The development of reliable electrical machines must consider the ageing phenomena of winding insulation system. When subjected to PWM-like voltages, the winding insulation degradation may be accelerated through partial discharges (PD). The use of wide band gap power electronics components implies to consider these degradations even for low-voltage applications. To assess the electrical insulation health state of the winding, PD detection can be performed. The aim of this study is to investigate the PD inception in polyimide-epoxy samples designed with an enclosed cavity. A detection system based on an electric field antenna combined with a spectrum analyzer is developed for this purpose. An impulse winding tester and a Silicon Carbide-based power generator are both used to carry out this PD study. Switching frequencies up to 80 kHz are analyzed in terms of PD inception voltage.

This paper relates the design of electromechanical actuators for camber actuation in a morphing flap. In order to reduce fuel consumption, the camber of an articulated wing or flap is controled to reach specific aerodynamic profiles. The wing is divided in 6 parts, connected with 5 hinges. The angles of the hinges are controled by the electromechanical actuators, through a proper leverage and a linear force. The leverages are specified for each articulation from the torques applied on it, which are calculated to reach the profiles under flight conditions. The electromechanical actuators consist in a motor, a gearbox and a screw and nut transmission. Their integration and their torque close control are presented

This paper reports on a study on the development of a hybrid bonding for electrical machine stacks. The hybrid bonding consists in an iron powder adding in the adhesive of the bonding layer of the stack. Two types of iron powder are used: the first is obtained with water atomization, the second with carbon monoxide reduction. Both types provide different properties. The two types of powder are loaded in the stack sample, which consists in a ring core. Characterization measurements are mainly iron losses and permeability measurements. Both powder types resulted in interesting performances, due to the magnetic permeability and potential thermal conductivity improvement. However, the preliminary results should be confirmed with a more detailed characterization, including reproducibility tests. Index Terms-Bonding, Electrical machine, Ferromagnetic steel sheets, Iron powder.

A new method for analyzing the impact of materials and architectures of Power Mechatronic assemblies on the parasitic electromagnetic couplings is presented. In this paper, the stray capacitance of a single-layer iron-core solenoid is analyzed using a PEEC-based 3D method. The results are compared to an analytical calculation of turn-to-turn and turn-to-core capacitance to validate the proposed method. The solenoid is subject to an EM field calculation in order to extract the coupling coefficients between different turns and the core of the inductor. The coupling coefficient matrix is extracted and imported into a Netlist circuit formalism for further analysis and comparison with the analytical calculations. These first derived results will be helpful in the modeling works for solving EMC issues such as transient over-voltage in wound structures of power Mechatronic systems. This is a first step of The Virtual Experimentation Method for future analyzing and designing of compatible Mechatronic subsystems, by integrating materials and architecture parameters into the design process.

In this paper, a multi-cellular piezoelectric actuator has been dimensioned, designed and integrated into an electro-active morphing wall heat exchange demonstrator. The design study was performed using finite element simulations. Numerical study shows that the obtained deflections vary from 77 to 462 μm for applied displacement ranging from 3 to 18 μm. Once the operating principle validated, a series of actuators has been machined and tested. Dynamic tests (unloaded) gives a maximum displacement about 230 μm for a frequency ranging up to 100 Hz. However the static tests give results with a good agreement with simulation. The developed actuators have been introduced into a demonstrator to show the feasibility of an intensification of heat exchange by electro-active morphing. The recovered data have demonstrated the feasibility of pumping for a traveling wave of 5 Hz closing quasi-totally the channel. Another result is the reduction of wall temperatures during the application of a traveling wave on the, thereby that the heat transfer was intensified. Moreover, an increase in the rate of flow was observed. All this results demonstrate the enhancement of heat transfer.

