POWER ELECTRONICS
DIGITAL NOTES
B.TECH
(III YEAR – I SEM)
Prepared by:
Mr.S.RAKESH, Asst.Prof
Department of Electrical & Electronics Engineering
MALLA REDDY COLLEGE
OFENGINEERING&TECHNOLOGY
(Autonomous Institution – UGC, Govt. of India)
Recognized under 2(f) and 12 (B) of UGC ACT 1956
(Affiliated to JNTUH, Hyderabad, Approved by AICTE - Accredited by NBA & NAAC – ‘A’ Grade - ISO 9001:2015 Certified)
Maisammaguda, Dhulapally (Post Via. Kompally), Secunderabad – 500100, Telangana State, India
, MALLA REDDY COLLEGE OF ENGINEERING AND TECHNOLOGY
III B.Tech EEE I Sem L T/P/D C
3 -/-/- 3
(R17A0210) POWER ELECTRONICS
COURSE OBJECTIVES:
To get an understanding of semiconductor devices and systems which have a large
application in the power generation, transmission, distribution and utilization.
To get an in depth understanding of the basic concepts of different types of power
semiconductor devices and their applications in converters, inverters, choppers,
cycloconverter, dual converters, etc.
UNIT - I
POWER SEMI CONDUCTOR DEVICES & COMMUTATION CIRCUITS: Thyristors
– Silicon Controlled Rectifiers (SCR’s) - Two transistor analogy - Static and Dynamic
characteristics - Turn on and turn off methods- UJT firing circuit - Series and parallel
connections of SCR’s – Snubber circuit details – Line Commutation and Forced
Commutation circuits – Power MOSFET, Power IGBT, their characteristics and other form
of thyristors.
UNIT - II
AC - DC CONVERTERS (1-PHASE & 3-PHASE CONTROLLED RECTIFIERS):
Phase control technique – Single phase Line commutated converters –Bridge connections –
Half controlled converters with R, RL and RLE loads – Derivation of average load voltage
and current – Numerical problems. Semi and Fully controlled converters, Bridge connections
with R, RL loads – Derivation of average load voltage and current. Three phase converters –
Three pulse and six pulse converters – Bridge connections average load voltage with R and
RL loads – Effect of Source inductance – Dual converters (both single phase and three phase)
- Waveforms –Numerical Problems.
UNIT - III
DC - DC CONVERTERS (CHOPPERS): Choppers – Time ratio control and Current limit
control strategies – Step down choppers Derivation of load voltage and currents with R, RL
loads- Step up Chopper and other class of chopper – load voltage expression, Problems.
,UNIT - IV
AC - AC CONVERTERS (AC VOLTAGE CONTROLLERS) & FREQUENCY
CHANGERS (CYCLO-CONVERTERS): AC voltage controllers – Single phase two
SCR’s in anti-parallel – With R and RL loads – modes of operation – Derivation of RMS
load voltage, current and power factor wave forms -Numerical problems - Cyclo converters –
Types- R and RL loads (Principle of operation only) – Bridge configuration of single phase
cyclo converter (Principle of operation only) – Waveforms.
UNIT - V:
DC - AC CONVERTERS (INVERTERS): Inverters – Single phase inverter – Basic series
inverter - operation and waveforms - Three phase inverters (120, 180 degrees conduction
modes of operation) - Voltage control techniques for inverters, Pulse width modulation
techniques - Numerical problems.
TEXT BOOKS:
1. Power Electronics, Dr. P. S. Bimbhra, Khanna Publishers
2. Power Electronics, M. D. Singh & K. B. Kanchandhani, Tata Mc Graw - Hill Publishing
Company.
REFERENCE BOOKS:
1. Power Electronics; Circuits, Devices and Applications, M. H. Rashid, Prentice Hall of
India.
2. Power Electronics, Vedam Subramanyam, New Age International (P) Limited,
Publishers.
3. Elements of Power Electronics, Philip T. Krein, Oxford University Press.
4. Power Electronics, P. C. Sen, Tata Mc Graw-Hill Publishing.
COURSE OUTCOMES:
At the end of the course the students get:
A thorough knowledge on construction operation V-I characteristics commutation firing
and protection of various power semiconductor devices, thyristors nature of the R, RL
and RLE loads for different power inputs.
AC-to-DC power conversion through 1-phase & 3-phase controlled rectifiers, DC-to-DC
power conversion through step-up and step-down choppers.
Different types of PWM (pulse-width modulation) techniques, steady-state and transient
state analysis of all the power converters, which can be to applied to concepts of real-
world electrical and electronics problems & applications.
, UNIT – I
Power semiconductor devices and commutation
circuits
Introduction to power electronics:
Power Electronics is a field which combines Power (electric power), Electronics and Control systems.
Power engineering deals with the static and rotating power equipment for the generation, transmission
and distribution of electric power. Electronics deals with the study of solid state semiconductor power
devices and circuits for Power conversion to meet the desired control objectives (to control the output
voltage and output power). Power electronics may be defined as the subject of applications of solid state
power semiconductor devices (Thyristors) for the control and conversion of electric power. Power
electronics deals with the study and design of Thyristorised power controllers for variety of application
like Heat control, Light/Illumination control, Motor control - AC/DC motor drives used in industries,
High voltage power supplies, Vehicle propulsion systems, High voltage direct current (HVDC)
transmission.
Power Electronics refers to the process of controlling the flow of current and voltage and converting it to
a form that is suitable for user loads. The most desirable power electronic system is one whose efficiency
and reliability is 100%.
Take a look at the following block diagram. It shows the components of a Power Electronic system and
how they are interlinked.
