New approach of frequency tuning for kinetic energy harvesters

In this paper a new approach of a frequency tunable operation for energy harvesting systems is presented. For its evaluation two prototypes were manufactured. To reuse the energy present in ambient vibration, these two prototypes are able to convert mechanical into electrical energy. The electrostatic and the piezoelectric transduction principles are realized, which are beside the electromagnetic the principles most commonly used. An analytic description of this type of tunable energy harvester is presented in this paper. It allows calculating the eigenfrequency by varying the position of an auxiliary mass. Additionally, its function principle is verified by two prototypes. They are designed for low vibration amplitudes and low frequencies.