# Luc DupréGhent University | UGhent · Department of Electrical Energy, Systems and Automation

Luc Dupré

full professor

## About

336

Publications

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4,017

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Citations since 2017

## Publications

Publications (336)

Background:
In magnetic drug targeting (MDT), micro- or nanoparticles are injected into the human body to locally deliver therapeutics. These magnetic particles can be guided from a distance by external magnetic fields and gradients from electromagnets.
Purpose:
During the particles' movement through the vascular network, they are affected by ma...

Welding has a severe impact on the efficiency of electrical machines. The heat added during the welding process affects the microstructure of the material and causes residual stress. This results in local degradation of the magnetic permeability and facilitates additional iron losses in the machine core. With the purpose of modeling and simulating...

Magnetic drug targeting (MDT) is an application in the field of targeted drug delivery in which magnetic (nano)particles act as drug carriers. The particles can be steered toward specific regions in the human body by adapting the currents of external (electro)magnets. Accurate models of particle movement and control algorithms for the electromagnet...

When optimizing the design of electrical machines, it is recommended to take into account the effect of the manufacturing processes on the core losses and magnetic properties of the electrical steel. This paper demonstrates a methodology for incorporating the effects of interlocking, a process frequently applied to fix a stack of laminations, on th...

The energy efficiency of electric machines can be improved by optimizing their manufacturing process. During the manufacturing of ferromagnetic cores, silicon steel sheets are cut and stacked. This process introduces large stresses near cutting edges. The steel near cutting edges is in a plastically deformed stress state without external mechanical...

Resonant wireless power transfer (RWPT) allows for efficient transfer of electrical energy over an air gap, by optimally tuning a receiver resonator. Next to transferring electrical energy to supply or charge a device, previous work demonstrated that the induced current in receiver resonators can be directly applied to exert mechanical torque on a...

In this paper, an evolutionary-based sparse regression algorithm is proposed and applied onto experimental data collected from a Duffing oscillator setup and numerical simulation data. Our purpose is to identify the Coulomb friction terms as part of the ordinary differential equation of the system. Correct identification of this nonlinear system us...

jats:p>In this paper, an evolutionary-based sparse regression algorithm is proposed and applied onto experimental data collected from a Duffing oscillator setup and numerical simulation data. Our purpose is to identify the Coulomb friction terms as part of the ordinary differential equation of the system. Correct identification of this nonlinear sy...

An increasing need for fast and reliable models has led to a continuous development of Fourier-based (FB) analytical modeling. This paper presents an overview of the techniques that are currently available in FB modeling for electric machines. By coupling that overview to the most relevant literature related to the subject, an interesting starting...

Resonant wireless power transfer has been employed to transfer electrical power from a transmitter to a receiver coil over an air gap and to remotely charge consumer devices. In this paper, the receiver coil is replaced by a stator-rotor topology, enabling magnetic resonance based motoring over substantial air gaps. The principles of resonant wirel...

A continuous demand for more efficient and more compact drives is pushing the popularity of high-speed permanent magnet synchronous machines (PMSMs). However, high rotational speeds and extreme power densities imply that an appropriate cooling of the rotor may be difficult. This is all the more important because of the risk of demagnetization when...

In this chapter, the basic elements of the usual instrumentation for characterizing materials for magnetic hyperthermia and for applying this therapy will be explained, with a special emphasis on coil design and temperature measurement. First, the importance of the shape of the coil and its cooling is discussed considering the dimension of the samp...

For the first time, a mm-wave personal exposure meter (mm-PEM) for the 5th generation of mobile networks (5G) exposure assessment in indoor diffuse fields is presented. The design is based on simulations and on-phantom calibration measurements in a mm-wave reverberation chamber (RC) at 60 GHz. The mm-PEM consists of an array of nine antennas on the...

Discovery of natural laws through input-output data analysis has been of considerable interest during the past decade. Various approach among which the increasingly growing body of sparsity-based algorithms have been recently proposed for the purpose of free-form system identification. There has however been limited discussion on the performance of...

