Design and performance of a microelectromagnetic vibration powered generator

In this paper we, report on the design, simulation and initial results of a microgenerator, which converts external vibrations into electrical energy. Power is generated by means of electromagnetic transduction with static magnets positioned either side of a moving coil located on a silicon structure designed to resonate laterally in the plane of the chip. The development and fabrication of a micromachined microgenerator that uses standard silicon based fabrication techniques and a low cost, batch process is presented. Finite element simulations have been carried out using ANSYS to determine an optimum geometry for the microgenerator. Electromagnetic FEA simulations using Ansoft's Maxwell 2D software have shown voltage levels of 4 to 9 V can be generated from the single beam generator designs. Initial results at atmospheric pressure yield 0.5 /spl mu/W at 9.81 ms/sup -2/ and 9.5 kHz and emphasise the importance of reducing unwanted loss mechanisms such as air damping.