Management of a Dual-Bus AC+DC Microgrid based on a Wind Turbine with Double Stator Induction Generator

Abstract

The topology and management of a sustainable dual-bus, AC and DC, microgrid designed to operate connected to a weak grid is presented. AC+DC hybrid microgrids are a robust and cost-competitive solution for poorly connected areas, as can be found in rural or island electrification. The versatile microgrid proposed in this work is developed around a wind turbine based on a particular induction generator with double stator winding and squirrel cage rotor (DWIG). This singular generator is especially suitable for a combined AC+DC coupled microgrid application. One of its stator windings is coupled to the DC bus via a controlled AC/DC converter. The other is directly connected to the AC bus, only during the periods of abundant wind resource. The DWIG is complemented with photovoltaic panels and a hybrid energy storage system, comprising flow batteries assisted by supercapacitors, which converge to the DC Bus. The DC bus exchanges power with the AC bus through an interlinking inverter. The article describes the topology and details the operation of its Supervisory Control system, which gives rise to the five operating modes of the proposed AC+DC DWIG based microgrid. Its performance under different generation conditions and load regimes is thoroughly assessed by simulation.