High-speed electric machines with permanent magnets are sometimes equipped with a shielding cylinder; a conductive sleeve that is wrapped around the magnets in order to reduce the rotor losses and/or retain the magnets. Despite the every increasing popularity of such high-speed permanent-magnet synchronous machines (PMSMs), there are still a lot of...

In this paper we aim to apply an adaptation of the recently developed technique of sparse identification of nonlinear dynamical systems on a Duffing experimental setup with cubic feedback of the output. The Duffing oscillator described by nonlinear differential equation which demonstrates chaotic behavior and bifurcations, has received considerable...

Magnetic nanoparticles exposed to alternating magnetic fields have shown a great potential acting as magnetic hyperthermia mediators for cancer treatment. However, a dramatic and unexplained reduction of the nanoparticle magnetic heating efficiency has been evidenced when nanoparticles are located inside cells or tissues. Recent studies suggest the...

Yokeless and segmented armature (YASA) axial flux permanent magnet synchronous machines may have asymmetrical demagnetisation defects in their two rotors. Condition monitoring, therefore, becomes more complicated than in conventional single rotor machines. To develop a real-time condition monitoring algorithm for demagnetisation faults in YASA mach...

In this paper we aim to apply an adaptation of the recently developed technique of sparse identification of nonlinear dynamical systems on a Duffing experimental setup with cubic feedback of the output. The Duffing oscillator described by nonlinear differential equation which demonstrates chaotic behavior and bifurcations, has received considerable...

Nowadays, field-driven chiral bubble dynamics in the presence of the Dzyaloshinskii-Moriya interaction (DMI) are a topic of thorough investigation. In this paper, a semi-analytical approach is used to derive equations of motion that express the bubble wall (BW) velocity and the change in in-plane magnetization angle as function of the micromagnetic...

Lagrangian-based collective coordinate models for magnetic domain wall (DW) motion rely on an ansatz for the DW profile and a Lagrangian approach to describe the DW motion in terms of a set of time-dependent collective coordinates: the DW position, the DW magnetization angle, the DW width and the DW tilting angle. Another approach was recently used...

An increasing interest in both efficient electric machines and more extensive control strategies demands evermore faster simulation tools. In that context, Fourier-based models, which combine low computational times with a high accuracy, have already proven their value. However, even Fourier-based models may encounter problems related to CPU usage....

Despite an ever-growing interest, a lot of questions related to the design and operation of high-speed permanent-magnet synchronous machines remain unanswered. One aspect of such high-speed machines that requires special attention is the effect of the shielding cylinder, a conductive sleeve that is wrapped around the magnets and which’ goal is to r...

A time-harmonic analytical model is presented for a combined study of demagnetization and rotor eccentricity in single-stator double-rotor axial flux permanent magnet synchronous machines (AFPMSM). Demagnetization defects are modeled by scaling the magnetization 'square wave' by magnetization factors for each individual magnet on both rotors. Stati...

Percutaneous vertebroplasty comprises the injection of Polymethylmethacrylate (PMMA) bone cement into vertebrae and can be used for the treatment of compression fractures of vertebrae. Metastatic bone tumors can cause such compression fractures but are not treated when injecting PMMA-based bone cement. Hyperthermia of tumors can on the other hand b...

Magnetic nanoparticles in colloidal dispersions are important for biomedical applications like magnetic drug targeting, magnetic particle hyperthermia, and several imaging applications. For a physical understanding of these applications, the particles' hydrodynamic size distribution should be well characterized. Magnetorelaxometry is a fast method...

Magnetorelaxometry and thermal magnetic noise spectroscopy are two magnetic characterization techniques enabling one to estimate the magnetic nanoparticle hydrodynamic size distribution. Both techniques are based on the same physical principle, i.e. the thermal fluctuations of the magnetic moment. In the case of magnetorelaxometry these fluctuation...

The paper studies demagnetization detection in Axial Flux Permanent Magnet Synchronous Machines of the Yokeless and Segmented Armature (YASA) type. In YASA machines, asymmetrical defects can occur: the demagnetization defect in the permanent magnets of both rotors differ from each other. Many techniques can indicate that there is a defect, even if...

