A novel piezoelectric energy harvester designed for single-supply pre-biasing circuit

Abstract

In this paper, the design and test of a novel screen printed piezoelectric energy harvester for the single-supply pre-biasing (SSPB) circuit is presented. It was demonstrated previously that by using the SSPB circuit, power delivered to the load was over three times greater than that in the case of using a bridge rectifier circuit. For maximum power extraction from energy harvesters using the SSPB circuit, the SSPB switches must be triggered when the piezoelectric beam reaches its maximum point of displacement. These points coincide with the peaks and troughs of the voltage across the piezoelectric material, thus accurate peak detection is required. A new design of piezoelectric energy harvester was presented to integrate a sensing piezoelectric component with the main piezoelectric layer for energy harvesting. Maximum power generation by SSPB requires the sensing voltage to be in phase with the generating voltage in order to correctly detect the peaks. However, the difference in areas between the sensing piezoelectric component and the energy harvesting piezoelectric component leads to a difference in capacitance that causes phase shift between the two signals. To overcome this issue, impedance matching was performed. Simulations and experimental rests were presented.