IEC 62109-3:2020 pdf free download – Safety of power converters for use in photovoltaic power systems
The temperature test will be based on:
a) Environmental temperature as defined in lEC 61730-1:2016 in degrees Celsius for the geographic installation_ location. The minimum shall be 40 c as required byiEC61730-1:2016 and lEC 61730-2:2016.The environmental temperature Tamb is used tocalculate the PV module maximum backsheet temperature (TmaxBs) using formula (1) in4.3.2.1.302.
b) PV Module nominal backsheet temperature (TNBs) in degrees Celsius that is used to calculate the PV module maximum backsheet temperature (TmaxBs)using formula (1) in4.3.2.1.302.The value used for TNBsshall be either:
1) the PV module Nominal Module Operating Temperature(NMOT) rating,
2) the Pv module Nominal Operating Cell Temperature (NOCT) rating,
3) the value of 50 C, or
4) the value according to the method in Annex A on the actual PV element.
NOTE1 Some PV modules may have a NOCT rating instead of a NMOT rating.As defined above, either ratingcan be used to calculate Tm..E, since both ratings are evaluated at 8oo w/m- and an ambient temperature of20 *C. The method used to determine NOCT is considered to produce a higher value than the NMOT methodand represents a more severe test condition.
c)Behind the module air temperature in degrees Celsius will be based on the environmental temperature above and the installation instructions.This temperature shall be the chambertest temperature and is typically greater than the environmental temperature.The followingguidance is provided for determining the behind the module air temperature based on themodule mounting distance according Figure 302 and Figure 303;
MIEinstalled with the entire backsheet exposed to the environmental air temperatureand mounted greater than 1 m above the ground or any other surface: environmentaltemperature or greater;
Multiple MlE installed greater than 100 mm to 1 m above a surface with no baffling thatobstructs air flow: environmental temperature plus 10°C;
Multiple MlE installed greater than 50 mm to 100 mm above a surface with no bafflingthat obstructs air flow: environmental temperature plus 15 °C;
Other constructions and installation methods that are mounted 50 mm or less to asurface，provided with baffling and/or enclosures shall have a separate evaluationperformed before testing the individual module to determine the behind the module airtemperature based on the environmental temperature and heating from the MlE underthe most severe installation condition according to the installation instructions.
NOTE2 Building-integrated or building-attached photovoltaics architectural applications using MIE, have less or noair circulation behind the PV modules for cooling. For such configurations, properties of behind the module airtemperature require further study for MIE thermal testing condition.
The electronic device under test shall not be subjected to direct air movement from an aircirculation chamber. Ilf tested in an air circulation chamber, the electronic device portion ofthe assembly shall be shielded from direct air movement from the chamber fans.Air shieldsor chamber design shall not impede the natural convection flow from the electronics.
The power output of the heat source in 4.3.2.1.300 c) shall be adjusted for the temperatureof the back sheet to stabilize to within -0 °C to 5 °C of the value calculated in b).
The electronic device shall be energized from a power source adjusted to provide the outputpower that would be available from the intended photovoltaic module at an irradiance of 1200 W/m2 and adjusted based on the PV Module temperature coefficient using thetemperature TmaxBs determined in b).For electronics that limit the PV module power orcurrent, this shall be considered in the calculation.