Magnetorelaxometry (MRX) is a well-known measurement technique which allows to retrieve magnetic nanoparticle (MNP) characteristics such as their size distribution and clustering behavior. This technique also enables the non-invasive reconstruction of the spatial MNP distribution by solving an inverse problem, referred to as MRX imaging. Although M...

Magnetorelaxometry (MRX) imaging and electron paramagnetic resonance (EPR) are two non-invasive techniques capable of recovering the magnetic nanoparticle (MNP) distribution. Both techniques solve an ill-posed inverse problem in order to find the spatial MNP distribution. A lot of research has been done on increasing the stability of these inverse...

The use of power electronics has led to a growing importance of higher time-harmonic content in electrical machines. To gain insight in phenomena related to these higher harmonics, such as noise and losses, a good understanding of the magnetic field’s harmonic content is mandatory. Moreover, the development of fast and accurate, harmonic-based, ana...

Fast domain wall (DW) propagation through perpendicularly magnetized nanostrips with a Dzyaloshinskii-Moriya interaction (DMI) offers promising opportunities for the development of magnetic memory and logic devices. However, as the DW speed increases, the DW magnetization is also progressively affected which ultimately leads to an unstable DW and a...

Magnetic nanoparticle hyperthermia is a cancer treatment in which magnetic nanoparticles (MNPs) are subjected to an alternating magnetic field to induce heat in the tumor. The generated heat of MNPs is characterized by the specific loss power (SLP) due to relaxation phenomena of the MNP. Up to now, several models have been proposed to predict the S...

In this paper, a method is proposed to detect asymmetrical demagnetization defects in single-stator double-rotor axial flux permanent magnet synchronous machines (AFPMSMs). Sensing coils back-EMF data and an analytical model are combined to solve an electromagnetic inverse problem. The method is validated with numerical and experimental data.

When delivered over a specific cortical site, TMS can temporarily disrupt the ongoing process in that area. This allows mapping of speech-related areas for preoperative evaluation purposes. We numerically explore the observed variability of TMS responses during a speech mapping experiment performed with a neuronavigation system. We selected four ca...

In this paper, a complete sensitivity analysis of the optimal parameters for the axial flux permanent magnet synchronous machines working in the field weakening (FW) region is implemented. Thanks to the presence of a parameterized accurate analytical model, it is possible to obtain all the required parameters of the machine. The two goals of the id...

An increasing interest in both efficient electrical machines and more extensive control strategies demands evermore faster simulation tools. One of the modeling techniques that meets this demand is Fourier-based modeling. However, even Fourier-based models may encounter problems related to CPU usage. To cope with these problems the authors present...

Radiofrequency ablation (RFA) is an alternative cancer treatment that applies radiofrequency electric fields to biological tissues. The subsequent electrical currents induce Joule heating and inflict local thermal damage to the biological tissue. Previous clinical studies demonstrate the possibilities and benefits of applying RFA for the treatment...

Magnetic nanoparticle hyperthermia is an alternative cancer treatment where magnetic nanoparticles are delivered to the tumor. The magnetization response due to an alternating magnetic field causes the magnetic nanoparticles to act as a heating power source and thermally damage the tumor cells. The heating capability of magnetic nanoparticles depen...

Objective.
Transcranial magnetic stimulation (TMS) is a promising non-invasive tool for modulating the brain activity. Despite the widespread therapeutic and diagnostic use of TMS in neurology and psychiatry, its observed response remains hard to predict, limiting its further development and applications. Although the stimulation intensity is alwa...

Among the different geometrical parameters to be chosen during design of axial flux permanent magnet synchronous machines, the width of the stator slot openings near the air gap is an important parameter: it has a major influence on the power loss in the stator core and in the permanent magnets on the two rotors of the studied type of axial flux ma...

The motion of domain walls in magnetic materials is a typical example of a creep process, usually characterised by a stretched exponential velocity-force relation. By performing large-scale micromagnetic simulations, and analyzing an extended 1D model which takes the e ects of nite temperatures and material defects into account, we show that this c...

