Comprehensive wave-to-wire model and control strategy design for wave energy conversion system

Considering the practical application of wave energy generation, a comprehensive wave-to-wire (W2W) model is proposed in this paper. A novel wave energy conversion (WEC) system with a center of gravity adjustment mechanism is proposed. The proposed W2W model involves the coupling modeling between the absorber and the center of gravity adjustment mechanism as well as the coupling modeling between the absorber and the power take-off (PTO) system. Based on the coupling relationship between the absorber and the center of gravity adjustment mechanism, a resonance control strategy is proposed. In addition, based on the coupling relationship between the absorber and the PTO system, an impedance-matching control strategy is proposed. Combined with the above two control strategies, the two conditions of optimal power capture can be met at the same time, so the WEC system can realize the maximum power point tracking (MPPT). In addition, in order to ensure the safe operation of the WEC system under extreme wave conditions, a power constraint control strategy is proposed to constrain the absorbed power. Finally, the feasibility of the W2W model and the accuracy of the proposed control strategies are verified under the regular and irregular waves. •A comprehensive wave-to-wire model is proposed for the practical application.•A novel WEC with an adjustable natural period characteristic is proposed.•Coupling modeling of the wave-to-grid system is given.•The maximum power point tracking under regular and irregular waves is realized.•A power constraint control strategy is proposed to limit the power of the system.