Uncorrected Author Proof
Journal of Intelligent & Fuzzy Systems xx (20xx) x–xx
DOI:10.3233/JIFS-201279
IOS Press
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Photovoltaic power forecasting using
wavelet Neuro-Fuzzy for active solar
trackers
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St´ efano Frizzo Stefenon
a,b,∗
, Christopher Kasburg
a
, Roberto Zanetti Freire
c
,
Fernanda Cristina Silva Ferreira
a
, Douglas Wildgrube Bertol
b
and Ademir Nied
b
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Electrical Engineering, Center of Exact and Technological Sciences (CCET), University of Planalto Catarinense
(UNIPLAC), Lages SC, Brazil
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Electrical Engineering Graduate Program (PPGEE), Department of Electrical Engineering, Santa Catarina
State University (UDESC), Joinville SC, Brazil
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Industrial and Systems Engineering Graduate Program (PPGEPS), Polytechnique School (EP), Pontifical
Catholic University of Parana (PUCPR), Curitiba PR, Brazil
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Abstract. The generation of electric energy by photovoltaic (PV) panels depends on many parameters, one of them is the
sun’s angle of incidence. By using solar active trackers, it is possible to maximize generation capacity through real-time
positioning. However, if the engines that update the position of the panels use more energy than the difference in efficiency,
the solar tracker system becomes ineffective. In this way, a time series forecasting method can be assumed to determine the
generation capacity in a pre-established horizon prediction to evaluate if a position update would provide efficient results.
Among a wide range of algorithms that can be used in forecasting, this work considered a Neuro-Fuzzy Inference System due
to its combined advantages such as smoothness property from Fuzzy systems and adaptability property from neural networks
structures. Focusing on time series forecasting, this article presents a model and evaluates the solar prediction capacity using
the Wavelet Neuro-Fuzzy algorithm, where Wavelets were included in the model for feature extraction. In this sense, this
paper aims to evaluate whether it is possible to obtain reasonable accuracy using a hybrid model for electric power generation
forecasting considering solar trackers. The main contributions of this work are related to the efficiency improvement of PV
panels. By assuming a hybrid computational model, it is possible to make a forecast and determine if the use of solar tracking
is interesting during certain periods. Finally, the proposed model showed promising results when compared to traditional
Nonlinear autoregressive model structures.
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Keywords: Photovoltaic panels, Neuro-Fuzzy inference system, time series forecasting, wavelets, solar trackers 26
1. Introduction 27
There exist different types of solar trackers, from 28
sensor-based to sensorless systems. A sensor-based 29
solar tracker considers a closed-loop system where 30
photosensors are used for tracking the sun direc- 31
∗
Corresponding author. St´ efano Frizzo Stefenon, E-mail:
stefanostefenon@gmail.com.
tion using a feedback control scheme [1]. Frequently, 32
light-dependent resistors (LDRs) are assumed to pro- 33
vide feedback signals to obtain the correct azimuth 34
angle showing the daily path of the sun. In appli- 35
cations involving photovoltaic (PV) panels, solar 36
trackers can maximize the amount of energy to be 37
captured by changing panels position. To obtain the 38
best performance, motors are used for position adjust- 39
ment, however, if the motors are not correctly sized 40
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