Purpose - The purpose of this paper is to investigate the impact of different mathematical formulations of the problem of optimal design of electrical machines on the results obtained using a local optimization solver. The aim is to investigate the efficiency and reliability of standard local solvers when handling different mathematical formulations. This could provide guidelines for designers in practical engineering applications.Design/methodology/approach - The paper proposes six equivalent mathematical formulations of the optimal design problem of a slotless permanent-magnet electric rotating machine. The authors investigate the impact of these different mathematical formulations on the results obtained using a local optimization solver which is well-known in the engineering community: MatLab's fmincon function. The paper first computationally compares the six proposed formulations with a fixed value for the number of pole pairs p, that gives continuous optimization problems, then discusses some results when p is free on three mixed-integer formulations.Findings - The paper shows that, even though the considered formulations are mathematically equivalent, their numerical performances are different when an optimization solver, such as the one proposed by MatLab in fmincon, is used. Thus, the designer must take care about the formulation of the design problem in order to make more efficient the use of these kind of algorithms.Originality/value - In the context of engineering applications, one usually resorts to well known and easy to use optimization solvers. The same optimization problem can be often formulated in different ways. Furthermore, the formal description of optimization problems has an impact on the applicability and efficiency of the corresponding solution methods. This is usually not taken into account when optimization solvers are exploited. The originality of this paper is in building on the theory of reformulations in mathematical optimization to investigate and highlight the impact of formulation differences.

This paper focuses on the analysis, the modeling and the control of a linear-switched reluctance motor. The application under consideration is medical, and the actuator is to be used as a left ventricular assist device. The actuator has a cylindrical or tubular shape, with a mechanical unidirectional valve placed inside the mover, which provides a pulsatile flow of blood. The analytical expression of the effort based on the linear behavior of the actuator is given. The identification of the characteristics of the prototype actuator and the principle of position control is performed. A modeling of the actuator is proposed, taking into account the variation of inductance with respect to the position. The closed-loop position control of the actuator is performed by simulation. A controller with integral action and anticipatory action is implemented in order to compensate the effects of disturbing efforts and tracking deviations. Moreover, a magic switch is performed in the controller to avoid overshoots. The results show that the closed-loop response of the actuator is satisfactory.

The aim of this work is to study the ability of harvesting energy using a lead-lanthanum-zirconate-titanate (7/60/40 PLZT) pyroelectric cell. For this purpose, the active element is subjected to temperature variations. The pyroelectric cell is directly connected to a load to realize a resistive cycle of energy harvesting. In this work, an analytical calculation of the electrical output power and voltage obtained for a time variation of the pyroelectric element temperature is done. The theoretical results show a dependence of the output voltage and power according to the load value, temperature amplitude and frequency of variation. Moreover a matched value of load is observed according to the frequency of variation. This matched load gives a maximum output power. The experimental study shows maximum voltage values on the load ranging form 7.25 V to 11 V for frequencies of 50 and 100 mHz, respectively. This results show an increase of voltage according to the frequency increase. The same evolution is observed for the load power, it evolves from 0.64 to 1.65 μ W according to frequency for the matched load (26.9 MΩ). This study demonstrated the feasibility of harvesting energy using a 20 mm diameter pyro-cell and that for values of load voltage compatible with a power supply level of sensors.

This paper studies pyroelectric conversion using PLZT cell and diode rectifier. The objective of this work is to observe the possibility of a power supply via an active element. For this purpose, an active diode based rectifier for pyroelectric harvesting systems is presented, simulated and tested on an experimental device. Moreover a comparison between this structure and 2 other is done. The novelty of the proposed rectifier lies in the positioning of the elements, specially the comparators, and the use of resistors to take into account the time response of the comparators. As a result, a constant output voltage of 2.47 V was obtained using the active diode rectifier for temperature oscillation of 32 °C at a frequency of 100 mHz and for a 32.6 MΩ load connected. This represents a gain of 32 % compared with a structure based on p-MOS and a 179 % profit in comparison with a conventional Schottky diode structure. Furthermore, results showed that the maximum power is extracted with the proposed structure and it reaches 0.113 μW for a frequency of 50 mHz and 0.244 μW for a 100 mHz temperature variation. This represents a gain of at least 93 % compared to the two other structures.

