Design and experimental assessment of an electromagnetic energy harvester based on slotted disc springs

Efficient conversion of ambient energy, being intrinsically variable and in the low frequency range is a fundamental issue for the development of self-powered electronic systems. Simple and reliable solutions are based on piezoelectric or electromagnetic transducers. This work presents an innovative electromagnetic vibration-based energy converter, relying on two counteracting slotted disc springs, which originate a low stiffness mechanical system under a given preload. The electromagnetic converter, involving cylindrical permanent magnets, features coils with a peculiar '8' loop configuration, on opposite sides of the magnets. The prototype was built with commercial components and purposely developed parts, manufactured through rapid prototyping. The experimental validation highlights an excellent response, both in terms of the multi-frequency behaviour and with regard to the significant power output also at low input accelerations.