Permanent magnet synchronous generator for wind turbines: Modelling, control and Inertial Frequency Response

Offshore wind power generation is expected to increase in the following years, but there are still some economic and technical challenges to overcome. Because of the difficult access to the offshore facilities, the reduction of maintenance is an essential point. The use of Permanent Magnet Synchronous Generators (PMSG) is considered a suitable option in this wind farm topology to satisfy this purpose. On the other hand, these generators along with full-rated Voltage Source Converters (VSC) are expected to provide ancillary services for the onshore AC grid. Particularly, Inertial Frequency Response is an interesting option considering the stored kinetic energy in the rotor of the wind turbines. Therefore, in this paper a description of the model and control system of a PMSG using full-rated VSC are reviewed and their Inertial Frequency Response capability is presented through two methodologies. At the end, simulation and experimental tests results are shown in order to compare these two different options and analyse their viability.