I think the main problem in your case is maintaining generation and load balance for which your system has a stable frequency. Normally, if you have a conventional generation (that mainly uses synchronous generators ) are equipped with governors can regulate the frequency effectively.

I suggest you to look at hybrid power system models in SIMULINK and try to learn and modify them from there rather than trying to build from scratch.

Is your grid work with AC or DC?. If AC, so the DC generator should be connected to the grid through a converter

Mohammed Al-Saadi

I used AC not DC. But I didn't understand how to connect the DC generator to grid through converter. Can you give me more details!

Omar H. Abdalla

The research point is about adjusting harmonic of multi-generator standalone power system. And to add a harmonic for the system I used H-bridge thyristor rectifier to be harmonic source (because it is the simplest way to add harmonic). This rectifier isn't efficient as PWM rectifier for the system stability. So, it effected badly on the system stability.

Note: When I connect a small-value load (R,L,C) the stability isn't bad. But for large-value loads the stability is bad.

The DC generator connected to a converter (DC/AC), then you have to use a transformer for the connection point with the grid.