Abdallh, Ahmed

Belie, Frederik De

Dupre, Luc

Melkebeek, Jan A.

Rasilo, Paavo

Salem, Aboubakr

Aaltodoc

This is an electronic reprint of the original article.
This reprint may differ from the original in pagination and typographic detail.
Author(s): Rasilo, Paavo & Salem, Aboubakr & Abdallh, Ahmed & Belie,
Frederik De & Dupre, Luc & Melkebeek, Jan A.
Title: Closure to Discussion on Effect of Multilevel Inverter Supply on Core
Losses in Magnetic Materials and Electrical Machines
Year: 2015
Version: Post print
Please cite the original version:
Rasilo, Paavo & Salem, Aboubakr & Abdallh, Ahmed & Belie, Frederik De & Dupre, Luc
& Melkebeek, Jan A. 2015. Closure to Discussion on Effect of Multilevel Inverter Supply
on Core Losses in Magnetic Materials and Electrical Machines . IEEE Transactions on
Energy Conversion. Volume 30, Issue 4. 1605-1605. ISSN 0885-8969 (printed). DOI:
10.1109/tec.2015.2494641.
Rights: © 2015 Institute of Electrical & Electronics Engineers (IEEE). Personal use of this material is permitted.
Permission from IEEE must be obtained for all other uses, in any current or future media, including
reprinting/republishing this material for advertising or promotional purposes, creating new collective works,
for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other
work.
All material supplied via Aaltodoc is protected by copyright and other intellectual property rights, and
duplication or sale of all or part of any of the repository collections is not permitted, except that material may
be duplicated by you for your research use or educational purposes in electronic or print form. You must
obtain permission for any other use. Electronic or print copies may not be offered, whether for sale or
otherwise to anyone who is not an authorised user.
Powered by TCPDF (www.tcpdf.org)
1 
HE AUTHORS appreciate Prof. Ruderman’s additions to
the literature review of the paper. Indeed, [1] and [2]
provide a theoretical approximation for the core losses of
magnetic components and electrical machines subject to
multilevel pulse-width modulated (PWM) voltage supply. The
main emphasis is on the classical eddy-current losses, which
are assumed to be the dominating PWM-induced additional
loss component. In [1], the additional eddy-current losses are
derived to be proportional to the mean-squared supply voltage
ripple. In [2], the normalized mean-squared (NMS) voltage
ripples are derived for multilevel converters with an arbitrary
number of voltage levels.
The assumption that the eddy-current loss is the
dominating additional iron loss component is supported by
our numerical simulations for the ring core (Table II of the
paper) and for the synchronous machines (Figs. 8 and 11). It
is noteworthy that in the larger machine, the additional
damper-winding loss is several times larger than the
additional iron loss. In [2] it is predicted that increasing the
number of voltage levels reduces the core losses, which is also
