Integrated Energy Storage-Based Low Cost Wave Energy Conversion System for Grid-Forming Applications

This paper presents a cost-effective and robust wave energy conversion system tailored for grid-forming applications. The proposed system employs a permanent magnet synchronous machine as the primary energy conversion interface, coupled with a Lyapunov-based nonlinear controller that governs both torque and speed regulation to ensure stable and responsive operation. To address intermittency in wave energy, a hybrid energy storage architecture comprising a battery and a capacitor is integrated at the dc bus, providing auxiliary power support during low-wave conditions and enhancing the reliability of load power delivery. On the load or consumer side, a similar control framework is deployed to maintain voltage quality, effectively minimizing total harmonic distortion even in the presence of unbalanced or nonlinear load conditions. The complete system architecture is engineered to maintain high operational efficiency and reliability under dynamically changing sea states. Comprehensive simulation studies conducted in MATLAB/Simulink and PLECS validate the performance of the proposed solution, demonstrating its effectiveness in delivering stable power and preserving waveform quality under a wide range of oceanic and load scenarios.