Vincent Lanfranchi

• Professor
• Full professor head of M2EI team at University of Technology of Compiègne

Electric machines are often perceived as silent, yet the noise they produce has become a significant issue. This paper presents a focused approach to understanding the source of this noise, aiming to enhance machine design. Our study centers on the vibratory model of a permanent magnet synchronous electric machine. The stator and rotor components (...

Purpose The purpose of this paper is to propose a new method that allows to compare the magnetic pressures of different pulse width modulation (PWM) strategies in a fast and efficient way. Design/methodology/approach The voltage harmonics are determined using the double Fourier integral. As for current harmonics and waveforms, a new generic model...

Across various applications, electrical machines are intensely replacing conventional hydraulic and pneumatic actuators in applications with a higher degree of complexity. In our previous study, a SynRM machine with a segmented rotor was designed to operate as a clutch actuator, to be placed in the gear housing which suffers from a high ambient tem...

For electric vehicle motors, it is essential to control the sources of loss which could reduce the overall efficiency of the system. In this context, this article aims to present a detailed comparison of machine and inverter losses between the space vector pulse width modulation (SVPWM) and the discontinuous pulse width modulation 2 (DPWM2). To com...

The magnetic pressure generated in the stator of electric machines can be a significant source of noise and vibration. The vibration behavior of the stator and such mechanical structures primarily depends on their geometry. Although the stator is often considered a simple structure, its teeth are not included in this assumption. In this paper, we e...

Abstract This study presents a sensitivity analysis methodology used for electric motor design. This innovative approach evaluates both global effects of parameter variations in their design range and of parameter deviations in their tolerance intervals on design objectives. For the purpose of robust optimisation, this method helps to select the mo...

Purpose This paper deals with the study of the influence of the phase shift between currents and back-electromotive forces (back-EMF) on torque ripple and radial magnetic forces for a low power synchronous machine supplied with 120 degrees square-wave currents. This paper aims to establish a good compromise between efficiency, harmonics of torque a...

Synchronous reluctance machine (SynRM) is reemerging as a thermally robust and inexpensive actuator solution mainly due to the lack of permanent magnet. Added to that, the possibilities of having different rotor topologies make it very versatile where further optimization is possible depending on the objective, be it cost, ease of fabrication, powe...

Purpose This paper aims to propose a method to evaluate the information obtained on harmonics calculations and to estimate the precision of results using finite element method for an innovative motor topology in which some well-known meshing rules are difficult to apply. Design/methodology/approach The same magnetostatic problem is solved with sev...

This paper shows the influence of the shift phase angle ψ between phase currents and back-electromotive forces on magnetic radial forces and torque ripple for a specific low power permanent magnet synchronous machine. This influence is firstly demonstrated through analytical development considering only the first harmonic values. Then, magnetic pre...

In this article, an easily implementable method to reduce the CPU time for some 3-D finite-element method (FEM) problems is presented. A translational displacement between two parts on both sides of a planar air gap is considered with a change of coordinates in the air-gap region along the $z$ -axis. To achieve this, formulation and postprocessin...

Synchronous reluctance machine (SynRM) has been studied widely in order to reduce its high torque ripple and improve its low power factor. This paper proposes a torque ripple reduction method for SynRM by defining a novel parameter-torque function. With the help of torque function, the optimal currents aiming to compensate torque harmonics are obta...

High voltage devices such as dry-type air-core reactors are subjected to environmental noise standards. Their excitation is due to Lorentz forces originated from the magnetic field, created by the coil itself, combined with the feed current. The objective of this paper is to show how spectral components present in the supply current of industrial d...

This paper presents a stochastic study to predict the effect of uncertainties on the natural frequencies and frequency response functions (FRFs) of an electrical motor stator with quantification of experimental variability. Experimental measurements are performed on 4 theoretical identical stators in order to quantify the response variability. A fi...

Due to environmental standards, noise reduction solutions for high voltage devices such as dry-type air-core reactors are needed. The objective of this paper is to predict the vibroacoustic response of a single layer air-core reactor from its electrical feed to its acoustical response. Since the coil is a non-ferromagnetic powered conductor placed...