Today, power electronic reliability is a main subject of interest for many companies and laboratories. The main process leading to the IGBT failure is the cycling thermal stress. Indeed the current flow induce local heating and then mechanical stress. This paper deals with electro thermal stress under steady and transient current states. The main objective is to test bonded wires with active current cycle. Consequently, the thermo mechanical stress is obtained. A numerical 3D finite element model is presented and some experimental results are given. Indeed an infrared system monitors the temperature dispatching from an experimental test bench under active current cycle. The overall study is a first step before a global simulation (electrical thermal–mechanical) in order to optimize some geometric parameters of the packaging.

The present contribution deals with the development of a magneto-active pump devoted to ventricular assist device. The actuator studied is a cylindrical linear switched reluctance motor equipped with a unidirectional mechanical valve inside the tubular mover in order to allow a pulsatile flow. On the bases of theoretical results, a demonstrator has been designed and built in the laboratory. Finite element analysis of this demonstrator has performed and preliminary tests are detailed showing the flow and pressure characteristics.

Background and aim of the study: Valve repair is currently performed to treat mitral regurgitation, but aortic valve repair remains a surgical challenge. In contrast, aortic valve replacement leads to complications and constraints on the patients' quality of life and valve durability. The mechanisms that produce malcoaptation of the aortic leaflets, with resultant insufficiency, are mainly due to prolapse or retraction of the leaflets. Thus, a new strategy has been proposed to correct valvular insufficiency, using magnetic force.Methods: Low-profile permanent magnets were implanted in seven sheep, under cardiopulmonary bypass (CPB), through a transverse aortotomy, and maintained in place for three months. No aortic insufficiency was created in these first experiments. Two-dimensional color Doppler echocardiography was used to assess the function and safeguarding of the aortic valve. Blood samples were withdrawn to assess hemolysis, and histopathologic examinations performed at necropsy.Results: Direct implantation of the three permanent magnets was possible in all seven animals, but the surgical procedure resulted in major complications in three cases. Only five animals could be weaned from CPB, and only four survived the procedure at three months. One magnet was also shown to have migrated postoperatively. Echocardiography confirmed the stability of the aortic leaflet contours. The biocompatibility of the implanted magnets (i.e., absence of hemolytic reaction) was found to be satisfactory, without a need for postoperative anticoagulation.Conclusion: The use of magnetic force to correct valvular insufficiency has not previously been reported, and is an interesting field of investigation. Whilst these experiments are at an early stage of development, future changes in magnet design and surgical approach are indicated.

Le bureau d’étude « Conception Machine » (COMACH) proposé aux élèves de 3ème année option TEMA (Transformation de l’énergie et Mécatronique Avancée) du Département Génie Electrique Automatique de l’ENSEEIHT est un enseignement transversal permettant d’effectuer la synthèse des connaissances acquises durant la scolarité. Sur la base d’un cahier des charges de système électromécanique pour l’aéronautique proposé par l’industriel donneur d’ordre (AIRBUS), les élèves, organisés en groupe de projet (4 équipes animées par un élève chef de projet), fournissent une proposition technique complète selon un déroulement d’appel d’offre industriel. Guidés en cela par un industriel expert de ce genre de démarches (NOVATEM), les élèves appliquent les méthodologies académiques enseignées, visualisent leurs limites et appréhendent une approche industrielle pragmatique pour le dimensionnement d’un tel système. Le groupe d’élèves est considéré par Airbus comme un équipementier mis en compétition parmi d’autres. Les élèves se retrouvent donc idéalement placés entre un environnement purement industriel (tendant à favoriser le juste choix technico-économique) et un cadre scolaire de bureau d’études rassurant (favorisant les solutions alternatives et la prise de risques). Les enseignants de la thématique conversion électromécanique du département deviennent une ressource qui donne des conseils et des voies de recherche dans la définition de la solution. En fin de bureau d’étude, les élèves livrent leur solution à Airbus lors d’une présentation devant un jury dirigé par les industriels en justifiant les choix et dimensionnement effectués ainsi que les technologies employées (structure de moteurs, d’électronique, capteurs, système de commande, plans mécaniques et matériaux choisis). Les élèves montrent un réel enthousiasme dans la réalisation de ce projet car ils sont dans une situation qui leur donne une vision réaliste des contraintes du milieu industriel que ce soit d’un point de vue scientifique, technique ou même relationnel et de gestion de projet.

