Conversores estáticos com controle digital para aplicações em sistemas monofásicos.

Abstract

This work deals w i t h control strategies of static converters for single-phase systems. The proposed strategies are based on a vector model for representing the single-phase system. These strategies include the current control and the voltage control that provide high power factor and minimize the harmonic distorlion. The development of the vector model has required the introduction of a virtual single-phase circuit to create the quadrature axis of the vector framework. Reversible AC/AC and AC/DC/AC static converters have been considered in this work. The transient and steady-state characteristics of the conversion systems have been investigated. In the steady-state characteristics, the influence of the values of the parameters of the passive elements (resistances and inductances) over the power factor control and the control of the voltage of the DC link bus was studied. In the case of the AC/DC and AC/DC/AC converters, the steady-state also includes the evaluation of the capacitor current and 1 lie harmonic components resulting from the modulation of the switch voltage. To reduce lhe cost of lhe conversion system based on the AC/DC/AC converter, the concept of sharing one leg is investigated. The shared leg is used either by the input rectifier and the output inverters employed to supply the loads. The generation of the gating signals is done using scalar and vector pulse width modulation techníques conceived for each one of the configurations being studied. The work presents results obtained from digital simulation as well experimental results obtained with a Iaboratory prototype in which ali the proposed strategies were for ali the configurations. The experimental results were satisfactory and demosntrate the correctness of the proposed methodology.