Pascal Brochet

• Doctor of Philosophy Applied Mathematics
• Professor (Full) at École Centrale de Lille

Purpose – The purpose of this paper is to present an application of a multidisciplinary multi-level design optimization methodology for the optimal design of a complex device from the field of electrical engineering throughout discipline-based decomposition. The considered benchmark is a single-phase low voltage safety isolation transformer. Desig...

Purpose – Discrete highly constrained optimization of induction machine taking into consideration two objective functions: efficiency and total costs of production. The paper aims to discuss these issues. Design/methodology/approach – Interactive and semi-interactive interval-based optimization methods were used. Two concepts of multi-objective di...

Purpose – The purpose of this paper is to develop an optimal approach for optimizing the dynamic behavior of incremental linear actuators. Design/methodology/approach – First, a parameterized design model is built. Second, a dynamic model is implemented. This model takes into account the thrust force computed from a finite element model. Finally,...

The work described in this paper deals with the analytical design and optimization of a line-start permanent magnet synchronous motor (LSPM) with a series magnetic circuit structure. The design approach considers a LSPM as an induction motor (IM) combined with a permanent magnet rotor arrangement and takes into account the characteristics of both a...

For the design and analysis of a linear electrical motor, an analytical solution of electric and magnetic fields is barely achieved with the required accuracy, due to the end and edge effects, and the nonlinear characteristic of the materials. Optimal design with the finite element models (FEM) is often expensive, in terms of the computation time....

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...

In the paper the platform facilitating the process of design of induction machines are presented. It is deployed at the manufacturer of high power induction machines and used for aiding design engineers in the process search of the set of optimal configurations. It permits treating the highly constrained problem with discrete variables and make use...

Introduction Multi-level approaches Optimization using models with different granularities Hierarchical decomposition of an optimization problem Conclusion Bibliography

Purpose The purpose of this paper is to present two optimization methodologies based on interval branch‐and‐bound algorithm. Design/methodology/approach These techniques decrease the total time of computation, even in spite of discrete nature of some of the design variables. Computational experiments performed on multivariable optimization problem...

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...

In this paper, we propose an application of interval analysis to the problems of optimal design of high power induction machines. The considered tool proved its usefulness as a decision-support system for design engineers. Interactive algorithm for bi-objective optimization is implemented. Generally, it is suitable for any problems with discrete va...

An optimal design approach is developed for permanent magnet motors. First, parameterized design model is built. Second the significant shape parameters are identified using the Fisher test of ANOVA. Finally, an optimal design loop, delivering as final output optimized geometries of Permanent Magnet motors, is implemented.

The Capability and Stability Domain curve of large Synchronous Generator provided with Hybrid Excitation system is analyzed in this paper. The machine consists of a conventional salient pole synchronous generator with additional surface mounted permanent magnets. For obvious reasons to limit time calculation Magnetic Equivalent Circuit (MEC) based...

This paper describes the modeling of a permanent magnet synchronous machine (PMSM) by using lumped models (LMs). Designing electrical machines necessarily involves several fields of physics, such as electromagnetics, thermics, mechanics, and acoustics. Magnetic, electrical, electronic, and thermal parts are represented by LMs, whereas vibro-acousti...

Purpose The purpose of this paper is to present a low evaluation budget optimization strategy for expensive simulation models, such as 3D finite element models. Design/methodology/approach A 3D finite element electromagnetic model and a thermal model are developed and coupled in order to simulate the linear induction motor (LIM) to be conceived. U...

Optimal design with finite element model is often expensive in terms of computation time. The output space mapping technique allows benefiting both the rapidity of the analytical model and the accuracy of the finite element model. In this paper, a three-level output space-mapping technique is proposed to reduce the computation time. Three models ha...

An optimal design approach is applied to an incremental linear actuator in the goal to maximize the thrust force. First, parameterized design model is built. Second the optimization problem is formulated. Finally, optimization problem is solved using two developed algorithms.

Multi-objective optimization with 3D finite element model is a complex and time consuming process. Output space-mapping techniques allow having an affordable computation cost with a minimum number of computationally expensive FEM evaluations. In this paper, a three-level adapted output space-mapping technique is proposed to assist two-objective opt...

