04/15/14
“IN THE NAME OF ALLAH
THE MOST MERCIFULAND
THE MOST BENEFICIAL”
04/15/14
POWER ELECTRONICS
Presented By:
Engr.Tafseer Ahmed
BS in Electrical (Electronics) Engineering
CIIT, Abbottabad
a....
04/15/14
What is Power Electronics
Power electronics deals with the
applications of power semiconductor
devices such as Th...
04/15/1404/15/14 4
Relationship of Power Electronics
04/15/14
Elements of Power Electronics
• Analogue circuits
• Control Systems
• Power Systems
• Electronics Devices
• Elect...
04/15/14
POWER ELECTRONICS MAIN AREAS
• As the technology for the power semiconductor devices and integrated
circuit devel...
04/15/14
Diagram Block of Converters
04/15/14
• AC to DC Converters: An AC to DC converter circuit can convert AC
voltage into a DC voltage. The DC output volt...
04/15/14 9
04/15/14 10
04/15/14 11
04/15/14 12
04/15/14
1.Uncontrolled turn on and off (Power Diode)
2.Controlled turn on uncontrolled turn off (Thyristors)
3.Controlled...
04/15/14
COMMONLY USED DEVICES
• Power Diodes
• Power Transistors
• Thyristor Family
• SCR( Silicon Controlled Rectifier)
...
04/15/14
Devices Along with Symbols &
Characteristics
04/15/1404/15/14 16
Power Ratings of Devices
04/15/1404/15/14 17
Ratings of Power Devices
04/15/1404/15/14 18
Applications of Power Devices
04/15/1404/15/14 19
Control Characteristics of Devices
04/15/1404/15/14 20
Control Characteristics of Devices
04/15/1404/15/14 21
Uncontrolled Rectifiers (AC to DC)
( )
2 m
o average
V
V
π
=
04/15/14
Controlled Rectifier( AC to DC)
• AC to DC Converters
-Single phase, half wave AC to DC converter
Input voltage
O...
04/15/14 23
AC-DC Rectifier( Full Wave)
04/15/1404/15/14 24
( ) (1 cos )m
o
V
V average α
π
= +
1 sin 2
(( ) )
22
m
rms
V
V
α
π α
π
= − +
04/15/1404/15/14 25
AC-AC (Voltage Regulator)
1/2
( )
1 sin 2
22
m
o rms
V
V
α
π α
π
  
= − + ÷ 
  
04/15/1404/15/14 26
AC to DC Converters
Single phase, Full wave AC to DC converter
The average output voltage can be found...
04/15/1404/15/14 27
AC to DC Converters
Three-phase, Half wave AC to DC converter
If the phase voltage is : van= Vm Sin(wt...
04/15/1404/15/14 28
AC to DC Converters
Three-phase, Full Wave AC to DC converter
04/15/1404/15/14 29
DC-DC CONVERTER (DC Chopper)
• In many industrial application , DC-DC converter is required to
convert...
04/15/1404/15/14 30
DC-DC CONVERTER (DC Chopper)
Principle Of Step-Down Operation
When the switch SW is closed for a time ...
04/15/1404/15/14 31
The average output voltage is given by :
The average output current is given by :
The rms output volta...
04/15/1404/15/14 32
STEP UP DC to DC CONVERTER
When switch SW is closed for t1, the inductor current rises and energy is
s...
04/15/1404/15/14 33
When this DC to DC converter is turned on “switch SW is closed, the
voltage across the inductor L is :...
04/15/1404/15/14 34
Buck – Boost Regulators
• Abuck–boostRegulatorprovidesanoutputvoltagethatmaybelessthanorgreaterthanthe...