Purpose:
The performance of an increasing number of biomedical applications is dependent on the accurate knowledge of the spatial magnetic nanoparticle (MNP) distribution in the body. Magnetorelaxometry (MRX) imaging is a promising and noninvasive technique for the reconstruction of this distribution. To date, no accurate and quantitative measure...

Typically, the dynamic behaviour of magnetic nanoparticles is investigated by measuring their response to externally applied magnetic fields. In contrast, we present a study of the magnetic fluctuations in an ensemble of magnetic nanoparticles recorded in the absence of any external excitation. Several samples of magnetic nanoparticles with varying...

Presents a closure to the discussion from the following paper, “Electrical machine PWM loss evaluation basics (Ruderman, A. and Welch,R.) in Proc. Int. Conf. Energy Efficiency Motor Driven Syst.,Sep. 2005, vol. 1, pp. 58–68.

The importance of extensive optimizations during the design of electric machines entails a need for fast and accurate simulation tools. For that reason Fourier-based analytical models have gained a lot of popularity. The problem, however, is that these models typically require a current density as input. This is in contrast with the fact that the g...

Purpose:
Magnetic nanoparticles (MNPs) are an important asset in many biomedical applications. An effective working of these applications requires an accurate knowledge of the spatial MNP distribution. A promising, noninvasive, and sensitive technique to visualize MNP distributions in vivo is electron paramagnetic resonance
(EPR). Currently only 1...

A demand for more efficient electrical machines with a high power density is driving the interest for high-speed permanent-magnet synchronous machines (PMSMs). However, the design of such machines is a challenging task. One of the problems is that the effect of the shielding cylinder, a conductive sleeve around the magnets, on the machine’s perform...

Axial flux permanent magnet synchronous machines (AFPMSMs) have been extensively used in different applications due to their excellent performances [1]. Particularly, AFPMSMs are well dedicated for applications that acquire high power density, such as substantial energy applications. In practice, these types of machines suffer from different faults...

We introduce a non-volatile digital logic and memory concept in which the binary data is stored in the transverse magnetic domain walls present in in-plane magnetized nanowires with sufficiently small cross sectional dimensions. We assign the digital bit to the two possible orientations of the transverse domain wall. Numerical proofs-of-concept are...

The effect of multilevel inverter supply on power losses in magnetic cores and electrical machines is studied. A dynamic numerical model for the hysteresis, eddy-current and excess losses in a core lamination is first developed. By both measurements and simulations for a ring-core inductor, we demonstrate how increasing the number of inverter volta...

Magnetic domain walls are proposed as data carriers in future spintronic devices, whose reliability depends on a complete understanding of the domain wall
motion. Applications based on an accurate positioning of domain walls are inevitably influenced by thermal fluctuations. In this letter, we present a micromagnetic study of the thermal effects on...

This paper studies the effect of common-mode voltage elimination (CMVE) on the iron loss of electrical machine core laminations under multilevel converter supply. Three identical magnetic ring cores are excited by either a three-level T-type or five-level dual T-type voltage source converter to study the behavior of CMVE on a three-phase system. Bo...

The interest for high-speed Permanent-Magnet Synchronous Machines (PMSMs) is high. Often such machines are equipped with a conductive sleeve that is wrapped around the magnets, i.e. the Shielding Cylinder (SC). Its goal is to reduce the overall rotor losses, thereby protecting the magnets from overheating. In such machines torque is produced in two...

Magnetic nanoparticles play an important role in several biomedical applications such as hyperthermia, drug targeting, and disease detection. To realize an effective working of these applications, the spatial distribution of the particles needs to be accurately known, in a non-invasive way. Electron Paramagnetic Resonance
(EPR) is a promising and s...

The magnetic material characteristics of a wound-field synchronous machine are identified based on global calorimetric coreloss and no-load curve measurements. This is accomplished by solving a coupled experimental-numerical electromagnetic inverse problem, formulated to minimize the difference between a finite-element (FE) simulation-based Kriging...

