K. Kassmi

Analysis, optimization and modelling of electrical energies produced by the photovoltaic panels and systems

The works realized in this article concern the simulation in Pspice and the experimentation operation of the photovoltaic (PV) panels and systems. We have analyzed the optimal operation of PV panels as a function of the weather conditions (solar irradiation, temperatures…), and design of a PV system provided with MPPT control ensuring instantaneously the optimal operation of PV panels. The various results obtained show that the optimal electrical properties (voltage, current and power) of PV panels depend on the solar irradiation and the panels association (parallels or series). Also, the PV system optimizes the operation of PV panels independently the load nature: number of batteries,…

Design and realization of a photovoltaic system equipped with a digital MPPT control

The work presented in this paper concerns the conception and the realization of a photovoltaic system (PV) provided with a digital MPPT control. More particularly, we present the functioning and the improvement of the performances of a PV system adapted by a digital MPPT control further to the sudden variations of the weather conditions (solar irradiation,…) and the load. This is obtained by the implementation of a digital MPPT control extremal with a microcontroller PIC. The role of this MPPT control is to follow the maximal power point (MPP) of the PV panel independently to disturbances of the system (variation of the irradiation). We have experimented the PV system during days, when the solar irradiation presents sudden variations. The obtained results show the immediate oscillation of the point of functioning of the panel around the MPP independently of the variations of the irradiation. The good functioning of the DC-DC converter Boost (in order of 90 %) and the low energy power losses by the PV panel (lower than 10 %) allowed us to conclude the good functioning and satisfactory performances of the PV system realized in this work.

Regulation of electric power of photovoltaic generators with DC-DC converter (buck type) and MPPT command

In this paper we have analysed in Pispce and in experiments the operation of a PV system formed with a converter DC-DC of the buck type, MPPT command and Circuit Command buck (CCB). We have showed that the CCB circuit commands the switch of the DC-DC converter and the PV panel operates at its optimal voltage. The later is fixed in function of ambient weather conditions.

Regulation of electric power provided by photovoltaic panels systems

In this article we analyzed the design in Pspice and carried out a photovoltaic system (PV) of average power (100 W). In this system the operation of generator PV is controlled by an analog command MPPT and a DC/DC converter (Boost). In the case of two batteries (12V, 115 Ah) in series, we showed that the generator PV functions instantaneously under the optimal conditions independing of the solar radiation variation, and that the converter efficiency is very satisfactory (about 90%). The whole of the results show in one hand very an good agreement between the results simulated in Pspice and those experimental, and in the other hand the possibility of using system PV in an installation PV

Design and realization of a photovoltaic system equipped with MPPT command and detection circuit of the dysfunction and convergence the system (CDCS)

In this paper we have analyzed the design, realization and optimization of a photovoltaic (PV) system provided with MPPT command and detection circuit of dysfunction and reconvergence the system (CDCS) to the new maximum power point (MPP) following a perturbation due to weather variation (solar irradiation, temperature, ‥) and the load. The results obtained show very good agreement between simulation and experiment. The experimental system realized during cloudy days or by varying the load, shows that it operates under optimum conditions independently of meteorological variations. At each perturbation the system detects it and CDCS reconvergence the system without restart it. The good efficiency of the DC-DC (about 90 %) converter used and the low loss (less than 7%) shows that the system realized can be used in a PV installation to minimize losses due to connecting the panels to the load and in particular to minimize the cost of the installation.

A PV System Equipped with a Commercial and Designed MPPT Regulators

In this work, we present the results concerning the design, implementation and test of a photovoltaic installation with two regulation systems, one is a commercial regulator and the other is designed in this work. This latter optimizes the installation operation by a new approach with improved control blocks: MPPT, charging/discharging process, estimates the state of charge and manages the energy between blocks. The regulation systems experiment during 4 days with weather disturbances shows the robustness of the designed one which improves the battery life: the accuracy and speed on the maximization of the power supplied by panels, precision of the state of charge estimation, improvement of the energy management at the charge/discharge.

Modeling and simulation of a solar oven box-type with thermal storage

The purpose of this study is to analyze the energy behavior of a solar oven box-type with four reflectors inside and outside and with thermal storage. To achieve this work, we have modeled the equations of heat balances transient by numerical simulation by using Matlab (the method of runge-kutta of order 4). Hence, we were able to determine the temperature profiles in different parts of the oven as well as in the material storage.

A new MPPT approach for photovoltaic stand-alone systems

This work has an interest to study the performance of the MPPT control proposed in the case of standalone PV installations where batteries are used for the storage of the energy produced. We analyze the feasibility, the rapidity of our MPPT control and also its precision. In addition to that, a special attention was given to compare performances of the proposed MPPT control to simulation results (optimums) obtained from Pspice software. The results obtained during the installation testing show an average improvement of efficiency, precision and energy production.

Design and modeling of a photovoltaic system connected to the electrical network

In this paper we propose the structure and the functioning of a photovoltaic (PV) connected to the electric distribution and transmission network, equipped with the malfunction detection blocks. The studies that were carried focused on the injection of a power of 16 KW, produced by a PV panel field, on the electrical network of medium voltage (25 KV). In order to the reliability of the injection system on the network and minimize power losses, we have inserted the blocks that control the opening and closing of power switches of the DC / AC converter that synchronize the phase, amplitude and that the frequency of the voltage and the current injected on the power grid. The obtained results show that the designed system detects the dysfunction of the network side system (voltage dips, phase load shedding, frequency fluctuation, imbalance three-phase system), the field side of PV panel (distrust converters …) and ensures the injection of electrical energy on the network during operation of the PV system.

Monte Carlo simulations of thin semiconductor films deposition. Case of InAs/GaAs

Monte Carlo simulation of heteroepitaxial growth with large mismatch is reported. The simulation model combines Monte Carlo method with an energetic model derived from the Valence Force Field (VFF). The energetic model is needed to determine stress and strain in the deposited film. Through the use of Monte Carlo method, it was possible to handle the random nature of the heteroepitaxial growth based on Arrhenius law and Poisson process. The results concern (1) the morphology of the surface, particularly the formation of islands defined by the (111) facets, (2) the growth mode as well as the formation of cavities in the deposited layers defined by these facets, (3) the strain relaxation in the deposited film. The case of In/As/GaAs transition (8% lattice mismatch) is investigated.