Working on an islanded microgrid consisting of two grid-forming units fed by ideal dc sources and there is a common load. initially, only one unit is supplying the load and the other unit is disconnected. synchronization starts at t=1 s and after a specified synchronization criteria is met, the unit is connected. The problem is that the unit does not contribute in power sharing though it is properly synchronized. The control system includes droop control for power sharing, secondary control for voltage amplitude and frequency restoration, and synchronization loop.

Attached simulation results from MATLAB/SIMULINK

Yellow for first unit initially operating alone

Blue for second unit connected approximately at t=3.5 s

Magenta for load