Sistemas de conversão de energia eólica com conexão à rede monofásica utilizando gerador de indução duplamente alimentado

Abstract

The use of the Doubly-Fed Induction Generator (DFIG) for wind power generation has been consolidated mainly due the possibility to run at variable speed and decoupled active and reactive stator power control. However, there are still few solutions for wind energy conversion systems connecting the DFIG to the single-phase grid. Even the existing solutions in literature either operate at variable speed, or guarantee balanced three-phase machine voltages with constant frequency in order to feed three-phase loads without an additional converter. This work presents three novel wind energy conversion systems topologies, in order to connect the DFIG to the single-phase grid. The proposed systems use bidirectional CA-CC-AC converters with different number of legs that transform the single-phase grid voltage into balanced three-phase voltages at the generator stator terminals,aswellasathree-phaserotor-sideconverterthatguaranteesthegeneratoractive and reactive power control. In addition, a sensorless rotor position estimation technique was developed. Generator and converter models, pulse width modulation (PWM) and control strategies are presented. The comparisons between the topologies are performed in terms of minimum DC-link voltage and the power switches losses. Several scenarios are simulated, with and without connection of three-phase loads to the system, besides the converters power losses study. Experimental results are also presented and discussed, in order to verify the operation of the proposed topologies.