Development of a photovoltaic low voltage DC microgrid for buildings with energy storage systems

In order to develop a sustainable datacenter, which would help to validate energy management and task scheduling algorithms, a low voltage direct current (LVDC) microgrid (MG) has been deployed in the ADREAM Building-Integrated Photovoltaic (BIPV) of the LAAS-CNRS in Toulouse, France. This MG is composed of a 1 kWp PV source, 300 Ah – 36 V lead-acid batteries, 330 F – 48 V supercapacitor (SC) pack and DC loads (cloud servers, USB chargers, sensors monitoring an apartment...). A very simple and efficient energy flow management strategy, based on the “DC bus signaling” approach has been implemented. It takes advantage of the DC bus architecture and enables a scalable electrical structure constituted of several sources, loads and storage elements easy to connect/disconnect via their converters. The development of this MG put in evidence the need for future theoretical developments regarding the determination of optimal DC bus signaling thresholds.