Dear Ahmed Shaaban

The so-called droop control mainly refers to the electric inverters simulating the active power-frequency (P–f) curve and reactive power-voltage (Q–V) curve modulation characteristics of the traditional grid, and making the system voltage and frequency modulation by means of decoupling the droop characteristics.

Kind Regards

Qamar Ul Islam

Dear Ahmed Shaaban ,

The droop control can applied in PV systems on-grid to support voltage problems on Electric Power System, for example.

Dear Ahmed,

Droop control is the most traditional method to control voltage and frequency in both grid-connected and islanded modes.

Taking your microgrid consists of two inverters,

Both inverters can be controlled by droop control, and even you can select inverters contribution to controlling voltage and frequency.

At least one inverter needs to be in a grid-forming mode to generate reference voltage and frequency, similar to synchronous machines; then another will follow references. If you have already a synchronous machine in your system, then both inverters grid-following mode is not a problem.

I hope that answers your questions.

Good luck

I am agree with Md Ruhul Amin sir, but one think I would like to add that most probably droop controlled inverter needs a controllable input source. Please correct if I am wrong. Thanks.

Dear Shamsher Ansari you are not wrong and I agree that the inverter needs a controllable input. However, this can also be represented by transferfunctions having said that, for example, BESS is considered as an input with sufficient stored energy, only the response characteristics are taken into the account.