One promising way to address the problem of the synthesis of the design of electrical machines is to set it up as an optimization problem in order to benefit from the most effective optimization algorithms to solve it. Some consequences are here derived from this statement concerning the modeling of electrical machines, the formalization of the opt...

Throughout this paper we are developing a kernel modular extensible platform, allowing new modules addition and optimizing structure's modeled in different design environments with "black box" approach. This platform identifies electrical structure parameters from their design files on which the user define optimizing problem constants and variable...

The optimization of electromagnetic devices by direct use of finite element models is computationally expensive. This paper presents two effective surrogate-assisted optimization algorithms: Output Space Mapping and Efficient Global Optimization which are employed with regard to a minimum number of finite element model evaluations. A parallel betwe...

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 (...

This paper presents performance comparison of three inverter control techniques. These techniques are respectively hysteresis control, PWM control and direct voltage control (DVC). They are applied for a PM Linear Tubular Synchronous Actuator (PMTLSA) drive fed, using a three phase voltage source inverter (VSI). This VSI is working with constant sw...

Current economic situation force manufacturers to find the new ways of designing electrical machines. In order to succeed in competitive market, industry has to create new approaches of finding the solutions which will satisfy customer's requirements. Task of determining this set of optimal configurations must be done in the least possible time fra...

A Permeance Network Analysis (PNA) of the dynamic behavior of a three phase Switched Reluctance Motor fed from a full-bridge inverter is presented. The non-linear effects due to global and local saturation are taken into consideration as well as the mutual coupling between phases. All permeances in the magnetic circuit are analytically computed in...

The modeling of electrical machines by equivalent circuits requires an appropriate calculation of inductance values. The energy-perturbation and flux-linkage methods are extremely used to determine inductance values of electrical machines from two-dimensional finite element solutions. Both methods are numerically equivalent and give approximately t...

Optimal design by means of finite element models is complex and time consuming. The Efficient Global Optimization (EGO) based on the progressive construction of a Kriging model used to drive the optimization problem allows for an affordable optimization time. In this paper, a linear induction motor (LIM) with double primaries for the subway system...

This paper describes the modeling of a permanent magnet synchronous machine by lumped models. Several fields of physics, such as electromagnetics, thermics, mechanics and acoustics are necessary for designing electrical machines. The aim of this study is to build a design model of a permanent magnet synchronous machine for traction applications whi...

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...

In order to optimize the design of an enclosed induction machine of railway traction, a multi-physical model is developed taking into account electromagnetic, mechanical and thermal-flow phenomena. The electromagnetic model is based on analytical formulations and allows calculating the losses. The thermal-flow modeling is based on an equivalent the...

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...

Multi-objective optimization with 3D finite element model is a complex and time consuming process. Output space-mapping techniques allow having an affordable computation cost with a minimum number of computationally expensive FEM evaluations. In this paper, a three-level adapted output space-mapping technique is proposed to assist two-objective opt...

Conceiving electromagnetic devices using finite element modeling tools is a complex task and also time-costly. The Efficient Global Optimization method, based on the progressive construction of surrogate models, is studied. The method uses Kriging models and allows for multiobjective optimization. An original infill criterion, combining the surroga...

In order to minimize the oscillations and the overflow of the dynamic response of linear step actuators over two successive step displacements, a control approach, based on commutation instant optimization, is developed and applied to a linear step actuator. The obtained results are, then, validated using an experimental test bench.

This paper proposes a solution for the optimization of a full-bridge three-phase inverter-fed switched reluctance motor (SRM) simultaneously accounting for the geometry of the motor as well as for its switching strategy. The optimization method proposed for this is Particle Swarm Optimization (PSO), allowing a multi-objective optimization. By means...

The end effects are the particular sensitive difficulty to model linear drives. Moreover an electrical machine model which only considers single physical aspect is not sufficiently accurate. In this paper, 3D magnetic and thermal models are achieved taking into account the end effects and the multi-physical aspects. For the first step, the linear m...

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...

