SOARES, E. L.; http://lattes.cnpq.br/6868300575712352; SOARES, Emerson de Lacerda.
Resumo:
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.