Linear tubular switched reluctance motor for heart assistance circulatory: Analytical and finite element modeling

A linear tubular switched reluctance motor is presented. This actuator is devoted to be used as a left ventricular assist device (LVAD). In order to avoid thrombosis, this actuator includes pump and valve functions. By using a St. Jude Medical mechanical valve inside the tubular mover, a pulsatile flow is created in the descending aorta. A linear model of a basic pattern of the actuator based on a reluctance network is developed. Then, a two dimensions finite element method analysis is performed in order to check the analytically calculated performances. Relying on these both models, specific requirements for the design of this kind of motor are discussed

Commande d'un actionneur électrique par communication sans fil Zigbee

CNR IUT Angers 2010Nous présentons ici un asservissement de position en sans fil d'un moteur à courant continu. La consigne élaborée au niveau d'un PC distant est envoyée via un module Zigbee à un autre module Zigbee, qui lui relié au moteur à commander, renvoie la mesure de la position. La commande numérique mise en œuvre doit être suffisamment robuste et la période d'échantillonnage judicieusement choisie pour s'affranchir des contraintes imposées par la communication hertzienne. Nous utilisons dans la commande, un prédicteur estimateur à base de filtre de Kalman. Ce dernier substitue, au retour de l'information réelle éventuellement perdue ou retardée (en l'occurrence ici la position du moteur), une information anticipée adéquate. Nous assurons ainsi par ce biais la stabilité de l'asservissement numérique en boucle fermé de ce moteur piloté par des modules Zigbee

Dimensionnement d'un générateur photovoltaïque pour un système communicant autonome

National audiencePour rendre autonome un système communicant utilisant la technologie bluetooth, nous avons choisi de l'équiper d'un générateur photovoltaïque. Pour dimensionner ce générateur, il faut tenir compte de la consommation énergétique journalière, des caractéristiques de l'accumulateur à charger, de l'encombrement disponible et des caractéristiques d'ensoleillement. Nous donnons ainsi dans cet article un exemple de dimensionnement pour un système situé en extérieur dans le sud de la France

Original optimization procedures of halbach permanent magnet segmented array

This paper presents a direct design and optimization procedures of an arbitrary PM Halbach Segmented Array. The direct design is based on the ideal PM Halbach definition. The arc width, magnitude and orientation of polarization of each segment are taken as optimization variables after calculation of PM thickness. A new optimization procedure based on integration of Least Square Method inside the well-known Sequential Quadratic Programming method is proposed to improve the optimization results and to reduce time computation

Experimental Study of Iron Losses Generated by a Uniform Rotating Field

This paper introduces a mock-up with a solid iron cylinder rotating in a fixed excitation frame powered by dc current. A uniform field is created in the rotating cylinder, which is driven by an external motor. The braking torque is measured, allowing the study of iron losses generated by a uniform rotating field. The aim is to advance toward a vector iron loss model that takes into account different magnetization directions and their interdependency. The eddy current losses are the dominant loss source in the mock-up, rendering it easier to model. A standard eddy currents model is proposed. It models well the losses at low and medium magnetic flux density, but lower losses are measured near saturation levels. This could be due to the high thickness to radius ratio changing the eddy current paths near the edges of the rotor, which can be later analyzed by a full 3-D finite-element method analysis. A 2-D finite-element method simulation is performed, which estimates the magnetic flux heterogeneity in the rotor. Several lessons are drawn from this mock-up, which prepares a second version with a higher speed and a longer laminated stack rotor. A higher air gap will decrease the voltage fluctuation in the primary winding, a smaller angular opening of the excitation frame will improve the uniformity of the flux in the rotor

Modeling quasi-static magnetic hysteresis: a new implementation of the play model based on experimental asymmetrical B(H) loops

This paper relates a new model of quasi-static magnetic hysteresis based on the Play model hysterons, which builds the magnetic field density B from the magnetic field H. In the original model, H is discretized into temporal values H(t m ), which is itself modeled by a hysteron chain of m sub-values. B is then reconstructed from these sub-values through a function experimentally determined by measuring B(H) centered cycles, using a constraint optimization method. The new proposed method is to measure asymmetrical B(H) loops, which give additional equations leading to a fully determined linear square invertible system. The asymmetrical B(H) loop is included in a bigger symmetrical loop with a magnetic flux density turnaround in order to be regulatable

3D magnetic field model of a permanent magnet ironless axial flux motor with additively manufactured non-active parts

A simulation model of an ironless Axial-Flux Permanent-Magnet (AFPM) machines is presented. Indeed as accurate analytical methods do not yet exist for ironless AFPM, 3D Finite Element Analysis (FEA) is required at each time of an operating point. The purpose of this article is to show that for any operating point of the motor, the torque can be calculated from the distribution of the axial magnetic flux density obtained from only one 3D FEA. The proposed simulation model is validated by using a prototype of an AFPM ironless whose non-active parts are additively manufactured. This first step through the 3D printing technology is simplified by the use of cylindrical magnets and plastic mechanical supports

Two synchronous permanent magnet machine frameworks for a direct drive active stick application

This paper deals with the comparison of two actuators with different frameworks for a direct drive active stick application. The set of specifications impose many constraints as torque, torque ripples, temperature etc… The high required torque per unit of mass and the small volume allowed oblige us to use synchronous permanent magnet topologies which have the best torque performances. We will compare a tubular linear synchronous permanent magnet actuator to a double airgap rotating synchronous permanent magnet actuator. We will calculate the torque with the Laplace force and the magnetic flux density without loads thanks to the Ampere law. Then we will make an optimization with the analytical expressions of the torques we get previously. We will make simulations on the optimized structures in order to validate the analytical model. Finally we will compare the two actuators in order to give the best compromise for the stick application

Joint Design of Halbach Segmented Array and Distributed Stator Winding

In the past, designers develop analytical models that are useful to size rapidly surface mounted permanent magnet synchronous motor with sinusoidal waves and a high specific power. In order to ensure the assumptions of sinusoidal waves, a joint design of the stator winding and the rotor is presented. First, an Halbach permanent magnet array is optimized to obtain the desired airgap magnetic flux density wave. Then, in order to obtain a surface current density wave consistent with the desired wave, the conductor distribution along the stator bore is determined

Magnetic field continuity conditions in finite-element analysis

This paper deals with the magnetic field continuity conditions in finite-element analysis. Our study is based on numerical and analytical models. Different known finite-element codes, based on 2-D nodal finite element or 3-D edge element, are used to analyze the magnetic field in a linear motor-like device. The use of an analytical model gives interesting insight on interface errors problems in finite-element analysi