Design optimization of an electric energy production system for power supplying the nodes of wireless sensor networks

Abstract

The widespread utilization of the Wireless Sensor Networks (WSNs) that are power supplied by Renewable Energy Sources (RES) is now leading scientific research towards the development of innovative sizing optimization techniques and configurations that aim in the service of multi-criteria objectives of economical and/or technical nature. The most frequently used ones have to do with the minimization of the overall cost and the maximization of the overall system efficiency, in terms of energy redundancy and operational reliability. Sizing optimization techniques are being introduced, where there is a tradeoff amongst similar to the aforementioned criteria that often contradict to each other (e.g. reliability is improved when economical cost or energy redundancy are increased). In this thesis, two complementary design optimization methods (a circuit level and a system level study) are presented for deriving the optimal configuration of the RES based energy production system of a WSN node, such that its total lifetime cost is minimized, while simultaneously guaranteeing that the data acquisition equipment is uninterruptedly power supplied during the entire year. The experimental results verify that, by applying the design variables as they were derived by the proposed optimization techniques at both the circuit and the system level, RES-based power-supply structures with a lower lifetime cost and higher power-processing efficiency are derived, compared to the non-optimally designed configurations. The design optimization and experimental results indicate that by using the proposed techniques, the total cost of the RES-based power supply system is reduced by 15.7 % and the DC DC converter efficiency is increased by 5.5 % compared to the corresponding results obtained by non-optimized power-supply structures.