Correção do fator de potência de cargas monofásicas utilizando microcontrolador

Abstract

In this work, a system for power factor correction was developed and tested, consisting of three main blocks. Initially, a circuit was designed to measure and process the current and voltage signals from the electrical grid, using zero-crossing detectors to identify the phase shift between the signals. The second block was responsible for controlling the acquired data, using a microcontroller programmed to calculate the power factor based on the current and voltage readings. This microcontroller also determined, as needed, the activation of correction capacitors in the grid. The third block was dedicated to activation, where a relay was responsible for connecting the capacitors to the system when the power factor remained below 0.92 for a certain period. The entire process was simulated and later implemented in a functional prototype. The tests demonstrated the effectiveness of the system, with the zero-crossing detectors operating reliably and the current sensor presenting acceptable measurements when compared to an ammeter. The programming performed proved to be efficient, correcting the power factor automatically. Despite small discrepancies between the prototype and simulation results, the system as a whole worked as expected, contributing to improving the system's energy efficiency.