J.J.H. Paulides

In‐wheel PM motor: compromise between high power density and extended speed capability

Purpose – Todays brushless permanent magnet (PM) drive systems usually adopt motors including the advancements in magnet technology, e.g. better thermal characteristics and higher magnetic strength. By this means, they become capable in the roughest applications yet maintain a high accuracy at competitive prices. These drive systems are not only appreciated for their high performance, but they are also advantageous for the applications requiring tough, dependable, and continuous‐duty operations, e.g. hybrid or complete electrical vehicles, extruders, wire drawers, winders, cranes, conveyors, and roll formers. The purpose of this paper is to provide an extended comparative study of the different motor configurations for the hybrid electric drive application, aiming at a compromise between high power density and extended speed capability.Design/methodology/approach – To suit strict design requirements, such as the very limited volumetric envelope, high‐output power, wide constant power speed range, and pre...

Cogging Force Reduction in Tubular Permanent Magnet Actuators

This paper describes a method to reduce 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, which enables the determination 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. In order to reduce the total cogging force, sinusoidal skewing is implemented on the tubular structure. This paper investigates the validity of the cogging force predictions and the effectiveness of skewing techniques using a representation of the tubular structure in a 2D axial rotating finite element model.

Series hybrid vehicle system analysis using an in-wheel motor design

Hybrid vehicles, which employ a technology combining gasoline and electric motors, are a hot item these days for transporters looking for ways to cut their fuel bills. To date, commercial systems implement diesel assisted electrical drives. As such the electrical motor is placed in a series or parallel configuration to assist the combustion engine. In the series configuration, the generator mounts directly to the engine, and most of the engine power is converted into electric energy to drive the traction motors at the axle/wheel ends. This enables the exclusion of the mechanical drive path between the engine and the drive wheels.

Sinusoidal behavior of a di-pole magnetization for position sensing applications

Magnetic position sensing is based on the measurement of the magnetization pattern of a di-pole, or multipole, magnetic ring using a Hall sensor, which shows the variation of the magnetic field density along the circumference of the ring. The ideal magnetic behavior of the permanent magnet ring has a sinusoidal hall-sensor output, which makes it suitable for sensing applications. However, practical measurements show that the sinusoidal behavior sometimes occurs with errors. This paper describes the investigation of these errors by means of mismatch in the magnetization pattern of the dipole permanent magnet (PM)-ring.

Power From the People

Most human-powered energy-harvesting systems are used to power ubiquitously deployed sensor networks and mobile electronics. These systems scavenge power from human activity or derive limited energy from ambient heat, light, or vibrations. In this article, systems that use human power by walking or running are analyzed, where an alternative system has been designed and implemented that generates energy from people dancing in a club environment.

Efficiency of a regenerative direct-drive electromagnetic active suspension

The efficiency of a given direct-drive electromagnetic active suspension system for automotive applications is investigated. A McPherson suspension system is considered where the strut consists of a direct-drive brushless permanent magnet tubular actuator in parallel with a passive spring and damper. This suspension system has besides delivering active forces the possibility of regenerating power due to imposed movements. An LQR controller is developed for improvement of comfort and handling (dynamic tire load). Finally, the overall efficiency of the system is simulated for various road profiles.

Active roll compensation for automotive applications using a brushless direct-drive linear permanent magnet actuator

There is a growing interest in employing brushless permanent magnet actuators in direct-drive linear automotive applications. In these applications, the combination of low voltage (typically 12V) and high force levels, inevitably gives rise to very demanding actuator designs. This paper describes the design of such a linear actuator for active roll control. Notable features of this linear actuator are the relatively high force and limited volumetric space envelope, this in turn has a marked influence on the performance requirements for the electrical linear actuator, hence the specific force density. Numerous authors have commented on more electrical loads resulting in the next significant change for the current 12V standards to increase in working voltage to 42V. Such a system will provide higher power, enabling a range of new technologies, although the cost of converting to 42V is clearly a major challenge for the automotive industry. This paper describes the electromagnetic semi-active suspension requirements. An analytical design study is described for the specific force level. Further, an optimized design is investigated, by using an optimization algorithm, which reduces the specific space envelope requirements. Finally, these designs are thermally evaluated using various convection coefficients, which show the applicability of electromagnetic actuation in semi-active suspension systems.

Slotless PM Machines With Skewed Winding Shapes: 3-D Electromagnetic Semianalytical Model

The 3-D modeling technique presented in this paper, predicts, with high accuracy, electromagnetic fields and corresponding dynamic effects in conducting regions for rotating machines with slotless windings, e.g., self-supporting windings. The presented modeling approach can be applied to a wide variety of slotless winding configurations, including skewing and/or different winding shapes. It is capable to account for induced eddy currents in the conductive rotor parts, e.g., permanent-magnet (PM) eddy-current losses, albeit not iron, and winding ac losses. The specific focus of this paper is to provide the reader with the complete implementation and assumptions details of such a 3-D semianalytical approach, which allows model validations with relatively short calculation times. This model can be used to improve future design optimizations for machines with 3-D slotless windings. It has been applied, in this paper, to calculate fixed parameter Faulhaber, rhombic, and diamond slotless PM machines to illustrate accuracy and applicability.

