Sistemas de acionamento de baixo custo para motores de indução.

Abstract

This work aims to contribute for making-up the utilization of inductions motor drives to implement low cost sistems for low power applications. The static power converter is implemented by a single-phase rectifier cascaded with a four-switch inverter. The static power conversion is realized in two stages: i) an AC/DC conversion achieved by the rectifier side and i i ) a DC/AC conversion achieved by the inverter. Four types of induction machines are supplied with the static power converter. In the first scheme a standartd three-phase induction machine is employed. In the second the load is a three-phase induction machine where only two windings are used. In the third a standartd two-phase induction machine is employed. In the fourth scheme a singlephase machine is used. This type of machine may be considered as an assimetrical two-phase machine. Three PWM patterns will be adopted to rank the different schemes in terms of efficiency. The control strategies applied to the conventional drives systems are conformed to the respective low cost systems. The vector control of a single-phase machine is also investigated.