This document provides an overview of the syllabus for the Power Electronics course. It includes 6 topics: 1) Thyristors and other power semiconductor devices, 2) Controlled rectifiers, 3) Inverters, 4) DC to DC converters, 5) Auxiliary circuits, and 6) Applications of power electronics. Some key concepts covered are half and full bridge inverters, 180 and 120 degree modes of three phase inverters, PWM techniques for inverters, and the differences between voltage source inverters and current source inverters. Recommended textbooks and applications of power electronics such as motor control and power systems are also mentioned.

1. POWER
ELECTRONICS
(TE ELECTRICAL)
By Prof. Shruti Nema
Power Electronics
1

2. Structure
Power Electronics
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3. Examination Scheme
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4. Examination Scheme of PE
Power Electronics
 Theory exam 80
Internal test (02 of 20
marks each)
20
Term work 25
Oral/Practical 25
Total 150
4

5. PE Syllabus (06 topics )
 1 Thyristors:
Basic operation of silicon controlled rectifier, two
transistor analogy, Static and Dynamic
characteristics, Gate characteristics, Firing circuits,
Commutation circuits, Protection circuit of SCR,
Basic operation and characteristic of Triac, GTO,
Diac
Power Electronics
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6. PE Syllabus
 2 Power semiconductor devices:
Basic operation and characteristics of power diodes,
power BJTs, power MOSFETs, IGBTs, Silicon
Carbide (SiC)and GaN devices, Safe Operation Area
(SOA) for each devices. Comparison of devices,
selection of devices for various applications,
conduction and switching losses; Gate Drive
Circuitry for Power Converters and snubber circuits,
heat sinks.
Power Electronics
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7. PE Syllabus
 3 Controlled Rectifiers:
 Single phase rectifiers:
half and full wave rectifiers (mid-point and bridge configuration)
for R and R-L load, freewheel diode, harmonic analysis of input
current and input power factor for single phase fully controlled
rectifier, effect of source inductance (concept only),
 single phase dual converter
 Three phase semi converter and full converter :
with R load, Applications, Numerical for calculation of output
voltage, single phase PWM rectifier, basic working principle and
applications
Power Electronics
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8. PE Syllabus
 4 Inverter:
Principle of operation, Performance parameters,
Single phase voltage source bridge Inverters, Three
phase VSI (120° and 180° conduction mode), control
of inverter output voltage , PWM techniques-Single
PWM, Multiple PWM, Sinusoidal PWM,
Introduction to Space vector modulation, Current
source inverters, comparison of VSI and CSI,
Power Electronics
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9. PE Syllabus
 5 DC to DC Converter:
Basic principle of dc to dc conversion, switching
mode regulators – Buck, Boost, Buck-Boost, Cuk
regulators, bidirectional dc to dc converters, all with
resistive load and only CCM mode, Applications:
Power Factor Correction Circuits, LED lamp driver,
Numerical included
Power Electronics
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10. PE Syllabus
6. Auxiliary Circuits:
 Types of drivers-level shifters, bootstrap drivers,
isolated drivers, Gate Drive circuitry for Power
Converters, methods of current and voltage
measurement, snubber circuits and heat sinks.
Power Electronics
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11. Books for Power Electronics
Power Electronics
 Text books:
 1. “Power Electronics” M.H.Rashid, Prentice-Hall of India
 2. Power Electronics”, Ned Mohan, Undeland, Robbins, John
Wil“ey Publication
 3. “Power Electronics”, M.D Singh and Khanchandani, Tata
McGrawhill
 Reference Books:
 1. “Power Electronics”, P.S Bhimbra, Khanna Publishers
 2. “Power Electronics for Technology”, Ashfaq Ahmed,
Pearson
11

12. Applications of Power
Electronics
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 Motor control- (AC /DC )
 Consumer Applications
 Electric Vehicles
 Power system Applications
 Other industrial applications

13. PE Syllabus 4rd unit
 4 Inverter:
Principle of operation, Performance parameters,
Single phase voltage source bridge Inverters, Three
phase VSI (120° and 180° conduction mode), control
of inverter output voltage , PWM techniques-Single
PWM, Multiple PWM, Sinusoidal PWM,
Introduction to Space vector modulation, Current
source inverters, comparison of VSI and CSI,
Applications.
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14. Inverter
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 Inverter converts dc power to ac power
 Applications –variable speed ac motor drive, Induction
heating, UPS, HVDC transmission, Aircraft power supplies.
 Classification –according to
-Input source (VSI/CSI)
-nature of output voltage waveforms(square, quasi-
square, sinusoidal)
-type of configuration used (bridge, series, parallel)
-type of commutation circuit (class A,B ,C,D,E)
-type of switch

