Performance evaluation of low-power wireless sensor node with hybrid energy storage

In this paper, we evaluate the performance of low-power energy-harvesting wireless sensor node (SN) which has hybrid energy storage unit (ESU) for monitoring applications. This hybrid ESU has super capacitor (SC) as well as thin film battery (TFB) for energy storage. After the deployment of SN, temporal energy outage (TEO) occurs when the stored energy in ESU falls to a minimum level due to uncertain energy-harvesting process and leakage of energy, rendering it unable to transmit information to base station. In this paper, we estimate the duration to reach TEO state which is an important parameter for evaluating the performance of the hybrid ESU. The proposed model considers variation of leakage energy in SC. We also determine design perspectives of hybrid ESU for different range of performance parameters to maximize the performance criteria. Further, given total cost constraints, we determine the SC and TFB capacity that optimizes the performance criteria. The analytical results are validated by Monte Carlo simulation using MATLAB. The estimated TEO duration can ensure precautions in monitoring applications.