In this paper, a coupled experimental-mathematical inverse problem based methodology for the detection of inter-turn faults in an asynchronous induction machine is presented. The fault detection is accomplished by interpreting well-defined measurements into the machine mathematical model. First, the studied machine is modeled by means of a dynamic...

Electron Paramagnetic Resonance (EPR) is a sensitive measurement technique which can be used to recover the 1-dimensional spatial distribution of magnetic nanoparticles (MNP) non-invasively. This can be achieved by solving an inverse problem that requires a numerical model for interpreting the EPR measurement data. This paper assesses the robustnes...

Several future spintronic devices are based on domain wall propagation through magnetic nanowires. Next to experiments and simulations, theoretical models are an indispensable tool to understand the magnetic domain wall mobility. In this paper, we extract the collective coordinates and derive the equations of motion that describe the domain wall dy...

Magnetic nanoparticles (MNPs) can interact with alternating magnetic fields (AMFs) to deposit localized energy for hyperthermia treatment of cancer. Hyperthermia is useful in the context of multimodality treatments with radiation or chemotherapy to enhance disease control without increased toxicity. The unique attributes of heat deposition and tran...

In transcranial magnetic stimulation (TMS), an applied alternating magnetic field induces an electric field in the brain that can interact with the neural system. It is generally assumed that this induced electric field is the crucial effect exciting a certain region of the brain. More specifically, it is the component of this field parallel to the...

This paper studies the effect of common-mode voltage elimination (CMVE) on the iron loss of electrical machine core laminations under multilevel converter supply. Three identical magnetic ring cores are excited by either a three-level converter or a five-level voltage source converter to study the behavior of CMVE on a three-phase system. Both mult...

Magnetic properties of the electromagnetic devices core materials are reconstructed by solving a coupled experimental-numerical electromagnetic inverse problem. However, the measurement noise as well as uncertainties of the forward model parameters and structure may result in dramatic recovery errors in the recovered values of the material paramete...

The goal of this paper is to investigate the accuracy of modeling the excess loss in electrical steels using a time domain model with Bertotti's loss model parameters n0 and V0 fitted in the frequency domain. Three variants of iron loss models based on Bertotti's theory are compared for the prediction of iron losses under sinusoidal and non-sinusoi...

In this paper, a coupled experimental-mathematical
inverse problem based methodology for the detection of interturn faults in an asynchronous induction machine is presented.
The fault detection is accomplished by interpreting well-defined
measurements into the machine mathematical model. First, the
studied machine is modeled by means of a dynamic s...

This paper presents an analytical method for permanent magnet demagnetization detection in an axial flux permanent magnet synchronous machine. First, a forward model is built to calculate the three phase terminal voltages with inputs of three phase currents, the geometry of the machine, and the electromagnetic properties of the machine. To model th...

Magnetorelaxometry (MRX) is a sensitive measurement technique frequently employed in biomedical applications for imaging magnetic nanoparticles (MNP). In this article, we employ a first principles model to investigate the effects of different iron oxide MNP sample properties on the Neel relaxation time constant tau(N) in magnetorelaxometry. Using t...

For yokeless and segmented armature (YASA) axial flux permanent-magnet machines, several lamination stacking methods are discussed. For the same global machine geometry, it is shown that some are easier and cheaper to produce, while others have a higher output torque, lower cogging torque, better efficiency or higher power density. Apart from the d...

Recently the interest in permanent-magnet syn-chronous machines (PMSMs) operating at high speed has grown. However, a lot of design and operation questions remain unan-swered. This work aims at studying the effect of the number of pole pairs, the number of slots per pole per phase and the coil throw on the torque and the torque ripple in high-speed...

The goal of this paper is to study the additional loss caused by Pulse Width Modulation (PWM), on the one hand in an axial flux permanent magnet synchronous machine (PMSM), and on the other hand in the voltage source inverter (VSI) that supplies the machine. Via a computationally efficient technique, the losses are computed in the stator iron and i...