Weighted DC Virtual Generator Control Scheme for Interlinking Converters in DC Microgrids

This article proposes a new control strategy for power electronic converters interfacing two dc networks. The proposed control, based on a modification of the dc virtual generator concept, has grid-forming capability in both sides of the converter simultaneously without intermediate energy storage device. Departing from the dc virtual generator control concept, capable of controlling voltage in one of the converter sides while withdrawing the power from the other side, an adaptation is done to make it reversible. A priority weight is assigned to each side voltage control. A weight calculation method, proportional to the voltage deviation from its rated value, is proposed. This weight calculation strategy makes the control system to contribute to the side most in need (using voltage deviation with respect to rated value as an indicator of the neediness). The interlinking converter with the proposed weighted strategy is capable of stable work in grid-forming mode at both sides simultaneously, just requiring a grid-feeding converter with
$P/V$
droop to be connected in either side. No control architecture was found in the literature with this capability for dc–dc interlinking converters. The theoretical discussion has been supported with small-signal analysis and hardware-in-the-loop validation.