Method for determining a corrected current-voltage characteristic curve of an electrical system

Patent metadata

Field	Value
Publication number	US-11336225-B2
Application number	US-201916691674-A
Country	US
Kind code	B2
Filing date	Nov 22, 2019
Priority date	Nov 28, 2018
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

A method for determining a corrected current-voltage curve of an electrical system, the method including the following steps: obtaining a first current-voltage characteristic curve of the electrical system, by varying the voltage across its terminals at a first measurement rate, obtaining a second current-voltage characteristic curve of the electrical system, by varying the voltage across its terminals at a second measurement rate, different from the first rate, using a single notional capacitance to model an intrinsic stray effect to be corrected between an input voltage without the stray effect and the output voltage, determining a correction value representative of the stray effect and a step of determining a corrected current value on the basis of the determined correction value.

First claim

The invention claimed is:

1. A method for determining a corrected current-voltage curve of an electrical system that has two terminals and that is configured to deliver an electric current as a function of an output voltage between its two terminals, comprising the following steps:
obtaining a first current-voltage characteristic curve of the electrical system, by varying the voltage across its terminals at a first measurement rate,
obtaining a second current-voltage characteristic curve of the electrical system, by varying the voltage across its terminals at a second measurement rate, different from the first rate,
determining a plurality of voltage operating points belonging both to the first current-voltage curve and to the second current-voltage curve,
using a single apparent capacitance to model an intrinsic stray effect to be corrected between an input voltage without said stray effect and said output voltage, and wherein
for each voltage operating point, a step of determining a correction value representative of said stray effect and a step of determining a corrected current value on the basis of the determined correction value.

2. The method according to claim 1 , wherein the first current-voltage curve is obtained by varying the voltage in an increasing direction and in that the second current-voltage curve is obtained by varying the voltage in a decreasing direction.

3. The method according to claim 1 , wherein the electrical system is photovoltaic and wherein the method comprises:
for each voltage operating point that is obtained, a step of determining, on the basis of the first current-voltage curve, a first current and a first voltage variation slope as a function of time and a step of determining, on the basis of the second current-voltage curve, a second current and a second voltage variation slope as a function of time,
wherein for each voltage operating point, said correction value is determined on the basis of said first current, of said first slope, of said second current and of said second slope.

4. The method according to claim 3 , wherein said correction value of said stray effect is expressed by the following relationship:

g
⁡

(
V
)

=

I
A

⁡

(
V
)

-

I
R

⁡

(
V
)

dV
R

dt

⁢

(
V
)

-

dV
A

dt

⁢

(
V
)

wherein:
g(V) corresponds to said stray effect to be eliminated;
I A (V) corresponds to said first current;
I R (V) corresponds to said second current;

dV
A

dt

⁢

(
V
)

corresponds to said first slope; and

dV
R

dt

⁢

(
V
)

corresponds to said second slope.

5. The method according to claim 1 , wherein the step of determining a plurality of voltage operating points belonging both to the first current-voltage curve and to the second current-voltage curve is implemented by using an interpolation method.

6. A device for determining a corrected current-voltage curve of an electrical system that has two terminals and that is configured to deliver an electric current as a function of an output voltage between its two terminals, said device comprising:
means for measuring a first current-voltage characteristic curve of the electrical system, by varying the voltage across its terminals at a first measurement rate,
means for measuring a second current-voltage characteristic curve of the electrical system, by varying the voltage across its terminals at a second measurement rate, different from the first measurement rate,
a module for determining a plurality of voltage operating points belonging both to the first current-voltage curve and to the second current-voltage curve,
a module for using a single apparent capacitance to model a stray effect to be corrected between an input voltage without said stray effect and said output voltage, and
wherein for each voltage operating point, a module for determining a correction value representative of said stray effect and a module for determining a corrected current value on the basis of the determined correction value.

7. The device according to claim 6 , wherein said first current-voltage curve is obtained by varying the voltage in an increasing direction and wherein the second current-voltage curve is obtained by varying the voltage in a decreasing direction.

8. The device according to claim 6 , wherein the electrical system is photovoltaic and wherein the device has:
for each voltage operating point that is obtained, a module for determining, on the basis of the first current-voltage curve, a first current and a first voltage variation slope as a function of time and a module for determining, on the basis of the second current-voltage curve, a second current and a second voltage variation slope as a function of time,
wherein for each voltage operating point, said correction value is determined on the basis of said first current, of said first slope, of said second current and of said second slope.

9. The device according to claim 8 , wherein said correction value of said stray effect is expressed by the following relationship:

g
⁡

(
V
)

=

I
A

⁡

(
V

Assignees

• Commissariat Energie Atomique

Inventors

• Lespinats Sylvain
• Amhal Mohamed

Classifications

• H02S50/10 Primary

  Testing of PV devices, e.g. of PV modules or single PV cells (testing of semiconductor devices during manufacturing {H10P74/00}) · CPC title

• G01R31/2603 Primary

  for curve tracing of semiconductor characteristics, e.g. on oscilloscope · CPC title

• G01R31/40

  Testing power supplies (testing photovoltaic devices H02S50/10) · CPC title

• H02S40/30

  Electrical components · CPC title

• Y02E10/50

  Photovoltaic [PV] energy · CPC title