The document discusses various types of rectifier circuits including uncontrolled and controlled single phase and three phase rectifiers. It also discusses different power electronic converters such as inverters, choppers, and cycloconverters. Key devices for power electronics applications discussed include transistors, MOSFETs, IGBTs, and thyristors. Application areas mentioned include UPS, HVDC transmission, and motor drives. The document provides circuit diagrams, operating principles, and example calculations for different power electronic converters.

1. Uncontrolled & controlled
Rectifiers
Engr. Jahangeer badar soomro

3. CLASSIFICATION OF RECTIFIER
CIRCUITS
1. Single Phase Half Wave Uncontrolled
Rectifier
2. Single Phase Full Wave Uncontrolled Rectifier
3. Three Phase Full Wave Uncontrolled Rectifier
4. Single Phase Half Wave Controlled Rectifier
5. Single Phase Full Wave Controlled Rectifier
6. Three Phase Full Wave Controlled Rectifier.

4. Single Phase Half Wave Uncontrolled Rectifier

5. Single Phase Full Wave Uncontrolled Rectifier
using center tap

6. Single Phase Full Wave Uncontrolled Rectifier
using Bridge

17. Important Question
• Explain the operation of single phase half
wave converter with RL load with the help of
circuit diagrams and waveforms. Also discuss
that why flywheel diode is connected in such
type of circuits.
• https://www.youtube.com/watch?v=F57tKwX
63M0

23. Also discuss that why flywheel diode is connected in
such type of circuits

31. Single Phase Full Wave Controlled Rectifier Using Center tap/Two
Pulse Converter/Mid point Converter

38. Single Phase Full Wave Controlled Rectifier
Using Bridge

42. Single Phase Full Wave Controlled Rectifier
Using Bridge
• You guys now know very well about this circuit
that how it will operate.
• This is our today lab.
• Design this circuit in MATLAB. And show the
satisfactory results.

43. Three Phase Full Wave Uncontrolled Rectifier
• https://www.youtube.com/watch?v=Ij9aCSC8
QBY
• It is your assignment to cover three phase
uncontrolled rectifier from this video.
• Very easily explained and informative.
• You must listen this video.

44. Three Phase Full Wave controlled Rectifier
• https://www.youtube.com/watch?v=Ij9aCSC8
QBY
• It is your assignment to cover three phase
controlled rectifier from this video.
• Very easily explained and informative.
• You must listen this video.

45. AC VOLTAGE
CONTROLLER/REGULATOR.
ENGR.JAHANGEER BADAR

55. DC TO DC CONVERTER
OR
CHOPPER
ENGR. JAHANGEER BADAR SOOMRO

59. Efficiency & Power Losses
• Efficiency is a good measure of the success of a given
converter technology.
• With very small amount of power lost, the converter
elements can be packaged with high density, leading to a
converter of small size and weight, and of low temperature
rise.
• How can we build a circuit that changes the voltage, yet
dissipates negligible power?

76. Linear Regulators Vs Switch Mode
Conversion Converter
• Linear Regulators are inefficient
• Linear Regulators have a high drop out voltage.
• They are limited to output voltage smaller than input
voltage .
• Linear regulators can however provide a very high
quality output voltage but they are used for application
of low power level as low drop-out-voltage voltage
regulators.
• At higher power levels switching regulators are used.
• Switched mode conversion offers you high efficiency as
discussed in class. (Due to switching phenomenon)

81. Linear Regulators Vs Switch Mode
Conversion Converter
• A 7 minute video comparing beautifully linear
regulator vs switch mode conversion
converter.
• https://www.youtube.com/watch?v=giGRrOD
KJSE

82. Principle of Step Down
Chopper

86. Design procedure for Buck Converter
• Calculate D to obtain required output voltage.
• Select a particular switching frequency:
– –preferably >20KHz for negligible acoustic noise
• Higher fs results in smaller L, but higher device losses.
– Thus lowering efficiency and larger heat sink.

87. Design procedure for Buck Converter
• Inductor requirement
• C Calculation
• Possible switching devices: MOSFET, IGBT and BJT. Low power
MOSFET can reach MHz range.
𝑟 =
1 − 𝐷
8𝐿𝐶𝑓2
𝐿 ≥ 𝐿 𝑚𝑖𝑛 =
1 − 𝐷
2𝑓
𝑅

90. Example-2
• A buck converter has an input voltage of 50V and output of 25V.
The switching frequency is 10KHz. The power output is 125W. (a)
Determine the duty ratio, (b) value of L to ensure continuous
current, (c) value of capacitance to limit the output voltage ripple
factor to 0.5%.
90
Solution
(a) output voltage
𝑉𝑜 = 𝐷𝑉𝑠
(b) Value of L
𝐷 =
𝑉𝑜
𝑉𝑠
𝐷 =
25
50
= 0.5
𝐿 ≥ 𝐿 𝑚𝑖𝑛 =
1 − 𝐷
2𝑓
𝑅
𝐿 ≥ 𝐿 𝑚𝑖𝑛 =
1 − 0.5
2 × 10𝐾
𝑅
𝑃𝑜 =
𝑉2
𝑅

91. Example-2
• Resistance is calculated as
• L must at least be 10 times greater than Lmin.
91
𝑅 =
𝑉2
𝑃𝑜
=
252
125
= 5Ω
𝐿 ≥ 𝐿 𝑚𝑖𝑛 =
1 − 0.5
2 × 10𝐾
× 5
𝐿 ≥ 𝐿 𝑚𝑖𝑛 =
2.5
20𝐾
= 125𝜇𝐻
𝐿 = 1.25𝑚𝐻

