A Novel Vector-based Hysteresis Current Regulator for Doubly-fed Induction Generator Wind Turbines under Non-ideal Supply Conditions

Abstract

This paper proposes a novel vector-based hysteresis current regulator (VBHCR) in the rotor-side converter of doubly-fed induction generator (DFIG) based wind turbine to enhance its operation under non-ideal supply voltage conditions. First, the induction generator is modelled using the 'gamma-form' equivalent circuit and the stator-voltage-oriented vector control of DFIG is introduced. Then, the principle and practical implementation of the proposed VBHCR in the rotor-side converter of DFIG is presented. This current regulator employs two sets of hysteresis comparators working in three-phase and rotor reference frames, integrated with a switching table. Compared to the commonly-used proportional-integral current regulators, it reveals very fast transient response with a simple control structure. Simulation results, obtained for a 1.5 MW DFIG, show the validity of the proposed control scheme under normal operation conditions, as well as its desirable steady-state performance. Furthermore, the advantages of the proposed current regulator under non-ideal supply voltage conditions (including unbalance and harmonic distortions) are illustrated.