A very old article from TI may be useful to you:

http://www.ti.com/lit/ml/slup094/slup094.pdf

For your information, there are many other old but useful technical articles about switching circuits and power supply design in the TI website.

Dear Peter,

In AC systems, the droop method is used in both frequency droop and voltage droop. The method has been applied to UPS systems, microgrids, and others.

Usually, frequency droops control active power sharing, and voltage droop controls reactive power sharing.

Here are two useful references:

Lasseter, R.H., "MicroGrids," Power Engineering Society Winter Meeting, 2002. IEEE , vol.1, no., pp.305,308 vol.1, 2002. http://dx.doi.org/10.1109/PESW.2002.985003

Chandorkar, M.C.; Divan, D.M., "Decentralized operation of distributed UPS systems," Power Electronics, Drives and Energy Systems for Industrial Growth, 1996., Proceedings of the 1996 International Conference on , vol.1, no., pp.565,571 vol.1, 8-11 Jan 1996. http://dx.doi.org/10.1109/PEDES.1996.539675

I hope this helps.

Best,

Patricio

Hi I found an article. I hope you may be able to get some idea from this

Fast and adaptive under Frequency Load Shedding and restoration technique using rate of change of frequency to prevent blackouts

an IEEE paper