04/15/1404/15/14 35
04/15/1404/15/14 36
DC-AC Converter (Inverter)
1( )
4
0.90
2
s
o rms fundamental S
V
V V
π
− = =
04/15/14 37
04/15/14 38
04/15/1404/15/14 39
Examples of
Some
Applications
04/15/14
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Power electronics overview

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Power electronics overview

  1. 1. 04/15/14 “IN THE NAME OF ALLAH THE MOST MERCIFULAND THE MOST BENEFICIAL”
  2. 2. 04/15/14 POWER ELECTRONICS Presented By: Engr.Tafseer Ahmed BS in Electrical (Electronics) Engineering CIIT, Abbottabad a.tafseer@gmail.com
  3. 3. 04/15/14 What is Power Electronics Power electronics deals with the applications of power semiconductor devices such as Thyristor and transistors for the conversion and control of electrical energy at high power levels.
  4. 4. 04/15/1404/15/14 4 Relationship of Power Electronics
  5. 5. 04/15/14 Elements of Power Electronics • Analogue circuits • Control Systems • Power Systems • Electronics Devices • Electric Machines • Numerical Simulation
  6. 6. 04/15/14 POWER ELECTRONICS MAIN AREAS • As the technology for the power semiconductor devices and integrated circuit develops, the potential for applications of power electronics become wider. The power semiconductor devices or power electronic converter fall generally into four categories : • Thyristor Devices • AC to DC Converter (Controlled Rectifier) • DC to DC Converter (DC Chopper) • AC to AC Converter (AC voltage regulator) • DC to AC Converter (Inverter)
  7. 7. 04/15/14 Diagram Block of Converters
  8. 8. 04/15/14 • AC to DC Converters: An AC to DC converter circuit can convert AC voltage into a DC voltage. The DC output voltage can be controlled by varying the firing angle of the thyristors. The AC input voltage could be a single phase or three phase. • AC to AC Converters: This converters can convert from a fixed ac input voltage into variable AC output voltage. The output voltage is controlled by varying firing angle of TRIAC. These type converters are known as AC voltage regulators. • DC to DC Converters : These converters can converte a fixed DC input voltage into variable DC voltage or vice versa. The DC output voltage is controlled by varying of duty cycle. • DC to AC Converters: These converters can convert a constant DC input voltage into a variable AC voltage with variable frequency.
  9. 9. 04/15/14 9
  10. 10. 04/15/14 10
  11. 11. 04/15/14 11
  12. 12. 04/15/14 12
  13. 13. 04/15/14 1.Uncontrolled turn on and off (Power Diode) 2.Controlled turn on uncontrolled turn off (Thyristors) 3.Controlled turn on and off characteristic (Power Transistor, BJT, MOSFET, GTO, IGBT) 4.Continuous gate signal requirement (BJT, MOSFET, IGBT) 5.Pulse gate requirement (SCR(Silicon-Controlled Rectifier) , GTO) 6.Bidirectional current capability (TRIAC) 7.Undirectionalcurrent capability (SCR, GTO, BJT, MOSFET, IGBT) POWER ELECTRONIC SWITCHING DEVICES
  14. 14. 04/15/14 COMMONLY USED DEVICES • Power Diodes • Power Transistors • Thyristor Family • SCR( Silicon Controlled Rectifier) • SCS( Silicon controlled Switch) • GTO( Gate Turnoff Thyristor ) • The DIAC • The TRIAC • MCT( The MOS-Controlled Thyristor)
  15. 15. 04/15/14 Devices Along with Symbols & Characteristics
  16. 16. 04/15/1404/15/14 16 Power Ratings of Devices
  17. 17. 04/15/1404/15/14 17 Ratings of Power Devices
  18. 18. 04/15/1404/15/14 18 Applications of Power Devices
  19. 19. 04/15/1404/15/14 19 Control Characteristics of Devices
  20. 20. 04/15/1404/15/14 20 Control Characteristics of Devices
  21. 21. 04/15/1404/15/14 21 Uncontrolled Rectifiers (AC to DC) ( ) 2 m o average V V π =
