Experimental Validation of Photovoltaic Direct and Reverse Mode Model. Influence of Partial Shading

AbstractComplete modeling of cells/modules/generators in photovoltaic (PV) systems presents a high interest in actual research in electrical systems in the renewable energies to improve the global generator efficiency. Nevertheless, only a low level of publications treating this subject exists in literature. In the past, Bishop has suggested a model based on a computed mathematical function that supports the reverse mode biased effect of solar cells, i.e. the mode existing when the cells are partially or completely shaded and as a consequence, when these cells behave as receiver instead of source. In Ref. 2 and Ref. 3, Gow and Campbell, have developed physical models respectively but have treated the behaviour of the solar cell under full or reduced illumination in direct mode only. In the present contribution, we discuss experimental results modeled by this DRM model, pointing out the influences of partial shading defects on a single PV cell. The experimental procedure was based on the use of a thermal camera to highlight the rise in temperature and hot spots. Results point out that the shady and the healthy sides of a PV cell are almost in the same state of suffering, in case of non uniform illumination. The experimental results of the DRM were positively compared to the simulation ones based on the model, which is thereby validating together with the experimental process. Finally, using the experimental results, the DRM model is also compared to classical models, and with an implicit model, showing its suitability