A Wearable Electromagnetic Energy Harvester for Ultra-Low Frequency Vibrations with Enhanced Power Output

In response to the technical bottleneck of low energy output in electromagnetic energy harvesters under low-frequency excitation, this study proposes an electromagnetic vibration energy harvester (VEH) based on a helical gear clutch transmission system. By integrating three key modules—linear-to-rotational conversion, claw clutch, and energy storage/release—this system efficiently converts low-frequency excitations in the range of 0.18-5 Hz into 50 Hz high-frequency unidirectional rotational motion, achieving nearly 270-fold mechanical frequency-upgrading. Experimental results show that the device can maintain a continuous output for up to 30 seconds in an open-circuit state. Under load, the maximum rotational speed reaches 800 rpm, with the single-layer and double-layer generator modules achieving peak powers of 1.3 W and 2.6 W, respectively, and an average power of 140 mW. The compact structural design supports wearable integration, providing an innovative solution for human kinetic energy harvesting and self-powered he Internet of Things (IoT) nodes.