Electro-Thermal Modeling of Solar Photovoltaic Arrays

Abstract

The objective of the present work is to develop a dynamic electro-thermal model for photovoltaic cells to optimize both electrical and thermal performance of such systems. The thermal model is developed by generating the equivalent RC network (resistance-capacitance) parameters. Then, the thermal model is combined with electrical model and implemented by PSIM simulation program to evaluate performance parameters for any predefined operating condition. The electro-thermal model predicts instantaneous temperature of photovoltaic device at the actual circuit working conditions. Consequently, the temperature rise during the system startup and during load transient is investigated. The thermal model predicts the junction temperature based on transient heat dissipation calculated from the electrical model. The calculated junction temperature is used as an input to the electrical model. The factors that control the junction temperature are module reaching irradiance, optical properties of the photovoltaic cell, photovoltaic conversion efficiency, heat transfer and electrical characteristic of the load. If the junction temperature exceeds a certain limit, it causes hotspot on the photovoltaic module surface. Consequently, the formed hotspots result in reducing the system efficiency and life time. The predicted dynamic behavior of photovoltaic cell is compared with theoretical predictions and other reported data in order to validate the developed model. The obtained results show a good concurrence with the predictions of other works. Detailed comparisons between predicted and measured results are reported and discussed.