Power and Voltage Control in a Grid-Connected Microgrid Syst

This paper proposes to use a back-to-back converter as the interlink between a utility grid and a microgrid.
To justify this proposal, two modes of operation are explained
and the benefits of the back-to-back converter over conventional
static switches are shown. In mode-I, the inter-link converter
injects prespecified amounts of active and reactive power to the
microgrid. This mode is identified as PQ control mode. Mode-2 is
the voltage control mode in which, the back to back converter
controls the voltage of the microgrid and maintains the power
quality of the current drawn from the utility grid in spite of nonlinear
and unbalanced loads in the microgrid.