15. Single phase half bridge inverter with
R load
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

16. Waveforms for half bridge inverter with R
load
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17. Single phase half bridge inverter with
RL load
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

18. Waveforms for single phase half
bridge inverter with RL load
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

19. Full bridge Inverter with R load
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20. Waveforms for full bridge Inverter
with R load
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

21. full bridge Inverter with RL load
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

22. RMS output voltage for Inverter
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 Full bridge Inverter
 Half bridge Inverter
𝑉
𝑜,𝑟𝑚𝑠 = [
1
𝑇
2
𝑉𝑠2
𝑑𝑡
𝑇
2
0
]1/2

23. 3 ɸ Inverters
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-DC to AC conversion
- at output three phase AC can be obtained.
Modes of operation
-180° mode of operation
-120° mode of operation

24. 3 ɸ Inverters
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

25. 3 ɸ Inverters
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 A B C
DC
Supply

26. 180° mode of conduction
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I II III IV V VI I II III
 S1
 S2
 S3
 S4
 S5
 S6

27. 180° mode of conduction
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28. 180° mode of conduction
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Incoming
switch
Conducting
switches
Outgoing
switch
Mode I S1 S5,S6, S1 S4
Mode II S2
Mode III
Mode IV
Mode V
Mode VI

29. 180 mode of conduction
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
Incoming
switch
Conducting
switches
Outgoing
switch
Mode I S1 S5,S6, S1 S4
Mode II S2 S6,S1,S2 S5
Mode III S3 S1,S2,S3 S6
Mode IV S4 S2,S3,S4 S1
Mode V S5 S3,S4,S5 S2
Mode VI S6 S4,S5,S6 S3

30. Interval I
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 incoming switch S1
 Conducting switch S5, S6, S1
 A B C

31. Interval I (Phase voltage and Line voltage)
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 VAN =Vdc/3 I=2Vdc/3R
 VBN =-2Vdc/3
 VCN =Vdc/3
 VAB =Vdc
 VBC =-Vdc
 VCA =0

32. Interval II
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 incoming switch S2
 Conducting switch S6, S1, S2
 A B C

33. Interval III
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 incoming switch S3
 Conducting switch S1, S2, S3
 A B C

34. Interval IV
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 incoming switch S4
 Conducting switch S2, S3, S4
 A B C

35. Interval V
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 incoming switch S5
 Conducting switch S3, S4, S5
 A B C

36. Interval VI
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 incoming switch S6
 Conducting switch S4, S5, S6
 A B C

37. Phase voltages, 180° mode of conduction
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38. Line voltages,180° mode of conduction
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I II

39. 3 phase inverter (120° mode of
conduction)
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 Vdc

40. Switching pulses
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 for 120°
Interval I Interval II Interval III Interval IV Interval V Interval VI Interval I
S1
S2
S3
S4
S5
S6

41. Switching pulses for 120° mode of
conduction
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

42. Table for 120° mode of conduction
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Incoming
switch
Conducting
switches
Outgoing
switch
Interval I S1 S6, S1 S5
Interval II S2 S1,S2 S6
Interval
III
S3 S2,S3 S1
Interval
IV
S4 S3,S4 S2
Interval V S5 S4,S5 S3
Interval
VI
S6 S5,S6 S4

43. Interval I, equivalent diagram
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Conducting switches:- S6,S1
VAN= Vdc/2
VBN= -Vdc/2
VCN= 0
VAB= Vdc
VBC=-Vdc/2
VCA=-Vdc/2

44. Interval II, equivalent diagram
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Conducting switches:- S1,S2
VAN= Vdc/2
VBN= 0
VCN= -Vdc/2
VAB= Vdc/2
VBC=Vdc/2
VCA=-Vdc

45. Interval III, equivalent diagram
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Conducting switches:- S2,S3
VAN= 0
VBN= Vdc/2
VCN= Vdc/2
VAB= -Vdc/2
VBC=Vdc
VCA=-Vdc/2

46. Interval IV, equivalent diagram
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Conducting switches:- S3,S4
VAN= -Vdc/2
VBN= Vdc/2
VCN= 0
VAB= -Vdc
VBC= Vdc/2
VCA= Vdc/2

47. Interval V, equivalent diagram
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Conducting switches:- S4,S5
VAN= -Vdc/2
VBN= 0
VCN= Vdc/2
VAB= -Vdc/2
VBC= -Vdc/2
VCA= Vdc

48. Interval VI, equivalent diagram
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Conducting switches:- S5,S6
VAN= 0
VBN= -Vdc/2
VCN= Vdc/2
VAB= Vdc/2
VBC= -Vdc
VCA= Vdc/2

