A Laboratory-Scale Prototype of a Smart User Network with DBS Control

A Renewable Energy Community of DC Nanogrids for Providing Balancing Services

“…Figure 7 illustrates the case study of this paper: five modern houses or nanogrids, equipped with a set of PV plant installed on the rooftop and a set of lithium-ion batteries. It is worth underlining that the effectiveness of the proposed DBS for a single nanogrid, demonstrating how the single converters interfacing the nanogrid sources (PV plant, battery storage) operates based on the DC bus voltage changes, was reported by the authors in previous papers [10,11,44]. As before mentioned, the effectiveness of DBS is not influenced form the load variability, thus in this paper, the load modeling has not been investigated otherwise faced by the authors in [45,46].…”

“…In [9], a review of AC and DC microgrids, which consider renewable energy resources, storage systems, and loads was shown, then economic, environmental, and technical aspects were considered to carry out a comparison. A DC microgrid mounted with several micro-production systems, storage systems, electric vehicles, and power/heat loads was also presented in [10,11]; the power electronic interface, which joins the microgrid to the utility grid, provides the desired flexibility, power quality, and power flow at the Point of Delivery (POD).…”

“…This logic guarantees communication between the various power converters that interface the sources/storage systems to the DC bus, by means of As anticipated in the state of the art (in Section 2), the DBS control strategy was based on the concept of using charge/discharge levels in order to program single sources according to a distributed logic. This logic guarantees communication between the various power converters that interface the sources/storage systems to the DC bus, by means of the variation of the DC bus voltage, which determines the variation in the behavior of the single power converter [10,11]. The control function of the DBS control logic is distributed among the various micro-source controllers of the nanogrid, as occurs in the case of distributed control.…”

“…This maximum voltage variation was evaluated using a trial-and-error technique. It is worth to note that this voltage variation between two DC bus voltage levels, associated to two consecutive operation modes, must not be very small or large [10,11]: not too small because a change in the operating mode could occur due to measurement errors or due to external disturbances; not too large because the converters would work in operating modes with low voltage levels and high currents and vice versa, this could determine a high probability of failures and low efficiency. Considering the implementation procedure proposed in [42], each threshold is also verified with the aid of a DC load flow and using a priority logic to maximize the use of renewable energy sources.…”