This paper presents a method to characterize the main magnetic force waves occurring in a sinusoidally fed induction machine. Three main force types are identified: slotting force waves, winding force waves, and saturation force waves. Slotting force waves are characterized in terms of number of nodes, velocity, propagation direction, and magnitude...

Purpose Analytical target cascading (ATC) is a hierarchical multi‐level design methodology. According to the state‐of‐the‐art, it is confirmed that for problems with unattainable targets, strict design consistency cannot be achieved with finite weighting factors. This paper aims to address these issues. Design/methodology/approach A new formulatio...

In this paper, traction system design in carried out with a multilevel optimization technique called Target Cascading. This methodology is based on a hierarchical breaking down and allows solving a problem with multiple parallel optimizations. The large-scale system design problem is usually decomposed into several linked optimization subproblems a...

Although many empirical rules have been established for correctly choosing the number of stator and rotor slots so as to limit the audible magnetic noise level radiated by induction machines, these rules never take into account the stator natural frequencies or the fact that the motor is run at variable speed. In this paper, we present a fast simul...

This paper first presents the analytical models of an ALSTOM simulation software, DIVA, which computes the vibratory and acoustic behavior of a variable-speed induction machine due to Maxwell forces. This radial magnetic pressure in the air-gap makes the stator vibrate in the audible range, creating the so-called magnetic noise characterized by a h...

In high-performance servo applications, a rapid and accurate torque control is required, preferable without the use of the motion-state sensor. The use of permanent magnet synchronous motors combined with direct torque control techniques provides many opportunities to achieve this goal. The purpose of this paper is to improve the modeling and the c...

In high-performance servo applications, a rapid and accurate torque control is required, preferable without the use of the motion-state sensor. The use of permanent magnet synchronous motors combined with direct torque control techniques provides many opportunities to achieve this goal. The purpose of this paper is to improve the modeling and the c...

The authors present the full analysis of the vibration behaviour responsible for audible magnetic noise in a pulse-width modulation (PWM)-fed fractional-slot induction machine, including theoretical predictions, numerical simulations and experimental validations (stator modal analysis and deflection shapes visualisation). Magnetic force waves cause...

This paper derives the analytical characterization of Maxwell radial vibrations due to saturation effects in induction machines, and especially in traction motors. The number of nodes and the velocity of these particular force waves are experimentally validated by visualizing some operational deflection shapes of the stator. It is shown that accord...

This paper presents a new method to handle discrete or mixed constrained optimization problems based on a high-fidelity 3-D finite element computational model. The original idea aims to combine branch-and-bound method that is enabling to ensure a global optimal solution and space-mapping techniques that allow to speed-up the optimization procedure...

This paper proposes different approaches for the ecodesign of safety transformer based on optimization methods. The first approach consists in a life cycle analysis to highlight the stage of the product life that has the most considerable impact. An effective way to reduce the environmental impacts is to maximize the transformer efficiency. The sec...

At low speed, the acoustic power radiated by electrical transport systems can be dominated by a special source of noise called audible magnetic noise. This particular noise comes from magnetic vibrations due to magnetic forces, which are especially strong in traction motors. Some of them are called air-gap Maxwell forces and excite the stator struc...

'. L'evolution des moyens de calcul permet le deploiement de nouvelles demarches de conception, dont un exemple est presente dans cet article. Un modele multiphysique simple est construit pour le dimensionnement d'un moteur synchrone a aimants. La demarche consiste a associer a chaque phenomene physique le modele le plus approprie. Un modele elemen...

In this paper is proposed a microstep control strategy, developed for linear switched reluctance step actuators characterized by magnetic dissymmetry between the end and the central phases. In this way, a parameterized finite element model is developed for the studied actuators, and used for electromagnetic force evaluation according to the plunger...

This paper proposes multidisciplinary design optimization (MDO) as a methodology to solve electrical machine design problem. The possibility and needs in performing such kind of approach in electrical engineering application are evaluated. Permanent magnet motor optimal design problem is chosen and three formulations are tested to point out their a...

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

Purpose – The purpose of this paper is to present the original study of an industrial device. Industrial inductors are used to decrease the current variations, resulting from the use of modern power converters. To reduce these variations, the magnetic energy stored in these components is automatically used when the receptor is unconnected to the pr...

