Method and apparatus for determining a corrected monitoring voltage

• US 8,666,561 B2
• Filed: 02/05/2010
• Issued: 03/04/2014
• Est. Priority Date: 02/05/2009
• Status: Active Grant

• Current Assignee: Enphase Energy Incorporated
• Original Assignee: Enphase Energy Incorporated
• Inventors: Fornage, Martin, Dargatz, Marv
• Primary Examiner(s): KASENGE, CHARLES R
• Application Number:
  US12/701,262
• Publication Number:
  US 20100195357A1
• Time in Patent Office: 1,488 Days
• Field of Search: 700/286, 700/295, 700/297, 700/298, 702/57, 702/61, 702/64, 363/55, 363/95, 323/371, 324/120, 361/18
• US Class Current: 700/298
• 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 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: H02M 7/44 by static converters
• 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

Abstract

A method and apparatus for determining a corrected monitoring voltage, at least a portion of the method being performed by a computing system comprising at least one processor. The method comprises generating power at a first location; monitoring the generated power by measuring a first voltage proximate the first location; measuring a second voltage proximate a second location, the first and the second locations electrically coupled; and determining, based on the measured second voltage, a corrected monitoring voltage to compensate the measured first voltage for a distance between the first and the second locations.

Claims

1. A method for determining a corrected monitoring voltage, at least a portion of the method being performed by a computing system comprising at least one processor, the method comprising:

generating power at a first location;

monitoring the generated power by measuring a first voltage proximate the first location, wherein measuring the first voltage comprises obtaining a first voltage measurement of the first voltage;

measuring a second voltage proximate a second location, the first and the second locations electrically coupled, wherein measuring the second voltage comprises obtaining a second voltage measurement of the second voltage;

computing a correction coefficient based on the first and the second voltage measurements; and

determining, based on the correction coefficient, a corrected monitoring voltage to compensate the measured first voltage for a distance between the first and the second locations.

2. The method of claim 1, wherein measuring the first voltage further comprises obtaining a third voltage measurement of the first voltage, and wherein determining the corrected monitoring voltage comprises:

obtaining a first power measurement proximate the first location;

obtaining a second power measurement proximate the first location; and

computing the corrected monitoring voltage based on the first and the second power measurements, the third voltage measurement, and the correction coefficient.

3. The method of claim 2, further comprising:

determining that the corrected monitoring voltage is not within an operating range; and

disabling a device generating the power at the first location or performing AC voltage regulation.

4. The method of claim 2, further comprising determining, subsequent to computing the correction coefficient and prior to computing the corrected monitoring voltage, that the correction coefficient is within a correction coefficient range.

5. The method of claim 2, further comprising:

determining that the correction coefficient has exceeded a time window; and

setting the correction coefficient to a value of one.

6. The method of claim 2, further comprising:

determining that the correction coefficient has not exceeded a time window;

obtaining a third power measurement proximate the first location;

determining whether the third power measurement is within an output power range; and

resultant from determining whether the third power measurement is within the output power range, (i) setting the correction coefficient to a value of one, or (ii) recomputing the correction coefficient based on the third power measurement.

7. The method of claim 2, wherein the corrected monitoring voltage is computed as V_corr=V₃*(1−

(P₂*(1−

(V₂/V₁))/P₁)), wherein P₁=the first power measurement, P₂ =the second power measurement, V₁ =the first voltage measurement, V₂ =the second voltage measurement, and V₃ =the third voltage measurement.

8. An apparatus for determining a corrected monitoring voltage, comprising:

a voltage monitoring module adapted for;

monitoring generated power at a first location by measuring a first voltage proximate the first location, wherein measuring the first voltage comprises obtaining a first voltage measurement of the first voltage;

receiving a second voltage measurement of a second voltage proximate a second location, the second location electrically coupled to the first location;

computing a correction coefficient based on the first and the second voltage measurements; and

determining, based on the correction coefficient, a corrected monitoring voltage to compensate the measured first voltage for a distance between the first and the second locations.

