Improving a Piezoelectric Energy Harvester Output Using a Synchronized Switch Harvesting Design

The purpose of this work will be to simulate the design of a piezo-electric bi-morph using MULTISIM and then verify that simulation using a lead (Pb) zirconium titanite (PZT) bimorph model to verify the output. Piezoelectric energy harvesters undergo spontaneous polarization, based on existing literature. This suggests that the devices can generate an electrical displacement without an external electric field. A mechanical stimulus can be applied to a piezoelectric bimorph which is configured as a cantilever to achieve high bending moments. During the harvesting process, the bimorph is subject to an energy conversion whose efficiency is governed by the electromechanical coupling factor. Regardless of the coupling factor, the amount of extracted energy is still limited by the electrical losses in the external storage circuit. The harvested power has been shown a large increase using a synchronized switch harvesting (SSH) design. This circuit employs a self-switching inductor in parallel with the piezoelectric device’s output to ensure the voltage amplitude always increases in one cycle and that its sign will always match the speed of the bimorph’s displacement. Together this maximizes the transferred energy. This design will be simulated using MULTISIM and then applied to a lead (Pb) zirconium titanite (PZT) bimorph model to verify the output.