Photovoltaic Output Prediction using Monotonic Fuzzy System

This paper presents a method to predict photovoltaic (PV) output using a fuzzy system. Firstly, we estimate the solar radiation using weather information which is obtained from Korea Meteorological Administration. In this process, we utilize the qualitative relationship between the cloudiness and solar radiation; that is, the solar radiation is monotonically decreasing with respect to the cloudiness. To reflect this monotonicity on predicting the solar radiation, we use a fuzzy system whose input-output relationship is constrained by the monotonicity; it is called a monotonic fuzzy system (MFS). Secondly, we predict the PV output based on the predicted solar radiation, the capacity of PV system and so on. In the simulation, we show that the results of the MFS are better than those of conventional fuzzy system for the PV output prediction.