A new type of time-varying terminal load energy harvester: Design, simulation, and experiments

To achieve stable power output under low-intensity, broadband, time-varying vibrations, this paper proposes a Variable Stiffness Magnetic Oscillation (VSMO) energy harvester. The VSMO energy harvester is based on an integrated concept design, where the end magnet of the basic cantilever beam is replaced by a sliding magnetic element. Utilizing the kinetic energy generated by a magnet sliding in a cavity, this VSMO device achieves broadband energy harvesting without requiring manual adjustments. The working principle of the VSMO was analyzed through dynamic equations, and experiments were conducted to verify the effects of cantilever beam thickness, length, and sliding magnet mass on the output performance. Experimental data indicate that the VSMO can achieve a maximum power output of 47.4 mW, marking a 217.4 % enhancement in power output compared to the original technology. The minimum acceleration required for operation is only 0.05g. The VSMO enables enhanced output power over a broadband frequency range of 1 Hz–30.6 Hz. In addition, the device was able to power commercial sensors and use Bluetooth for data transmission. This device holds promise for condition monitoring in vibration environments, thus facilitating distributed monitoring within the realm of the Internet of Things.