Active shunt filter for harmonic mitigation in wind turbines generators

One of the preferred technologies in variable speed wind turbines (VSWT) is formed by a wind rotor, permanent magnet synchronous generator (PMSG), three-phase bridge rectifier (BR) with a bulky capacitor, and power electronics converter for grid interface. High-intensity, low-frequency harmonic currents flows into the PMSG as electric load has a non-linear characteristic. This paper presents an analysis and simulation of an active shunt filter (ASF) for harmonic mitigation in wind turbines generators. Currents are represented in d-q synchronous reference frame (SRF) and PWM carrier strategy is used to control the active filter. A new scheme to synchronize d-q currents using mechanical rotor angular speed is adopted. A dynamic wind turbine model and the active filter are implemented on software PSIM©. Representative waveforms and spectral analysis is presented. Simulations show that the proposed active filtering configuration can mitigate harmonic content into the PMSG.