Model and Experimental Study of Permanent Magnet Vibration-to-Electrical Power Generator

The vibration energy exists widely and is always wasted. Energy harvesting devices that convert kinetic energy into electrical energy have attracted much interest. A variety of vibration driven generators using electromagnetic principles to convert the kinetic energy into electrical energy, are being studied for powering sensors. However, the power supply is always a bottleneck problem to the development of handheld electronic equipments and some other low power electrical apparatus. In this paper, the vibration-to-electrical power generator has been designed and its magnetic field distribution has been analyzed by using Finite Element method (FEM). Then, the input-output model of the generator is built on the basis of vibration equation and law of electromagnetic induction. The calculation result has shown that output voltage of the generator depends on the amplitude, frequency and waveform of a vibration source. A generator prototype has been fabricated and tested at open-circuit and different loads, such as resistances, inductances and capacitances. The comparison of experimental result with calculating one has shown that the model can describe the input-output relation of the vibration-to-electrical power generator.