Sistemas de geração de energia elétrica utilizando máquinas de seis fases e fontes primárias controladas e não controladas.

Abstract

This work presents four AC-DC-AC conversion systems utilizing Alternate sixphases eletric machines working as eletric energy generators. The primary source that supplies the energy to the system may be of two different types. The first type is the Controlled Primary Source. In this case, the control system acts in order to adjust the power generated by the electric machine to the power required by an eletric charge. Exemples of this kind of source are the vapor turbines and the gas turbines. The second type is the non-controlled Primary Source. For this type, the control system acts in order to adjust the power required by the electric charge to the generation capability of the eletric machine. A very well-known source of this type is the eolic. The conversion systems are composed of AC-DC-AC converters that make use of conventional topologies as single-phase bridges and single-phase bridge-less converters (a leg formed of controlable switches and the other leg formed of diodes) and the three-phase three-leg conventional topology. The rectifier, connected to the machine, is composed of the single-phase bridge converters or by the bridge-less converters or by the conventional three-phase converter. On the other hand, the inverter, connected to the grid or to a hreephase electric charge, is composed of series-connected single-phase bridge converters or by the three-phase conventional converter series-connected to single-phase bridge converters. The series-connection of these converters permits to obtain multilevel converters. That is, the voltages generated by these converters present a higher number of levels if compared to the voltages generated by the conventional converters, bringing the possibility to decrease the harmonic distortion of voltages and currents. Besides, the seriesconnection permits the reduction of the DC-link voltage values, reducing the stress over the semiconductor switches and the switching losses. The PWM and control strategies of the proposed systems are discussed. Simulation and experimental results are presented.