A model of photo-voltaic generator for education

Photo-voltaic generators are no longer an energy source mainly useful for off-grid applications, such as satellites. Their presence in the energy mix of developed countries has substantially increased. Moreover, their price downward trend, together with the upward trend of electric energy prices, might increase their role, if allowed by the legal context. The behavior of photo-voltaic generators is complex, especially under partial shading. In order to enhance the learning of their characteristic current-voltage curve, the paper presents an easy and fast to apply model. The state of the art for modelling photo-voltaic cells has been reviewed. Upon the different types of models, a balanced option between complexity and precision has been chosen. Then, a model of a panel is built, by connecting an arbitrary number of cells, with an arbitrary number of bypass diodes. An arbitrary number of panels are connected to construct a string, including the correspondent blocking diode, and a set of strings constitute the generator matrix of panels. The model has been implemented in Matlab. Finally, several exercises have been developed, following a "learning by doing" methodology: students learn, from the influence of the cell parameters on its current-voltage curve, to the generator behavior under partial shading.