Soft ferromagnetic materials constitute the main components of magnetic circuits in electromechanical devices. However, their magnetic and magnetostrictive properties are strongly affected by mechanical loading. This can lead to a decrease in the performance and the efficiency of these devices and to a potential increase of the emitted noise. Aware...

The noise generated by rotating machines and electrical transformers is harmful and its reduction has been the subject of several studies. Such systems are likely to come into resonance and become noisier. This resonance may come from mechanical or magnetic forces. The phenomenon of resonance is usually studied only if the frequency and the known s...

Automotive industry is moving towards electrification of steering system due to efficiency and active safety integration concerns. Studies on actuators for Steer-by-Wire (SBW) application is very limited, and no thermal effects on the actuator related to utilization in SBW have yet been looked into. Using a valid thermal model, and steer torque dat...

Le bruit généré par les machines tournantes et les transformateurs électriques est nocif et sa réduction fait l'objet de plusieurs études. De tels systèmes sont susceptibles d'entrer en résonance et de devenir encore plus bruyants. Cette résonance peut provenir de forces mécaniques ou magnétiques. Cet article propose d'étudier l'interaction entre l...

This paper aims to present the relation between acoustic noise and torque ripple by introducing a method to express the radial magnetic pressure (RMP) by torque and an equation to evaluate the variation of acoustic noise caused by reducing torque ripple in synchronous reluctance machine (SynRM). First, the qualitative relation between the torque an...

The research about synchronous reluctance machine (SynRM) has been revived in the last decades because of its advantages. But the torque ripple limits the performances of SynRM. Based on the feature of SynRM, this paper proposes a new method in order to calculate the optimal currents which contain many harmonics. Based on the proposed torque functi...

Magnetostrictive vibration of ferromagnetic core is an important source of noise in electromagnetic devices like transformers. Magnetostrictive noise can easily be reduced by operating at lower core induction but this leads to larger size and weight transformers which is penalizing for aeronautical applications where the weight parameter is importa...

The absence of high-cost rare-earth magnet on the rotor of Synchronous Reluctance machine makes it one of the best option for an actuator in applications with high ambient temperature. Combined with an optimized rotor structure, it can deliver good performance. In the early design phase of the machine, development cost reduction of prototyping and...

Due to the changing environmental standards and constraints, noise reduction solutions generated by high voltage devices are needed. Among these devices, transformers and reactors are generally the ones producing the highest level of permanent noise. A high-voltage device generates electromagnetic fields that interact with the electric current. Thi...

The torque ripple limits the performances of synchronous reluctance machine (SynRM). Considering the structure feature of SynRM, this paper applies a general torque expression to calculate optimal currents which are not sinusoidal and are used to reduce torque ripple. Besides, the compensated torques by supplying different orders of optimal current...

This paper studies the influence of magnetic saturation on the method used to reduce the torque ripple of a segmented synchronous reluctance machine. First, the method to reduce torque ripple which are based on changing the currents of stator is presented. Then the reduction method is verified in the working range when saturation does not exist by...

RESUME Ces travaux visent à comprendre et modéliser le comportement vibroacoustique des inductances de type sec de RTE en vue de la réduction du bruit d'origine électromagnétique qu'elles génèrent. L'objectif est de chainer des outils de modélisation numérique, pour mieux prédire le comportement vibroacoustique de l'inductance de type sec. Cette ch...

This paper shows the influence of the manufacturing process of a claw-pole alternator on its acoustic noise. First, the stator welds and the assembly of the stator in the brackets are linked to deformations of the inner diameter of the stator. Then, the influences of these deformations on the magnetic forces and the subsequent acoustic noise are in...

The noise of electrical machines such as electric motors, power transformers and electrical inductors increasingly interested designers and manufacturers of several industries (automotive, rail, etc.). This interest concerns the reduction of noise caused by these machines in transportation vehicles for example, to provide better comfort to users. I...

This paper focuses on the variability in vibration from electromagnetic origin for an electric motor. The multiphysics modeling is introduced by the magnetic force density computation and by the coupling of the 2D electromagnetic and 3D structural dynamic finite element models. The modal stability procedure (MSP) and the Monte Carlo Simulation (MCS...

