Automatic outdoor monitoring system for photovoltaic panels

Long-term acquisition of solar panel performance parameters, for panels operated at maximum power point in their real environment, is of critical importance in the photovoltaic research sector. However, few options exist for the characterization of non-standard panels such as concentrated photovoltaic systems, heavily soiled or shaded panels or those operating under non-standard spectral illumination; certainly, it is difficult to find such a measurement system that is flexible and affordable enough to be adopted by the smaller research institutes or universities. We present here an instrument aiming to fill this gap, autonomously tracking and maintaining any solar panel at maximum power point while continuously monitoring its operational parameters and dissipating the produced energy without connection to the power grid. The instrument allows periodic acquisition of current-voltage curves to verify the employed maximum power point tracking approach. At the same time, with hardware schematics and software code being provided, it provides a flexible open development environment for the monitoring of non-standard generators like concentrator photovoltaic systems and to test novel power tracking approaches. The key issues, and the corresponding solutions, encountered in the design are analyzed in detail and the relevant schematics presented.