Speed Ripples Effects on the SEIG Performances for Isolated-Site Wind-Turbine Application

For supplying isolated sites in islanding mode or in micro-network, following a conjunction with other source based on renewable energies, the production of wind turbine based electrical energy is mainly supported by self-excited induction generators (SEIG). The monitoring of such system in real time is of great importance since it gives us the opportunity to intervene in the event of fault occurring on the system to fix the undesirable malfunction as soon as possible. In this work, we address the effect of low frequency drive speed oscillations on the quality of the currents absorbed by a resistive load as well as the quality of the instantaneous power delivered by a self-excited squirrel cage machine. In order to finalize our monitoring approach, we have performed several experiments on a laboratory bench while simulating the drive speed with a DC motor. The acquired signals were analyzed in the frequency domain as well as following Park approaches. The obtained results show that despite their weak low extent, these speed ripples affect significantly the quality of the intended power output.