Energy balance for peak detection method in piezoelectric energy harvester

Abstract

Numerous methodologies using switching circuits for harvesting vibrational energy via piezoelectric materials have been put forth. These methods generally require knowledge of the occurrence of peak deflections in the vibrations, so that the amount of harvested energy can be maximized. Below, a method of peak detection is outlined that satisfies the missing link between mechanical vibrations and systems that harvest energy from those vibrations. The system employs passive differentiation to initially identify peak positions in the time domain, followed by an active zero-crossing detector coupled with a latch circuit to record the peak detection. A microprocessor is used to check the state of the latch and begin harvesting when a peak is identified. The method requires low power for its operation and has wide bandwidth of operation.