Purpose The purpose of this paper is to present an original study of industrial inductors with different air-gap materials in order to reduce the vibration and noise of inductors. Acoustic comfort is an increasingly important factor at the design stage of industrial inductors associated to converters. In addition, power converters in the railway d...

This paper shows the influence of the manufacturing process of a claw-pole alternator on its acoustic noise. First, the stator welds and the assembly of the stator in the brackets are linked to deformations of the inner diameter of the stator. Then, the influences of these deformations on the magnetic forces and the subsequent acoustic noise are in...

This study aims at minimizing the acoustic noise from a magnetic origin of a claw-pole alternator. This optimization is carried out through a multiphysics simulation, which includes the computation of magnetic forces, vibrations, and the resulting noise. Therefore, a mechanical model of the alternator has to be developed to determine its main modes...

This paper presents a Finite Element Analysis (FEA) of a 24kW six-phase Axial Flux Permanent Magnet Synchronous Machine (6AFPMSM) and its validation through experimental tests for fault tolerant generation purposes. The presented topology contains a high pole number and is suited for wind turbines applications in direct-drive or hybrid one-step gea...

Embedded automotive application has one of the harshest environment for electrical machine, especially in terms of thermal requirement. In this study, thermal evaluation of a small synchronous reluctance (Syncrel) machine intended to be used as clutch actuator is presented. A lumped parameter (LP) thermal model was built and validated experimentall...

This paper introduces a model of magnetostriction based on minimization of total energy. An identification of each term from measurements of the magnetization and magnetostriction is presented, assumptions supporting the model are mentioned. To validate the proposed model, a comparison between experiments — on FeSi single sheet — and the calculatio...

During the manufacturing process and use of ferromagnetic sheets, operations such as rolling, cutting, and tightening induce anisotropy that changes the material’s behavior. Consequently for more accuracy in magnetization and magnetostriction calculations in electric devices such as transformers, anisotropic effects should be considered. In the fol...

Magnetic and magnetoelastic properties of soft ferromagnetic materials, used as laminated sheets, are sensitive to manufacturing processes such as rolling, cutting and coating. One of the effects of these processes is to induce an anisotropic behavior of materials. Therefore, an anhysteretic magnetostriction and magnetization calculation taking int...

In this paper, a thermal study of Synchronous Reluctant motor is proposed. A specific experimental method is applied in order to identify the thermal parameters, this method focus on the study of contact resistances and total thermal capacity. Generally, in the classical thermal modeling, the thermal contact resistance (TCR) is estimated by empiric...

This study aims at minimizing the acoustic noise from a magnetic origin of a claw-pole alternator. This optimization is carried out through a multiphysic simulation which includes the computation of magnetic forces, vibrations and the resulting noise. Therefore, a mechanical model of the alternator has to be developed to determine its main modes. P...

The acoustic optimization of claw-pole alternators can be carried out with finite element simulations but suffers from long electromagnetic computation time (i.e. 3D transient simulations). On the other hand, analytical models cannot predict magnetic forces with accuracy in such machines. Therefore, a new hybrid model is proposed in order to achiev...

Nowadays, developing electric motorization for land vehicles is essential due to the crucial need to save energy. Regarding the specific speed-torque characteristics (high saturation level, high speed, considerable flux weakening) and manufacturing cost, the Interior Permanent Magnet (IPM) Synchronous Machine (SM) provides considerable advantages....

Audible noise of automotive alternators is a key point for future cars. Its reduction requires a multiphysic approach including electromagnetic, vibro-acoustic and thermal aspects. In this perspective, this paper investigates the influence of stator temperature on the acoustic noise of a claw-pole alternator. Experimental results show a clear reduc...

A simulation methodology is described in this paper. It consists in a multi-physical approach to simulate the dynamic forces and noise radiated by electric motors. The principle is first to calculate the excitation due to electromagnetic phenomena using an electromagnetic finite element solver. This excitation is then projected onto the structure m...

p>Les propriétés magnétiques et magnétoélastiques des matériaux ferromagnétiques doux, utilisés sous forme de tôles laminées, sont sensibles aux conditions d'élaboration (laminage, revêtement...). Ainsi, une méthode de calcul de la magnétostriction et de l'aimantation anhystérétique dans le plan de la tôle à l'échelle macroscopique tenant compte de...