92. Example-2
• Value of capacitance to limit the output voltage ripple factor to
0.5% can be calculated using following equation.
92
(c) Value of C
𝑟 =
1 − 𝐷
8𝐿𝐶𝑓2
0.005 =
1 − 0.5
8 × 1.25𝑚 × 𝐶 × (10𝐾)2
𝐶 =
1 − 0.5
8 × 1.25𝑚 × 0.005 × (10𝐾)2
𝐶 =
0.5
5000
= 100𝜇𝐹

114. Step-Up Converter (Boost Converter)
• Boost Converter Design
• Minimum inductor value
• Capacitor Value
𝐿 𝑚𝑖𝑛 =
𝐷(1 − 𝐷)2
𝑅
2𝑓
𝑟 =
𝐷
𝑅𝐶𝑓

116. http://www.learnabout-
electronics.org/PSU/psu33.php
Buck-Boost Converter
Please refer to following link for excellent
material on buck-boost.

117. Concept Of Commutation
Engr. Jahangeer Badar Soomeo

123. Power Converters
Engr. Jahangeer Badar Soomro

128. One particular reason why you need Power Electronics is that you do not have DC
transformers and AC batteries.

134. DC TO AC CONVERTER
OR
IINVERTER
ENGR.JAHANGEER BADAR

135. WHAT IS INVERTER?

137. • Thyristor based inverters are used for high
power applications.
• For low and medium power inverters fully
controlled devices such as Power BJT and
Power Mosfet, IGBT, GTO, SIT are used. In
addition to having fully controlled these
devices high switching frequencies.
• Therefore these devices may be employed
very efficiently in inverters where the output
voltage is controlled using PWM techniques.

146. TYPICAL APPLICATIONS
– Un-interruptible power supply (UPS)
146

147. TYPICAL APPLICATIONS
– HVDC (High Voltage Direct Current)
147

148. Types of Inverters
• There are three basic types of dc-ac converters depending on
their AC output waveform:
– Square wave Inverters
– Modified sine wave Inverters
– Pure sine wave Inverters
148

149. Square Wave Inverters
– The square wave is the simplest and cheapest type, but nowadays it
is practically not used commercially because of low power quality
(THD≈45%).
149

150. Modified Sine wave Inverters
• The modified sine wave topologies provide rectangular pulses with
some dead spots between positive and negative half-cycles.
• They are suitable for most electronic loads, although their THD is
almost 24%.
• They are the most popular low-cost inverters on the consumer
market today,
150

151. Pure Sine Wave Inverters
– A true sine wave inverter produces output with the lowest total
harmonic distortion (normally below 3%).
– It is the most expensive type of AC source, which is used when
there is a need for a sinusoidal output for certain devices, such
as medical equipment, laser printers, stereos, etc.
– This type is also used in grid-connected applications.
151

152. Simple square-wave inverter
• To illustrate the concept of AC waveform generation

153. AC Waveform Generation

154. AC Waveforms

155. Output voltage harmonics
• Harmonics may cause degradation of equipment
(Equipment need to be “de-rated”).
• Total Harmonic Distortion (THD) is a measure to
determine the “quality” of a given waveform.
155
𝑇𝐻𝐷𝑣 =
𝑛=2
∞
𝑉𝑛,𝑅𝑀𝑆
2
𝑉1,𝑅𝑀𝑆
𝑇𝐻𝐷𝑖 =
𝑛=2
∞
𝐼 𝑛,𝑅𝑀𝑆
2
𝐼1,𝑅𝑀𝑆

156. Fourier Series
• Study of harmonics requires understanding of wave shapes.
• Fourier Series is a tool to analyse wave shapes.
• Where,
156
𝑣 𝑡 = 𝑎 𝑜 +
𝑛=1
∞
𝑎 𝑛 cos 𝑛𝜃 + 𝑏 𝑛 sin 𝑛𝜃
𝑎 𝑛 =
1
𝜋
0
2𝜋
𝑣 𝑡 cos 𝑛𝜃 𝑑𝜃
𝑏 𝑛 =
1
𝜋
0
2𝜋
𝑣 𝑡 sin 𝑛𝜃 𝑑𝜃
𝑎 𝑜 =
1
𝜋
0
2𝜋
𝑣 𝑡 𝑑𝜃

157. Filtering
• Low-pass filter is normally fitted at the inverter output to
reduce the high frequency harmonics.
157

158. 1-∅ Voltage source Inverters
• Single phase voltage source inverters are of
two types.
– Single Phase Half Bridge voltage source inverters
– Single Phase full Bridge voltage source inverters
158

162. CycloConverter
Engr. Jahangeer Badar Soomro

181. Power Transistors & Power
MOSFETS
Engr. Jahangeer Badar Soomro

183. INSULATED GATE BIPOLAR
TRANSISTOR (IGBT)
IGBT is a voltage controlled device. It has high input
impedance like a MOSFET and low on-state conduction losses
like a BJT.
Figure below shows the basic silicon cross-section of an IGBT.
Its construction is same as power MOSFET except that n+ layer at
the drain in a power MOSFET is replaced by P+ substrate called
collector.
n epi

n Bufferlayer

p

p
n

n

Gate Gate
Emitter
Collector
G
E
C

207. http://www.learnabout-electronics.org/Downloads/Fig3116_new.swf
Conceptual understanding of JFET