Performance evaluation of multiphase induction generator in stand-alone and grid-connected wind energy conversion system

This study presents a detailed performance analysis of multi-phase (six-phase) induction generator in conjunction with different types of wind energy conversion systems (WECS). It targets to emphasise the advantages of considering an asymmetrical six-phase induction generator (ASIG) in stand-alone, grid-connected fixed speed and grid-connected variable speed operation. Various aspects such as efficiency, reliability and productivity are considered while performing the analysis. In stand-alone mode, reliability and efficiency of the self-excited ASIG are ascertained by disconnecting one of the two three-phase sets connected to a resistive load. In grid-connected fixed speed mode, two different scenarios are implemented to pursue the applicability of ASIG. In the first scenario, only one three-phase winding set is connected to the grid and another set is connected to a local resistive load. In the second scenario, both three-phase windings are connected to the grid via Y-Delta/Y three-winding transformer. Variable speed operation in grid-connected mode is accomplished by employing back-to-back pulse-width modulation converters between the generator and grid. In this configuration, ASIG is operated with indirect field oriented control to obtain maximum aerodynamic efficiency. Transmission of active and reactive power is monitored with vector-oriented control. Experimental results of considered scenarios are presented to verify the viability of ASIG in various configurations of WECS.