Advanced PV module performance characterization and validation using the novel Loss Factors Model

The Loss Factors Model (LFM) [1] allows PV modules of any technology to be characterized by outdoor IV measurements into six normalized, independent and physically significant coefficients plus correction factors for module temperature and spectral mismatch. These fitted coefficients allow the prediction and validation of PV module performance under any weather conditions. Their magnitudes at higher irradiance levels extrapolate to the STC values to be compared with flash test or datasheet values, values at lower irradiance give the low light performance (LLEC), their gradients vs. module temperature determine temperature coefficients alpha, beta, gamma etc. Differences of the individual LFM coefficients can be seen between single or double junction thin film vs. crystalline silicon technologies with the latter having lower resistance losses. The shapes of any changes with time allow the seasonal annealing or degradation of performance to be distinguished and evaluated.