# Jean-Philippe LecointeUniversité d'Artois · LSEE Laboratoire des Systèmes Electrotechniques et Environnement

Jean-Philippe Lecointe

Professor

## About

83

Publications

21,403

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928

Citations

Citations since 2017

Introduction

Additional affiliations

September 2004 - present

September 2004 - September 2013

## Publications

Publications (83)

Due to an increasing demand for power transformers with lower losses and cost, mixing several grades in the same core could be an innovative answer for both performance and economics points of view. The objective of this paper is to analyze, for a defined roportion of two grain oriented electrical steel (GOES) grades mixed in the same magnetic core...

In a magnetic core with step-lap joints, the global losses generated by the core can be separated into two main components : the ones from the limb, only occuring in rolling direction ; and the ones in the corners, using both rolling, transverse and normal direction. The purpose of this academic research is to propose an experimental process allowi...

This paper studies the performance of an axial-flux switched reluctance machine (AFSRM) using GOES (grain-oriented electrical steel) in its rotor and comparing it to a NOES (non-oriented electrical steel) rotor. Indeed, the AFSRM structure lends itself well to the use of GOES, especially at the rotor. In order to evaluate the intrinsic capabilities...

The Maxwell stress tensor (MST) method is commonly used to accurately compute the global efforts, such as electromagnetic torque ripple and unbalanced electromagnetic forces in electrical machines. The MST has been extended to the estimation of local magnetic surface force for the vibroacoustic design of electrical machines under electromagnetic ex...

Reducing induction motor losses is very important because of the fulfilment of increasingly stringent requirements set by international regulations for reducing electricity consumption. Since core losses begin to dominate in motors operating at higher frequencies the exact calculation becomes more and more important. The common view is that losses...

This paper aims to present and analyze the materials adapted to design a machine that can work with a high current density without any specific cooling system. In other words, the machine is equipped with material that supports high internal temperature, about 500°C. Candidate materials are selected and the authors indicate that inorganic insulatio...

Purpose
This paper aims to deal with a performance comparison of an 8/6 radial-flux switched reluctance machine (RFSRM) and an axial-flux switched reluctance machine (AFSRM), presenting equivalent active surfaces.
Design/methodology/approach
An axial machine was designed based on the equivalent active surfaces of a radial one. After estimating the...

The Maxwell Stress Tensor (MST) method is commonly used to accurately compute the global efforts, such as electromagnetic torque ripple and unbalanced electromagnetic forces in electrical machines. The MST has been extended to the estimation of local magnetic surface force for the vibroacoustic design of electrical machines under electromagnetic ex...

This paper presents an experimental setup dedicated to the analysis of noise and vibration due to Maxwell magnetic forces in electrical machines, a significant NVH source in hybrid and electric vehicles traction motors. Both electromagnetic excitations and structural response of the electrical machine are simplified to provide the first public benc...

Airgap Maxwell tensor is widely used in numerical simulations to accurately compute global magnetic forces and torque but also
to estimate magnetic surface force waves, for instance when evaluating magnetic stress harmonics responsible for electromagnetic vibrations and acoustic noise in electrical machines. This article shows that airgap surface f...

In electrical machine numerical simulations, the Maxwell Tensor is widely used to compute global forces or local surface force density along a surface in the air. This communication proposes to highlight the limits of the method with an academic case of slotless stator and rotor. In particular an analytic demonstration shows the existence of coeffi...

Purpose
Technological innovation has made it possible to review how a film cues particular reactions on the part of the viewers. The purpose of this paper is to capture and interpret visual perception and attention by the simultaneous use of eye tracking and electroencephalography (EEG) technologies.
Design/methodology/approach
The authors have...

This paper presents a novel method to determine the electromagnetic torque of grid-powered induction machines (IM). The torque determination constitutes a key point for the energy diagnosis and for choosing the well adapted motor in industrial processes. The proposed method is non-invasive as it is based on the measurement of the current and the ma...

