Microgrid and virtual inertia coordinated control method thereof

Abstract

A microgrid coupled to a mains power system includes a first converter resource device, an alternator, and a controller. The first converter resource device generates a first energy. The alternator generates a second energy. The controller is coupled to and controls the first converter resource device and the alternator. The controller is configured to: in response to a decrease or increase in the power supply frequency of the mains power system, cause the microgrid to output at least one of the first energy and the second energy. The first energy is virtual inertial energy, and the second energy is non-virtual inertial energy.

Claims

1. A microgrid coupled to a mains power system, comprising: a first converter resource device for generating a first energy; an alternator for generating a second energy; and a controller coupled to and controlling the first converter resource device and the alternator for: detecting a power supply frequency of the mains power system via a measuring device; responding to a decrease or increase in the power supply frequency of the mains power system from the operating frequency of the mains power grid, causing the microgrid to output at least one of the first energy and the second energy to the mains power system, and restoring the power supply frequency of the mains power system to the operating frequency of the mains power grid, wherein the first energy is virtual inertial energy and the second energy is non-virtual inertial energy.

2. The microgrid as claimed in claim 1, wherein the controller is further configured to: cause the microgrid to output the first energy in response to the first energy being not less than an inertial energy threshold.

3. The microgrid as claimed in claim 1, wherein the controller is further configured to: increase the first energy and cause the microgrid to output the increased first energy in response to the first energy being lower than an inertial energy threshold and the first energy not reaching a first upper limit; and cause the microgrid to output the first energy and the second energy in response to the first energy being lower than the inertial energy threshold and the first energy reaching the first upper limit.

4. The microgrid as claimed in claim 1, wherein the first converter resource device is one of a solar generator and an energy storage system.

5. The microgrid as claimed in claim 1, further comprising: a second converter resource device for generating a third energy, wherein the third energy is virtual inertial energy, wherein the controller is further configured to: in response to a decrease or increase in the power supply frequency of the mains power system, cause the microgrid to output at least one of the first energy, the second energy, and the third energy.

6. The microgrid as claimed in claim 5, wherein the first converter resource device is one of a solar generator and an energy storage system, and the second converter resource device is the other of the solar generator and the energy storage system.

7. The microgrid as claimed in claim 5, wherein the controller is further configured to: in response to the first energy being below an inertial energy threshold, the first energy having reached a first upper limit value, and the second converter resource device having power generation capacity, cause the microgrid to output the first energy and the third energy.

8. The microgrid as claimed in claim 5, wherein the controller is further configured to: increase the third energy and cause the microgrid to output the first energy and the increased third energy in response to the sum of the first energy and the third energy being less than an inertial energy threshold, the first energy reaching a first upper limit and the third energy not reaching a second upper limit; and cause the microgrid to output the first energy, the second energy and the third energy in response to the sum of the first energy and the third energy being less than the inertial energy threshold, the first energy reaching the first upper limit and the third energy reaching the second upper limit.

9. A virtual inertial coordination control method for a microgrid coupled to a mains power system, the virtual inertial coordination control method comprising: generating a first energy through a first converter resource device; generating a second energy through an alternator; detecting a power supply frequency of the mains power system through a measuring device; and, in response to a decrease or increase in the power supply frequency of the mains power system from the operating frequency of a mains power grid, causing the microgrid to output at least one of the first energy and the second energy to the mains power system, thereby restoring the power supply frequency of the mains power system to the operating frequency of the mains power grid, wherein the first energy is virtual inertial energy and the second energy is non-virtual inertial energy.

10. The virtual inertial coordination control method as described in claim 9, further comprising: outputting the first energy in response to the first energy being not lower than an inertial energy threshold.

11. The virtual inertial coordination control method as described in claim 9, further comprising: in response to the first energy being lower than an inertial energy threshold and the first energy not reaching a first upper limit, increasing the first energy and outputting the increased first energy; and in response to the first energy being lower than the inertial energy threshold and the first energy having reached the first upper limit, outputting the first energy and the second energy.

12. The virtual inertial coordinated control method as described in claim 9, wherein the first converter resource device is one of a solar generator and an energy storage system.

13. The virtual inertial coordination control method as described in claim 9 further comprises: generating a third energy through a second converter resource device; and, in response to a decrease or increase in the power supply frequency of the mains power system, causing the microgrid to output at least one of the first energy, the second energy, and the third energy, wherein the third energy is virtual inertial energy.

14. The virtual inertial coordinated control method as described in claim 13, wherein the first converter resource device is one of a solar generator and an energy storage system, and the second converter resource device is the other of the solar generator and the energy storage system.

15. The virtual inertial coordination control method as described in claim 13, further comprising: in response to the first energy being lower than an inertial energy threshold and the first energy having reached a first upper limit and the second converter resource device having power generation capacity, outputting the first energy and the third energy.

16. The virtual inertial coordination control method as described in claim 13, further comprising: in response to the sum of the first energy and the third energy being lower than an inertial energy threshold, the first energy having reached a first upper limit value and the third energy not having reached a second upper limit value, increasing the third energy and outputting the first energy and the increased third energy; and in response to the sum of the first energy and the third energy being lower than the inertial energy threshold, the first energy having reached the first upper limit value and the third energy having reached the second upper limit value, outputting the first energy, the second energy and the third energy.

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