Proportional — Multiresonant current controller for harmonic elimination in stand-alone DFIG wind power systems

This paper proposes an improved harmonic elimination strategy for the stator output voltage of a stand-alone doubly-fed induction generator (DFIG) feeding a nonlinear load. The proposed elimination method is investigated based on a proportional plus multi-resonant current controller using the stationary reference frame, which is implemented in the rotor-side converter. The aim of the current controller is to achieve the satisfactory performance of rotor currents regulated at harmonic frequencies in order to eliminate fifth and seventh harmonic components in the stator output voltage. As a result, the control scheme allows the DFIG to deliver a pure sinusoidal stator voltage. The proposed control scheme was tested by experiments with 2.2kW DFIG feeding a nonlinear load to verify the feasibility and effectiveness in terms of harmonic compensation performance.