9. The apparatus of claim 8, wherein the voltage monitoring module determines the corrected monitoring voltage by (i) obtaining the first and a third voltage measurement of the first voltage, (ii) obtaining a first power measurement proximate the first location, (iii) obtaining a second power measurement proximate the first location, and (iv) computing the corrected monitoring voltage based on the first and the second power measurements, the third voltage measurement, and the correction coefficient.

10. The apparatus of claim 9, wherein the voltage monitoring module is further adapted for:

determining that the corrected monitoring voltage is not within an operating range; and

disabling a power generating device that generates the power at the first location or performing AC voltage regulation.

11. The apparatus of claim 9, wherein the voltage monitoring module is further adapted for determining, subsequent to computing the correction coefficient and prior to computing the corrected monitoring voltage, that the correction coefficient is within a correction coefficient range.

12. The apparatus of claim 9, wherein the voltage monitoring module is further adapted for:

determining that the correction coefficient has exceeded a time window; and

setting the correction coefficient to a value of one.

13. The apparatus of claim 9, wherein the voltage monitoring module is further adapted for:

determining that the correction coefficient has not exceeded a time window;

obtaining a third power measurement, the third power measurement measuring the output power from a power generating device that generates the power at the first location;

determining whether the third power measurement is within an output power range; and

resultant from determining whether the third power measurement is within the output power range, (i) setting the correction coefficient to a value of one, or (ii) recomputing the correction coefficient based on the third power measurement.

14. A system for determining a corrected monitoring voltage, the system comprising:

an inverter, adapted for generating power at a first location and monitoring the generated power by measuring a first voltage proximate the first location, wherein measuring the first voltage comprises obtaining a first voltage measurement of the first voltage; and

a measurement unit, adapted for measuring a second voltage proximate a second location, the first and the second locations electrically coupled, wherein measuring the second voltage comprises obtaining a second voltage measurement of the second voltage;

wherein the inverter is further adapted for computing a correction coefficient based on the first and the second voltage measurements, and determining, based on the correction coefficient, a corrected monitoring voltage to compensate the measured first voltage for a distance between the first and the second locations.

15. The system of claim 14, wherein the inverter determines the corrected monitoring voltage by (i) obtaining the first and a third voltage measurement of the first voltage, (ii) receiving the second voltage measurement, obtained by the measurement unit, of the second voltage, (iii) obtaining a first power measurement proximate the first location, (iv) obtaining a second power measurement proximate the first location, and (v) computing the corrected monitoring voltage based on the first and the second power measurements, the third voltage measurement, and the correction coefficient.

16. The system of claim 15, wherein the inverter is further adapted for:

determining that the corrected monitoring voltage is not within an operating range; and

disabling power production or performing AC voltage regulation.

17. The system of claim 15, wherein the inverter is further adapted for determining, subsequent to computing the correction coefficient and prior to computing the corrected monitoring voltage, that the correction coefficient is within a correction coefficient range.

18. The system of claim 15, wherein the inverter is further adapted for:

determining that the correction coefficient has exceeded a time window; and

setting the correction coefficient to a value of one.

19. The system of claim 15, wherein the inverter is further adapted for:

determining that the correction coefficient has not exceeded a time window;

obtaining a third power measurement proximate the first location;

determining whether the third power measurement is within an output power range; and

resultant from determining whether the third power measurement is within the output power range, (i) setting the correction coefficient to a value of one, or (ii) recomputing the correction coefficient based on the third power measurement.

20. The system of claim 15, wherein the corrected monitoring voltage is computed as V_corr=V₃*(1−

(P₂*(1−

(V₂/V₁))/P₁)), wherein P₁=the first power measurement, P₂ =the second power measurement, V₁ =the first voltage measurement, V₂ =the second voltage measurement, and V₃ =the third voltage measurement.