Nowadays, the development of the electric motorization for the land vehicles is essential since the energetic challenge is become very critical. Electrical machines dedicated to this operating segment have some specifics of torque characteristics (high saturation level, important flux weakening) over the speed range. This paper presents the develop...

Near field acoustical holography (NAH) consists in reconstructing the pressure field radiated by a set of sources from the measurements received by a microphone array. Originally developed for stationary sound fields, this technique is widely used in the transportation industry where many sources are actually non-stationary. The purpose of this pap...

Cet article porte sur les vibrations et le bruit acoustique d’origine magnétique (dû aux forces de Maxwell) dans les machines électriques tournantes synchrones (aimants permanents ou rotor bobiné - machines à réluctance variable exclues). Le phénomène de bruit magnétique y est analysé, et les différentes sources harmoniques d’efforts magnétiques so...

Audible noise of electric machines has become an important criterion in their design. A good amount of these vibrations are from magnetic sources. In order to predict and control these vibrations, a multi-physics numerical model (electromagnetic-dynamic) has been created. This model proposed to calculate magnetic pressure by using Maxwell equations...

With the ever increasing pressures in automotive industries to develop smaller and more efficient electrical motors for their applications, it becomes necessary to have a thermal model at the design stage. This study proposes a fast, precise and practical thermal model construction that requires minimal development time for a synchronous reluctance...

Audible noise of electric machines has become an important criterion in their design. In this paper we used a multi-physics numerical model (electromagnetic-dynamic) in order to predict mechanical vibration caused by magnetic pressure in a wound rotor synchronous machine. The final objective is to reduce this mechanical vibration. The novelty of th...

This paper presents methods and tools for the design of electric rotating machines for electric or hybrid vehicle applications. Many constraints and challenges have to be faced in such design situations and advanced optimization methods are very helpful to search the solution space using finite element evaluations. Because more and more computing p...

Cet article porte sur les vibrations et le bruit acoustique d’origine magnétique (dû aux forces de Maxwell) dans les machines asynchrones. Les différentes sources d’efforts harmoniques y sont caractérisées analytiquement. Des outils de prédiction du niveau de bruit rayonné sont présentés, ainsi que différentes règles de conception. Enfin, des métho...

Inverters and space vector PWM Geometric approach to the problem Space vector PWM and implementation Conclusion Bibliography

In this paper, an advanced control technique using fuzzy logic tuned by a genetic algorithm is proposed in order to obtain a high accuracy positioning of a six-phase induction machine. The proposed control scheme is fully insensitive to mechanical configuration changes as well to loss of one up to three phases. The effectiveness of the method has b...

A previous study has shown that the current low frequency harmonics, even with low amplitudes, have a strong influence on the global vibrations of a wound rotor synchronous machine. Therefore an harmonic dedicated regulation of the machine currents, allowing to manage in a low cost way their harmonic content, can drastically improve the acoustic no...

In electric vehicles, a major emphasis is placed on iron loss reduction to maximize machine efficiency and its vibratory and acoustic behavior to meet users' expectations of a silent drive. This paper describes a method to simultaneously reduce iron losses and magnetic noise of a wound-field synchronous machine considering various stator tooth leng...

This paper presents the full analysis of the radial forces behavior responsible for audible magnetic noise in a PWM-fed permanent magnet synchronous traction machine with surface permanent magnet. Magnetic force waves due to slotting harmonics, pulse-width modulation (PWM) are characterized for different speeds, Including theoretical predictions an...

Eccentricity is considered as a major problem for every people dealing with the realization of an electrical machine. Generally linked to manufacturing tolerances and rotor balance quality, rotor dynamic eccentricities contribution to vibro acoustic behaviour of the machine is here investigated for a synchronous machine during a full run up. We wil...

