Power-neutral computing for IoT devices

Energy harvesting has shown considerable promise for IoT systems, particularly in applications where battery replacement or recharging is undesirable. However, energy harvesting (often referred to as 'energy-neutral') systems, typically add energy storage (a battery or supercapacitor) to smooth temporal dynamics in source. For many applications where space is premium (e.g. wearable/implantable) this is problematic. In this presentation, I will present the concept of 'power-neutral' computing, where systems operate from the instantaneous available power without requiring energy storage to be added to the system. In particular, I will present a control approach to adapt the power consumption on IoT microcontrollers which uses software-based maximum power point tracking (MPPT) to maximise the extraction and consumption of power from the energy harvesting supply. It does this without any additional hardware being added to the platform, and is the first MPPT approach we are aware of that performs this using only software. The MPPT approach achieves this by leveraging the opportunities provided by power-neutral computing, and operates by adaptively adjusting properties of the control algorithm. Practical validation of the power-neutral approach demonstrates successful operation without added energy storage, and allows execution of nearly 50% more instructions compared to static approaches