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This article concerns the applicability of the 13-09 law on renewable energy in Morocco for free production of electric power from photovoltaic stands. The maximum power permitted is 20 kW. First, we present the structure of the PV platform allowing this production with the highest voltage possible. Afterward, we consider the inverter for transforming the DC to the AC voltage. We have adopted a three-phase topology. Indeed, article 5 of the act states that the connection of the renewable power sources to the public grid can be only on the medium, high or extra high voltage. For reducing the harmonics effect, we have chosen a multilevel inverter. As the authorized power is low, the transformer characteristics are not standardized, which leads to additional costs.

Most of the simplified models consider that the diffuse irradiance received by a sloped plane can be split into a hemispherical part and a circumsolar part. This paper deals with the hemispherical part, as obtained by integration of the hemispherical sky radiance contribution. It is based on the Perez assumption, widely used in practice, that hemispherical sky radiance is uniform on the entire sky with the exception of a horizon band assigned to a different radiance value. Perez uses an approximate formula for the contribution of that horizon band. In this paper, an exact analytical expression of the irradiance due to the Perez horizontal band is developed and used for comparing exact and simplified values. Significant differences with the simplified Perez formula are observed. The use of our exact formula is thus advisable.

The PV systems are rapidly expanding and have increasing roles in electric power technologies, providing more secure power sources and pollution free electric supplies. Since the PV electricity is expensive compared to the electricity from the utility grid, users want to use all the available output PV power. Therefore, the PV systems should be designed to operate at their maximum output power for any temperature and solar radiation level. In this paper, we consider a photovoltaic panel supplying a battery. For maximizing the output power of this panel, we have using a boost dc/dc converter controlled by a PI regulator. For synthesizing this regulator, we have replaced the converter with an equivalent continuous model when we have considered the mean values, over the chopping period, of the electric quantities. Then, we have developed the transfer function of the system by using the small signal modeling around an optimal operating point. A PI synthesis has been achieved by using Bode method. In the study, we have taken into account the converter losses. Coefficients Kp and KI obtained of PI regulator lead to good simulations. The theoretical results confirm excellent tracking effectiveness response. The regulator operates correctly on a large range.

A model of a photovoltaic array is developed using only the nominal values of the modules: open-circuit voltage, short-circuit current, maximum power point, and the temperature coefficients of the first two parameters. Its originality is that, although the model uses four degrees of freedom for the characteristics I-U at nominal junction temperature, these are fitted without using the temperature coefficients. After that, the temperature coefficients are still available for the determination of the temperature behavior of the elements of the model. A numerical example is presented and the source code used is made available.

In this paper we present the maximum power point tracking (MPPT) for a photovoltaic pumping system by using a fuzzy logic control approach. The system consists of a photovoltaic generator (PVG) with a power electronic converter allowing the optimal operating point tracking, the whole is feeding a DC motor coupling with a centrifugal pump. For the best use, the photovoltaic panel (PV) must operate at its maximum power point (MPP). However the PV panel efficiency, for given conditions, is maximal when its voltage equals a certain value. This optimal voltage depends on irradiance, temperature and panel state. Because it’s robust character and superior performance under the existence of the disturbances and parameters variations, the fuzzy logic control technique is used to adjust continuously the duty cycle of the converter, which is considered as the control law of the system, to track the MPP. Simulation results show the good performances of the system when the proposed control law is applied. Dans cet article, nous présentons une stratégie de poursuite du point de puissance maximale (PPM) d’un système de pompage photovoltaïque, en appliquant une commande robuste à logique floue. Le système considéré est constitué par un générateur photovoltaïque (GPV), avec un convertisseur électronique de puissance, qui alimente un moteur DC associé à une pompe centrifuge. La puissance du panneau photovoltaïque, pour des conditions données, est maximale quand sa tension est égale à une certaine valeur. Cette valeur optimale dépend de l’irradiation, de la température et de l’état du panneau. Nous proposons l’application d’une commande robuste pour l’ajustement du rapport cyclique du convertisseur électronique de puissance, dont l’objectif est de forcer le système à fonctionner à sa puissance maximale. La synthèse de la loi de commande proposée est basée sur l’approche de la logique floue grâce à sa grande robustesse aux variations des paramètres du processus, aux erreurs de modélisa

Un modèle de module photovoltaïque est développé en utilisant seulement les valeurs nominales du module : tension en circuit ouvert, courant de court-circuit, tension et courant au point à puissance maximale, ainsi que les coefficients de température des deux premiers paramètres et de la puissance maximale. Son originalité est que, bien que le modèle n’utilise que quatre degrés de liberté pour fixer la caractéristique I-U à la température de jonction de référence, ceux-ci sont identifiés sans faire appel aux coefficients de température. Ces trois derniers sont donc encore disponibles pour déterminer le comportement en température des éléments du modèle. Un exemple numérique est présenté et le programme de calcul utilisé est rendu disponible.

Doctorat en sciences appliquées -- UCL, 1997