Laurentiu Encica - Academia.edu (original) (raw)

Papers by Laurentiu Encica

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, 2005

PurposeOptimisation in electromagnetics, based on finite element models, is often very time‐consu... more PurposeOptimisation in electromagnetics, based on finite element models, is often very time‐consuming. In this paper, we present the space‐mapping (SM) technique which aims at speeding up such procedures by exploiting auxiliary models that are less accurate but much cheaper to compute.Design/methodology/approachThe key element in this technique is the SM function. Its purpose is to relate the two models. The SM function, combined with the low accuracy model, makes a surrogate model that can be optimised more efficiently.FindingsBy two examples we show that the SM technique is effective. Further we show how the choice of the low accuracy model can influence the acceleration process. On one hand, taking into account more essential features of the problem helps speeding up the whole procedure. On the other hand, extremely simple auxiliary models can already yield a significant acceleration.Research limitations/implicationsObtaining the low accuracy model is not always straightforward. ...

Abstract: Amidst burgeoning attention for local manufacturing, manufacturing must adopt innovatio... more Abstract: Amidst burgeoning attention for local manufacturing, manufacturing must adopt innovations that lie at the heart of the Industry 4.0 transformation. All need to offer (or at least start to think about offering) a unique combination of high-quality electric drives that incorporate electrical machines, software, mathware, mechatronics, electronics, assembly ánd predictive maintenance. In integrated drives data driven rapid development will be paramount to the electric drive systems (motor with power electronics drive and embedded intelligence). This will allow for predictive maintenance to illustrate the state of both the electrical machine as the power electronics.<br/><br/>Integrating or bringing the power electronics in very close proximity to the electrical machines is not new. Engineers have been pursuing this for a few decades due to the obvious potential benefits including: higher system power density/smaller system footprint, reduced system cost, reduced c...

2018 Thirteenth International Conference on Ecological Vehicles and Renewable Energies (EVER), 2018

In comparison with common combustion motor driven vehicles future electric driven vehicles vary m... more In comparison with common combustion motor driven vehicles future electric driven vehicles vary more in their reachable range because of the high drive train efficiency and the different energy demand requirements in different drive conditions. One of the main issues to improve the overall range is the minimization of energy consumption. On the one hand an adapted energy management strategy is needed to achieve a more comfortable and acceptable equalization in the range. On the other hand it is important to recuperate mechanical, electrical and thermal energy, both inside and from the vehicles wherever possible. For example, it is thinkable to use the kinetic energy of braking vehicles outside the vehicle to power traffic lights. If a combustion process is used, a lot of waste thermal energy can be reused from the tailpipe. Or solar energy may be used. If a vehicle has a varying duty-cycle it makes sense to adapt the powertrain to suit the power need. Whatever the available energy, it has to go hand in hand with minimizing the energy consumption. This paper is based on the knowledge and combination of future technologies [2], which are useful to collect and convert energy coming from different sources within a vehicle.

Hybrid or full electric propulsions for inland ships are becoming more popular. In these applicat... more Hybrid or full electric propulsions for inland ships are becoming more popular. In these application, direct-drive PM propulsion motors are a preferred machine configuration. This paper discusses the challenges to determine the losses, as estimated with simulations, during the testing procedures of a 350kW at 300rpm, respectively. The full-load testing of the drive system is performed by mechanically coupling two identical machines, of which one operates as a motor and the other as a generator, or “back-to-back” testing configuration. Two Direct-Drive PM machines have been manufactured to validate key findings from the modelling, particularly in terms of loss predictions, thermal modelling and influence of the design features such as magnet segmentation. A back-to-back set-up is created for testing these machines with a speed range of 0-450 rpm. Before the measurement commended, tests were carried out in accordance with IEC60034-1, IEC60034-15, IEC60085-1, IEEE43, IEEE118 and Lloyd&...

Journal of international Conference on Electrical Machines and Systems, 2013

Applications such as vibration isolation, gravity compensation, pick-and-place machines, etc., wo... more Applications such as vibration isolation, gravity compensation, pick-and-place machines, etc., would benefit from (long-stroke) cylindrical/tubular permanent magnet (PM) actuators with integrated passive gravity compensation to minimize the power consumption. As an example, in component placing (pick-and-place) machines on printed circuit boards, passive devices allow the powerless counteraction of translator including nozzles or tooling bits. In these applications, an increasing demand is arising for high-speed actuation with high precision and bandwidth capability mainly due to the placement head being at the foundation of the motion chain, hence, a large mass of this device will result in high force/power requirements for the driving mechanism (i.e. an H-bridge with three linear permanent magnet motors placed in an H-configuration). This paper investigates a tubular actuator topology combined with passive gravity compensation. These two functionalities are separately introduced, where the combination is verified using comprehensive three dimensional (3D) finite element analyses.