Background and Aim of the Study Nowadays valvular repair is currently performed for mitral regurgitation, whereas aortic valve repair remains still a surgical challenge. In another hand, aortic valve replacement leads to complications and constraints. The mechanisms that produce malcoaptation of the leafl ets and cardiac valve insuffi ciency are mainly due to prolapsus or retraction of the leafl ets. We elaborated a new strategy to correct valvular insuffi ciency, using the magnetic force. Methods : Under cardiopulmonary bypass (CPB) and through a transverse aortotomy, low size permanent magnets were implanted in seven sheep for three months. No aortic insuffi ciency was created in this fi rst set of experiments. Two-dimensional color Doppler echocardiography was used to assess the function and the safeguarding of the aortic valve. Blood samples were performed to detect haemolysis and histopathological exams were performed at necropsy. Results : Direct implantation of the three permanent magnets was possible in all cases however the surgical procedure resulted in major complications in three cases. Only fi ve animals could be weaned from CPB and only four survived the procedure at three months. Migration of one magnet (3/7) was the major event observed. The safeguarding of the shape of the aortic cusps in spite of the weight of the magnets sutured on their free border was studied with echocardiography (absence of aortic cusp prolapse or signifi cative aortic regurgitation). The biotolerance with the implanted magnets (absence of hemolytic reaction) was found satisfactory without any postoperative anticoagulation treatment, tested with laboratory markers. Conclusions : The use of magnetic force to correct valvular insuffi ciency has never been reported and is an interesting fi eld of investigation. These experiments are still at an early stage of development. Changes in magnets design and surgical approach are indicated.

In this paper, the authors compare the numerical results obtained from a strong formulation using finite difference schemes (FDS) and a weak formulation using finite element method (FEM). The main purpose of our study is to know which method computes accurately the distribution of magnetic field in an experimental device. Numerical results are compared with a set of experimental data.

La technologie des actionneurs electromecaniques repose sur l'exploitation de procedes physiques relativement varies. Si les effets electrodynamiques, fondes sur l'interaction de champs et de sources electromagnetiques, donnent lieu aux solutions les plus classiquement employees pour produire un effort ou un mouvement a partir d'une source d'energie electrique, l'idee d'utiliser les deformations produites au sein de certains types de materiaux, dits electroactifs, constitue une alternative de plus en plus credible, notamment dans le cas d'actions electromecaniques distribuees (structure intelligente). Sur la base de la classification des procedes et structures exposee dans le dossier precedent [D 5 341], le present dossier precise les conditions de mise en œuvre des solutions techniques correspondantes. Les elements de conception et de dimensionnement de l'actionneur font l'objet de la premiere partie. Les techniques d'alimentation electronique employees pour le pilotage des differentes structures a armature inductive ou capacitive sont ensuite examinees. Enfin, les lois de commande permettant le controle de l'actionneur selon differentes strategies (commande en position vitesse ou en effort) font l'objet de la derniere partie (cf. dossiers sur les machines asynchrones [D 3 620] [D 3 622] et [D 3 623]).

This article deals with the presentation of an experimental bench dedicated to the teaching of electromechanical systems during undergraduate curriculum. This bench permits to explain the main principles of an elementary synchronous motor by a practical approach of the physical phenomena. At first, students start to describe theoretically the motor based on the fundamental electromagnetic relations and concretise their calculations by a progressive realization of their coil windings and finally the electromechanical characterization of the motor. The educational approach is done in order to bring students to face with essential questions about machines and electrical drives.