=%.2f W\" %P_T1)\n",
"print(\"Value of R_B for an overdrive factor 5 = %.2f ohm\" %R_B2)\n",
"print(\"Power loss in transistor = %.2f W\" %P_T2)\n",
"print(\"Forced current gain=%.0f\" %B_f)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"value of R_B in saturated state= 26.36 ohm\n",
"Power loss in transistor=13.38 W\n",
"Value of R_B for an overdrive factor 5 = 5.27 ohm\n",
"Power loss in transistor = 15.32 W\n",
"Forced current gain=8\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.2, Page No 24"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"\n",
"#initialisation of variables\n",
"I_CEO=2*10**-3 #A\n",
"V_CC=220.0 #V\n",
"P_dt=I_CEO*V_CC #instant. power loss during delay time\n",
"t_d=.4*10**-6 #s\n",
"f=5000\n",
"P_d=f*I_CEO*V_CC*t_d #avg power loss during delay time\n",
"V_CES=2 #V\n",
"t_r=1*10**-6 #s\n",
"I_CS=80 #A\n",
"\n",
"#Calculations\n",
"P_r=f*I_CS*t_r*(V_CC/2-(V_CC-V_CES)/3) #avg power loss during rise time\n",
"t_m=V_CC*t_r/(2*(V_CC-V_CES))\n",
"P_rm=I_CS*V_CC**2/(4*(V_CC-V_CES)) #instant. power loss during rise time\n",
"\n",
"#Results\n",
"P_on=P_d+P_r \n",
"print(\"Avg power loss during turn on = %.2f W\" %P_on)\n",
"P_nt=I_CS*V_CES \n",
"print(\"Instantaneous power loss during turn on = %.0f W\" %P_nt)\n",
"t_n=50*10**-6\n",
"P_n=f*I_CS*V_CES*t_n\n",
"print(\"Avg power loss during conduction period = %.0f W\" %P_n)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Avg power loss during turn on = 14.93 W\n",
"Instantaneous power loss during turn on = 160 W\n",
"Avg power loss during conduction period = 40 W\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.3 Page No 26"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"\n",
"#initialisation of variables\n",
"I_CEO=2*10**-3 #A\n",
"V_CC=220 #V\n",
"t_d=.4*10**-6 #s\n",
"f=5000\n",
"V_CES=2 #V\n",
"t_r=1*10**-6 #s\n",
"I_CS=80 #A\n",
"t_n=50*10**-6 #s\n",
"t_0=40*10**-6 #s\n",
"t_f=3*10**-6 #s\n",
"\n",
"#Calculations\n",
"P_st=I_CS*V_CES # instant. power loss during t_s\n",
"P_s=f*I_CS*V_CES*t_f #avg power loss during t_s\n",
"P_f=f*t_f*(I_CS/6)*(V_CC-V_CES) #avg power loss during fall time\n",
"P_fm=(I_CS/4)*(V_CC-V_CES) #peak instant power dissipation\n",
"P_off=P_s+P_f\n",
"\n",
"#Results\n",
"print(\"Total avg power loss during turn off = %.2f W\" %P_off)\n",
"P_0t=I_CEO*V_CC\n",
"print(\"Instantaneous power loss during t_0 = %.2f W\" %P_0t)\n",
"P_0=f*I_CEO*V_CC*t_0 #avg power loss during t_s\n",
"P_on=14.9339 #W from previous eg\n",
"P_n=40 #W from previous eg\n",
"P_T=P_on+P_n+P_off+P_0 \n",
"print(\"Total power loss = %.2f W\" %P_T)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Total avg power loss during turn off = 44.91 W\n",
"Instantaneous power loss during t_0 = 0.44 W\n",
"Total power loss = 99.93 W\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.4, Page No 28"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#initialisation of variables\n",
"I_CS=100.0 \n",
"V_CC=200.0 \n",
"t_on=40*10**-6\n",
"\n",
"#Calculations\n",
"P_on=(I_CS/50)*10**6*t_on*(V_CC*t_on/2-(V_CC*10**6*t_on**2/(40*3))) #energy during turn on\n",
"t_off=60*10**-6\n",
"P_off=(I_CS*t_off/2-(I_CS/60)*10**6*(t_off**2)/3)*((V_CC/75)*10**6*t_off) #energy during turn off\n",
"P_t=P_on+P_off #total energy\n",
"P_avg=300.0\n",
"f=P_avg/P_t\n",
"\n",
"#Results\n",
"print(\"Allowable switching frequency = %.2f Hz\" %f)\n",
"#in book ans is: f=1123.6 Hz. The difference in results due to difference in rounding of of digits"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Allowable switching frequency = 1125.00 Hz\n"
]
}
],
"prompt_number": 10
}
],
"metadata": {}
}
]
}
|