In this study, the authors aimed to analyse the influence of massive ferromagnetic shaft on the distribution of the electromagnetic field and to evaluate the magnetising current from the mains. To achieve this, they used motors powered by 50 and 200 Hz. They also used both numerical two-dimensional (2D) and 3D field-circuit methods as well as an an...

This study presents an analytical and experimental method for detecting internal turn-to-turn short circuits both in the rotor or in the stator in Salient-pole Synchronous Generator Machines (SSGM) connected to local power grid. Two main measurements are proposed to confirm or discard these electric faults: external magnetic field and External Hous...

L’objectif de cet article concerne la comparaison de différentes approches analytiques permettant d’estimer le contenu spatio-temporel des forces radiales dans l’entrefer d’une machine asynchrone. En effet, lors d’une phase de conception intégrant la problématique du bruit des machines électriques, il est intéressant de prédire les harmoniques de f...

This paper proposes an improved subdomain model of squirrel-cage induction machines (SCIMs) with imposed stator currents. This new model enables to accurately compute electromagnetic quantities such as air-gap flux density, instantaneous torque and forces, and electromotive force including all harmonic contents. The first improvement is to explicit...

This paper proposes an improved subdomain model of squirrel cage induction machines with imposed stator currents. This new model enables to accurately compute electromagnetic quantities such as air gap flux density, instantaneous torque and forces, electromotive force including all harmonic content. The first improvement is to explicitly account fo...

Purpose
This paper aims to study the influence of supply voltage variations on the external magnetic field emitted by grid-powered induction machines (IMs).
Design/methodology/approach
Two models are developed in the paper to analyse, for different supply voltage values, the influence of the variations of the magnetizing voltage for which there...

This paper reviews the recent developments of semi-analytical subdomains modeling techniques to compute the flux density distribution in electrical machines by the exact solving of Maxwell equations. It is shown that with an appropriate development methodology and numerical implementation, these harmonic models break the traditional compromise betw...

This paper concerns a coupled analysis of the stray magnetic field and the external housing vibration of a synchronous machine to detect rotor short-circuit faults. Indeed, in addition to the possibility to measure these parameters with non-invasive equipment, these two measures depend on the air-gap flux density that is directly impacted by the sh...

Mixed eccentricity fault is one of the most common faults occurring in squirrel cage induction motors. Several techniques have been used
to detect this type of fault, such as those based on vibration, axial leakage monitoring, zero-sequence component, negative sequence current, and
motor current signature analysis. However, these techniques do not...

RESUME – Cet article étudie l'effet de l'angle de charge sur les composantes harmoniques des forces de Maxwell (tangentiels et radiaux) dans deux machines synchrones à aimants permanents (MSAP) surfaciques d'architectures très différentes : une machine à 6 dents et 2 paires de pôles, à faible couple et très haute vitesse, et une autre à 120 dents e...

An experimental method to characterize the magnetic properties of Grain Oriented Electrical Steel in the rolling direction is proposed in this paper. It relies on the use of three 25 cm Epstein frames combined to generate three test-frames of different lengths. This enables the identification of the effective specific losses of the electrical steel...

The most critical areas in power transformers are their corner joints where the magnetic flux distribution presents a very high heterogeneity. This heterogeneity results from several parameters such as the geometry of the magnetic core, the anisotropy level of the electrical steel laminations and a critical induction. This paper is focused on the m...

The mixed eccentricity fault is one of the most common faults occurring in squirrel cage induction motors. Several techniques have been used to detect this type of fault, such as those based on vibration, axial leakage monitoring, zero-sequence component, negative sequence current, and motor current spectrum analysis. However, these techniques do n...

The clamping of the power transformer magnetic circuit allows maintaining the sheet stack and provides an additional mechanical rigidity. It has consequences on the acoustic noise of transformers as the magnetic cores of power transformers vibrate because of the magnetostriction and, if the corners are considered, Maxwell’s forces. The indirect imp...

