Brushless Doubly-Fed Reluctance Generator under Voltage Dips for Wind Energy Conversion System: Modelling and Simulation

Abstract

Under current trends in the wind energy market, the Brushless Doubly-Fed Reluctance Generator (BDFRG) is regarded as one of the generators that could replace the Doubly-Fed Induction Generator (DFIG), which dominates the current wind energy market. In various literature, BDFRG is proposed to possess advantages over DFIG under current trends, such as the use of offshore wind and the stricter grid codes, while possessing the advantages of DFIG. Thus, some aspects of BDFRG have been researched; however, other aspects have not yet been investigated, including its behaviour under voltage dips, which is one of the main grid issues for wind energy conversion systems (WECS). This thesis aims, therefore, to investigate the behaviour of BDFRG under voltage dips using simulations, in order to compare the dynamic behaviours of the two generators, DFIG and BDFRG, in four different cases varying in power ratings (4kW and 2MW) and the magnitude of the voltage dips (50% and 95%) under both symmetrical and unsymmetrical voltage dips. The findings of this study show that BDFRG is superior to DFIG under all cases of voltage dips tested. The reasons for these phenomena are explained in the discussion chapter, which is followed by the conclusion and suggestions for future work.