International Renewable Energy Congress November 5-7, 2009 - Sousse Tunisia Monitoring and control of the performances for photovoltaic systems M.Hamdaoui 1 , A. Rabhi 2 , A. El Hajjaji 2 , M. Rahmoun 1 , M. Azizi 1 1 Université Mohamed 1 st Faculty of Science Oujda Morocco 2 M.I.S (Laboratory of Modeling, Information and Systems) 7, Rue Moulin Neuf, 80610 Amiens hamdaoui_mohammed@yahoo.fr ABSTRACT In this article we propose a method for the monitoring and control of the performances of the PV (photovoltaic) systems. The method is divided into two parts. In the first, one carries out the characterization of PV modules under various weather conditions (temperature and illumination) in order to follow the degradation of the performances of the solar panels. The second part is dedicated to real-time comparison of the power produced by PV to that obtained from simulation model developed using Matlab/simulink software. This last was validated by using the data accessible on the software from NASA “HOMER”. The real results show the effectiveness of the method suggested. Index Terms— Photovoltaic, control, data acquisition, dimensioning, system of measurement, fault detection. 1. INTRODUCTION The fast evolution of the renewable energy sources (SRE) during the two last decades had as consequence the installation of many systems in the world. The disadvantage of the latter is the high cost of installation. The good dimensioning of a PV installation is very important initially for the optimization of its size and its cost. Then, it is important to continuously follow and control the performances of this PV installation. Electrical faults and the aging of PV modules cause a malfunction of the photovoltaic system. Several research laboratories were interested about the SRE [2,3] and various techniques were developed either for dimensioning, the regulation to have a maximum of power [4],or for the fault detection [5,6,7]. The monitoring and the control of the performances of system state and their produced powers are the higher importance to evaluate them continuously, to monitor the evolution of their capabilities, and to detect the faults. In this article, we present a technique which contributes to the detection of the faults and to monitoring the degradation of the performances of a PV system. 2. CONTROL AND MONITORING OF THE PERFORMANCES FOR SOLAR MODULES 2-1 Modeling of generator statement The electric power generated from the PV panels depends on the intensity of the sunning, and the temperature of the cells. The equivalent electric diagram of a PV cell is given by figure 1. - Where I L represents the photocurrent developed in the photovoltaic cells by the solar radiation. - Resistances R S and R P respectively represent resistances of the metal contacts and escapes of junction PN. - D represents a junction PN. Current I D circulating in this diode, polarized by a tension V D , is given by the expression:                1 exp KT qV I I D Sat D The model of a photovoltaic cell under a solar radiation is Ipv R S Vp R p I L D I D V D Figure 1: Electric diagram equivalent of a cell of a PV module - 69 -