This paper is based on a method recently developed by the authors to characterize analytically, without switching angle determination, the voltage harmonic three-phase systems generated by the switching of PWM inverters. On this basis, it is possible to define control strategies that modify the spectral content of the output signals. The presented...

This paper presents an analytical method that makes it possible to define the pulsewidth modulation (PWM) supply output voltage spectral content, particularly the harmonic phase sequences, without switching instant determination. The results obtained from these developments lead to define a PWM control strategy that allows deleting some switching h...

This paper describes a new non-invasive method for the fault diagnosis of inter-turn short circuit in induction machine. The proposed diagnosis procedure is based on the analysis of the external magnetic field in the machine’s vicinity and more particularly its space variations measured by two coil sensors. The principle consists in the comparison...

his paper investigates a back to back test simulation of an interior permanent magnet (IPM) synchronous machine with fractional slot concentrated windings (FSCW). The studied machine is designed to equip a floating vertical axis wind turbine. The principal characteristics and the structure of the machine are presented, as well as the back to back t...

This paper presents an analytical approach to characterize a flux concentration permanent magnet synchronous machines (PMSM) with fractional slot concentrated winding (FSCW). The very particular configuration of the studied machine leads the authors to associate a fictive winding to the stator coils in order to be able to determine the Ld and Lq in...

The magnetic material quality of transformer cores influences their emitted acoustic noise. The latter is generated by vibrations resulting from the effects of Maxwell's forces, located in the corners, and the magnetostriction inside the magnetic steel. In this paper, two annular structures allow differentiating these two phenomena and analyzing th...

This paper presents the normal permeability mu(z) of different grades of electrical sheets (Grain oriented, non oriented and amorphous). A specific test bench allows determining the intrinsic static B(H) cycle. The magnetization in static mode makes it possible to suppress the eddy current influence, contrary to others classical methods. The B-H cu...

This paper compares three winding wires commercially available for operating at high-temperatures. These wires are stressed by thermal constraints in the temperature range of 20-500°C. The insulation resistance, the tan δ, the parallel capacity and the behaviour under AC voltage strength are quantified with the temperature. The curvature radius, wh...

This paper deals with a new AC electric motor magnetic circuit structure made of shifted non-segmented grain oriented steel laminations. The aim of the paper is to understand with a finite element approach the local distribution of the magnetic flux density inside shifted laminations as well as in the air-gaps between them. It is shown that the air...

The stray flux in the vicinity of an electrical machine is inherent to its running. It is tied to the magnetic state of the machine and therefore can be affected by the presence of a fault in the machine. Accurate modeling of the external magnetic field is quite complicated and simple models are required in order to analyze the effect of an interna...

This study focuses on the external flux in the vicinity of AC electrical rotating machines. The influence of the external housing, constituted of the external yoke and the clamping-plates, is studied with a finite-element modelling, an analytical model and experimental measurements. Two induction machines are analysed; the first is equipped of an e...

The study proposes an automated procedure for linking an identification algorithm implemented in a general-purpose environment (MatLab) with a commercial finite-element code for magnetic field analysis (VF-Opera). The method is used to identify the B-H curves of anisotropic magnetic laminations in the direction normal to the sheet surface with the...

Vibrations and noise in transformers core have two main origins: the Maxwell's forces, located in the corners, and the magnetostriction inside magnetic steel. In this paper, these two phenomena are differentiated and analyzed and analyzed using a test bench, which allows comparing the vibrations of two different annular structures. In the first cas...

This paper proposes the identification of the B-H curve of anisotropic magnetic laminations in the direction normal to the sheet surface. An automated procedure for linking an identification algorithm implemented in a Matlab environment with a commercial finite-element code Opera for 3-D magnetic field analysis has been used. In particular, an opti...

This paper deals with a process to harvest energy from the external flux generated by the AC electrical rotating machines. Such an energy harvesting can be useful for energy autonomous devices used to monitor these machines. The goal of the paper is to estimate if the external flux can be a full-fledged energy source or if it constitutes only an ex...