our conclusion. However, Table II and Figs. 8 and 11 show
significant dependency of the eddy-current loss on the
switching frequency. This contradicts with the suggestions of
[1]  and  [2],  which  base  on  the  fact  that  the  NMS  voltage
ripple is independent from the switching frequency at least on
practical frequency ranges. The proportionality of the eddy-
Manuscript received October X, 2015.
P. Rasilo is with the Department of Electrical Engineering, Tampere
University of Technology, P.O. Box 692, FI-33101 Tampere, Finland and also
with the Department of Electrical Engineering and Automation, Aalto University
School of Electrical Engineering, FI-00076 Espoo, Finland (e-mail:
paavo.rasilo@tut.fi).
A. Abdallh, A. Salem, F. De Belie, L. Dupré, and J. A. Melkebeek are with
the Department of Electrical Energy, Systems and Automation, Ghent
University, Technologiepark 913, BE-9052 Gent-Zwijnaarde,
(e-mail: ahmed.abdallh@ieee.org; SalemMohamed.AboubakrSalem
@UGent.be; Frederik.DeBelie@UGent.be; luc.dupre@ugent.be;
jan.melkebeek@ugent.be).
A. Abdallh is also with the Electrical Power and Machines Department,
Cairo University, EG-12613 Giza, Egypt.
Digital Object Identifier ….
current loss to the NMS voltage is only valid under the
assumption that the winding resistance and leakage
inductance as well as the skin effect of the eddy currents in
the core lamination are negligible, and thus the problem in
practice is not so trivial, as also mentioned in [2]. Our
numerical iron-loss calculations model the skin effect, and the
windings are accounted for by supplying the model with the
measured flux-density waveforms (Table II) or by coupling
the finite element model to the circuit equations (Figs. 8 and
11). When the skin effect becomes non-negligible, magnetic
nonlinearity and the interdependency of the eddy currents on
the hysteresis and excess losses [3] make analytical prediction
of the losses difficult if not impossible. Nevertheless, [1] and
[2] offer interesting reference formulas for further iron-loss
measurements and simulations in devices under PWM supply.
REFERENCES
[1] A. Ruderman and R. Welch, “Electrical Machines PWM loss evaluation
basics,” in Proc. Int. Conf. on Energy Efficiency in Motor Driven Systems,
(EEMODS), Vol. 1, pp. 58-68, Sep. 2005.
[2] A. Ruderman and B. Reznikov, S. Busquets-Monge, “Asymptotic time
domain evaluation of a multilevel multiphase PWM converter voltage
quality,” IEEE Trans. Ind. Electron., Vol. 60, No. 5, pp. 1999-2009, May
2013.
[3] E. Dlala, A. Belahcen, J. Pippuri, A. Arkkio, “Interdependence of
Hysteresis and Eddy-Current Losses in Laminated Magnetic Cores of
Electrical Machines,” IEEE Trans. Magn., Vol. 46, No. 2, pp. 306-309,
Feb. 2010.
Closure to “Effect of Multilevel Inverter Supply
on Core Losses in Magnetic Materials and
Electrical Machines”
Paavo Rasilo, Aboubakr Salem, Ahmed Abdallh, Frederik De Belie, Luc Dupré,
and Jan. A. Melkebeek, Senior Member, IEEE
T


