Comparative study of two PWM control wind system based on DFIG and multilevel NPC inverter

Abstract

The present paper is a comparative study of two supplying modes of a wind energy conversion system (WECS) based on Doubly Fed Induction Generator (DFIG). This work is conducted with a multi-level neutral-point inverter (NPC) supplying a DFIG.

The first method based on conventional pulse width modulation (PWM) while the second is based on space vector modulation (SVM). This work aimed to control active and reactive power delivered to the electrical networks and satisfying the distribution requirements. The performance evaluation of each method is performed using spectral analysis to calculate total harmonic distortion (THD). Simulation results have showed that the harmonic rate (THD) is reduced. Therefore; the quality of the produced power by this type of wind chain is efficient. The results obtained with SVM have revealed that this technique uses inverter DC bus voltage more efficiently, reduces power losses and minimizes torque ripples.

Keywords: DFIG, NPC, Multilevel, PWM, THD, Power control