Acionamento e proteção de motor de indução trifásico via microcontrolador com leitura de tensão por meio de dispositivo optoacoplador

Abstract

The three-phase induction motors are widely used in the industry, this fact makes possible to claim that improvements in the protection system, and the increasing of the drive system reliability of these engines are highly technically and economically relevant. This paper presents a design of a microcontroller system for driving and protection of three-phase induction motors, with voltage measurement through an optocoupler device. To this, triacs optocouplers have been used in multiplexing of three-phase voltages, providing the measurement of phases by only one channel of the microprocessor, and an device for processing the sinusoidal power signal, transforming it into DC voltage. The drive system is designed to provide a direct match with star-delta switch or compensator switch, automatically. The objective of protection system is to protect the motor against voltage disturbances such as: i) voltage unbalance ; ii) temporary undervoltage; iii) temporary voltage increasing; and iv) phase failure.