One-power-point operation for variable speed wind/tidal stream turbines with synchronous generators

This study presents a new operating scheme for variable speed wind/tidal stream turbines employing synchronous generators. Current maximum power tracking schemes for variable speed wind energy conversion systems rely on periodic comparison of the output power for guiding the direction of maximum power tracking or an online algorithm which continuously provides a generator torque/speed reference corresponding to the maximum power status at different wind speed conditions. The proposed scheme utilises only one-power-point on the maximum power curve. Once the information for the maximum power status of a local wind speed is known, then the wind energy conversion system implements maximum power tracking and constant power control for different wind speed conditions using simple control. The operation strategy is applicable to tidal stream turbines. Simulation results demonstrate the concept.