A Virtual Inertia Method for Stability Control of DC Distribution Systems with Parallel Converters

Abstract

DC distribution systems are a typical power electronic system with low inertia, low-rotational kinetic energy, and poor antidisturbance capability when loads fluctuate or parameters change. In this paper, a virtual inertia control with an additional first-order filtering link is proposed on the basis of P-Udc droop control. The results of the simulations and experiments verify that the additional inertia control reduces the voltage change rate and improves the system inertia by adjusting the virtual capacitance value on the DC side of the converter, which can achieve a smoother and more accurate voltage control and suppress the continuous voltage oscillation.

Grid Connected PV Based Grid Forming Inverter with Decoupled DC Bus Controller

“…For that, conventional VSG-based GFM finds application in one station of an HVDC transmission system and in a grid energy storage system interface for the control of active and reactive power [16]. Another type of GFM based on the DC link voltage variation was developed and is mainly designed to regulate the DC link voltage to calculate its inertia and frequency regulation while its active power is determined by the network's active power flow [19]. In this [20] the DC link-controlled GFM was proven to have similar dynamics as SG, though the grid not much was said about the grid synchronization unit.…”