PV Irradiance Meters & I-V Digital Analyzers (Curve Tracers)

I-V curve illustrates the electrical output profile of a PV cell, module or array and certain points on a I-V curve are used to rate the module or the string performance. That is most of the time achieved in conjunction with additional reporting software. An I–V curve characteristics are changing with the temperature or with the level of the irradiance. In order to trace an I-V curve on all four channels: current, voltage, temperature and irradiance we have to sample both the Idv and Vdc respective temp and irradiance with a frequency of hundreds measurements per minute  and the I–V curve analyzer has to provide a capacitive load at its own end to resonate the outgoing and incoming waves signals against a calibrated probe. 

Our I–V curve analyzer products promoted by Clean Energy Brands are used to commission, to troubleshoot or to retrofit PV system installations. Modules are ratted based on electrical performance for the purpose of marketing or as an aid during the PV system design.  Financial incentives are granted based on performance of the PV system.  Every PV module is delivered with a “Name Plate” ratting at Standard Test Conditions (STC) corresponding to any NEC requirements. The most significant ratted values are I-V standard values and the "Pick Power" value. Those are listed on the name plate attached to the back of the solar module. The I-V values measured are short circuit ampacity and open circuit voltage at standard test conditions (STC). Manufacturers have to guaranty the pick power value for a +/- 10% from the pick power listed on the name plate.

Some states respective some of the utility companies require different other type of ratting certificates which are being provided by independent laboratories. This type of ratings try to simulate and match the real life cycle of a PV module.  In  this way we will have a flattening of the I –V curve with a reduction in "Pick Power" value listed for the module.