A simple approach to predictive control for small wind turbines with an application to stress alleviation

Small wind turbines (SWT) generally operate under unsupervised conditions, often exposed to varying environmental conditions including high turbulence and gust levels. While traditional SWT control focuses on maximum power point tracking (MPPT), a reliabilityoriented design should also consider an appropriate strategy for mitigating mechanical loads in the rotor and other structural elements. In the present work, a predictive control-based strategy is presented which allows to upgrade an existing small wind system by implementing a supervisory control considering a joint optimization of output power and the stress in the rotor blades. Innovations include a simple yet robust implementation of an adaptive predictive control for a custom-designed rectifier and the construction of a compound objective function through advanced beam modelling of the rotor blades. The proposed strategy has been demonstrated experimentally using a laboratory test bench, showing a significant reduction of rotor stress while maintaining the SWT near optimal power extraction conditions.