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.