US 12,633,872 B2 · Outdoor photoluminescence imaging of photovoltaic arrays via optical string modulation

Abstract

Methods and apparatus are presented for determining data indicative of a photoluminescence (PL) response to solar irradiation from at least one photovoltaic module in a first string of series-connected modules that is one of a plurality of parallel-connected strings connected to an operating inverter. Two or more signals from a module in the first string are measured while modulating its operating point by modulating the illumination intensity incident on selected portions of one or more modules in that string. Measured signals are processed to determine data indicative of a PL response from the module, discriminating the response from the much brighter reflected sunlight. Importantly, this approach has an extended effect whereby modulating the illumination incident on a subset of modules in a string affects the operating point (PL intensity) of all modules in the string, offering increased throughput, reduced cost and improved versatility for outdoor PL imaging of photovoltaic arrays.

Claims38

Dependent claims

A method for determining data indicative of a response to solar irradiation of at least one photovoltaic module in a first string of series-connected photovoltaic modules, the first string being one of a plurality of strings of series-connected photovoltaic modules connected in parallel to an inverter and exposed to solar irradiation, the method comprising the steps of:

(i) using one or more optical modulators to modulate an intensity of illumination incident on selected portions of one or more photovoltaic modules in the first string selected to be one or more control modules, other photovoltaic modules in the first string being test modules, thereby modulating the operating points of the test modules and the one or more control modules;
(ii) detecting, using a measurement system, first and second signals from each of one or more of the test modules or control modules at first and second operating points induced by the modulation of the intensity of illumination incident on the one or more control modules;
and
(iii) processing, by a computing device, the measured first and second signals to determine data indicative of the response to the solar irradiation of the one or more test modules or control modules, wherein the processing comprises differencing or performing lock-in detection on the measured signals to separate the data from background data indicative of ambient light.

1 more element

An apparatus for determining data indicative of a response to solar irradiation of at least one photovoltaic module in a first string of series-connected photovoltaic modules, the first string being one of a plurality of strings of series-connected photovoltaic modules connected in parallel to an inverter and exposed to solar irradiation, the apparatus comprising:

(i) one or more optical modulators for modulating an intensity of illumination incident on selected portions of one or more photovoltaic modules in the first string selected to be one or more control modules, other photovoltaic modules in the first string being test modules, thereby modulating the operating points of the test modules and the one or more control modules;
(ii) a measurement system for measuring, at first and second operating points induced by the modulation of the intensity of illumination incident on the one or more control modules, first and second signals from each of one or more of the test modules or control modules;
and
(iii) a computer for processing the measured first and second signals to determine data indicative of a response to solar irradiation of the one or more test modules or control modules, wherein the processing comprises differencing or performing lock-in detection on the measured signals to separate the data from background data indicative of ambient light.

1 more element

Dependencies are inferred from the claim text.

Outdoor photoluminescence imaging of photovoltaic arrays via optical string modulation

Life of this patent

Outdoor photoluminescence imaging of photovoltaic arrays via optical string modulation

Life of this patent

Abstract

Claims38