Switchable tribo-electromagnetic composite generator based on magnetic-spring dynamic coupling for low-velocity flow energy harvesting

Abstract

This study introduces a novel switchable energy harvesting composite generator (SEHCG), a groundbreaking solution that integrates a triboelectric nanogenerator (TENG) with an electromagnetic generator (EMG) via a magnetic-spring coupling mechanism. The core mechanism enables automatic switching between TENG (low-speed) and EMG (high-speed) modes, using a 0.5-mm-diameter compression spring, with switching thresholds ranging from 0.181 to 0.212 m s⁻¹. SEHCG captures energy at ultralow flows (≥0.072 m s⁻¹) via the TENG operation. Compared with conventional EMGs, SEHCG dramatically widens the effective flow range by overcoming the low-speed barrier, providing a viable solution for low-velocity marine current energy harvesting.