Harmonic analysis and performance improvement of a wind driven double output induction generator

Wind turbines with double output induction generators can operate at variable speed permitting conversion efficiency maximization over a wide range of wind velocities. This paper presents the performance analysis of a wind driven double output induction generator (DOIG) operating at varying shafts speed. A periodic transient state analysis of a DOIG equipped with two converters is carried out using a hybrid induction machine model. This paper simulates the harmonic content of waveforms in various points of the drive at different speeds, based on the hybrid model (dqabc). Then the sinusoidal and trapezoidal pulse-width-modulation control techniques are used in order to improve the power factor of the machine and to weaken the injected low order harmonics to the supply. This is based on the frequency spectrum, total harmonics distortion, distortion factor and power factor. Finally, the advantages of sinusoidal and trapezoidal pulse width modulation techniques are compared.