Syllabus For The Subject Power Electronics & Devices



1 What is power electronics


Power electronics applications

Power semiconductor devices and their classifications

Power semiconductor devices: characteristics and ratings

Ideal and real switches: comparison of characteristics

Ideal switch characteristics

Desirable characteristics of a real switch

Power loss characteristics of an ideal switch

Power loss characteristics in a real switch

Power loss characteristics in a real switch

Power electronic systems

Types of power electronic circuits/converters

Merits and demerits of power electronic converters

Recent developments


Solved examples

Review questions



2 Power switching devices and their characteristics


Power diodes

Diode v-I characteristics

Diode reverse recovery characteristics

Types and ratings of power diodes

Series and parallel operation of diodes


Structure, symbol, and V-I characteristics

Transistor analogy

Thyristor  turn-on methods

Thyristor turn-off methods

Switching characteristics of thyristors

Switching characteristics during turn-on

Switching characteristics during turn-off

Thyristor gate characteristics

Thyristor commutation methods

Natural commutation

Forced commutation

Thyristor protection

Over voltage protection

Suppression of overvoltage’s

Overcurrent protection

Snubber circuits

Thyristor ratings

Anode voltage ratings

Current rating

Surge current ratings dildt rating

Series and parallel operation of thyristors

Series operation

Parallel operation

Triggering of thyristors

Triggering of thyristors in series

Triggering of parallel connected SCRs

Heat sinks heating, cooling and mounting of thyristors

Thermal resistance

Thyristor trigger circuits

RC firing circuits

Synchronized UJT triggering

Ramp and pedestal triggering

Pulse transformers

Other thyristor devices




Programmable unilateral transistor

Silicon unilateral  switch

Reverse  conducting thyristor

GTO thyristor

Power transistors

Bipolar junction transistor


Comparison of MOSFET and BJT

Insulated gate bipolar transistor

Basic structure

Equivalent circuit

Operation models

Output characteristics

Transfer characteristics

Switching characteristics


Safe operating area


MOS controlled thyristor

Typical rating of high power devices

Driver circuits for gate communication devices

GATE drive circuits for power MOSFET


Driver circuits for IGBT

Base-drive circuits for power BJT

GATE drive circuits for GTO

Solved examples

Review questions



3 AC to DC converters


The principle of phase control

Converter classifications

Single-phase half wave thyristor rectifier with RL load

Single phase half wave thyristor rectifier with RL load and

Free-wheeling diode

Single-phase half wave thyristor rectifier with RLE load

Single phase full wave mid-point thyristor recitifier converter

Single-phase full wave bridge converters

Single-phase bridge rectifier connected to resistance load

Series RL load

RL load with free-wheeling diode

Full wave bridge rectifier feeding RLE load

Single-phase semi-converter

Calculation of  active and reactive power inputs

Effect of load inductance

Three-phase thyristor converter circuits

Three-phase half wave converter

Three-phase full converters bridges

Dual converters

Dual converters without circulating current

Dual converters

Two semi converters in series

Two single phase full converters in series

Twelve-pulse converters

Gating circuits

Cosine firing scheme

Solved examples

Review questions



4  AC to AC converters


AC voltage controllers

Types of AC voltage controllers

Methods of voltage control

Single-phase AC voltage controller supplying R loads

Single-phase AC voltage controller

Single-phase transformer tap changer


Principle of operation

Single-phase to single-phase cycloconverter feeding RL load

Single-phase to single-phase cyclonverters

Three-phase to single-phase cycloconveters

Output voltage equation

Effect of source inductance

Solved examples

Review questions



5 DC to DC converters


Principle of chopper operation

Control schemes

Constant frequency scheme

Variable frequency scheme

Current limit control

Step up choppers

Chopper circuits: classification

Steady state time-domain analysis of type a chopper

Thyristor  based chopper circuits

Voltage commuted chopper

Current commutated chopper

Load commutated chopper

Multiphase choppers

Switch mode power supplies

Switch mode DC-DC converter

Buck converter

Boost-type converter

Buck boost converter

Cuk converters

Switch mode DC-D converter

Fly back converter

Push-pull converter

Half-bridge converter

Full-bridge converter

Resonant converter

Zero-current switching resonant converters

Zero-voltage switching resonant converters

Comparison between ZCS and ZVS converters

Solved examples

Review questions



6 Inverters



Parallel inverters

Basic parallel inverter

Modified parallel inverter

Series inverters

Basic series inverter

Modifications of series inverter

Single-phase bridge voltage source inverter

Single-phase half bridge inverter

Single-phase full bridge inverter

Steady state response of single-phase inverters

Force commutated thyristor inverter

Mc Murray inverter

Modified Mc Murray full bridge inverter

Mc murray-bedford half bridge inverter

Three-phase bridge inverters

Three-phase inverter under 180* mode operation

Three phase inverter under 120* mode operation

Voltage control in single-phase inverters

External control of the AC output voltage

External control of the DC input voltage through variable DC link

Internal control of the inverter voltage

Pulse width modulated inverters

Voltage control to three-phase inverter

Harmonic reduction in the output voltage

Harmonic reduction by transformer connections 

Current source inverter

Single-phase capacitor commuted current source inverter

With R load

Single-phase auto-sequential commuatated inverter

Three-phase current source inverter

Solved examples

Review questions



7 Power controllers: their applications


DC motor speed control

Principle of speed control

Phase controlled converters

Single-phase DC drives

Three-phase DC drives

Dual converter drives

Chopper controlled DC drives

AC drives

Induction motor drives

Speed control by stator voltage control

Variable voltage variable frequency control

Speed control by chopper controlled rotor reistance

Slip power recovery control

Synchronous motor control

Static circuit beakers

DC circuit breakers

AC circuit breakers

HVDC transmission

Types of HVDC lines

Converter station

Static Var systems

Thyristor controlled reactor-fixed capacitor

Thyristor switched capacitor-thyristor controlled reactor

Uninterrupted power supply

On-line UPS

Off-line UPS

Salient features of an on-line inverter


Transfer switch

Solved examples

Review questions


8 Microcontroller based control and protection circuits


The 8051 pin configuration

8051 Architecture

Memory organization

The special function register


The serial interface

The interrupts

The power control register

The instruction set

Addressing modes

Arithmetic instructions

Logical instructions

Data transfer instructions

Boolean instructions

The program branching and machine control instruction

Instruction timing

Interfacing the 8051 microcontroller

Interfacing external memory

Interfacing an input/output devices

Interfacing an analog to digital converter

Interfacing a digital to analog converter

Interfacing a relay and an opt coupler

Interfacing a pulse transformer


SCR triggering


Fault diagnosis in three-phase thyristor converters using


ASICs for motor control applications

Need for DSP based motor control

Motor control peripherals

Review questions









 Protection Status