Conversores duais para conexão do gerador de indução duplamente alimentado à rede em corrente contínua.

Abstract

The doubly-fed induction generator (DFIG) is widely used in wind energy conversion systems connected to the three-phase power grid. However, the search for systems that interconnect diferent types of loads, batteries, and power sources, has given rise to interest in energy conversion systems connected to the direct current (DC) grid. In this work, three diferent converters are proposed to connect the DFIG to the DC grid. The presented systems are based on open-end converters connected to the generator stator windings, using diferent combinations of controlled-, uncontrolled-, and half-controlled converters. The main advantage of these conĄgurations is the lower voltage stress across each converter switch, when compared to traditional converters, which reduces power losses in the system. The generator model, converter operating principles, control strategies, and pulse width modulation (PWM), are presented. The discussed conĄgurations are compared with traditional converters in terms of the number of components, minimum required DC -link voltage, current harmonic distortions, torque ripple, and semiconductor power losses. Simulations and experimental results are presented to validate the proposed conĄgurations, showing both steady-state and transient results. Finally, this work shows that the proposed dual converters have lower current harmonic distortions, torque ripple, and power losses than the traditional conĄgurations, despite the larger number of switches.