This paper is focused on the analysis of the acoustic noise of the magnetic origin emitted by ac electrical machine variable-speed drives. First, the principle of noise generation is presented as well as the method for taking into account the effects of the current harmonics on noise generated by the pulsewidth modulation supply. The experimental r...

This paper proposes a mixed experimental/numerical technique to characterize magnetic laminations in the direction normal to their surface. The principle, which uses static excitation to avoid errors caused by eddy currents, is explained and a specific test bench is proposed. Measurements of the magnetic flux density are made using a sensor being m...

Cet article consacré aux circuits magnétiques à tôles à grains orientés (GO) comporte un double objectif. Il vise d'abord à comprendre comment le champ se répartit dans un circuit magnétique à joints step-lap. L'importance des composantes de champ normales au plan des tôles est mise en évidence par l'intermédiaire d'un dispositif expérimental instr...

This paper focuses on the noise and vibrations of induction motors. It proposes an analytical method to distinguish the phenomenon responsible on the magnetic noise, especially the toothing and the saturation. A 3-speed 3-phase induction motor, which works sporadically at low speed for hoisting, serve as a support for experiments. Its acoustic nois...

This paper deals with the influence of the AC machine pole number on vibrations and noise of electromagnetic origin. First, rules of design of AC machines are reminded, pointing out the influence of the pole number. Then, the origin of magnetic vibrations and noise is explained. Analytical mechanical relations are given, allowing to estimate vibrat...

This paper focuses on the external flux in the vicinity of AC electrical rotating machines. The influence of the external housing, the external yoke and the end-bells, is studied with a Finite Element modelling, an analytical model and an induction machine equipped of flux sensors.

The paper proposes an automated procedure for linking an identification algorithm implemented in a general purpose environment (MatLab™) with a commercial Finite-Element code for magnetic field analysis (VF Opera™). This procedure is applied to identify automatically the B-H curve of anisotropic magnetic laminations in the direction normal to the s...

This chapter covers the modeling of laminated structure made with grain-oriented electrical steel sheets. It introduced a
homogenization technique which takes into account the anisotropy due to laminations rolling direction overlapping and the
one due to the crystals orientation. The homogenization method is based on the minimization of energy. Tha...

This paper proposes an experimental method to characterise magnetic laminations in the direction normal to the sheet plane. The principle, which is based on a static excitation to avoid planar eddy currents, is explained and specific test benches are proposed. Measurements of the flux density are made with a sensor moving in and out of an air-gap....

This paper presents a non invasive method for estimating the energy efficiency of induction motors used in industrial applications. This method is innovative because it is only based on the measurement of the external field emitted by the motor. The paper describes the sensors used, how they should be placed around the machine in order to decouple...

Purpose
The purpose of this paper is to present a comparative analysis concerning the influence of eddy currents on the distribution of the magnetic flux density in the laminated anisotropic structures.
Design/methodology/approach
The influence of the magnetic flux normal to the lamination surface is particularly analysed. Several models containin...

Purpose
The purpose of this paper is to suggest a procedure which makes it possible to reduce the radial vibrations of doubly salient switched reluctance motors (SRMs).
Design/methodology/approach
An analytical method for the SRM radial vibration determination is first described. It is then extended to the active vibration reduction. An auxiliary...

This paper is about the exploration and the analysis of the AC rotating machine external magnetic field. An experimental procedure is presented: it makes it possible to distinguish the stator and rotor leakage inductances which occur in the induction machine single phase equivalent circuit.

The paper presents a application of wireless sensor network used to diagnose the efficiency of AC electrical machines. It explains the functions of the cell and the constraints which makes it a real tool for industry. The key point of the energy diagnosis consists in determining the electromagnetic torque in steady state, taking into account only t...

The main purpose of these 3D simulations is to estimate the effect of the eddy currents, induced by the transverse and normal fluxes, on the field distribution in laminated anisotropic structures. The comparison of the results of full 3D simulation with and without eddy currents makes it possible to elaborate a mathematical model with appropriated...