Search

The model predictive torque control (MPTC) schemes of three-level neutral point clamped (3L-NPC) inverters have multiobjective cost functions, including three weighting factors (WFs). With the lack of theoretical approaches that make rapid the WFs online-tuning, the paper proposes a predictive flux control strategy with weighting factor free cost function (WFFPFC) for 3L-NPC inverter fed induction motor (IM) drives. It consists in discarding the following: 1) the flux WF through a generation of the reference stator flux vector; 2) the NP voltage WF by introducing a comparative condition of the dc-bus capacitors voltages at the beginning of each sector; and 3) the switching number WF by selecting a group of seven voltage vectors per sector that enables the clamping of the stator phase voltages at low or high level of the dc-bus voltage. The proposed approach is then applied to a case study, considering a comparison among the performance of the proposed WFF-PFC, the model predictive flux control (MPFC), and the MPTC strategies, considering both steady-state and transient behaviors of the 3L-NPC inverter-fed IM drive. It is found that the elimination of the WFs leads to an improvement of drive features except a slight increase of the NP voltage. Simulation results are validated by experiments.

Marine vascular plants such as Posidonia oceanicaform symbiotic associations with microbiota to enhance nutrient acquisition, supporting plant growth and fitness. The beneficial symbiotic bacteria can theoretically persist in Posidonia oceanicaleaves and balls deposed on sandy beaches as marine cellulosic wastes, opening up new opportunities for their valorization in biotechnological processes. The objective of this work was to characterize the bacterial communities associated with P. oceanicawaste (POW) samples collected from four sandy beaches in northeastern Tunisia. Analysis of metataxonomic datasets showed high bacterial diversity and richness in POW samples with a prevalence of bacteria belonging to the phyla proteobacteria, firmicutes, and actinobacteria. Analysis of alpha and beta diversity metrics also indicated that POW samples show distinct bacterial profiles and abundances at taxa levels from species to phylum. Combined metataxonomic and chemical data revealed that low bacterial diversity correlated with low contents of cellulose and hemicellulose in POW samples, maybe indicating stressed microbial communities. Both culture-dependent and culture-independent techniques showed that POW harbored halophilic bacteria with tremendous potential for carbohydrate-active enzymes (CAZymes) production (cellulases, xylanases, laccases, peroxidases, etc.) and plant growth-promoting activities such as enhancement of nutrients supply/availability and resistance to salt stress by accumulating osmolytes. The selected enzyme-producing halotolerant PGPB, Nocardiopsis synnemataformansPT2, and Halobacillus trueperiPHm3 have been successfully applied in the bioconversion of POW into bioethanol. A maximum bioethanol yield of 41.17% (equal to 10.45 g ethanol/100 g of POW) was recorded at 30 °C and 37 °C for 72 h of fermentation. These results indicated that POW maybe considered as a source of enzyme-producing–plant growth-promoting bacteria with potential applications in sustainable agriculture and bioenergetics.