Sistemas de acionamento de máquinas de indução: controle indireto orientado pelo campo independente da velocidade e da constante de tempo rotórica e eliminação da tensão de modo comum.

Abstract

In this work two distinct subjects concerning induction motor drive systems are studied: indirect field oriented control independent of speed and rotor time constant and elimination of common mode voltage. The proposed control of the induction motor is based on indirect field oriented control (IFOC) in which the rotor flux and torque are decoupled. The elimination of the speed sensor is achieved from the estimation of the rotor flux speed employing four models. These strategies also permit control the induction motor independently of rotor time constant. For the estimation are employed four distinct models: d-axis voltage model, q-axis voltage, reactive power model and active power model. The common mode voltage in induction motors results of using voltage-source PWM inverters for its feedind. This voltage is responsible for premature mechanical damage. For reduction or even the elimination of the common mode voltage is employed a fourphase induction machine. Thus, it was necessary the modeling of the four-phase machine and development of new modulation strategies. A four-phase induction machine was build for the experiments with the proposed modulation strategies.