We present the first piezoelectric energy harvester with a self-sufficient frequency tuning mechanism. The system consists of a frequency tunable piezoelectric generator combined with a control unit made of a low power microcontroller with some peripheral electronics. The deployed generator is an enhanced version of the device presented in [1], manufactured from a triple layer piezoceramic plate. Its relatively large output power (up to 90 μW @ 0.6 g) combined with its efficient low-power tuning mechanism, allowed us to build a device which is not only self-sufficient, but which also delivers up to 90 % of the harvested energy for the operation of the supplied embedded system. The amount of energy required for the largest tuning step is in the range of 200 μJ, which signifies that the recovery will take place within a few seconds. The presented system is able to self-tune its resonance frequency between 188 Hz and 150 Hz (with 2 V to 50 V actuator voltages respectively).
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