Electromagnetic generators employing planar inductors for autonomous sensor applications

Autonomous sensors are receiving increasing interest, mostly because they offer flexibility for measurements into inaccessible location. Moreover, measurement application requiring long-lived capability does not commonly match the performance of the batteries. An autonomous sensor consisting of completely embedded structures with no physical links to the outside world, exploiting power from the ambient sources is an alternative solution. An electromechanical power generator is proposed for converting mechanical energy in the form of vibrations available in the measurement environment into electrical energy. The operating principle is based on the relative movement of a planar inductor with respect to permanent magnets. A specific configuration of magnets is proposed and analyzed with the aim to improve the conversion efficiency, increasing the spatial variation of magnetic flux. Furthermore, the proposed configuration can be adopted for its low profile and modularity.