A Self-Reconfigurable and Fault-Tolerant Induction Motor Control Architecture for Hybrid Electric Vehicles

International audienceThis paper describes an adaptive control system for an induction motor drive that propels a Hybrid Electrical Vehicle (HEV). It has been designed to comply with the major requirements of HEVs electric propulsion. The fault tolerant controller is based on a Field Oriented Control with 4 IP regulators, a speed sensor and two observers (Extended Kalman Filter (EKF) and an Adaptive Observer (AO)) to guarantee the best dynamic performances required by the application and also to improve the reliability in the event of sensor loss or sensor recovery. The tuning of the observers is based on extensive simulations, experimental results and optimization procedure within an open-loop type approach. The fault tolerant controller reorganization is based on a control decision block implemented with a Maximum Likelihood voting algorithm. The results of the control system show the effectiveness of the approach. Indeed experimental results of the EKF used in closed loop confirm the validity of the sensorless controller and the fault tolerant controller simulation results in the event of speed sensor loss and recovery are very promising even in case of stator resistance variation

A Passivity-Based Controller Under low sampling for speed control of PMSM

LGEP 2014 ID = 1517International audienceController performances are strongly limited by the switching frequency of the converter and the computa- tional capacity of the target board. The refore, in such a context the design of controllers that provide good performances Under possible large sampling period length is necessary. To tackle these limitations, a digital design is described for speed control of permanent magnet synchronous machines. It is based on the interconnection and the damping assignment passivity-based contro l(IDA-PBC) techniques extensions to the sampled-data context

Reducing the sampling frequency for the control of the switched reluctance machine

This paper presents two solutions for dramatically reduce the sampling frequency and therefore the CPU demand while keeping the same performance in terms of torque ripple and efficiency on a SRM. The problem of a low sampling frequency with a regular control is first highlighted. Then, two different solutions are proposed for the self switching's function. Such solutions tries to magnetize the stator phase at an accurate instant in order to reduce the inherent torque ripple. Simulations results on a 8/6 SRM corroborate the validity of the proposed solutions and show the improvements of its performance.Peer ReviewedPostprint (author’s final draft

Validation expérimentale d'une commande aux perturbations singulières d'un système pile à combustible/super capacités

International audienceCet article traite du problème de la gestion d'énergie d'un système pile à combustible (PaC) à hydrogène associé à des supers condensateurs (SCs) avec de fortes variations de la charge (cf. traction d'un véhicule électrique). La théorie des perturbations singulières est utilisée pour le contrôle et la coordination de deux convertisseurs statiques, l'un associé à la PaC et l'autre aux SCs sous les contraintes suivantes : charge variable et inconnue, en présence des pertes des 2 convertisseurs et une variation du courant de la PaC ne devant pas dépasser 4A/s. La convergence des tensions de la charge et des SCs est analysée en utilisant la théorie de Lyapunov. Des résultats expérimentaux du système PaC-SCs, sont présentés sur un benchmark représentatif de l'application véhicule électrique. Ils permettent de montrer l'intérêt de l'approche utilisée et de souligner les difficultés introduites par la présence des pertes des 2 convertisseurs

Suivi de raies spectrales avec un faible coût de calcul

·Cet article présente le principe et les premiers résultats de caractérisation d'un nouvel algorithme d'estimation de fréquence et de suivi de composantes sinusoïdales. Son principe s'appuie sur la technique de réallocation des représentations temps-fréquence, qui est modifiée pour pouvoir traiter économiquement des signaux à valeurs réelles. Les résultats obtenus ne semblent pas moins intéressants que ceux fournis par les approches récemment publiées

Educational Fiscal Policy and Its Effects on How our Children Learn: Comparing Minnesota and Illinois

The study compares Illinois’ and Minnesota’s education fiscal policies. Illinois funds it’s education system mainly from the local level, whereas Minnesota funds it’s mainly from the state level. Thus, in Illinois, if there are discrepancies between household incomes in wealthier and poorer areas, the schools in wealthier areas would receive more money than those in poorer areas. Test scores are then compared. Illinois typically has lower scores than Minnesota. The conclusion is that Illinois’ policies are hindering their students’ learning, compared to Minnesota students, with some mixed results

Industrial applications of the Kalman filter:a review

International audienc

Response of the mantle to flat slab evolution: Insights from local splitting beneath Peru

