Design and Simulation of MEMS based Inertial Electromagnetic Harvester

Abstract

Due to the advent in low power wireless electronics, devices are becoming compact and power requirements have reduced to the levels of microwatts. So intensive research is being carried on to scavenge energy from ambient sources found in environment to power portable electronics and ultra-low power wireless sensors by external sources. This thesis investigates the development of one of the technique of harvesting electrical energy from vibrations based on the Faraday's law of electromagnetic induction. Focus was to design a harvester completely compatible with MEMS fabrication techniques, can work on multiple frequencies and to take advantage of magnetic flux distribution of an array of permanent magnets in the specific direction (also called Active side) by using Halbach Array of magnets. The micro fabricated coils connected in series with each other are placed towards an Active side. Finally, the proposed design resulted in a maximum output voltage of 18mV with a maximum power of 0.53nW at a resistive load of 98kΩ and frequency of 40.7Hz.