Voltage control of DC-DC Three level Boost converter using TS Fuzzy PI controller

International audienceAppropriate control contributes essentially in the design of efficient DC-DC converters. With this intention, a study deals with the synthesis of a controller for DC-DC Three-level Boost converter (TLBC), has been addressed. The studied TLBC, known as nonlinear system, has been locally modeled using transfer function models. For instance, PI controllers were designed using the local models, and then they were combined using Takagi-Sugeno fuzzy (TSF) approach to form a TSF-PI controller. Simulation tests show the flexibility of the proposed controller, its rejection capability to different disturbances, and its ability to achieve the performance specification overall the wide operating range of the system

Contribution to efficiency enhancement of a photovoltaic energy conversion chain

Grâce à son caractère d’abondance et d’innocuité pour l’environnement, l'énergie photovoltaïque représente l'une des technologies les plus prometteuses pour relever le défi mondial du changement climatique et répondre au besoin d’une énergie propre et d’un développement durable. L'objectif de cette thèse est d'apporter une contribution scientifique au domaine de la conversion de l’énergie photovoltaïque. Cette contribution vise principalement l’optimisation de la production de l’énergie photovoltaïque ainsi que son transfert vers la charge avec le minimum de pertes possibles. Dans un premier temps, nous avons modélisé les éléments d’une chaîne typique de conversion d’énergie photovoltaïque et validé ces modèles dans le but de les utiliser pour la synthèse d’algorithmes de contrôle fiables. Ensuite et afin d'obtenir un rendement énergétique maximal, nous avons développé une nouvelle commande (MPPT), basée sur la logique floue et le contrôle non linéaire backstepping, permettant une poursuite du point de puissance maximum rapide et précise. Cette commande est validée en simulation et expérimentalement sous des conditions atmosphériques réelles. Pour réduire les pertes dans les composants de puissance lors de la conversion d’énergie, nous avons choisi d’utiliser un convertisseur DC-DC Boost trois-niveaux, connu par ses caractéristiques intéressantes en termes d’efficacité et de fiabilité. Une présentation détaillée de la conception pratique de ce convertisseur a été donnée. Nous nous sommes intéressés ensuite au développement de stratégies performantes pour la commande en poursuite du convertisseur et pour l’équilibrage des tensions des condensateurs en sortie.The transition to renewable energy sources has recently received a greater consideration due to their incredible reduction of the greenhouse gas emissions. Solar photovoltaic energy is one of the cleanest and most abundant energy sources on the planet, which make it a reliable means of supplying electricity to the world. This thesis mainly focuses on the optimization of the photovoltaic energy production as well as its transfer to the load with the minimum possible losses. First, the elements of a typical photovoltaic power conversion chain are modeled in order to use the resulted models for the synthesis of reliable control algorithms. Then and in order to obtain maximum energy efficiency, we have developed a Takagi-Sugeno Fuzzy- integral backstepping- based hybrid MPPT technique enabling rapid, accurate and efficient tracking. This MPPT technique is verified through simulations via Matlab/Simulink and experimental outdoor tests. To reduce the losses in the PV power conversion system, we have chosen to use the three-level DC-DC Boost structure, known for its interesting characteristics in terms of efficiency and reliability. A detailed presentation of the practical design of this converter structure has been given. Afterwards, we focused on the development of effective strategies for the converter output control and for the balancing of the output capacitors voltages

Simulation and Experimental Validation for Takagi-Sugeno Fuzzy-Based Li-ion Battery Model

International audienceThe significant growth in electric vehicles use has increased the demand for lithium-ion batteries. Battery modeling is vital for optimal and safe usage of batteries. In this paper, a novel battery model based on the Takagi-Sugeno fuzzy has been proposed. It has been demonstrated that the battery behavior is strongly dependent on its state of charge (SoC). As a result, the developed model takes into account the SoC effect, which can significantly improve the model accuracy. Simulation and experimental tests validated the pertinence of the proposed model. It has been also shown that the estimated battery internal voltage is identical to the experimental ones with a low root-mean-square error under different operating conditions. Overall, a model with high accuracy and reasonable computational time of a lithium-ion battery is created.&nbsp

A Novel Control Technique for Voltage Balancing in Bipolar DC Microgrids

International audienceThe bipolar DC microgrid topology is characterized by three voltage levels and is able to transfer power more efficiently than a conventional DC microgrid. This paper proposes an advanced control strategy aiming to ensure the voltage balancing between the upper and lower terminals of a bipolar DC microgrid regardless of the distribution of loads. The proposed controller is based on the backstepping method, which is well known for its the robustness and the global asymptotic stability that can be guaranteed for the system. A particle swarm optimization algorithm has also been adopted for an optimal design of the proposed controller parameters. Simulation results in a Matlab/Simulink environment has been presented to verify the effectiveness and reliability of the proposed voltage-balancing controller

Advanced cascade control strategy applied to an indirect hybrid solar-gas dryer: Numerical and experimental investigations

International audienceIn this paper, a cascade control strategy is applied to control the temperature inside a hybrid solar-gas dryer. In order to use the dryer even at night and in unfavorable weather conditions, the drying chamber is heated by two systems. The first one is the solar air heater and the second one is the gas heater. The solar collector heater is relatively slow compared to the gas heating system. Static and dynamic studies were established and haverevealed the nonlinear behavior of each dryer subsystem. The cascade control approach was developed to control the drying temperature at different setpoints in a temperature range of [50 °C, 90 °C] by managing the gas flow delivered to burners according to received solar energy. Simulation tests followed by experimental investigations have revealed that the proposed control strategy has been able to fulfill the desired dryer performances at different temperatures level, with apropitious steady-state error, reduced overshoot, and a fast transient settling time. Hence, for controlled temperatures at 60 °C, 70 °C, and 80 °C temperatures, the following performances were respectively obtained: a steady-state error of 0.5%, 0.28%, and 1.28%, an overshoot of 2.6%, 4.1%, and 2.5%, and a settling time of 20 min, 18 min, and 30 min. The developed control approach has shown also an effective perturbance rejection during the dryer operation. The proposed controltechnique and the manufactured kit can be easily integrated into hybrid dryers and it’s an adequate and compatible solution with solar dryers for a drying operation of wide agro-food products. This solution also makes it possible to optimize the energy consumption of the secondary source

Modeling and design of a solar-powered refrigerator for vaccines transportation in remote regions

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A Reliable Power Management Strategy of a PV-Based Electric Scooters Charging Station

International audienceThe charging infrastructure is one of the most important incentives for widespread electric vehicles adoption. This paper presents an example of an off-grid photovoltaic-based charging infrastructure for e-scooters with six chargers installed at Cadi Ayyad University in Marrakesh, Morocco. The principal configuration of the station has been introduced. Moreover, a power management strategy has been proposed. Specifically, an efficient distribution of the energy between PV array, battery storage and loads under different operating conditions, has been developed and simulated under MATLAB/Simulink