Single phase grid connected multilevel inverter for isolated and unbalanced PV sources

Large scale photovoltaic fields are favoured for their low cost-per-watt, but exposed to partial shading and other mismatches where the decentralized Maximum Power Point Tracking (MPPT) is recommended. For a grid connection, an inverter is required, but the decentralized inverter solution is expensive and produces poor current Total Harmonic Distortion (THD). Central three level inverter is lower cost but power limited and has also a poor current THD. We propose a decentralized MPPT boost converter based, followed by a central non-uniform multilevel inverter. The PV-generators are the separated DC sources; however they are unbalanced due to unexpectedly variations of lighting, temperature and system faults. The idea here is to limit the power in each level when dimensioning, respecting the Safety Operation Area of the used semiconductors. So, the voltage amplitude of each level depends on the corresponding PV-group and the entire power where a non-uniform multilevel wave can be obtained. The grid current is controlled by a hysteresis relay for power transfer, where an external current and internal voltage control loops are used based on a simple PI regulator. In many Grid-PV systems, the transferred power reference is generated by PV power measurement requiring numerous long wires to the control-unit. Here, the voltage and current references (transferred power) are generated via DC-link voltages feedback. Simulation results show an active power transfer to the grid with a very low current THD even under a hard-unbalanced PV conditions

Performance Analysis of a Flywheel Energy Storage System

The flywheel energy storage systems (FESSs) are suitable for improving the quality of the electric power delivered by the wind generators and to help these generators to contribute to the ancillary services. In this paper, a flywheel energy storage system associated to a grid connected variable speed wind generation (VSWG) scheme using a doubly fed induction generator (DFIG) is investigated. Therefore, the dynamic behavior of a wind generator, including models of the wind turbine (aerodynamic), DFIG, matrix converter, converter control (algorithm of VENTURINI) and power control is studied. This paper investigates also, the control method of the FESS with a classical squirrel-cage induction machine associated to a VSWG using back-to-back AC/AC converter. Simulation results of the dynamic models of the wind generator are presented, for different operating points, to show the good performance of the proposed system

FCS-MPC Current Control of Parallel Photovoltaic Grid Connected Inverter with Common AC and DC Buses

International audienc

Model-Free Controller for Suppressing Circulating Currents in Parallel-Connected Inverters

International audienc

Robust Model Predictive Control (MPC) for large-scale PV plant based on paralleled three-phase inverters

International audienc

Circulating Currents Control for Parallel Grid-Connected Three-Phase Inverters

International audienc

A novel missense mutation in the gene encoding SLURP-1 in patients with Mal de Meleda from northern Tunisia

International audienceBackground : Mal de Meleda (MDM) is a rare autosomal recessive skin disorder which belongs to the clinically and genetically heterogeneous group of palmoplantar keratodermas (PPK). Clinically, MDM is characterized by erythema and hyperkeratosis of the palms and soles with sharp demarcation that appears soon after birth and progressively extends to the dorsal surface of the hands and feet.Objectives : Except for the molecular study reported in Algerian families, MDM has not yet been investigated in the Maghrebian population, characterized by its heterogeneous ethnic background and a high rate of consanguinity. In this study we report genetic and molecular investigations of eight unrelated consanguineous Tunisian families including 17 affected individuals.Methods : Eight large consanguineous MDM families who originated from cities of northern Tunisia, with a total of 17 patients and 22 unaffected family members were investigated. Families were genotyped with the following microsatellite markers: CNG003, D8S1751 and D8S1836. Mutation analyses were performed in affected patients, in both parents and in unaffected individuals. Linkage analysis was also performed.Results : All the clinical features of MDM were constantly present. Nevertheless variable severity was noted among patients. Histological details were recorded. The haplotype analysis of markers CNG003, D8S1751 and D8S1836 revealed that all affected offspring were homozygous by descent for the three polymorphic markers. The maximum lod score value, 3·22, confirmed the evidence for linkage to the ARS gene. Three haplotypes were observed, and the findings suggest that at least three different mutations within the ARS gene segregate with these haplotypes. Three different mutations were identified, the 82delT mutation previously described and two novel missense mutations.Conclusions : The results suggest that the ARS gene is likely to be responsible for MDM in the eight Tunisian families. The clinical variability in the expression of PPK in MDM Tunisian patients might be accounted for by the intervention of modifier genes influencing the MDM phenotype