The PVZEN Lab for Energy Communities: Monitoring System for Identification of Photovoltaic/Battery/Converter Energy Models

The main topic of this article is the photovoltaic zero energy network (PVZEN) laboratory, which is an energy community for research purposes established at the Politecnico di Torino campus. The PVZEN laboratory has three users, each equipped with a photovoltaic (PV) generator, lithium batteries with proper electronic converters, and emulators of electric appliances, including heat pumps. These users are capable of exchanging energy based on specific strategies conceived for maximizing the use of renewable energy sources. This work is focused on the identification of energy models that can describe the main components of the community. With the aim of providing reliable models that can enable other researchers to simulate the microgrid in different operating conditions, a monitoring system has been installed close to the relevant commercial devices, to obtain traceable measurements of electrical and environmental quantities. The reference results provided by the monitoring system allowed the multimeter internal to the inverters to be characterized. Furthermore, the dc measurements provided by the monitoring system allowed reliable models to be identified for PV generators and storage systems. For the former, the identified models exhibited rootmean-square errors between measured and predicted energy lower than 1% during a time interval of about three months; for the latter, charge and discharge efficiencies and self-discharge were in agreement with the expected values for the lithium batteries.