An automatic and fast numerical coupling method between 2-D electromagnetic and 3-D structural FEM software is presented. The described coupling method permits to compute the electromagnetic noise in electric machines for different realistic alimentation currents. Thanks to this tool, the strong influence of the supply harmonics on the acoustic lev...

This paper presents a new approach to the sensorless speed control of six-phase induction machine (6PIM). The new technique uses an Adaptive Neural Fuzzy Inference Systems (ANFIS) as a rotor speed estimator to avoid using mechanical sensor. This makes the reference model free of pure integration and less sensitive to stator resistance variations. T...

This paper compares two rotor topologies of permanent magnet synchronous machines about the level and the origin of electromagnetic noise. The aim is to establish the origin of these radial forces: PM field, armature reaction or slotting harmonics. The first rotor has surface permanent magnet (SPM) and the second one has internal permanent magnet (...

This paper compares two rotor topologies of permanent magnet synchronous machines about the level and the origin of electromagnetic noise. The aim is to establish the origin of these radial forces: PM field, armature reaction or slotting harmonics. The first rotor has surface permanent magnet (SPM) and the second one has internal permanent magnet (...

In this paper, a fuzzy PI (FPI) controller tuned using genetic algorithms (GA) is proposed for position control of six- phase induction motor (6PIM). The performance and the robustness of the control system are tested for healthy and several faulted operational modes and rotor inertia variations. The FPI controller presents many advantages such as...

This paper presents a new approach to the sensorless position control of six-phase induction machine (6PIM). A fuzzy-PI (FPI) system has been employed to estimate the rotor position and avoid using mechanical sensor. Also, high-accuracy positioning of a 6PIM rotor can be obtained using such FPI system in model control loops. The input-output scale...

In this paper, a fuzzy PI (FPI) controller is proposed for position control of six-phase induction motor (6PIM). The fuzzy controller is tuned by using the genetic algorithm so that a high performance of the overall system's response can be achieved. The performance and the robustness of the control system are tested for fully loaded and widely loa...

Nowadays, power converters in the railway indus- tries are increasingly more compact and powerful. This progress is due to the use of fast and efficient components capable of working at high frequency such as IGBT. However, this evolution leads to a considerable loss of harmonics in transformers and complicates their design. Moreover, the mean time...

Squirrel cage induction motors design requires making numerous trade-offs, especially between its audible electromagnetic noise level, its efficiency and its material cost. However, adding the vibro-acoustic and thermal models to the usual electrical model of the motor drastically increases the simulation time. A finite element approach is then inc...

RESUME – Cet article présente des résultats de simulations vibro-acoustique pour une machine à bobinage dentaire 10 pôles / 12 encoches équipée d'un rotor SPM (Surface Permanent Magnet). La machine répond à un cahier des charges type traction électrique. L'analyse du bruit d'origine électromagnétique, qui est pertinente pour des basses vitesses, de...

For the comfort and security of users, noise of electric motors is a critical issue. The harmonic content of the magnetic pressure inside the air gap being the source of the sound radiated by the stator, it suits to know the impact of field weakening. We will show that for some load angles the pressure harmonics change so that the field weakening c...

This paper presents a fully analytical model of the electromagnetic and vibro-acoustic behavior of variable-speed squirrel-cage induction machines. This model is integrated in a fast simulation tool that can be used to design motors with low magnetic noise levels on their whole speed range. Some simulation results at variable speed are favorably co...

Acoustics comfort is an increasingly important factor at the design stage of industrial inductors associated to converters. In addition, power converters in railway domain are more and more compact and powerful. That is why the lumped models for the electromagnetic, thermic and vibro-acoustic parts are developed. This aim of this paper is to detail...

The design of variable-speed electrical machines involves several fields of physics, such as electromagnetism, thermics, mechanics, and also acoustics. This paper describes the analytical multiphysics models of a computer-aided-design software which is applied to inverter-fed traction induction machines. The electromagnetic model computes rotor and...

This paper derives the analytical characterization of the Maxwell radial vibrations due to pulsewidth modulation (PWM) supply in induction machines and, particularly, in traction motors supplied with an asynchronous switching frequency. The number of nodes and the velocity of these particular force waves are experimentally validated by visualizing...