Illuminated outdoor luminescence imaging of photovoltaic modules
The present disclosure relates to a method that includes applying a first condition to a photovoltaic (PV) device, and applying a second condition to the PV device, where the first condition results in a first luminescing of a surface of the PV device at a first intensity, the second condition results in a second luminescing of the surface at a second intensity, measuring the first intensity using a detector to create a first representation of the surface, measuring the second intensity using the detector to create a second representation of the surface, and comparing the first representation with the second representation to create a third representation of the surface that identifies a defect in the surface, if present.
1. A method comprising:
applying a first condition to a photovoltaic (PV) device;
applying a second condition to the PV device;
a first switching between the first applying and the second applying; and
a second switching between the second applying and the first applying, wherein:
the first condition is maintained for a first period of time,
after the first period of time has ended, the first switching occurs,
the second condition is maintained for a second period of time,
after the second period of time has ended, the second switching occurs,
the first switching and the second switching are repeated between 1 and 1000 occurrences,
the first condition results in a first luminescing of a surface of the PV device at a first intensity,
the second condition results in a second luminescing of the surface at a second intensity,
measuring the first intensity using a detector to create a first representation of the surface,
measuring the second intensity using the detector to create a second representation of the surface, and
comparing the first representation with the second representation to create a third representation of the surface that identifies a defect in the surface.
2. The method of claim 1 , wherein the applying the first condition comprises applying a first current to the PV device.
3. The method of claim 2 , wherein:
the applying the second condition comprises applying a second current to the PV device, and
the second current is different from the first current.
4. The method of claim 1 , wherein the applying the first condition comprises drawing a third current from the PV device.
5. The method of claim 4 , wherein:
the applying the second condition comprises drawing a fourth current from the PV device, and
the fourth current is different from the third current.
6. The method of claim 3 , wherein the first current is achieved by short-circuiting the PV device, such that the first current is equal to the short-circuit current (I sc ) of the PV device.
7. The method of claim 6 , wherein the second current is achieved by regulating the second current to a value between 0.01 I sc and 0.99 I sc .
8. The method of claim 7 , wherein:
the second current corresponds to varying the second current between 0.01 I sc and 0.99 I sc , and
the measuring of the second intensity is performed during at least a portion of the varying.
9. The method of claim 1 , wherein at least one of the first luminescing or the second luminescing produces light comprising a wavelength between 800 nm and 1300 nm.
10. The method of claim 9 , further comprising filtering at least a portion of the light.
11. The method of claim 1 , wherein the applying the first condition and the applying the second condition are performed while the surface is exposed to sunlight.