Towards Accurate, High-Frequency I-V Curve Measurements of Photovoltaic Modules Applying Electronic Loads

摘要

We present a new measurement methodology for accurate, high-frequency outdoor I-V characterization of PV modules. A hybrid sweep is performed in order to obtain more detailed I-V curves of the PV module, hereby combining the advantage of a voltage sweep (for good resolution in the near-horizontal parts of the curve) with the advantage of a current sweep (giving precise information about the very steep parts). The new approach is compared to the state-of-the-art current and voltage sweep methods. Furthermore, an advanced data-point distribution algorithm is discussed, which ensures sufficient information in the ranges of interest, while keeping the total amount of required measurement points as low as possible to minimize the data storage, sweep time, and computational effort. The improved technique provides accurate, high-resolution characterization about the maximum power point, MPP without necessarily requiring too many measurement points. The new methods enable I-V measurement frequencies up to 1 Hz (which is essential for accurate energy yield estimations) while maintaining low computational effort.