1 | Power Electronics

1. What is Power Electronics? Definition: The study of converting, controlling, and conditioning electric power from one form to another using semiconductor switches. Key Formula (Efficiency): [ \eta = \fracP_outP_in \times 100% ] (Goal: >85% for most converters, often >95%) 2. The Four Basic Power Conversions | Conversion Type | Input → Output | Common Name | Example Application | | :--- | :--- | :--- | :--- | | AC-DC | Mains AC → DC | Rectifier | Phone charger, DC motor drive | | DC-DC | DC voltage (e.g., 12V) → Different DC (e.g., 5V) | Chopper / Regulator | Laptop voltage regulator module | | DC-AC | DC battery → AC sine wave | Inverter | Solar inverter, UPS, EV motor drive | | AC-AC | AC voltage (e.g., 220V) → Different AC (e.g., 110V) | Cycloconverter | AC motor speed control (low freq.) | 3. Key Power Semiconductor Switches (Ideal vs. Real) Ideal switch: Zero ON resistance, infinite OFF resistance, instant switching. Real switches have trade-offs.