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Power Electronics and Protection Circuits

Semester 2

Power electronics refers to control and conversion of electrical power from one form to another by power semiconductor devices. This course offers a comprehensive coverage of power electronic devices and circuits. It provides a basic knowledge of circuitry for the control and conversion of electrical power with high efficiency. It begins with the introduction of power semiconductor devices, their basic operations and characteristics. The required semiconductor physics background would have been covered in ELET2420 (semiconductor devices) which is a prerequisite for this course. The application of these devices to the design of controlled rectifiers, inverters, choppers, cyclo-converters, and dual converter circuits are presented. Typical commercial and industrial applications along with their waveform analyses are also discussed.  These converters can change and regulate the voltage, current, or power; dc-dc converters, ac-dc rectifiers, dc-ac inverters, and ac-ac cyclo-converters are in common use. Several low and high power applications are included. All high power circuits require some form of cooling and protection from over-current and/or over-voltages. The components, circuit design techniques and application of several cooling and protection circuits are presented.

  • Power semiconductor devices: SCRs (Thyristors), Power Transistors, TRIACS, DIACS
  • Single and 3-phase AC to DC Converters
  • Single and 3-phase DC to AC Inverters
  • Switched and Resonant DC to DC Converters
  • Single and 3-phase AC Power Controllers
  • Choppers and Cyclo-Converters
  • Applications: UPS, Electronic Ballast, Motor Drive, Armature voltage control, field current control, High voltage DC (HVDC) Transmission, Induction Heating; Electric Welding
  • Control of DC drives
  • Protection and cooling of power switching devices: Fuse and circuit breakers; Electromagnetic relays; Solid State Relays; Optical Isolators; Over-voltage protection – MOVs; Over-current protection; Circuit cooling

One 2-hour final exam                                      60%

One 1-hour in-course tests                                            20%

Five Take home assignments (equal weighting)  20%

Learning Objectives: 

After completing this course, students should be able to:

  • Describe operating principle of semiconductor power electronic switches.
  • Describe turn on & turn off methods of thyristor
  • Describe ac phase control method to control output power.
  • Compare and analyze the various types of power converters
  • Develop and quantify common performance objectives for power electronic circuits, such as efficiency, power factor, etc.
  • Develop simple power electronic converter topologies to meet certain functional specifications
  • Analyze power electronic converter operation to develop design guidelines for choice of switching devices and reactive elements
  • Identify and use switching device and reactive component performance characteristics to apply them appropriately in power electronic circuits
  • Design simple closed loop regulators for power electronic converters to meet functional objectives
  • Use simple power electronic converters to design inverters and rectifiers
  • Describe the operating principles of power electronic circuits in motor drives, UPS systems, voltage controllers, induction heating and electric welding
ELET2410 and ELET2420
  • Power Electronics.
    • Singh,M. D. &  Khanchandani, K. B.
    • Tata McGraw Hill – Electrical and Electronics Engineering Series
    • Edition: 2nd
  • DC Power Supplies: Power Management and Surge Protection for Power Electronic Systems.
    • Kularatna, N.
    • CRC Press
    • Edition: 1st (2011)
  • Power Electronics. (Supplemental)
    • Chitode, J. S.
    • Technical Publication Pune
    • Edition: 4th
  • Power Electronics. (Supplemental)
    • Sharma, S. S.
    • Laxmi Publications (India), University Science Press
    • Edition: 1st (2008)
  • Practical power and system protection
    • Hewitson, L. G., Brown, M. & Balakrishnan, R.
    • IDC Technologies
    • Edition: 1st


Internet Resources:

  1. Online Tutorials
  2. Switching Mode Power Supply Design
  3. Online forum on power electronics
Course Code: 
3 Credits
Level 3
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