Characterization and modeling of a grid-connected photovoltaic system using a Recurrent Neural Network

Photovoltaic (PV) system modeling is used throughout the photovoltaic industry for the prediction of PV system output under a given set of weather conditions. PV system modeling has a wide range of uses including: prepurchase comparisons of PV system components, system health monitoring, and payback (return on investment) times. In order to adequately model a PV system, the system must be characterized to establish the relationship between given weather inputs (e.g., irradiance, spectrum, temperature) and desired system outputs (e.g., AC power, module temperature). Traditional approaches to system characterization involve characterizing and modeling each component in a PV system and forming a system model by successively using component models. This paper lays the groundwork for using a Recurrent Neural Network (RNN) to characterize and model an entire PV system without the need to characterize or model the individual system components. Input/output relationships are “learned” by the RNN using measured system performance data and correlated weather data. Thus, this method for characterizing and modeling PV systems is useful for existing PV system installations with several weeks of correlated system performance and weather data.