Offshore Wind Energy Conversion System Based on Squirrel Cage Induction Generator Connected to the Grid by VSC-HVDC Link

This article deals with offshore wind energy conversion systems based on the squirrel cage induction generator with full scale back-to-back converter link, consisting of machine-side converter, DC-link and High Voltage Direct Current side converter. The machine-side converter is responsible for the maximum power point tracking, while the High Voltage Direct Current side converter is responsible for controlling the active and reactive power supplied to the grid. For connection to the mainland, a monopolar high voltage direct current transmission line with metal return is used with voltage source converters. This system consists of a generation-side converter, generation-side DC-link, high voltage direct current line, grid-side DC-link and grid-side converter. The generation-side converter is responsible for the voltage control on the generation-side DC-link, the active power control delivered to the grid and reactive power control in the PCC, while the grid-side converter is responsible for the voltage control on the grid-side DC-link and the active and reactive power control delivered to the grid. Simulation results have showed that the system is an efficient alternative to offshore wind energy conversion systems.