IEC 60904-3-2019 pdf download.Photovoltaic devices – Part 3: Measurement principles for terrestrial photovoltaic (PV) solar devices with reference spectral irradiance data.
This part of IEC 60904 applies to the following photovoltaic devices for terrestrial applications:
– solar cells with or without a protective cover;
– sub-assemblies of solar cells;
– modules; and
– systems.
NOTE The term “test specimen” is used to denote any of these devices.
The principles contained in this document cover testing in both natural and simulated sunlight.
Photovoltaic conversion is spectrally selective due to the nature of the semiconductor materials used in PV solar cells and modules. To compare the relative performance of different PV devices and materials a reference standard solar spectral distribution is necessary. This document includes such a reference solar spectral irradiance distribution.
This document also describes basic measurement principles for determining the electrical output of PV devices. The principles given in this document are designed to relate the performance rating of PV devices to a common reference terrestrial solar spectral irradiance distribution.
The reference terrestrial solar spectral irradiance distribution is given in this document in order to classify solar simulators according to the spectral performance requirements contained in IEC 60904-9.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60891 , Photovoltaic devices – Procedures for temperature and irradiance corrections to measured I-V characteristics
IEC 60904-1, Photovoltaic devices – Part 1: Measurements of photovoltaic current-voltage characteristics
IEC 60904-2, Photovoltaic devices – Part 2: Requirements for photovoltaic reference devices
IEC 60904-5, Photovoltaic devices – Part 5: Determination of the equivalent cell temperature (ECT) of photovoltaic (PV) devices by the open-circuit voltage method
IEC 60904-7, Photovoltaic devices – Part 7: Computation of the spectral mismatch correction for measurements of photovoltaic devices
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Measurement principles
In current practice the photovoltaic performance of a solar cell or module is determined by exposing it at a known temperature to stable sunlight, natural or simulated, and measuring its current-voltage (I-V) characteristic curve while measuring the magnitude of both the incident irradiance and the PV device temperature. Detailed I-V curve measurement procedures are included in IEC 60904-1 . The measured performances can then be corrected to standard test conditions (STC) or other desired conditions of irradiance and temperature according to IEC 60891 .
The corrected power output at the maximum power voltage and STC is commonly referred to as the rated power. Incident irradiance can be measured by means of a PV reference device (whose spectral responsivity shall be known) or, if measuring under natural sunlight, by means of a thermopile-type irradiance detector (pyranometer). If a PV reference device is used, it shall satisfy the requirements specified in IEC 60904-2. Temperature determination of the PV device under test shall be made according to IEC 60904-1 or IEC 60904-5. Since a solar cell has a wavelength-dependent response responsivity, its performance is significantly affected by the spectral distribution of the incident radiation, which in natural sunlight varies with factors such as location, weather, time of year, time of day, orientation of the receiving surface, etc., and with a simulator varies with its type and conditions of use according to IEC 60904-9.
Regardless of whether the irradiance is measured with either a thermopile-type radiometer (that is not spectrally selective) or with a reference solar device, the spectral irradiance distribution of the incoming light shall be known in order to use IEC 60904-7 to calculate the spectral mismatch between the measured performance and the predicted performance under the global or direct reference solar spectral distribution defined in this document. When performing measurements according to the standard test conditions, the spectral mismatch between the PV device under test and the thermopile is usually much larger than the spectral mismatch between the PV reference device and the PV device under test. When the spectral responsivity of the PV device is known as determined according to IEC 60904-8, it is also possible to use IEC 60904-7 to compute the performance of that PV device when exposed to light of any known spectral irradiance distribution.IEC 60904-3 pdf download.