Intentional islanding control of a Smart User Network

A Real-Life Application of a Smart User Network

“…The paper presents the experimental results of a real-life DC microgrid, the SUN, as described in Sections 3 and 5. It is worth to underline that the proposed DBS control strategy has been validated by the simulation results illustrated by the authors in [4,6,7,53]. In this paper the aim is to implement the propose DBS in a real-life application (see Section 5), to demonstrate and validate experimentally (see Section 6) the effectiveness of the proposed control strategy and of the simulation model.…”

“…Based on DBS control strategy, the SUN converters respond to the DC bus voltage level, but at the same time change the DC bus voltage level, automatically controlling the other converters in the SUN. The DBS control logic is designed to maintain the power balance and the stable operation of the SUN system in any operating condition, in grid-connected and stand-alone configuration, as illustrated by the authors in References [4,7,53].…”

“…The goal of the PEI control is to regulate the power flow between SUN and grid, as illustrated by the control scheme of Figure 2. The PEI converter operates based on DBS control logic tracking the properly DC bus voltage reference (V DCref ) when the SUN is in grid-connected configuration, otherwise the PEI tracking the AC voltage reference (V ACref ) when the SUN is in stand-alone configuration [53]. The transfer function of the PEI control is G(s) that generate the Sinusoidal Pulse Width Modulation (SPWM) signals to drive the PEI converter.…”

“…Moreover, the ∆ must not be large, since in this case the converters will operate in very different configurations, some with low voltage and high current, others with high voltage and low currents, this will result in low efficiency and possible failures for the converters. Considering the implementation procedure proposed in References [4,7,53], each threshold has been verified also with the help of a DC load flow utilizing a prioritized fashion to maximize the use of RESs. At this point, it is necessary to describe in details each operation mode (see Figure 4), taking into account the sign conventions reported in Table 1.…”

“…In Table 3 the values of DC bus voltage thresholds are reported. The DC bus voltage threshold characterizing each possible operation mode of the SUN can vary respect to the nominal DC bus voltage (Vref) of ±Δ [4,53,56]. In Table 3, the first voltage threshold value equal to 280 V corresponds to the start-up procedure when the SUN must operate in grid-connected configuration: The PEI charges the DC bus operating as a rectifier.…”