The dynamics of flat subduction, particularly the interaction between a flat slab and the overriding plate, are poorly understood. Here we study the (seismically) anisotropic properties and deformational regime of the mantle directly above the Peruvian flat slab. We analyze shear wave splitting from 370 local S events at 49 stations across southern Peru. We find that the mantle above the flat slab appears to be anisotropic, with modest average delay times (~0.28?s) that are consistent with ~4% anisotropy in a ~30?km thick mantle layer. The most likely mechanism is the lattice-preferred orientation of olivine, which suggests that the observed splitting pattern preserves information about the mantle deformation. We observe a pronounced change in anisotropy along strike, with predominately trench-parallel fast directions in the north and more variable orientations in the south, which we attribute to the ongoing migration of the Nazca Ridge through the flat slab system

A laboratory nanoseismological study on deep-focus earthquake micromechanics

Global earthquake occurring rate displays an exponential decay down to ~300 km and then peaks around 550 to 600 km before terminating abruptly near 700 km. How fractures initiate, nucleate, and propagate at these depths remains one of the greatest puzzles in earth science, as increasing pressure inhibits fracture propagation. We report nanoseismological analysis on high-resolution acoustic emission (AE) records obtained during ruptures triggered by partial transformation from olivine to spinel in Mg2GeO4, an analog to the dominant mineral (Mg,Fe)2SiO4 olivine in the upper mantle, using state-of-the-art seismological techniques, in the laboratory. AEs’ focal mechanisms, as well as their distribution in both space and time during deformation, are carefully analyzed. Microstructure analysis shows that AEs are produced by the dynamic propagation of shear bands consisting of nanograined spinel. These nanoshear bands have a near constant thickness (~100 nm) but varying lengths and self-organize during deformation. This precursory seismic process leads to ultimate macroscopic failure of the samples. Several source parameters of AE events were extracted from the recorded waveforms, allowing close tracking of event initiation, clustering, and propagation throughout the deformation/transformation process. AEs follow the Gutenberg-Richter statistics with a well-defined b value of 1.5 over three orders of moment magnitudes, suggesting that laboratory failure processes are self-affine. The seismic relation between magnitude and rupture area correctly predicts AE magnitude at millimeter scales. A rupture propagation model based on strain localization theory is proposed. Future numerical analyses may help resolve scaling issues between laboratory AE events and deep-focus earthquakes

Characterisation of adipocyte-derived extracellular vesicle subtypes identifies distinct protein and lipid signatures for large and small extracellular vesicles

Extracellular vesicles (EVs) are biological vectors that can modulate the metabolism of target cells by conveying signalling proteins and genomic material. The level of EVs in plasma is significantly increased in cardiometabolic diseases associated with obesity, suggesting their possible participation in the development of metabolic dysfunction. With regard to the poor definition of adipocyte-derived EVs, the purpose of this study was to characterise both qualitatively and quantitatively EVs subpopulations secreted by fat cells. Adipocyte-derived EVs were isolated by differential centrifugation of conditioned media collected from 3T3-L1 adipocytes cultured for 24 h in serum-free conditions. Based on morphological and biochemical properties, as well as quantification of secreted EVs, we distinguished two subpopulations of adipocyte-derived EVs, namely small extracellular vesicles (sEVs) and large extracellular vesicles (lEVs). Proteomic analyses revealed that lEVs and sEVs exhibit specific protein signatures, allowing us not only to define novel markers of each population, but also to predict their biological functions. Despite similar phospholipid patterns, the comparative lipidomic analysis performed on these EV subclasses revealed a specific cholesterol enrichment of the sEV population, whereas lEVs were characterised by high amounts of externalised phosphatidylserine. Enhanced secretion of lEVs and sEVs is achievable following exposure to different biological stimuli related to the chronic low-grade inflammation state associated with obesity. Finally, we demonstrate the ability of primary murine adipocytes to secrete sEVs and lEVs, which display physical and biological characteristics similar to those described for 3T3-L1. Our study provides additional information and elements to define EV subtypes based on the characterisation of adipocyte-derived EV populations. It also underscores the need to distinguish EV subpopulations, through a combination of multiple approaches and markers, since their specific composition may cause distinct metabolic responses in recipient cells and tissues