Yacine Amara

Bio: Yacine Amara is an academic researcher from University of Le Havre. The author has contributed to research in topics: Magnet & Magnetic reluctance. The author has an hindex of 18, co-authored 89 publications receiving 1316 citations.

Hybrid Excitation Synchronous Machines: Energy-Efficient Solution for Vehicles Propulsion

Abstract: In this paper, the suitability of a class of electric machines for vehicle traction applications is discussed. These machines, which are known as hybrid excitation synchronous machines, combine permanent-magnet (PM) excitation with wound field excitation. The goal behind the principle of hybrid excitation is to combine the advantages of PM excited machines and wound field synchronous machines. It is shown that these machines have good flux weakening capability compared with PM machines, and that they constitute an energy-efficient solution for vehicle propulsion.

Analytical Modeling of the Open-Circuit Magnetic Field in Axial Flux Permanent-Magnet Machines With Semi-Closed Slots

Abstract: This paper presents a multi-slice analytical model for prediction of the open-circuit magnetic field in slotted semi-closed permanent-magnet axial flux synchronous machines. The technique is based on 2-D exact solution of the Maxwell's equations using the separation of variables method. The magnetic field expressions are developed in slots regions, slot opening regions, magnetic air gap regions, and permanent magnet regions leading to an exact calculation of the slot effects on the air gap magnetic field. The model is established considering that ferromagnetic parts are infinitely permeable, and end effects at inner and outer radii are neglected. The open circuit machine's global quantities (electromotive force and cogging torque) are then deduced from the local magnetic field expressions. Finally, the accuracy of the presented analytical model is validated by comparing its results to corresponding finite-element analyses for two different axial flux machines.

Analytical Prediction of Eddy-Current Loss in Armature Windings of Permanent Magnet Brushless AC Machines

Abstract: This paper presents an analytical model for prediction of eddy current loss in armature windings of permanent magnet brushless AC machines. The developed model can either be used in the case of internal or external rotor radial-field machines topologies. First, a 2-D exact analytical solution of magnetic field distribution in an actual geometry of slotted surface mounted PM radial flux synchronous machines is established. It involves solution of Maxwell's equations in slots, airgap and PM's region. Then, magnetic vector potential solution in the slots is used for prediction of resistance limited eddy current in armature windings. Finally, results from this analytical model are compared to corresponding finite element analyses.

Two-Dimensional Exact Analytical Solution of Armature Reaction Field in Slotted Surface Mounted PM Radial Flux Synchronous Machines

Abstract: This paper presents an analytical solution for prediction of the armature reaction magnetic field in slotted surface mounted permanent magnet radial flux synchronous machines. This technique is used in the case of internal and external rotor radial-field machines. The magnetic field expressions are developed in both slots regions and magnetic airgap region leading to an exact calculation of the effects of slotting on the airgap magnetic quantities. Results from this analytical model are compared to corresponding finite element analyses. This analytical model is then used to estimate the self and mutual inductances.

Recent Advances in Axial-Flux Permanent-Magnet Machine Technology

Abstract: This paper reviews the progress that has been made in the analysis and design of axial-flux permanent-magnet machines over the past decade, with particular attention to aspects such as electromagnetic and thermal modeling, materials, manufacturing, pulsating torque, and extended speed range. Comparisons with other machine types and applications are also reviewed.

2-D Exact Analytical Model for Surface-Mounted Permanent-Magnet Motors With Semi-Closed Slots

Abstract: This paper presents an analytical subdomain model to compute the magnetic field distribution in surface-mounted permanent-magnet (PM) motors with semi-closed slots. The proposed model is sufficiently general to be used with any pole and slot combinations including fractional slot machines with distributed or concentrated windings. The model accurately accounts for armature reaction magnetic field and mutual influence between the slots. The analytical method is based on the resolution of two-dimensional Laplace's and Poisson's equations in polar coordinates (by the separation of variables technique) for each subdomain, i.e., magnet, air gap, slot-opening, and slots. Magnetic field distributions, back-EMF, and electromagnetic torque (including cogging torque) computed with the proposed analytical method are compared with those issued from finite-element analyses.

Modeling and Analysis of Electromagnetic Force, Vibration, and Noise in Permanent-Magnet Synchronous Motor Considering Current Harmonics

Abstract: This paper first derives the characteristics of radial electromagnetic force considering different types of current harmonics. By using two-dimensional fast Fourier transform, the force calculated by the finite element method is decomposed to obtain the frequencies of the force components in specific spatial order. Then, a multiphysics model for electromagnetic vibration and noise calculation is proposed. A modal test is implemented to validate the equivalent stator model and the nonuniform distribution of electromagnetic force acting on the teeth surface is taken into account through the nodal force transfer method. The calculated vibration and noise agree well with those obtained from experimental test. Finally, vibration and noise under different supply currents are investigated, and the variation patterns of the noise and vibration peaks are explained by the amplitude changes of the lowest spatial order force due to current harmonics. It is found that the influence of current harmonics on vibration and noise depends on their effect on the lowest spatial order force, and in order to figure out this effect, the phase angle, phase sequence, and frequency of current harmonics should all be considered.

An Improved Subdomain Model for Predicting Magnetic Field of Surface-Mounted Permanent Magnet Machines Accounting for Tooth-Tips

Abstract: The paper developed an improved analytical subdomain model for predicting the open-circuit magnetic field in surface-mounted permanent magnet machines accounting for the tooth-tips in the slots. The whole field domain is divided into four types of simple subdomains, viz. magnets, air-gap, slot openings, and slots. The analytical expression of each subdomain is derived and the field solution is obtained by applying the boundary conditions and interface conditions between subdomains. Compared with the conventional subdomain models, the subdomain model accounting for tooth-tips can accurately predict the flux density inside the slots. Based on the developed field model, the cogging torque is computed by the Maxwell stress tensor. The finite element analysis is carried out to validate the analytical model. It shows that the developed subdomain model accounting for tooth-tips is more accurate, especially for the machines having larger slot opening width compared with tooth-tip height.