Load reduction in wind turbines with smart rotors using trial varying iterative learning control law

Control of aerodynamic loads is a crucial issue in keeping wind energy economically competitive with traditional energy sources. This paper continues the investigation of the use of Iterative Learning Control (ILC) for load control in wind turbines with smart devices on rotor blades. A relatively simple computational fluid dynamics model is used to simulate the flow past an airfoil. Assuming no actuator delay, fluctuations in load due to periodic disturbances can be almost completely eliminated by a simple ILC control scheme. In application, however, delay due to the actuators will arise and could have a negative effect on real-time performance and influence the desired attenuation. This paper develops a novel method of using trial varying ILC to improve aerodynamic load performance in the presence of actuator dynamics. The results of a simulation based assessment of the new control system are also given and areas for possible future research discussed.