WE CLAIM:
Claim 1.A process for maximum power point tracking of at least one photovoltaic module,
comprising, according to a periodicity ݐߜ , ଴of the I/V operating point measurements (120) of
said module and positioning of said operating point at the maximum power point MPP
5 thereof,
characterized in that it comprises a monitoring of the degradation of said module, where
said monitoring comprises:
— according to a periodicity ݊ଵݐߜ ଴with n1 > 1 constant or variable, steps (130, 140) of
measurement of the parameters I and V of said module for points offset in voltage VMPP+α
10 and VMPP–β over the curve I(V) relative to the maximum power point MPP, a calculation of
the slope dI/dV+ at the point VMPP+α and of the slope dI/dV– at the point VMPP–β and
recording of said data along with the MPP;
— according to a periodicity ݊ଶݐߜ ଴with n2 ≥ n1 of steps (160, 170) of measurement of
values of I and V by sweeping the curve I(V) and calculation of parameters (Jsc, Voc, FF,
15 Rs, Rsh, I0, N) of said module and storage of said parameters and values;
— one or several steps (200) of calculation, tracing and display of ቀ
݌
2
ቁ curves of data pairs
based on p measured and calculated parameters;
— one or more steps of detecting degradation from said measured and calculated
parameters.
20 Claim 2.The process according to claim 1 for which at least some parameters p come from
calculation of derivatives d[X]/d[Y] with X = [performance and degradation indicator] and Y
= [meteorological data for the site], said performance and degradation indicator comprising:
Efficiency, Jsc, Voc, Impp, Vmpp, FF, Rs, Rsh, dI/dV+, and dI/dV-, and said “meteorological
data” comprising: humidity, environmental and module temperature, wind speed, pressure,
25 UV index, and irradiance by means of dedicated meteorological sensors communicating,
and the display of said derivatives.
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Claim 3.The process according to claim 1 or 2 for which the values of α and β are adjusted
according to the number of cells of said module included in said measurement steps.
Claim 4.The process according to claim 1, 2 or 3 comprising a modification (225) of the
values n1 and/or n2 during said monitoring.
5 Claim 5.The process according to claim 4 for which the values n1 and/or n2 are reduced
during detection of a degradation and in the absence of detection of development of the
degradation, the values n1 and/or n2 are increased with each loop of the algorithm.
Claim 6.The process according to any one of the preceding claims comprising one or more
steps (190) of selection of said data, parameters and values for storing said data,
10 parameters and values corresponding to meteorological conditions set by the user.
Claim 7. The process according to any one of the preceding claims for which at least some
of the p parameters come from a calculation of the ratio of the time integral of the power at
MPP to the product of the efficiency with the time integral of the received irradiance
according to daily cycles.
15 Claim 8.The process according to any one of the preceding claims for which at least some
of the steps (200) of calculation, tracing and displaying comprise a trace of curves of the
slope dI/dV– as a function of the slope dI/dV+ for the points measured throughout said
measurement steps.
Claim 9.The process according to any one of the preceding claims comprising a step (230)
20 of searching for degradation of the module and the case of degradation, a step (210) of
searching for a cause of degradation, for which said search is done by the comparison of
the offset of a curve obtained from the measurements from a set of model curves (Me1,
Me2, Me3, Me4, Me5) for various degradation modes.
Claim 10. The process according to claim 9 comprising a step of displaying a cause
25 of degradation.
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Claim 11. The process according to claim 9 or 10 comprising the comparison (240)
of one or more measured parameter curves with a degradation limit indicator beyond which
an anomaly detection alert (250) is sent to an operator.
Claim 12. A device for maximum power point tracking of a photovoltaic module
5 comprising a case (12) provided with a display screen (13) and a processor, and configured
for implementing the process according to any one of claims 1 to 11, and displaying the
resulting curves.
Claim 13. The device according to claim 12 for which said case is inserted between
one or more modules and a direct current/alternating current converter.
10 Claim 14. The device according to claim 12 or 13 for which said case comprises a
communication module (20) with external connection (25) towards a remote processor (24)
of a monitoring system configured for programming notably the types of measurements and
the periodicity of these measurements in the digital processor (18) or retrieving data from
measurements done by said case and for sending information to an operator about the
15 status of the modules and alerts upon anomaly detection.