Purpose The purpose of this paper is to apply a fast analytical model of the acoustic behaviour of pulse‐width modulation (PWM) controlled induction machines to a fractional‐slot winding machine, and to analytically clarify the interaction between space harmonics and time harmonics in audible electromagnetic noise spectrum. Design/methodology/appr...

The paper points out a rational methodology to design electric drive trains components taking into account the whole system via a global approach. The aim of this global approach is to assure an optimal global solution. Thus, all components are simultaneously and conjointly designed to obtain the best adaptation to the desired system specifications...

Particle swarm optimization (PSO) and ant-colony optimization (ACO) are novel multi-agent algorithms able to solve complex problem. By consequence, it would seem wise to compare their performances for solving such problems. For this purpose, both algorithms are compared together and with Matlab’s GA in term of accuracy of the solution and computati...

Induction motor design requires making numerous tradeoffs, especially when including electromagnetic noise criterion besides usual criteria like efficiency and cost. Moreover, adding the noise objective significantly increases computational time as it must be evaluated at variable speed in order to take into account resonance effects. In that case,...

In traction application, the electric motor design methodology is not trivial. This paper presents various design approaches using rated point or load cycle. Design optimizations of surface-mounted permanent magnet traction motor are carried out using these approaches. Therefore, a comparative study is done through optimal motors obtained from opti...

A comparative study of different configurations of an axial-flux nine-phase concentrated-winding permanent-magnet synchronous generator for direct-drive wind turbine is presented. Two-dimensional finite-element analyses are used to find the best configurations. An analytical sizing model is built and validated with measurements on a small-scale pro...

1. Abstract Analytical target cascading (ATC) is a hierarchical multi-level design methodology. This approach is well suited to hierarchy decomposition in railway product. In 1999 Alexandrov and Lewis classes ATC as the same category than Collaborative Optimization (CO) that is applied only for bi-level optimiza- tion multidisciplinary systems. Tze...

Throughout this paper, we are going to use two different methods for the optimization of a shape coefficient Sc for a linear tubular step actuator range, allowing to maximize the trust force by Joule losses ratio. The first method is based on analytical computation and the second one is based on reluctance network modelling. These two methods conve...

The behavior of brushless DC motor with its drive and converter is described and highlights the requirements for accurate simulation at full-load operation. Results obtained with two commercial software packages are presented. Tricks for models developed with both softwares are provided in order to obtain good results. The simulation results are co...

Continuous decreasing in price of permanent magnet attracts many industries to invest in the development of permanent magnet synchronous motor, especially in traction application because of its high efficiency and compactness. In this paper a design of surface-mounted permanent magnet (SMPM) synchronous motor has been studied. The optimal design of...

The sequential quadratic programming and genetic algorithms are finely tuned on the optimal design of a brushless DC wheel motor. Combining both methods, a hybrid approach is tested. Multiobjective optimizations are performed using Nondominated Sorting Genetic Algorithm, Strength Pareto Evolutionary Algorithm, and a variable weighted sum of objecti...

Two analytical models and two finite element models (2D and 3D) are built and compared in terms of accuracy and computation time. They can be used as a benchmark to compare algorithms for multi-level and combinatorial optimizations. The discrete optimization of the transformer is done using branch and bound methods. The multi-level optimization is...

Induction motors optimal design can involve many variables and objectives, and generally requires to make several trade-offs, especially when including the audible electromagnetic noise criterion beyond the usual performance criteria. Multiobjective optimization techniques based on Pareto optimality are useful to help us finding the most interestin...

The classical model of the tubular switched reluctance stepping motor presents a number of limitations. To design a better model, a new modeling approach based on the use of Artificial Neural Networks is proposed in this paper. It takes into account the real inductances and propulsive force characteristics. The concordance observed between the simu...

In order to increase the power capability of direct-drive PM wind generators with respect to established quality criteria like the electromagnetic torque and the power transferred to the grid, a polyphased multi-star system is studied. The influence of the number of stars, their phase shift and the waveform of the electromotive force are investigat...

