Self-Powered Plant Microbial Fuel Cell Monitoring Node with Autonomous Dynamic Capacitance

Plant Microbial Fuel Cells (PMFCs) are at the forefront of green energy production, yet their interaction with the environment is still unclear. On-field monitoring poses a great opportunity to learn more about the in-place behavior of these energy sources, but also presents significant technical challenges if the monitoring is to be executed on PMFC power alone. We present a self-powered, ultra-low power monitoring system that aims to improve the collection of useful information for PMFC research away from mains. We explore the possibilities of simultaneous sensing and energy harvesting by executing converter-driven I/V scanning. We also propose method for integrating intermittent harvesting into the energy conditioning of PMFCs, leading to improved power and energy levels. By supplying the application with our novel autonomous dynamic capacitor bank (CapDYN), we improve the energy utilization efficiency by 93.7% with respect to a fixed capacitor storage, consequentially doubling the throughput of the application tasks. Moreover, CapDYN speeds up the execution of tasks of between 56% and 96% when charging from an empty storage, greatly improving system reactivity and cold start.