Simulation and model verification of shoe embedded piezoelectric energy harvester

As the power required to run micro-electronics circuitry is decreasing these days, an untiring attempt of the contemporary researchers has been to find new environmental energy sources that may have the potential to replace the battery usage in wearable subsystems. In this paper the study of an unobtrusive piezoelectric device has been presented that can be integrated within human shoe-sole, thereby converting a part of the mechanical energy originated from human locomotion into electrical energy for running such low power portable devices and wireless sensors, without affecting the user's gait. To serve the desired purpose, a PZT bimorph and a flexible PVDF stave have been used to harness the heel strike energy and sole bending energy respectively. The proposed system has been mathematically modeled, simulated in COMSOL environment and the results have also been compared with the experimental values. The power output was found to be much lower than the desired one and hence an attempt was made for the enhancement of charge accumulation by parasitic harvesting technique using soft sneakers and an innovative charge extraction circuitry. This provided a considerable amount of power gain, sufficient to run a low-power electronics device.