Single phase AC voltage controller

A Single-Phase AC Voltage Controller is a power electronic device used to control the RMS voltage supplied to a load by phase-angle control

Basic Operating Principle

• It adjusts the RMS value of the output voltage by controlling the conduction angle of the AC waveform.
• Uses thyristors (SCRs) or triacs to switch the AC voltage on and off within each half-cycle.

🔧 Types of Control

1. Phase-Angle Control

• Controls the firing angle (α) of the thyristor.
• The thyristor conducts after a delay in each half-cycle.
• Output voltage is a portion of the input sine wave.

2. On-Off Control (Integral Cycle Control)

• Entire cycles of AC are turned ON or OFF.
• Good for heating applications (thermal inertia smooths out output).