Advancements in renewable energy sources, such as solar, thermal or wind, are increasing the attention in autonomous Wireless Sensor Networks (WSN). Everlasting energy harvesting allows long-term operations of wireless nodes, which can extremely reduce the cost of battery charging or replacement. Moreover, it has opened a new paradigm for designing Power Managers in self-powered autonomous nodes. Instead of minimizing the consumed energy to maximize the system lifetime as in battery-powered nodes, the PM dynamically adapts the consumed energy according to the fluctuations of the harvested energy, leading to Energy Neutral Operation (ENO).
Hardware Architecture of our Energy Harvesting Nodes
The GRANIT team activities in EH-WSN aim at designing and implementing new PM able to deal with the environment constraints and ensure ENO by tuning processing and communicating parameters such as
- Radio activity (wake-up interval of nodes)
- Radio transmission power
- Computation/radio trade-off…
WU interval adaptation (red) with respect to harvested power (green) respecting ENO, i.e. the voltage at the supercap (dotted blue) remains between max and min bounds (dotted black)
