The PowerPath project aims to maximise off-grid energy output for rural communities through the delivery of a microgrid interconnecting module featuring remote monitoring and metering for grid stabilisation, along with an innovative solar panel coating that will allow 20-25% increased performance.
The first innovation pillar is a smart Direct Current (DC)-DC power converter.
The second innovation pillar is the State of Charge (SoC) estimation method, as the amount of energy shared by each interconnected nanogrid should depend on the state of charge of its battery. A nanogrid with a fully charged battery will want to inject current in the common bus to “help” other nanogrids and, on the contrary, a nanogrid with a very discharged battery will absorb current from the common bus to be helped by other nanogrids. The interconnection module should be able to accurately estimate the State of Charge of each battery, which is a critical task.
The SoC estimation is operated through a Modified Coulomb Counting Method, based on the measurement and integration over time of the battery current and two reset actions (one for the SoC and one for the battery capacity). This SoC estimation only requires one quick lab test before field installation.
This project aims at developing a State of Charge estimator for lead-acid batteries that is suitable to be embedded in the nanogrid interconnection module firmware.