The Distributed PV Generation Output Power Forecasting Based On Wavelet Neural Network

PV output prediction is an important part of the planning of the grid. The PV array output power is affected by the environment. The output power has randomness, Intermittent and instability. The forecast accuracy of PV output power that related to the power system security, stability, operation. It have a great impact to network planning, power system scheduling, power marketing and power generation companies bidding. Therefore, improve PV output prediction accuracy is the main contents of this thesis.On the basis of the analysis of existing BP neural network, wavelet neural network prediction method, this paper proposed a prediction model that based on improved wavelet neural network algorithm, the model combines the excellent performance of the wavelet neural network and Levenberg-Marquardt algorithm for numerical optimization. On the selection of training samples, this paper using data mining techniques, the use of improved combination of similarity and Euclidean distance to classify the sample database. BP neural network, wavelet neural network and improved wavelet neural network of the three models on the sunny, cloudy, cloudy to overcast, moderate set of four samples were carried out to predict and the actual value of the analysis and comparison, by the relative error and average relative error indicators to assess the predictive models used in this article. Results show that the improved algorithm of wavelet neural network prediction model prediction of sunny to cloudy, cloudy to overcast, moderate rain, the accuracy should be high, cloudy, cloudy to overcast, moderate rain samples using improved wavelet neural network algorithm model can predict the approximate reaction PV output trends, still has high reference value for the photovoltaic power generation system with the power system to develop power generation plan, to prove the correctness and effective of this thesis based on improved wavelet neural network PV output prediction model. The same time, this thesis use ADRC control technology that used to control in photovoltaic DC-DC. Displayed by the simulation results show that ADRC control technology can improve the output characteristics of PV in the external conditions change, PV maximum power output and improve the efficiency of the photovoltaic power generation.