Direct regulation of large speed excursions for variable speed wind turbines

In above rated wind speed the pitch control system of a pitch regulated variable speed wind turbine aims to maintain the rotor speed within a permitted range. However, this requirement can be difficult to satisfy during extreme gusts with conventional controllers, particularly for large-scale machines where the pitch actuation capability may be quite limited. This paper investigates the design of a pitch controller for 1 MW variable speed turbine which directly responds to a strong gust by pitching the rotor blades at the maximum permissible rate, thereby exploiting the maximum capability of the actuation system. The performance assessed and compared to that of a conventional pitch controller by simulation studies