Modelling and robust control of wave energy converters based on LPV techniques

Wave energy conversion has emerged as a promising renewable energy technology, yet its commercialisation remains hindered by technical challenges, including device control and reliability. This paper presents a control framework which addresses two critical aspects of wave energy converter (WEC) operation: accurate system modelling and robust energy-maximising control. Firstly, a nonlinear dynamical model based on Cummins’ equation is presented, enhanced through a Linear ParameterVarying (LPV) formulation that explicitly incorporates key hydrodynamic nonlinearities, with particular emphasis on viscous drag effects, which can be dominant for typical WEC geometries. Secondly, for control synthesis, a twostage strategy, combining impedance-matching principles for optimal reference generation with robust tracking control, is introduced. The system is reformulated using Linear Fractional Transformations (LFTs) to systematically handle both parametric uncertainties (environmental variations) and non-parametric uncertainties (unmodelled dynamics). Results demonstrate that the proposed approach maintains consistent performance across wave periods from 5-20 seconds while ensuring robust operation under significant uncertainty. In summary, a modular structure with solid theoretical foundations is presented, enabling advancement of WEC technology towards commercial viability with enhanced energy capture and reliability.