A Hybrid Electromagnetic–Piezoelectric Wave Energy Harvester: Design, Optimisation, and Laboratory Validation

ABSTRACT This study presents a novel hybrid wave energy harvester that synergistically combines electromagnetic (linear alternator) and piezoelectric transduction mechanisms to enhance energy extraction from low‐amplitude ocean waves. The system employs a floating buoy design with two coil‐magnet linear alternators and four piezoelectric transducers (PZTs), uniquely configured to harvest energy during both wave ascent (via both mechanisms) and descent (via alternators only). An optimised rectification circuit minimises diode losses, achieving a peak conversion efficiency. Experimental evaluations under varying wave periods (2–5 s), rise velocities (0.27–0.32 m/s), and load resistances (165–470 kΩ) demonstrate that the linear alternator generates a maximum voltage of 14.30 V and power output of 858.78 µW (with two magnets, 0.27 m/s, 165 kΩ), while the PZTs contribute up to 3.07 V and 28.48 µW (one magnet, 0.32 m/s, 330 kΩ). The hybrid system outperforms standalone designs in power density, demonstrating its potential to sustainably power marine sensors or IoT devices. Key innovations include phase‐dependent energy harvesting and a scalable architecture adaptable to real‐wave conditions.