Field-Oriented Control and Harmonic Analysis of Standalone DFIG-DC System

This paper focuses on the simulation and experimental results of a standalone Doubly Fed Induction GeneratorDC Link (DFIG-DC) System. The proposed configuration is very suitable for the High Voltage Direct Current (HVDC) transmission. In the DFIG-DC energy topology, a diode rectifier is used to connect the stator side to the DC link while the rotor side is connected to a DC voltage through a Pulse Width Modulation (PMW) power converter. The Field Oriented Control (FOC) strategy is the chosen control method of the proposed DFIG-DC system, including relatively simple and effective first order Sliding Mode Controllers (SMC). The incorporation of a diode rectifier in a standalone DFIG-DC system introduces significant harmonic distortion in current, voltage, and torque waveforms. This phenomenon not only degrades power quality but also necessitates the DFIG to supply reactive power, affecting system efficiency. To address these challenges, the implementation of a Shunt Active Filter (SAF) between the stator windings and the diode rectifier presents a promising solution. The objective of this paper is to conduct a harmonic analysis aimed at minimizing harmonic currents while maintaining the DC voltage and stator frequency close to their reference values.