A fast semi-analytical model for the slotted structure of induction motors

Abstract- Afast,semi-analyticalmodelforinductionmotors(IMs)with36/28stator/rotorslotcombinationispresented.Incomparisontotraditionalanalyti-calmodelsforIMs,suchaslumpedparameter,magneticequivalentcircuitandanisotropiclayermodels,thepresentedmodelcalculatesacontinuousdistri-butionofthemagneticfluxdensityintheairgapandboththestatorandrotorslotsoftheIM.Duetoitssemi-analyticalnature,thecomputationtimeofthemodelisshortincomparisontoFiniteElementAnalysis(FEA)simulations.Also,itisshownthatthemodelresultsareingoodagreementwithlinearFEAsimulationresults.Thismakesthemodelverysuitablefordesigntools. Keyword- Harmonicmodeling,inductionmotor,semi-analytical,slotting 1 I NTRODUCTION Acrucialelementinthedesignofinductionmotors(IMs)istheavailabilityofasuitableelectromagneticmodeltopredicttheperformanceofthemotor. Typ-ical demandsforsucha modelare shortcomputa-tiontimes,highaccuracyandflexibilitywithrespecttoparametervariations. Historically,thelumpedpa-rametermodelisveryextensivelyusedforIManal-ysisanddesign[1,2]. Thismethodgenerallyhasashortcomputationtime, buttheaccuracyislimitedduetoitsdependenceonthemodelparametercalcu-lation. Manyeffectsareestimatedbycorrectionfac-tors,whichmeansthatthephysicaleffects,suchasleakageflux,arenotmodeledindetail. Ontheotherhand, a moreaccurateanddetailedanalysis ofIMperformanceisoftenobtainedusingFiniteElementAnalysis(FEA)[3].Thismethodcantakenon-linearsoft-magneticmaterialsandcomplexgeometriesintoaccount,butatthepriceofamuchlongercomputationtime. Also,parametervariationrequiresre-meshing,whichfurtherincreasescomputationtime.AlternativemethodsthathavebeeninvestigatedforIM analysis include Magnetic Equivalent Circuit(MEC)modeling[4,5]andAnisotropicLayerTheory(ALT)modeling[6,7].Boththesemethodscanhaverelativelyshortcomputationtimesandareabletotakeglobalsaturationeffectsintoaccount. However,forMEC modeling, themagneticfluxpathsshouldbeknowna-prioritoavoidverycomplexanddetailedmodelimplementations.Thisisnotpracticalforade-signtool.Furthermore,theALTmethodtakestheef-fectofthestatorandrotorslotsintoaccountglobally,butthelocalmagneticfluxdistributionisneglected.In this work, a semi-analytical model is presentedthat calculatesthestatic magneticfield distributionintheairgapandboththestatorandrotorslotsofanIM.Themodelisbasedontheharmonicmethoddescribedin[8]andimplementedforabenchmarkmotortopologyinpolarcoordinates. Theresultingmodelconsistsof33regionsand476systemequa-tions. Thetotalcomputationtimeforthismodelisintheorderoftenthsofasecond,includingthegen-erationoftheequationmatrix. ItisshownthattheresultsofthedevelopedmagneticfieldmodelareingoodagreementwithlinearFEAresults.Regardingthefuture,thedevelopedmodelpresentsthefirststeptowardsanadvancedsemi-analyticalde-signtoolforIMs. Althoughitisassumedthatthepermeabilityofthesoft-magneticmaterialisinfinite,theeffectsofsaturationcanbeaccountedforusingahybridcouplingtoasaturationmodel,e.g. basedonALTorMEC[9]. Furthermore,fixedcurrentdensi-tiesareappliedtothestatorandrotorslotsinordertovalidatethemagneticmodel.However,themagneticmodelcanbecoupledtostatorandrotorcircuitmod-elstoobtainasteady-stateoreventransientmodel.Fig.1.Halfofthebenchmarkmotorgeometry

Green turbine: A high speed double turbine solution for sustainable energy harvesting from waste heat

The GREEN TURBINE™ is a high speed double turbine generator which generates electricity from waste heat. This external combustion, e.g. from waste heat (steel mill), biomass or extracted from the tailpipe of an internal combustion engine, makes it possible to control combustion and therefore emission levels to a very high degree. As the temperature of the steam can be relatively low (140-220 °C), waste heat is very suitable to power this turbine, enabling combined cycle applications with the turbine as second stage. Herewith the Green turbine enhances the total efficiency of waste heat applications by a mere 15% without consideration of the heat that is present in the cooling water (around 40°C) following the turbine.