Figure: 1.1. Block diagram of DC power supply
2|Page
DIGITAL NOTES
B.TECH
(III YEAR – I SEM)
Prepared by:
Mr.S.RAKESH, Asst.Prof
Department of Electrical & Electronics Engineering
MALLA REDDY COLLEGE
OFENGINEERING&TECHNOLOGY
(Autonomous Institution – UGC, Govt. of India)
Recognized under 2(f) and 12 (B) of UGC ACT 1956
(Affiliated to JNTUH, Hyderabad, Approved by AICTE - Accredited by NBA & NAAC – ‘A’ Grade - ISO 9001:2015 Certified)
Maisammaguda, Dhulapally (Post Via. Kompally), Secunderabad – 500100, Telangana State, India
, MALLA REDDY COLLEGE OF ENGINEERING AND TECHNOLOGY
III B.Tech EEE I Sem L T/P/D C
3 -/-/- 3
(R17A0210) POWER ELECTRONICS
COURSE OBJECTIVES:
To get an understanding of semiconductor devices and systems which have a large
application in the power generation, transmission, distribution and utilization.
To get an in depth understanding of the basic concepts of different types of power
semiconductor devices and their applications in converters, inverters, choppers,
cycloconverter, dual converters, etc.
UNIT - I
POWER SEMI CONDUCTOR DEVICES & COMMUTATION CIRCUITS: Thyristors
– Silicon Controlled Rectifiers (SCR’s) - Two transistor analogy - Static and Dynamic
characteristics - Turn on and turn off methods- UJT firing circuit - Series and parallel
connections of SCR’s – Snubber circuit details – Line Commutation and Forced
Commutation circuits – Power MOSFET, Power IGBT, their characteristics and other form
of thyristors.
UNIT - II
AC - DC CONVERTERS (1-PHASE & 3-PHASE CONTROLLED RECTIFIERS):
Phase control technique – Single phase Line commutated converters –Bridge connections –
Half controlled converters with R, RL and RLE loads – Derivation of average load voltage
and current – Numerical problems. Semi and Fully controlled converters, Bridge connections
with R, RL loads – Derivation of average load voltage and current. Three phase converters –
Three pulse and six pulse converters – Bridge connections average load voltage with R and
RL loads – Effect of Source inductance – Dual converters (both single phase and three phase)
- Waveforms –Numerical Problems.
UNIT - III
DC - DC CONVERTERS (CHOPPERS): Choppers – Time ratio control and Current limit
control strategies – Step down choppers Derivation of load voltage and currents with R, RL
loads- Step up Chopper and other class of chopper – load voltage expression, Problems.
,UNIT - IV
AC - AC CONVERTERS (AC VOLTAGE CONTROLLERS) & FREQUENCY
CHANGERS (CYCLO-CONVERTERS): AC voltage controllers – Single phase two
SCR’s in anti-parallel – With R and RL loads – modes of operation – Derivation of RMS
load voltage, current and power factor wave forms -Numerical problems - Cyclo converters –
Types- R and RL loads (Principle of operation only) – Bridge configuration of single phase
cyclo converter (Principle of operation only) – Waveforms.
UNIT - V:
DC - AC CONVERTERS (INVERTERS): Inverters – Single phase inverter – Basic series
inverter - operation and waveforms - Three phase inverters (120, 180 degrees conduction
modes of operation) - Voltage control techniques for inverters, Pulse width modulation
techniques - Numerical problems.
TEXT BOOKS:
1. Power Electronics, Dr. P. S. Bimbhra, Khanna Publishers
2. Power Electronics, M. D. Singh & K. B. Kanchandhani, Tata Mc Graw - Hill Publishing
Company.
REFERENCE BOOKS:
1. Power Electronics; Circuits, Devices and Applications, M. H. Rashid, Prentice Hall of
India.
2. Power Electronics, Vedam Subramanyam, New Age International (P) Limited,
Publishers.
3. Elements of Power Electronics, Philip T. Krein, Oxford University Press.
4. Power Electronics, P. C. Sen, Tata Mc Graw-Hill Publishing.
COURSE OUTCOMES:
At the end of the course the students get:
A thorough knowledge on construction operation V-I characteristics commutation firing
and protection of various power semiconductor devices, thyristors nature of the R, RL
and RLE loads for different power inputs.
AC-to-DC power conversion through 1-phase & 3-phase controlled rectifiers, DC-to-DC
power conversion through step-up and step-down choppers.
Different types of PWM (pulse-width modulation) techniques, steady-state and transient
state analysis of all the power converters, which can be to applied to concepts of real-
world electrical and electronics problems & applications.
, UNIT – I
Power semiconductor devices and commutation
circuits
Introduction to power electronics:
Power Electronics is a field which combines Power (electric power), Electronics and Control systems.
Power engineering deals with the static and rotating power equipment for the generation, transmission
and distribution of electric power. Electronics deals with the study of solid state semiconductor power
devices and circuits for Power conversion to meet the desired control objectives (to control the output
voltage and output power). Power electronics may be defined as the subject of applications of solid state
power semiconductor devices (Thyristors) for the control and conversion of electric power. Power
electronics deals with the study and design of Thyristorised power controllers for variety of application
like Heat control, Light/Illumination control, Motor control - AC/DC motor drives used in industries,
High voltage power supplies, Vehicle propulsion systems, High voltage direct current (HVDC)
transmission.
Power Electronics refers to the process of controlling the flow of current and voltage and converting it to
a form that is suitable for user loads. The most desirable power electronic system is one whose efficiency
and reliability is 100%.
Take a look at the following block diagram. It shows the components of a Power Electronic system and
how they are interlinked.
Figure: 1.1. Block diagram of DC power supply
2|Page