English

Closure to Discussion on “Effect of Multilevel Inverter Supply on Core Losses in Magnetic Materials and Electrical Machines”

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

Mohamed Abouelyazied Abdallh, Ahmed

De Belie, Frederik

Dupré, Luc

Melkebeek, Jan

Ghent University Academic Bibliography

1 HE AUTHORS appreciate Prof. Ruderman’s additions tothe literature review of the paper. Indeed, [1] and [2]provide a theoretical approximation for the core losses ofmagnetic components and electrical machines subject tomultilevel pulse-width modulated (PWM) voltage supply. Themain emphasis is on the classical eddy-current losses, whichare assumed to be the dominating PWM-induced additionalloss component. In [1], the additional eddy-current losses arederived to be proportional to the mean-squared supply voltageripple. In [2], the normalized mean-squared (NMS) voltageripples are derived for multilevel converters with an arbitrarynumber of voltage levels.The assumption that the eddy-current loss is thedominating additional iron loss component is supported byour numerical simulations for the ring core (Table II of thepaper) and for the synchronous machines (Figs. 8 and 11). Itis noteworthy that in the larger machine, the additionaldamper-winding loss is several times larger than theadditional iron loss. In [2] it is predicted that increasing thenumber of voltage levels reduces the core losses, which is alsoour conclusion. However, Table II and Figs. 8 and 11 showsignificant dependency of the eddy-current loss on theswitching frequency. This contradicts with the suggestions of[1]  and  [2],  which  base  on  the  fact  that  the  NMS  voltageripple is independent from the switching frequency at least onpractical frequency ranges. The proportionality of the eddy-Manuscript received October X, 2015.P. Rasilo is with the Department of Electrical Engineering, TampereUniversity of Technology, P.O. Box 692, FI-33101 Tampere, Finland and alsowith the Department of Electrical Engineering and Automation, Aalto UniversitySchool of Electrical Engineering, FI-00076 Espoo, Finland (e-mail:paavo.rasilo@tut.ﬁ).A. Abdallh, A. Salem, F. De Belie, L. Dupré, and J. A. Melkebeek are withthe Department of Electrical Energy, Systems and Automation, GhentUniversity, Technologiepark 913, BE-9052 Gent-Zwijnaarde,(e-mail: ahmed.abdallh@ieee.org; SalemMohamed.AboubakrSalem@UGent.be; Frederik.DeBelie@UGent.be; luc.dupre@ugent.be;jan.melkebeek@ugent.be).A. Abdallh is also with the Electrical Power and Machines Department,Cairo University, EG-12613 Giza, Egypt.Digital Object Identiﬁer ….current loss to the NMS voltage is only valid under theassumption that the winding resistance and leakageinductance as well as the skin effect of the eddy currents inthe core lamination are negligible, and thus the problem inpractice is not so trivial, as also mentioned in [2]. Ournumerical iron-loss calculations model the skin effect, and thewindings are accounted for by supplying the model with themeasured flux-density waveforms (Table II) or by couplingthe finite element model to the circuit equations (Figs. 8 and11). When the skin effect becomes non-negligible, magneticnonlinearity and the interdependency of the eddy currents onthe hysteresis and excess losses [3] make analytical predictionof the losses difficult if not impossible. Nevertheless, [1] and[2] offer interesting reference formulas for further iron-lossmeasurements and simulations in devices under PWM supply.REFERENCES[1] A. Ruderman and R. Welch, “Electrical Machines PWM loss evaluationbasics,” in Proc. Int. Conf. on Energy Efficiency in Motor Driven Systems,(EEMODS), Vol. 1, pp. 58-68, Sep. 2005.[2] A. Ruderman and B. Reznikov, S. Busquets-Monge, “Asymptotic timedomain evaluation of a multilevel multiphase PWM converter voltagequality,” IEEE Trans. Ind. Electron., Vol. 60, No. 5, pp. 1999-2009, May2013.[3] E. Dlala, A. Belahcen, J. Pippuri, A. Arkkio, “Interdependence ofHysteresis and Eddy-Current Losses in Laminated Magnetic Cores ofElectrical Machines,” IEEE Trans. Magn., Vol. 46, No. 2, pp. 306-309,Feb. 2010.Closure to “Effect of Multilevel Inverter Supplyon Core Losses in Magnetic Materials andElectrical Machines”Paavo Rasilo, Aboubakr Salem, Ahmed Abdallh, Frederik De Belie, Luc Dupré,and Jan. A. Melkebeek, Senior Member, IEEET

Closure to discussion on 'Effect of multilevel inverter supply on core losses in magnetic materials and electrical machines'

