Course Introduction to Power Electronics

Prerequisites

• Basic understanding of Electrical Engineering (Network Theory).
• Basic knowledge of Analog Electronics.
• Understanding of Machines and Power Systems.

Overview of Power Electronics

• Power and Electronics are contradictory terms.
• Power Engineering deals with high power (generation, transmission, distribution, utilization).
  • Efficiency is a major concern.
• Electronics Engineering deals with low power applications (in milliwatts and watts).
  • Focuses on minimizing distortion rather than efficiency.

Example: Microphone and Speaker Analogy

• Microphone amplifies sound to speakers.
• The main concern is to transmit the signal distortion-free, not necessarily efficiently.

Definition of Power Electronics

• Application of electronic principles in power conditions to improve efficiency.
• Key focus: Combine electronic principles with power engineering to enhance efficiency.

Basic Structure of a Power Electronic System

1. Source: Can be voltage, current, frequency, etc.
2. Power Converter Circuit: Converts the input to the desired output level.
3. Load: Receives the output.
4. Control Circuit: Compares load values with reference values, adjusts accordingly.

Feedback Control Example

• Motor speed control using the V/f technique.
• Adjusts voltage and frequency based on speed requirements.
• Error signal sent to the power converter for adjustments.

Types of Power Converters

1. AC to DC Converters (Rectifiers)

   • Used in electric traction, battery chargers, and DC drives.
   • Can be controlled (adjustable output) or uncontrolled (fixed output).

2. DC to DC Converters (Choppers)

   • Step down (reduce voltage) or step up (increase voltage) DC signals.
   • Applications: DC drives, subway cars, battery-powered vehicles.

3. AC to AC Converters

   • AC Voltage Regulators: Change voltage while keeping frequency constant.
     • Used in speed control of household fans.
   • Cycloconverters: Change both voltage and frequency.
     • Used for V/f control in large AC drives.

4. DC to AC Converters (Inverters)

   • Convert DC to AC for various applications such as induction heating, UPS, HVDC transmission, and renewable energy systems (solar/wind).

Importance of Power Semiconductor Devices

• Basics of power semiconductor devices and their characteristics will be covered before discussing converters.

Course Materials and References

• Textbooks: P.S. Bhimra and M.H. Rashid.
• Additional references will be provided as needed.

How to Access Course Materials

• Videos and materials will be available in the YouTube channel playlist.
• Description sections under videos will have download links for lecture materials.

Notifications and Queries

• Students can leave comments for queries; responses will be sent via email notification.

Upcoming Lectures

• Next lecture will cover power semiconductor devices, followed by various converter types.