An Optimized Design of Compact Self-Powered Module Based on Electromagnetic Vibration Energy Harvester Considering Engineering Feasibility

Abstract

Electromagnetic vibration energy harvester (EVEH) is a promising technology for battery substitution to power the widely distributed wireless sensors. However, state-of-art EVEHs fail to satisfy both high output power and high output power density. The current optimization strategies require highly customized designs. All of these impede EVEH from commercialization. Therefore, this paper proposes an engineering applicable optimization approach for EVEH coils based upon comprehensive understanding of the system features and cross-relationships. The optimized coil is revealed under the constraint of EVEH volume for peak power density. This paper firstly reveals that the optimal coil design for maximizing output power and maximizing output power density are not same. The characteristic frequency for planar spring is also investigated to meet the external vibration frequency. A tubular EVEH based self-powered system is design with diameter of 21 mm and total height of 28 mm. The maximum output power of EVEH reaches to 27.2 mW and power density is 3.6 mW/cm3. The designed self-powered module provides sufficient power for the wireless temperature and humidity wireless sensor. The designed prototype has similar volume as AA battery and has almost infinity lifetime at stable vibrations. It is demonstrated to be good candidate of battery replacement.