Contribuição ao estudo dos sistemas de acionamento de máquinas assíncronas hexafásicas.

Abstract

The aim of this work is to contribute to develop six-phase induction motor drive systems. To achieve this goal advantages related with number of phases are exploited. Some of these advantages are: more control option, improved power range, well conditioned torque and high reliability when compared with a three-phase motor drive systems. Details about dynamic and steady-state models as well as leakage inductance are addressed. Analysis of these models addressed to evaluate mmfs allow to highlight the main characteristics of the most well known six-phase machines. For both machines parameters estimation of the continuous models are proposed. The procedure allow estimation of stator resistance and leakage inductance while the machines run without speed disturbance. Simulation and experimental estimation results are evaluated taking into account building characteristics of each machine. Pulse width modulation (PWM) strategies are proposed. They are evaluated in respect to harmonic distortion. Common-mode voltage reduction strategies are proposed. The strategies are ranked based on WTHD and torque oscillation. Four new reduced component six-phase induction motor drive are evaluated. The main characteristic of such topologies is to use the stator windings as boost inductors. The way that windings are arranged is relevant to achieve a variable decoupling and power factor as well as torque control. Finally models to represent incipient fault are developed, and short-circuit detection technique are proposed. v