DC integration of photovoltaic and DFIG wind turbine generation with electric storage

Patent metadata

Field	Value
Publication number	US-10819269-B2
Application number	US-201815880098-A
Country	US
Kind code	B2
Filing date	Jan 25, 2018
Priority date	Sep 9, 2016
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

A power generation and storage system is provided that supplies power to a power grid. The system includes a wind turbine, a doubly-fed induction generator coupled to the wind turbine, and one or more DC energy sources. A controller determines power requirements for the power grid and controls the operation of the wind turbine and the DC energy sources to meet the power requirements of the power grid.

First claim

What is claimed is:

1. A power generation and storage system comprising:
a wind turbine;
a doubly-fed induction generator connected to the wind turbine and to a power grid;
one or more DC energy sources coupled to the doubly-fed induction generator and to the power grid;
a programmable AC-DC converter having an input connected to a rotor of the doubly-fed induction generator and an output connected to the one or more DC energy sources and to the power grid; and
a controller that programs the output of the programmable AC-DC converter to produce a variable DC output voltage at a DC junction,
wherein power distributed to the power grid from the doubly-fed induction generator and the one or more DC energy sources is proportioned based on at least the variable DC output voltage at the DC junction,
wherein the one of more DC energy sources includes a DC energy storage source, and wherein the proportioned power distributed to the power grid is further determined by at least a state of charge of the DC energy storage source, and
wherein the one or more DC energy sources further includes a photovoltaic array and wherein the proportioned power distributed to the power grid is further determined by an effective output voltage of the photovoltaic array.

2. The power generation and storage system of claim 1 further comprising a DC-AC inverter having an input disconnectedly coupled to the output of the programmable AC-DC converter and to the one or more DC energy sources, and having an output connected to the power grid, the DC-AC inverter converting received DC power to AC power that has a frequency compatible with a frequency of the power grid.

3. The power generation and storage system of claim 2 , wherein the controller connects and disconnects the one or more DC energy sources to and from the programmable DC-AC inverter based on the maximum supplied generated power, the selectable grid limit, and an operational state of the wind turbine.

4. The power generation and storage system of claim 1 further comprising a DC-DC converter coupled to the one or more DC energy sources and disconnectedly coupled to the output of the programmable AC-DC converter.

5. The power generation and storage system of claim 4 , wherein when the DC-DC converter is coupled to the programmable AC-DC converter, the DC-DC converter receives DC power from the programmable AC-DC converter and adjusts a DC voltage level of the DC power prior to storing the DC power in one of the one or more DC energy sources.

6. The power generation and storage system of claim 1 , wherein the programmable AC-DC converter is a bidirectional converter that allows a power transfer from the one or more DC energy sources to the doubly-fed induction generator under start-up conditions to thereby start the rotor of the doubly-fed induction generator.

7. The power generation and storage system of claim 1 , wherein the DC energy storage source discharges to supply power to the power grid when the state of charge of the DC energy storage source is greater than the DC voltage at the DC junction.

8. The power generation and storage system of claim 1 , wherein the DC energy storage source charges when the state of charge of the DC energy storage source is less than the DC voltage at the DC junction.

9. A power generation and storage system comprising:
a wind turbine;
a doubly-fed induction generator connected to the wind turbine and selectively coupled to a power grid;
a photovoltaic array coupled to the power grid;
a DC energy storage source coupled to the doubly-fed induction generator, the photovoltaic array, and the power grid, the DC energy storage source storing power from at least one of the doubly-fed induction generator and the photovoltaic array; and
a controller that selectively connects at least one of the doubly-fed induction generator and the photovoltaic array to the DC energy storage source in response to determining that a maximum supplied generated power meets a selectable grid limit.

10. The power generation and storage system of claim 9 further comprising a programmable AC-DC converter having an input connected to a rotor of the doubly-fed induction generator and an output disconnectedly coupled to the DC energy storage source and to the power grid, wherein the controller programs the programmable AC-DC converter to output a DC output voltage at a DC junction, and wherein power distributed to the power grid from the doubly-fed induction generator, the photovoltaic array, and the DC energy storage source is determined by at least the DC output voltage at the DC junction.

11. The power generation and storage system of claim 10 further comprising a DC-AC inverter having an output connected to the power grid and an input disconnectedly coupled to the programmable AC-DC converter, the photovoltaic array, and the DC energy storage source, the DC-AC inverter converting DC power received from the programmable AC-DC converter, the photovoltaic array, and from the DC energy storage source to AC power that has a frequency compatible with a frequency of the power grid.

12. The power generation and storage system of claim 11 further comprising a first DC-DC converter connected to the DC energy storage source and disconnectedly coupled the programmable AC-DC converter and a second DC-DC converter disconnectedly coupled to the DC energy storage source and disconnectedly coupled the DC-AC inverter.

13. The power generation and storage system of claim 12 , wherein the programmable AC-DC converter converts the power from AC to DC and wherein the first DC-DC converter receives the DC power from the programmable AC-DC converter and adjusts a DC voltage level of the DC power prior to storing the DC power in the DC energy storage source.

14. The power generation and storage system of claim 11 , wherein the controller connects and disconnects the DC energy storage source to and from the DC-AC inverter based on the selectable grid limit and an operational state of at least one of the wind turbine and photovoltaic array.

15. The power generation and storage system of claim 9 further comprising a photovoltaic array sensor that measures a voltage and current output of the photovoltaic array, wherein the controller receives the voltage and current output from the photovoltaic array sensor and sets an effective output voltage of the photovoltaic array.

16. A method comprising:
determining a selectable grid limit of a power grid;
programming a programmable AC-DC converter to output a DC voltage to a DC junction;
determining a state of charge of a DC energy storage source;
determining an effective output voltage of a photovoltaic array;
distributing power to the power grid from at least one of a wind turbine via a doubly-fed induction generator, and the DC energy storage source and the photovoltaic array via a DC-AC inverter based on the DC voltage at the DC junction; and
storing power in the DC energy storage source from the at least one of the wind turbine and the photovoltaic array if a maximum supplied generated power meets the selectable grid limit.

17. The method of claim 16 further comprising discharging the power from the DC energy storage source to the power grid when the at least one of the wind turbine and the photovoltaic array are not producing sufficient power and the maximum supplied generated power is less than the selectable grid limit.

18. The method of claim 16 , wherein the DC-AC inverter converts DC power from the programmable AC-DC converter, the photovoltaic array, and the DC energy storage source

Assignees

• Inventus Holdings Llc

Inventors

• VIDHI Rachana
• Brake Daniel M
• Mcmorrow Ryan K

Classifications

• Y02E70/30

  Systems combining energy storage with energy generation of non-fossil origin · CPC title

• Y02E10/72

  Wind turbines with rotation axis in wind direction · CPC title

• F03D9/007

  the wind motor being combined with means for converting solar radiation into useful energy · CPC title

• H02S10/12 Primary

  Hybrid wind-PV energy systems · CPC title

• F03D9/255

  connected to electrical distribution networks; Arrangements therefor · CPC title