  22. 22. 04/15/14 Controlled Rectifier( AC to DC) • AC to DC Converters -Single phase, half wave AC to DC converter Input voltage Output average voltage : rms value of Output voltage : Waveform of single-phase, half wave AC to DC converter α
  23. 23. 04/15/14 23 AC-DC Rectifier( Full Wave)
  24. 24. 04/15/1404/15/14 24 ( ) (1 cos )m o V V average α π = + 1 sin 2 (( ) ) 22 m rms V V α π α π = − +
  25. 25. 04/15/1404/15/14 25 AC-AC (Voltage Regulator) 1/2 ( ) 1 sin 2 22 m o rms V V α π α π    = − + ÷    
  26. 26. 04/15/1404/15/14 26 AC to DC Converters Single phase, Full wave AC to DC converter The average output voltage can be found from :
  27. 27. 04/15/1404/15/14 27 AC to DC Converters Three-phase, Half wave AC to DC converter If the phase voltage is : van= Vm Sin(wt). The average output voltage for a continuous load current is :
  28. 28. 04/15/1404/15/14 28 AC to DC Converters Three-phase, Full Wave AC to DC converter
  29. 29. 04/15/1404/15/14 29 DC-DC CONVERTER (DC Chopper) • In many industrial application , DC-DC converter is required to convert a fixed-voltage DC source into a variable-voltage DC source. Like a transformer, DC-DC converter can be used to step down or step up a DC voltage source. • Application : Traction motor control in electric automobiles, trolley cars, marine hoists, forklift trucks, mine haulers, etc • Advantages : High Efficiency and fast dynamic response
  30. 30. 04/15/1404/15/14 30 DC-DC CONVERTER (DC Chopper) Principle Of Step-Down Operation When the switch SW is closed for a time t1, the input voltage Vs appears across the load Vo = Vs. If the switch remains off a time t2, the voltage across the load is zero, Vo= 0. The converter switch SW can be implemented by using Transistor, MOSFET, GTO, IGBT, BJT, etc.
  31. 31. 04/15/1404/15/14 31 The average output voltage is given by : The average output current is given by : The rms output voltage is given by : = Where : T is the chopping period k = t1/T is the duty cycle f = 1/T is chopping frequency
  32. 32. 04/15/1404/15/14 32 STEP UP DC to DC CONVERTER When switch SW is closed for t1, the inductor current rises and energy is stored in the inductor L. If the switch SW is opened for time t2, the energy stored in the inductor is transferred to load through diode D1and the inductor current falls.
  33. 33. 04/15/1404/15/14 33 When this DC to DC converter is turned on “switch SW is closed, the voltage across the inductor L is : And this gives the peak-to-peak ripple current in inductor as The average output voltage is :
  34. 34. 04/15/1404/15/14 34 Buck – Boost Regulators • Abuck–boostRegulatorprovidesanoutputvoltagethatmaybelessthanorgreaterthantheinputvoltage-hencethename"buck-boost";the outputvoltagepolarityisoppositetothatoftheinputvoltage.thisregulatorisalsoknownasan invertingregulator. • Thecircuitoperationcanbedividedintotwomodes.duringmode1,transistorQ1isturnedonanddiodeDmisreversedbiased.theinputcurrent, whichrisesflowsthroughinductorLandtransistorQ1.Duringmode2,transistorQ1isswitchedoffandthecurrent,whichwasflowingthrough inductorL,wouldflow throughL,C,Dm,andtheload.TheenergystoredininductorLwouldbetransferredtotheloadandtheinductorcurrent wouldfalluntiltransistorQ1isswitchedonagaininthenextcycle.Theequivalentcircuitforthemodesareshowninthenextslide.
  35. 35. 04/15/1404/15/14 35
  36. 36. 04/15/1404/15/14 36 DC-AC Converter (Inverter) 1( ) 4 0.90 2 s o rms fundamental S V V V π − = =
  37. 37. 04/15/14 37
  38. 38. 04/15/14 38
  39. 39. 04/15/1404/15/14 39 Examples of Some Applications
  40. 40. 04/15/14
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