Dual Converter Operating With Floating Capacitors Connecting Open-End Winding Doubly-Fed Induction Generator to the DC Microgrid

This article presents a novel configuration to connect a three-phase doubly-fed induction generator (DFIG) to the dc microgrid. The proposed topology connects an uncontrolled converter and a full-controlled converter in series with the generator stator windings in an open-end winding (OEW) configuration. The full-controlled converter is connected to an independent dc link based on floating capacitors. The article discusses the converter operating principles, pulse-width modulation (PWM), DFIG power control, and the floating capacitors' voltage regulation. The work compares the proposed and conventional systems regarding current harmonic distortions, torque ripple, and semiconductor losses. Simulations and experiments show steady-state and transient results for a 0.56-kW DFIG operating at the rated power. Finally, it was verified that the proposed topology presents lower power losses and low-distorted voltages and currents over the DFIG stator windings.