Как выбрать гостиницу для кошек
14 декабря, 2021
For the measurement of the internal series resistance (which desribes internal losses and losses due to bad contacts as well) two IV-curves of different irradiance but of the same spectrum and at the same temperature are necessary according to IEC 60891 [6].
From the two characteristics two working points V1 and V2 have to be obtained of which the series resistance can be calculated.
The two working points are determined as follows: Definition of a current interval AI. Here:
(8) (9) (10) |
(11) |
AI = 0.5 — Isc2
Determination of the working points V1 and V2 with (2)
Vi=V(Isci-AI, Rpvi, Vti, I01, Iphi) V2=V(Isc2-AI, Rpv2, Vt2, I02, Iph2) Calculation of the series resistance
Isc1 Isc2
Fig.4. Rs-Measurement of single PV-Modules |
For single cells and single modules the second IV-curve can be obtained by covering the cell or module with an insect-screen.
For large PV-generators (several kW) this method could not be applied. A new method is here necessary which allows to determine the internal series resistance out of only one IV — curve under illumination.