Super-Twisting Algorithm with Anti-Windup Applied to a Wave Energy Converter

The development of effective control strategies is essential to advance the commercialisation of wave energy converters by maximising energy capture. This study employs a novel control approach integrating an optimal control term, based on so-called moments, with a tracking term rooted in second-order sliding mode control. The optimal term determines the control action to optimise energy conversion under nominal conditions and provides an optimal velocity reference. Subsequently, a Super-twisting algorithm is deployed to robustly track the optimal reference. However, challenges of integral windup may arise when employing the Super-twisting algorithm within the tracking loop under conditions of actuator saturation. To address this, the paper implements two anti- windup techniques aimed at mitigating the windup effect in the Super-twisting algorithm. Simulation results validate the effectiveness of the proposed modification to the main control strategy in dealing with saturated actuators.