Calibration of the Sandia Array Performance Model Using Indoor Measurements

The Sandia Array Performance Model (SAPM) describes the DC output of a PV module under a range of irradiance and temperature conditions. Coefficients for SAPM are normally obtained through a sequence of on-sun tests, which can be expensive and time-consuming. We report progress towards developing test methods and analysis procedures to obtain coefficients for SAPM from indoor testing. We compared module output predictions from SAPM with coefficients extracted from indoor test results, to measured on-sun module output, and found biases in the predicted performance. We hypothesize that these biases result from the uniform cell temperatures during indoor testing, whereas measured cell temperatures vary by up to 10 degrees C among cells during on-sun conditions. However, we also hypothesize other explanations for the observed biases.