49. Waveforms (Phase and line voltage)
120° mode of conduction
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

50. Performance parameters of Inverters
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Performance of an inverter is usually evaluated in terms
of following parameters:-
 Harmonic factor of nth Harmonic (HFn)
 Total Harmonic Distortion (THD)
 Distortion Factor (DF)
 Lowest Order Harmonic (LoH)

51. Harmonic factor of nth Harmonic
(HFn)
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It is defined as the ratio of the rms voltage of a particular
harmonic component to the rms value of fundamental
component
HFn = Von/V01
Instantaneous output voltage is given by (by applying Fourier
series ):-

52. Total Harmonic Distortion (THD)
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It is defined as the ratio of the rms value of its total
harmonic component (excluding fundamental) of
the output voltage and the rms value of the
fundamental component

53. Distortion Factor (DF)
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Distortion factor indicates the amount of harmonics
that remains in the output voltage waveform after
the waveform has been subjected to second-order
attenuation ( ie divided by )


54. Lowest Order Harmonic (LoH)
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The lowest harmonic with a magnitude greater than
or equal to 3% of the magnitude of the fundamental
component of the output voltage is known as lowest
order harmonic.
Higher the frequency of the LoH, lower will be the
distortion in the current waveform.

55. Control of output voltage of Inverter
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Required because –
- to adjust output voltage of inverter
- if any change in input supply source or change in
load, the output also changes
- If frequency or speed changes, the output of inverter
also changes. (particular in case of speed control of
induction motor by inverter)

56. Control techniques for output voltage
of Inverter
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 External control
 By controling AC output
 By controling DC input

 Internal control
 PWM techniques

57. Control techniques for output voltage
of Inverter
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PWM techniques:
 Single pulse width modulation
 Multiple pulse width modulation
 Sinusoidal pulse width modulation

58. Single pulse width modulation
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

59. Single pulse width modulation
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Only one pulse will be obtained for each half cycle.
-Carrier signal triangular
in nature
-Reference signal
rectangular in nature

60. Single pulse width modulation
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rms output voltage

61. Multiple pulse width modulation
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

62. Multiple pulse width modulation
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63. Sinusoidal pulse width modulation
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

64. Sinusoidal pulse width modulation
( SINPWM )
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 The reference signal is taken as sinusoidal waveform
whereas the carrier signal is taken as triangular
waveform
 The width of pulse in the SINPWM is not equal due to
reference signal is taken as sinusoidal waveform.
 The width of gate pulse is determined by intersect point
of the sinusoidal waveform and triangular waveform.
 The frequency of inverter output voltage depends upon
frequency of reference signal fR and amplitude of
reference signal VR controls the modulation index (M).

65. Space vector Modulation
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 Space vector modulation (SVM) is an algorithm for the
control of PWM. It is used for the creation of AC, most
commonly to drive AC powered motors at varying speeds .
 A 3 phase inverter may be considered as 3 single phase
inverter and each single phase inverter is shifted by 120°.
 Space vector modulation is quite different from PWM
technique

66. Space Transformation
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Any three functions of time that satisfy
can be represented in a two dimensional space.
The coordinates are similar to those of 3ɸ voltage. ua along x
axis, ub and uc shifted by 120°

67. Space Transformation
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68. 8 unique states
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State
no
Switch
state
Vab Vbc Vca
Vector
(rectangular)
Vector
(phasor)
1 1,0,0 Vs 0 -Vs 1 + 𝑗0.577 𝑉
1 =
2
3
∠30°
2 1,1,0 0 Vs -Vs 0 + 𝑗1.155 𝑉2 =
2
3
∠90°
3 0,1,0 -Vs Vs 0 −1 + 𝑗0.577 𝑉3 =
2
3
∠150°
4 0,1,1 -Vs 0 Vs −1 − 𝑗0.577 𝑉
4 =
2
3
∠210°
5 0,0,1 0 -Vs Vs 0 − 𝑗0.577 𝑉5 =
2
3
∠270°
6 1,0,1 Vs -Vs 0 1 − 𝑗0.577 𝑉6 =
2
3
∠330°
7 1,1,1 0 0 0 0 𝑉7 = 0
8 0,0,0 0 0 0 0 𝑉8 = 0

69. Space vector Modulation
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

70. CSI (Current Source Inverter)
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In CSI, input behaves as a current source. The output
current is maintained constant irrespective of load on
inverter and output voltage is forced to change. VSI are
fed from voltage souce, load current is forced to flucuate

71. Waveforms for CSI
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

72. Comparison of CSI and VSI
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CSI drives use inductive energy storage—that is, they use
inductors in their DC link to store DC energy and regulate
current ripple between the converter and the inverter.
Conversely, VSI drives use capacitive storage, with capacitors
in their DC link, which stores and smooths the DC voltage for
the inverter.
Advantage of CSI:-
Disadvantages of CSI:-