Simulink_PV block not working if not grid connected

I used P V models from the example microgrid library.slx which i downloaded from resources file of mathworks example 'https://www.mathworks.com/matlabcentral/fileexchange/73139-microgrid-energy-management-system-ems-using-optimization'.

If i use components of the library(PV )without connecting to the grid, it doesn't show steady frequency.Kindy advice how i can connect these resources without utility grid connection and with a stable output power and frequency.