Hamid Ahmed - Academia.edu (original) (raw)

Papers by Hamid Ahmed

Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)

A new axial-field synchronous machine designed for a flywheel accumulator is presented herein. Th... more A new axial-field synchronous machine designed for a flywheel accumulator is presented herein. The armature and field windings fixed in the airgap are made with double-face printed circuits. A specific armature layout provides a sinedistributed m.m.f. and solves the problem of crossing the ends of the winding. A 2D semi-analytical model at the mean radius, using surfacic permeances, is then developed. Afterwards, inductances, torque and eddy current losses are calculated using this model and compared with experimental results.

The XIX International Conference on Electrical Machines - ICEM 2010, 2010

This paper presents and compares three topology optimization tools differing from the optimizatio... more This paper presents and compares three topology optimization tools differing from the optimization algorithms they implement. The first two are respectively based on a local optimization algorithm, i.e. a Nelder-Mead method, and a global one, i.e. a genetic algorithm. The third uses a hybrid algorithm associating the local and the global algorithms used in the first two. Each of them implements the same material distribution formalism, i.e. a dynamic formalism based on Voronoi cells. The results obtained on a practical study case, the design of an electromagnet, show the better performance of the hybrid algorithm as well in terms of speed of the convergence as in terms of quality of the final solution and therefore the interest of coupling the exploration abilty of the global search with the intensification abilty of the local search.

2008 18th International Conference on Electrical Machines, 2008

... de Louvain Place du Levant, 3 B-1348 Louvain-la-Neuve, Belgique E-mail : bruno.dehez@ uclouva... more ... de Louvain Place du Levant, 3 B-1348 Louvain-la-Neuve, Belgique E-mail : bruno.dehez@ uclouvain.be, jonathan.denies@uclouvain.be 2 SATIE laboratory, Ecole Normale Supérieur de Cachan, Campus de Ker Lann, 35170, Bruz, France E-mail : benahmed@bretagne.ens ...

Mathematics and Computers in Simulation, 2013

Topology optimization methods are aimed to produce optimal design. These tools implement optimiza... more Topology optimization methods are aimed to produce optimal design. These tools implement optimization algorithms that modify the distribution of some materials within a predefined design space without a priori ideas regarding the topology or the geometry of the best solution. In this paper, we study a specific tool that combines a genetic algorithm, a material distribution formalism based on Voronoi cells and a commercial FEM evaluation tool. In particular, this paper shows, through a simple but representative case study, that it is possible to improve the performance of the topology optimization tool during the local search phase, i.e. the geometrical and dimensional optimization phase for which the topology optimization methods are originally not well-suited.

2007 IEEE International Electric Machines & Drives Conference, 2007

This paper presents the first results of the ecodesign problematic in case of one of the simplest... more This paper presents the first results of the ecodesign problematic in case of one of the simplest electromagnetic energy converter: the single-phase electric transformer connected to a constant frequency and voltage power supply. The optimization of its sizes is led with the following objectives: the active mass and the global life cycle energy cost. We first compare optimization's results to those with "classic" mass versus power losses (copper and iron losses) optimization for several times of use ratio. This leads to recognition of the significant impact of the life cycle energy on the arrangement of the optimal Pareto fronts, explained by conflicting energy contribution in the life cycle global energy cost objective. Then we logically observe that the life cycle assessment impact is more significant when the real use duration is smaller than the lifetime. After that, the sensitivity of the optimization's results to the elementary raw materials energy costs is considered with the same times of use ratio. At last, some optimizations are run with a different raw material: aluminium instead of copper for the windings.