Modeling and Optimization of a Solar Energy Harvester System for Self Powered Wireless Sensor Networks

In this paper we propose a methodology for optimizing a solar harvester with maximum-power point tracking for self powered wireless sensors networks (WSN) nodes. We focus on maximizing the harvester’s efficiency in transferring energy from the solar panel to the energy storing device.A photovoltaic panel analytical model, based on a simplified parameter extraction procedure is adopted. This model predicts the instantaneous power collected by the panel helping the harvester design and optimization procedure. Moreover, a detailed modeling of the harvester is proposed to understand basic harvester behavior and optimize the circuit. Experimental results based on the presented design guidelines demonstrate the effectiveness of the adopted methodology. This design procedure helps in boosting efficiency, allowing to reach a maximum efficiency of 85% with discrete components. The application field of this circuit is not limited to self powered WSN nodes, but it can be easily extended also in embedded portable applications to extend battery life.