Efficiency-Aware: Maximizing Energy Utilization for Sensor Nodes Using Photovoltaic-Supercapacitor Energy Systems

Abstract

Recently, photovoltaic-supercapacitor-based energy systems have become more and more popular in the design of energy harvesting wireless sensor networks (EH-WSNs) as an alternative to battery power. Existing research on this area mainly focuses on hardware design and the improvement of the charging efficiency. However, energy is wasted not only by the inefficient charging process, but also the inefficient discharging process and energy leakage. Therefore, to maximize node lifetime and energy utilization, all the previous energy loss should be considered. In this paper, we develop realistic hardware models of the complete photovoltaic-supercapacitor energy systems and propose the efficiency-aware, a systematic duty cycling framework to maximize energy utilization. We formalize the maximization problem as a nonlinear optimization problem and develop two efficient algorithms for its optimal solutions. The performance of our approaches is evaluated via extensive numeric simulations, and the results show that our efficiency-aware framework can, respectively, achieve 60% and 56% more active time (i.e. energy utilization) than the fixed duty cycle scheme and leakage-aware, a state-of-the-art scheme for photovoltaic-supercapacitor energy systems.

Long Term Sensing via Battery Health Adaptation

“…The most relevant work to this paper comes from area of adaptive duty cycle [9] and duty cycle maximisation [10], which look at optimisation techniques to ensure energy is most effectively utilised to maximise sensing tasks while ensuring energy generation is greater than energy consumption. However, these work does not consider the dynamic capacity of a battery and therefore could not be applied to optimise battery lifetime.…”

Distributed optimization in energy harvesting sensor networks with dynamic in-network data processing

“…There exist a large body of theoretical and practical research results in EH-WSNs [15], including power management schemes [1], [16], [17], routing [1], sensing [1], [18], [19], and path traveling optimization in WSNs using wireless power transfer [20]. Recent approaches that use Lyapunov optimization techniques [12] for joint power management and network optimization [4], [5], [21], are most relevant to our work.…”

Improving the Output Power Stability of a High Concentration Photovoltaic System with Supercapacitors: A Preliminary Evaluation

“…The charging efficiency of the supercapacitor in the experimental circuit is determined by solar irradiance, temperature, the MPP voltage of the triple-junction solar cell mp , and the supercapacitor voltage . In addition, the charging efficiency is strongly related to the mismatch between mp and [17]. In this study, the triple-junction solar cell and the supercapacitor were directly connected in parallel, and was controlled to approximately equal mp by appropriately adjusting the load resistance.…”