Grid-linked power supply

• US 6,452,289 B1
• Filed: 07/10/2000
• Issued: 09/17/2002
• Est. Priority Date: 07/10/2000
• Status: Expired due to Term

• Current Assignee: Perfect Galaxy International Limited
• Original Assignee: Satcon Technology Corporation
• Inventors: Lansberry, Geoffrey B., Holmansky, Evgeny N.
• Primary Examiner(s): Jackson, Stephen W.
• Assistant Examiner(s): RIOS CUEVAS, ROBERTO JOSE
• Application Number:
  US09/612,996
• Time in Patent Office: 799 Days
• Field of Search: 307/25, 307/44, 307/46, 307/48, 307/59, 307/64, 307/72, 307/73, 307/74, 307/75, 307/76, 307/80, 307/87, 323/351, 363/34, 700/295
• US Class Current: 307/25
• CPC Class Codes: H02J 2300/20 The dispersed energy generation being of renewable origin
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/28 The renewable source being wind energy wind motors F03D
• CPC Class Codes: H02J 2300/30 The power source being a fuel cell
• CPC Class Codes: H02J 2300/40 wherein a plurality of decentralised, dispersed or local energy generation technologies are operated simultaneously
• CPC Class Codes: H02J 3/32 using batteries with converting means
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/466 Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 10/76 Power conversion electric or electronic aspects
• CPC Class Codes: Y02E 70/30 Systems combining energy storage with energy generation of non-fossil origin

Abstract

A grid-linked power supply is described. An inverter, at least one distributed energy source to meet normal, non-peak power demand, a connection to a public utility grid to meet peak power demand requirements, and a converter for regulating delivery of power from the distributed energy source or the public utility grid are connected by bus lines. A topology for the grid-linked power supply has an inverter and a DC/DC converter that is connected to the distributed energy source. The inverter and converter are connected by bus lines, and a bias voltage is provided to select drawing power from the distributed energy source or the public utility grid.

Claims

1. A grid-linked power supply, said power supply comprising:

an inverter;

at least one distributed energy source as a primary power source;

a connection to a public utility grid to provide a complementary power source; and

a controller for regulating delivery of power from said distributed energy source during normal power demand conditions and for mixing therewith power from said public utility grid during peak power demand conditions.

2. The grid-linked power supply as recited in claim 1, wherein the distributed energy source comprises a fuel cell.

3. The grid-linked power supply as recited in claim 1, wherein the distributed energy source is a device selected from the group consisting of a photovoltaic cell, a wind-powered turbine, a wave-powered generator, and a micro-turbine.

4. The grid-linked power supply as recited in claim 1, further comprising an energy storage device in combination with said distributed energy source.

5. The grid-linked power supply as recited in claims 4, wherein the energy storage device is a device selected from the group consisting of a battery, a flywheel, and an ultra-capacitor.

6. A topology for a grid-linked power supply that comprises a distributed energy source as a primary power source and a connection to a public utility grid, said topology comprising:

an inverter; and

a DC/DC converter connected to the distributed energy source,

said inverter and said converter connected by internal bus lines, wherein a bias voltage is provided to select drawing power from the distributed energy source during normal power demand conditions and, further, to mix therewith power from said public utility grid during peak power demand conditions.

7. The topology as recited in claim 6, wherein the grid-linked power supply further comprises an energy storage device in combination with said distributed energy source, said topology further comprising a second DC/DC converter connected to the energy storage device, wherein the bias voltage is provided to select drawing power from the distributed energy source or from the energy storage device during normal power demand conditions and, further, to mix therewith power from said public utility grid during peak power demand conditions.

8. A method of delivering electrical power to a user load, the method comprising:

providing a distributed energy source as a primary power source;

providing a connection to a public utility grid, which is coupled to an internal bus of a power supply in parallel with the primary power source, the power supply including an inverter and a DC/DC converter that is connected to the primary power source; and

regulating the bias voltage on the bus so as to draw power from the primary power source during normal power demand conditions and, further, to mix therewith power from the public utility grid during peak power demand conditions.

9. The method of delivering electrical power as recited in claim 8, wherein the distributed energy source comprises a fuel cell.

10. The method of delivering electrical power as recited in claim 8, wherein the distributed energy source is a device selected from the group consisting of a photovoltaic cell, a wind-powered turbine, a wave-powered generator, and a micro-turbine.

11. The method of delivering electrical power as recited in claim 8, further comprising providing an energy storage device in combination with said distributed energy source.

12. The method of delivering electrical power as recited in claim 11, wherein the energy storage device is a device selected from the group consisting of a battery, a flywheel, and an ultra-capacitor.

13. The method of delivering electrical power as recited in claim 8, wherein the regulating step includes comparing a demand voltage with a set point.

14. The method of delivering electrical power as recited in claim 13, wherein the set point is selected from (i) a value for normal demand voltage, (ii) a value for a transitional demand voltage, and (iii) a value for a peak demand voltage.

15. The method of delivering electrical power as recited in claim 14, wherein the value for normal demand voltage is compared with a voltage from the distributed energy source.

16. The method of delivering electrical power as recited in claim 14, wherein the value for transitional demand voltage is compared with voltage from an energy storage device.

17. The method of delivering electrical power as recited in claim 14, wherein the value for peak demand voltage is compared with voltage from the public utility grid.

18. The method of delivering electrical power as recited in claim 14, wherein the value for the normal demand voltage is about 390 volts.

19. The method of delivering electrical power as recited in claim 14, wherein the value for the transitional demand voltage is about 380 volts.

20. The method of delivering electrical power as recited in claim 14, wherein the value for the peak demand voltage is about 372 volts.