Method and apparatus for distributed VAr compensation

• US 8,076,802 B2
• Filed: 02/12/2009
• Issued: 12/13/2011
• Est. Priority Date: 02/12/2008
• Status: Active Grant

• Current Assignee: Enphase Energy Incorporated
• Original Assignee: Enphase Energy Incorporated
• Inventors: Fornage, Martin
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): KAPLAN, HAL IRA
• Application Number:
  US12/370,036
• Publication Number:
  US 20090200994A1
• Time in Patent Office: 1,034 Days
• Field of Search: 307/151
• US Class Current: 307/151
• CPC Class Codes: H02J 13/00006 characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/26 involving maximum power point tracking control for photovoltaic sources
• CPC Class Codes: H02J 3/18 Arrangements for adjusting, eliminating or compensating reactive power in networks for adjustment of voltage H02J3/16
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 40/30 Reactive power compensation
• CPC Class Codes: Y02E 40/70 Smart grids as climate change mitigation technology in the energy generation sector
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/123 the energy generation units being or involving renewable energy sources
• CPC Class Codes: Y04S 10/22 Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units
• CPC Class Codes: Y04S 40/12 characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment

Abstract

A method and apparatus for generating on-demand power. The method comprises receiving a peak reactive current request, generating a control signal based on the peak reactive current request, and utilizing the control signal to drive a DC/AC inverter to generate reactive power commensurate with the peak reactive current request.

Claims

1. A method for generating on-demand Volt-Ampere reactive (VAr) compensation, comprising:

determining an amount of VAr compensation required;

requesting at least one distributed generator (DG) to generate reactive power commensurate with the amount; and

driving at least one DC/AC inverter of the at least one DG to generate the reactive power, wherein the at least one DC/AC inverter is an optimum number of DC/AC inverters for minimizing a real power loss generated when producing the reactive power.

2. The method of claim 1, further comprising:

identifying the at least one DG, wherein the at least one DG is capable of generating reactive power.

3. The method of claim 1, wherein the determining an amount of VAr compensation required comprises:

obtaining power consumption data; and

utilizing the power consumption data to obtain the amount.

4. The method of claim 1, further comprising providing feedback on reactive power generated.

5. The method of claim 1, wherein the driving comprises:

providing a peak reactive current request to one or more of the at least one DC/AC inverters;

generating a control signal based on the peak reactive current request; and

applying the control signal to the one or more of the at least one DC/AC inverters.

6. The method of claim 5, wherein the generating a control signal comprises modulating the peak reactive current request with a cosine waveform having a frequency of a commercial power grid waveform and a phase lagging the commercial power grid waveform by 90°

.

7. The method of claim 1, wherein the reactive power is a negative reactive power.

8. A DC/AC inverter for generating on-demand power, comprising:

a DC/AC inverter controller for driving the DC/AC inverter to generate reactive power commensurate with a peak reactive current request; and

a first multiplier for modulating the peak reactive current request with a cosine waveform having a frequency of a commercial power grid waveform and a phase lagging the commercial power grid waveform by 90°

to generate a control signal, wherein the DC/AC inverter controller generates the control signal based on the peak reactive current request for driving the DC/AC inverter.

9. The DC/AC inverter of claim 8, wherein the DC/AC inverter controller generates the control signal based on a peak real current request in addition to the peak reactive current request.

10. The DC/AC inverter of claim 9, wherein the DC/AC inverter generates real power commensurate with the peak real current request simultaneously with the reactive power.

11. The DC/AC inverter of claim 9, further comprising a second multiplier for modulating the peak real current request with a sine waveform having a frequency and a phase of the commercial power grid waveform to generate the control signal.

12. The DC/AC inverter of claim 8, wherein the reactive power is a negative reactive power.

13. A system for generating on-demand Volt-Ampere reactive (VAr) compensation, comprising:

at least one distributed generator (DG) for generating AC power, wherein the at least one DG is coupled to a commercial power grid and comprises at least one DC/AC inverter; and

a gateway, communicably coupled to the at least one DG, for driving one or more of the at least one DC/AC inverters to generate reactive power commensurate with an amount of VAr compensation required, wherein the one or more of the at least one DC/AC inverters is an optimum number of DC/AC inverters for minimizing a real power loss generated when producing the reactive power.

14. The system of claim 13, wherein the gateway determines the amount based on power consumption data.

15. The system of claim 13, wherein the reactive power is a negative reactive power.

16. The system of claim 13, further comprising a VAr management entity NOC, communicably coupled to the gateway and the at least one DG, for determining the amount.