METHOD AND APPARATUS FOR COORDINATION OF GENERATORS IN DROOP CONTROLLED MICROGRIDS USING HYSTERESIS

1 . A method for autonomously operating a microgrid power generator comprising:

obtaining a first measurement of at least one grid parameter of a microgrid transmission line coupled to a power generator in a microgrid;

comparing the first measurement to a turn-on threshold;

initiating, when the first measurement satisfies the turn-on threshold, power generation by the power generator;

obtaining, after initiation of the energy generation, a second measurement of the at least one grid parameter of the microgrid transmission line;

comparing the second measurement to a shut-down threshold that is greater than the turn-on threshold; and

stopping, when the second measurement satisfies the shut-down threshold, the power generation by the power generator.

2 . The method of claim 1 , wherein the at least one grid parameter is the frequency of the microgrid transmission line.

3 . The method of claim 2 , wherein the shut-down threshold exceeds the turn-on threshold by an amount greater than the magnitude of an expected frequency change to the frequency of the microgrid that results from initiating the power generation.

4 . The method of claim 3 , where the magnitude of the expected frequency change is based on a minimum operating power of the power generator.

5 . The method of claim 2 , wherein the turn-on threshold is less than a frequency set point for activating energy retrieval from at least one storage asset of the microgrid.

6 . The method of claim 2 , wherein the turn-on threshold is less than a frequency set point for activating power generation by a distributed energy resource (DER) of the microgrid.

7 . Apparatus for autonomously operating a microgrid power generator comprising:

a generator controller for:

obtaining a first measurement of at least one grid parameter of a microgrid transmission line coupled to a power generator in a microgrid;

comparing the first measurement to a turn-on threshold;

initiating, when the first measurement satisfies the turn-on threshold, power generation by the power generator;

obtaining, after initiation of the energy generation, a second measurement of the at least one grid parameter of the microgrid transmission line;

comparing the second measurement to a shut-down threshold that is greater than the turn-on threshold; and

stopping, when the second measurement satisfies the shut-down threshold, the power generation by the power generator.

8 . The apparatus of claim 7 , wherein the at least one grid parameter is the frequency of the microgrid transmission line.

9 . The apparatus of claim 8 , wherein the shut-down threshold exceeds the turn-on threshold by an amount greater than the magnitude of an expected frequency change to the frequency of the microgrid that results from initiating the power generation.

10 . The apparatus of claim 9 , where the magnitude of the expected frequency change is based on a minimum operating power of the power generator.

11 . The apparatus of claim 8 , wherein the turn-on threshold is less than a frequency set point for activating energy retrieval from at least one storage asset of the microgrid.

12 . The apparatus of claim 11 , wherein the at least one storage asset is an AC battery comprising a bidirectional DC-AC inverter.

13 . The apparatus of claim 8 , wherein the turn-on threshold is less than a frequency set point for activating power generation by a distributed energy resource (DER) of the microgrid.

14 . The apparatus of claim 13 , wherein the DER comprises a plurality of photovoltaic (PV) modules couples to a plurality of DC-AC inverters.

15 . A computer readable medium comprising a program that, when executed by a processor, performs a method for operating a microgrid power generator, the method comprising:

obtaining a first measurement of at least one grid parameter of a microgrid transmission line coupled to a power generator in a microgrid;

comparing the first measurement to a turn-on threshold;

initiating, when the first measurement satisfies the turn-on threshold, power generation by the power generator;

obtaining, after initiation of the energy generation, a second measurement of the at least one grid parameter of the microgrid transmission line;

comparing the second measurement to a shut-down threshold that is greater than the turn-on threshold; and

stopping, when the second measurement satisfies the shut-down threshold, the power generation by the power generator.

16 . The computer readable medium of claim 15 , wherein the at least one grid parameter is the frequency of the microgrid transmission line.

17 . The computer readable medium of claim 16 , wherein the shut-down threshold exceeds the turn-on threshold by an amount greater than the magnitude of an expected frequency change to the frequency of the microgrid that results from initiating the power generation.

18 . The computer readable medium of claim 17 , where the magnitude of the expected frequency change is based on a minimum operating power of the power generator.

19 . The computer readable medium of claim 16 , wherein the turn-on threshold is less than a frequency set point for activating energy retrieval from at least one storage asset of the microgrid.

20 . The computer readable medium of claim 16 , wherein the turn-on threshold is less than a frequency set point for activating power generation by a distributed energy resource (DER) of the microgrid.