Microcontroller-based single-phase automatic voltage regulator

This paper proposes the design and implementation of a microcontroller-based single-phase automatic voltage regulator (AVR). The basic building blocks for this design include a PIC 16f 628 microcontroller, a triac, a step-up transformer, a zero crossing circuitry and a load voltage sensing circuitry. This design is based on the principle of phase control of ac voltage using a triac. The trigger pulse for the triac is delayed by the microcontroller to provide the desired regulator terminal voltage. This voltage is always sensed and fed back to the microcontroller via a measuring unit to get a continuous control system. One of the intensions to develop this AVR is to use it in domestic heating and lighting controls. It can also be used as an adjustable voltage source by adjusting a variable resistor in the voltage sensing circuitry. It is also intended to introduce a compact AVR and to demonstrate the usefulness of the PIC microcontroller in power control field.