Aaltodoc Publication Archive

This is an electronic reprint of the original article.This reprint may differ from the original in pagination and typographic detail.Author(s): Rasilo, Paavo & Salem, Aboubakr & Abdallh, Ahmed & Belie,Frederik De & Dupre, Luc & Melkebeek, Jan A.Title: Closure to Discussion on Effect of Multilevel Inverter Supply on CoreLosses in Magnetic Materials and Electrical MachinesYear: 2015Version: Post printPlease cite the original version:Rasilo, Paavo & Salem, Aboubakr & Abdallh, Ahmed & Belie, Frederik De & Dupre, Luc& Melkebeek, Jan A. 2015. Closure to Discussion on Effect of Multilevel Inverter Supplyon Core Losses in Magnetic Materials and Electrical Machines . IEEE Transactions onEnergy Conversion. Volume 30, Issue 4. 1605-1605. ISSN 0885-8969 (printed). DOI:10.1109/tec.2015.2494641.Rights: © 2015 Institute of Electrical & Electronics Engineers (IEEE). Personal use of this material is permitted.Permission from IEEE must be obtained for all other uses, in any current or future media, includingreprinting/republishing this material for advertising or promotional purposes, creating new collective works,for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in otherwork.All material supplied via Aaltodoc is protected by copyright and other intellectual property rights, andduplication or sale of all or part of any of the repository collections is not permitted, except that material maybe duplicated by you for your research use or educational purposes in electronic or print form. You mustobtain permission for any other use. Electronic or print copies may not be offered, whether for sale orotherwise to anyone who is not an authorised user.Powered by TCPDF (www.tcpdf.org)1 HE AUTHORS appreciate Prof. Ruderman’s additions tothe literature review of the paper. Indeed, [1] and [2]provide a theoretical approximation for the core losses ofmagnetic components and electrical machines subject tomultilevel pulse-width modulated (PWM) voltage supply. Themain emphasis is on the classical eddy-current losses, whichare assumed to be the dominating PWM-induced additionalloss component. In [1], the additional eddy-current losses arederived to be proportional to the mean-squared supply voltageripple. In [2], the normalized mean-squared (NMS) voltageripples are derived for multilevel converters with an arbitrarynumber of voltage levels.The assumption that the eddy-current loss is thedominating additional iron loss component is supported byour numerical simulations for the ring core (Table II of thepaper) and for the synchronous machines (Figs. 8 and 11). Itis noteworthy that in the larger machine, the additionaldamper-winding loss is several times larger than theadditional iron loss. In [2] it is predicted that increasing thenumber of voltage levels reduces the core losses, which is alsoour conclusion. However, Table II and Figs. 8 and 11 showsignificant dependency of the eddy-current loss on theswitching frequency. This contradicts with the suggestions of[1]  and  [2],  which  base  on  the  fact  that  the  NMS  voltageripple is independent from the switching frequency at least onpractical frequency ranges. The proportionality of the eddy-Manuscript received October X, 2015.P. Rasilo is with the Department of Electrical Engineering, TampereUniversity of Technology, P.O. Box 692, FI-33101 Tampere, Finland and alsowith the Department of Electrical Engineering and Automation, Aalto UniversitySchool of Electrical Engineering, FI-00076 Espoo, Finland (e-mail:paavo.rasilo@tut.ﬁ).A. Abdallh, A. Salem, F. De Belie, L. Dupré, and J. A. Melkebeek are withthe Department of Electrical Energy, Systems and Automation, GhentUniversity, Technologiepark 913, BE-9052 Gent-Zwijnaarde,(e-mail: ahmed.abdallh@ieee.org; SalemMohamed.AboubakrSalem@UGent.be; Frederik.DeBelie@UGent.be; luc.dupre@ugent.be;jan.melkebeek@ugent.be).A. Abdallh is also with the Electrical Power and Machines Department,Cairo University, EG-12613 Giza, Egypt.Digital Object Identiﬁer ….current loss to the NMS voltage is only valid under theassumption that the winding resistance and leakageinductance as well as the skin effect of the eddy currents inthe core lamination are negligible, and thus the problem inpractice is not so trivial, as also mentioned in [2]. Ournumerical iron-loss calculations model the skin effect, and thewindings are accounted for by supplying the model with themeasured flux-density waveforms (Table II) or by couplingthe finite element model to the circuit equations (Figs. 8 and11). When the skin effect becomes non-negligible, magneticnonlinearity and the interdependency of the eddy currents onthe hysteresis and excess losses [3] make analytical predictionof the losses difficult if not impossible. Nevertheless, [1] and[2] offer interesting reference formulas for further iron-lossmeasurements and simulations in devices under PWM supply.REFERENCES[1] A. Ruderman and R. Welch, “Electrical Machines PWM loss evaluationbasics,” in Proc. Int. Conf. on Energy Efficiency in Motor Driven Systems,(EEMODS), Vol. 1, pp. 58-68, Sep. 2005.[2] A. Ruderman and B. Reznikov, S. Busquets-Monge, “Asymptotic timedomain evaluation of a multilevel multiphase PWM converter voltagequality,” IEEE Trans. Ind. Electron., Vol. 60, No. 5, pp. 1999-2009, May2013.[3] E. Dlala, A. Belahcen, J. Pippuri, A. Arkkio, “Interdependence ofHysteresis and Eddy-Current Losses in Laminated Magnetic Cores ofElectrical Machines,” IEEE Trans. Magn., Vol. 46, No. 2, pp. 306-309,Feb. 2010.Closure to “Effect of Multilevel Inverter Supplyon Core Losses in Magnetic Materials andElectrical Machines”Paavo Rasilo, Aboubakr Salem, Ahmed Abdallh, Frederik De Belie, Luc Dupré,and Jan. A. Melkebeek, Senior Member, IEEET

Closure to Discussion on “Effect of Multilevel Inverter Supply on Core Losses in Magnetic Materials and Electrical Machines”

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