2016 Eleventh International Conference on Ecological Vehicles and Renewable Energies (EVER), 2016

Calculation of turn-to-turn capacitance (Ctt) in electrical machines (EMs) with formed windings i... more Calculation of turn-to-turn capacitance (Ctt) in electrical machines (EMs) with formed windings is presented in this paper for rectangular and round cross-section wire. Variation of Ctt with wire/coil properties in formed windings and deviation between analytical methods (AMs) and finite element method (FEM) have not been presented until now. This dearth in publications, necessitates this comparison between methods for Ctt calculation in formed windings. As such, three calculation methods are used in this paper for the calculation of Ctt in case of rectangular conductors: an FEM and two previously published AMs. The influence of wire thickness and wire corner radius on Ctt is investigated. For round cross-section wires, four methods are presented: an FEM and three different AMs. The influence of wire size, insulation thickness and relative dielectric constant of the wire insulation on Ctt are considered. The relative error, i.e. deviation among the methods applied is presented for both types of wires. Finally, the results presented here demonstrate that the method for Ctt calculation should be carefully considered for different cases, since the wrong selected method can result in a deviation of even 400%.

2015 International Conference on Sustainable Mobility Applications, Renewables and Technology (SMART), 2015

Calculation of turn-to-turn capacitance (Ctt) in electrical machines (EMs) with formed windings w... more Calculation of turn-to-turn capacitance (Ctt) in electrical machines (EMs) with formed windings with rectangular cross-section wire is presented. Three calculation methods are used for the calculation of Ctt in case of rectangular conductors - finite element (FE) method and two previously published analytical methods are applied. Three different sizes of wires are used for this calculation. Further, every model of the wire is considered as an ideal rectangle in the first case, i.e. without the corner radii, and in the second case as it exists in reality, including the corner radii.

An electromagnetic actuator (100) comprises magnets (109, 111, 113, 115, 11), and a ferromagnetic... more An electromagnetic actuator (100) comprises magnets (109, 111, 113, 115, 11), and a ferromagnetic structure (103) accommodating control conductors (118, 121, 123, 125). The magnets and the structure can move with respect to one another under control of control currents in the control conductors. The magnetic field in a gap (107) between the magnets and the ferromagnetic structure is oriented perpendicular to the direction of relative movement. The structure (103) accommodates damping conductors (127) that form closed loops of an electrically conductive material, different from the ferromagnetic material. The damping conductors (127) provide a damping force induced by the relative movemen

DOI to the publisher's website. • The final author version and the galley proof are versions of t... more DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:

The ever increasing quest for smaller details on computer chips requires increasingly accurate li... more The ever increasing quest for smaller details on computer chips requires increasingly accurate lithographic machinery. This paper discusses part of the design of a permanent magnet based vibration isolation system to be used within such machinery. In such system, the passive permanent magnets provide the gravity compensation and active electromagnets the accurate positioning. Flux-focusing materials may be incorporated for structural

Dit proefschrift is goedgekeurd door de promotoren: prof.dr.ir. J.H. Blom en prof.dr. P.W. Hemker... more Dit proefschrift is goedgekeurd door de promotoren: prof.dr.ir. J.H. Blom en prof.dr. P.W. Hemker Copromotor: dr. E.A. Lomonova MSc prof.dr.ir. J.H. Blom vervult namens wijlen prof.dr.ir. A.J.A. Vandenput de rol van 1 e promotor.

Biological Cybernetics

Tubular permanent magnet actuators are evermore used in demanding industrial and automotive appli... more Tubular permanent magnet actuators are evermore used in demanding industrial and automotive applications. However, these actuators can suffer from large cogging forces, which have a destabilizing effect on the servo control system and compromise position and speed control accuracy. This paper describes a method to analyze cogging force in the design of a tubular slotted PM actuator for industrial applications. A comprehensive analysis is undertaken by considering a pre-established design in coherence with extended 2D finite element analysis. The tubular structure is remodeled into a 2D axial rotating finite element model. This enables the determination and verification of the cogging force associated both with the stator slotting and finite length of the ferromagnetic armature core of a 3- phase slotted tubular brushless permanent-magnet actuator.

2015 Tenth International Conference on Ecological Vehicles and Renewable Energies (EVER), 2015

2010 12th International Conference on Optimization of Electrical and Electronic Equipment, 2010

Electronic Notes in Theoretical Computer Science, 2006

… and Systems, 2008. …, 2008

... iron core linear permanent magnet motor was selected (www.tecnotion.com) such that: • the y-a... more ... iron core linear permanent magnet motor was selected (www.tecnotion.com) such that: • the y-axis acceleration is increased by a factor 2, • y-axis settling behavior remains the same, • moving masses are minimized, and • maximum allowed ... [6] H. Goossens, G. Jansen, P. Van ...

Structural and Multidisciplinary Optimization, 2006

Engineering optimization procedures employ highly accurate numerical models that typically have a... more Engineering optimization procedures employ highly accurate numerical models that typically have an excessive computational cost, e.g. finite elements (FE). The space mapping (SM) technique speeds up the minimization procedure by exploiting also simplified (less accurate) models. We will use the SM terminology of fine and coarse in order to refer to the accurate and inaccurate models, respectively. SM implementation in the field of electromagnetic actuators design, in the context of constrained optimization, is a rather unexplored topic. A linear voice coil actuator is chosen as a benchmark test example. The key element in SM is the so-called SM function, which efficiently corrects the imprecise results that can be obtained with just coarse information. SM is used to solve a shape optimization problem. The design problem is stated as a minimization in which the computational cost lies completely in the constraint evaluation, thus SM is applied only to the constraints. A mathematical description of the approach is presented in this paper and two implementations are compared. The solution of the SM optimization is validated (locally) by means of a standard minimization routine. The numerical results obtained show a high efficiency of the SM-based optimization algorithm, reflected by a significantly low number of fine model simulations and an overall low computational effort.