Purpose – The purpose of this paper is to introduce a simplified method to calculate an estimation of local forces acting on a body submitted to electric or magnetic fields. With experimentations, the method is thereafter evaluated. Design/methodology/approach – When an external strength exists on a body, its deformation is an effect always observ...

Space-mapping optimization techniques allow to allign low-fidelity and high-fidelity models in order to reduce the computational time and increase the accuracy of the solution. The main idea is to build an approximate model from the difference of response between both models. Therefore the optimization process is computed on the surrogate model. In...

An analytical model of PWM controlled induction machine was developed in order to predict its sound power level of electromagnetic origin at variable speed. The electromagnetic model calculates the stator and rotor currents with a multilayer single-phase equivalent circuit. The mechanical and acoustic parts are based on a cylindrical shell stator m...

Différentes formulations permettent de calculer la force subie par un matériau plongé dans un champ magnétique statique. Selon les circonstances, elles peuvent ou non conduire à des résultats qui diffèrent significativement. L’objet de la présente étude est de les comparer numériquement et expérimentalement, puis de déterminer les plus appropriées....

A comparative study of different configurations of an axial-flux, 9-phase, concentrated winding, PM synchronous generator for direct-drive wind turbine is presented. 2D finite element analyses are used to find the best configurations. An analytical sizing model is built and validated with measurements on a small scale prototype. An optimization pro...

The development of HPCN and portable parallel implementations through BSP has encouraged developers and users of electromagnetic design software to address both the grand challenge problems and replace analysis of a design with synthesis. The paper describes the approach adopted by the EPOCH consortium.

The paper points out a rational methodology to design electric or hybrid drive trains components taking into account the whole system by a global approach. The aim of this global approach is to assure an optimal global solution, all components being simultaneously and conjointly designed to obtain the best adaptation to the desired system specifica...

This paper describes a hybrid fuzzy-conventional control technique of a linear induction motor. This technique, based on the use of the vector control method associated to a choice of combined analogical and fuzzy controllers, is proposed to ameliorate the dynamics of the secondary flux and the thrust force. The results of the numeric simulation ar...

A microstep control strategy, developed for linear switched reluctance step actuators, is proposed in this paper. The design of the studied actuator using finite element simulations has allowed to put, especially, in evidence the important dissymmetries observed on electromagnetic force characteristics developed by the different actuator phases. Fr...

L'article presente une demarche de conception qui aboutit a la realisation d'un moteur synchrone et a son integration dans une pompe etanche pour fluides corrosifs. La machine synchrone a flux axial est proposee et sa construction dans le cadre de petites et moyennes series est simplifiee. Pour cela, une structure a bobinages concentres et a encoch...

The command approach proposed in this paper, in order to ameliorate dynamics relating to the secondary flux and the electromagnetic thrust force for a linear induction motor, is based on the use of the vector control technique associated to fuzzy logic controllers. This technique is adopted to decouple the thrust force and the flux. The implantatio...

The aim of this paper is to use an analytical multi-physical model – electromagnetic, mechanic and acoustic – in order to predict the electromagnetic noise of an asynchronous machine. This machine operating at variable speed generate vibrations that can be harmful for the machine itself and its environment. Thus, it is necessary for the manufacture...

The modeling of a turbo-alternator using permeance network is described. This approach allows implementing electrical and magnetic coupling as well as mechanical coupling. Such processes as saturation, movement, and three-dimensional (3-D) effects are taken into account. The aim of this study is to set up a design model of 10-100mW turbo-alternator...

In the design process of any device, the computation of the forces or the torque is often a decisive step. Finite element solutions give accurate solutions in terms of magnetic field or flux density. But for local force computation associated to a magnetic field, many formulations are available. They use different physical interpretations of the sa...

The concept of multiphysics optimization is applied to the design of an electric motor. It combines finite elements and analytical models to form together a multiphysics model of the electric motor. The different models represent different machine phenomena as electromagnetic, thermal and vibro-acoustic. These models are strongly coupled through a...

A multi-physical parametric model of the induction machine and its pulse width modulation (PWM) supply was developed in order to predict its sound power level of electromagnetic origin at variable speed and load, and perform optimal design search including noise minimization. The electromagnetic model calculates the stator phase currents by the aid...