Integrating robust lidar-based feedforward with feedback control to enhance speed regulation of floating wind turbines

The structural cost of offshore wind energy can be drastically reduced by the development of floating wind turbines. However, the design of a feedback controller for rotor speed control of such turbines faces fundamental bandwidth limitations because of the presence of nonminimum phase zeros. New developments in lidar technology enable turbines to measure the incoming wind and use the measurements for feedforward control. This paper explores the possibility of combining lidar feedforward with feedback control for floating wind turbines to enhance the speed control performance and increase controller bandwidth without affecting stability. Robust stability and performance of the controllers are investigated. The controllers are validated using the high-fidelity simulation environment FAST for floating turbines with lidar, and enhanced control performance is achieved.