Optimizing the design of wide magneto-mechano-electric generators to maximize their power output and lifetime in self-powered environmental monitoring systems

Abstract

Magneto-mechano-electric (MME) generators are increasingly being investigated as a sustainable power source for Internet of Things (IoT) systems owing to their ability to efficiently harvest electrical energy from stray magnetic field noise. However, to be practical, this technology must achieve a longer lifespan while maintaining high-power output and withstanding magnetic field fluctuations. To address this, extensive numerical simulations and experimental verifications have been performed to amplify the magneto-mechanic vibration by increasing the magnetic proof mass volume, generate high electrical output through a larger active piezoelectric volume, and enhance lifetime by optimizing the cantilever structure in a wide-structural MME architecture. MME generators with a wide and short (WS) trapezoidal structure (WS-MME) have demonstrated excellent performance, with a high output power of 7.4 mW (equivalent power density of 0.58 mW/cm3. Oe) and an excellent lifespan of over 1012 fatigue cycles under a magnetic noise field level of 3 Oe. Moreover, a self-powered environmental IoT sensor node has been demonstrated by continuously powering the multifunctional (temperature, humidity, light, sound noise, UV index, pressure, discomfort index, and heatstroke) sensor and wireless communication systems by utilizing the stray magnetic field noise around the electrical power cables of various home appliances. In conclusion, the combination of a longer lifespan and high-power generation achieved with WS-MME generators is a significant step towards the commercialization of MME generators for powering wireless sensor technology.