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In this paper, we propose a method for the identification of the differential inductance of saturable ferrite inductors adopted in DC–DC converters, considering the influence of the operating temperature. The inductor temperature rise is caused mainly by its losses, neglecting the heating contribution by the other components forming the converter layout. When the ohmic losses caused by the average current represent the principal portion of the inductor power losses, the steady-state temperature of the component can be related to the average current value. Under this assumption, usual for saturable inductors in DC–DC converters, the presented experimental setup and characterization method allow identifying a DC thermal steady-state differential inductance profile of a ferrite inductor. The curve is obtained from experimental measurements of the inductor voltage and current waveforms, at different average current values, that lead the component to operate from the linear region of the magnetization curve up to the saturation. The obtained inductance profile can be adopted to simulate the current waveform of a saturable inductor in a DC–DC converter, providing accurate results under a wide range of switching frequency, input voltage, duty cycle, and output current values.
Salvatore Musumeci; Luigi Solimene; Carlo Ragusa. Identification of DC Thermal Steady-State Differential Inductance of Ferrite Power Inductors. Energies 2021, 14, 3854 .
AMA StyleSalvatore Musumeci, Luigi Solimene, Carlo Ragusa. Identification of DC Thermal Steady-State Differential Inductance of Ferrite Power Inductors. Energies. 2021; 14 (13):3854.
Chicago/Turabian StyleSalvatore Musumeci; Luigi Solimene; Carlo Ragusa. 2021. "Identification of DC Thermal Steady-State Differential Inductance of Ferrite Power Inductors." Energies 14, no. 13: 3854.
We investigate in theory and experiment the frequency dependence of magnetic losses in Grain-Oriented 0.29 mm thick high-permeability steel sheets up to 10 kHz. Such an unusually broad frequency range, while responding to increasing trends towards high-frequency regimes in applications, is conducive to a complex evolution of the magnetization process, as imposed by increasing frequencies to a non-linear high-permeability saturable material. We show that the concept of loss decomposition, supported by observations of the domain wall dynamics through Kerr experiments, is effective in the assessment of the broadband frequency dependence of the energy loss. By calculating, in particular, the instantaneous and time averaged macroscopic induction profiles across the sheet thickness through the Maxwell’s diffusion equation, the classical loss component Wclass, versus frequency f and peak polarization Jp, is obtained. A simplified theoretical approach is pursued in this case by identifying the normal magnetization curve with the magnetic constitutive equation of the material. While the hysteresis loss Whyst is shown to invariably increase with frequency, the excess loss Wexc, the quantity directly associated with the eddy currents circulating around the moving domain walls, tends to vanish upon increasing both frequency and induction values. The Kerr experiments actually show that, while the oscillating 180° domain walls can adjust to the depth of the induction profile by bowing at low Jp values, the magnetization reversal at high inductions and high frequencies occurs by inward motion of symmetric fronts originating at the sheet surface, according to a classical framework.
A. Magni; A. Sola; O. De La Barrière; E. Ferrara; L. Martino; C. Ragusa; C. Appino; F. Fiorillo. Domain structure and energy losses up to 10 kHz in grain-oriented Fe-Si sheets. AIP Advances 2021, 11, 015220 .
AMA StyleA. Magni, A. Sola, O. De La Barrière, E. Ferrara, L. Martino, C. Ragusa, C. Appino, F. Fiorillo. Domain structure and energy losses up to 10 kHz in grain-oriented Fe-Si sheets. AIP Advances. 2021; 11 (1):015220.
Chicago/Turabian StyleA. Magni; A. Sola; O. De La Barrière; E. Ferrara; L. Martino; C. Ragusa; C. Appino; F. Fiorillo. 2021. "Domain structure and energy losses up to 10 kHz in grain-oriented Fe-Si sheets." AIP Advances 11, no. 1: 015220.
Magnetic-optical methods are used to investigate the magnetic microstructure of an epitaxial film of (Lu,Bi) substituted rare earth iron garnet. In particular, we focused our study on a bi-dimensional domain configuration, the Néel spike, which is induced and pinned at defects inside the sample or at its edges. Imaging of magnetic domains and domain-walls is obtained by direct magneto-optical interaction in the sample under study. The visualization of the stray-field distribution that is generated by single domain-walls is achieved by means of magneto-optical imaging with an indicator film. Furthermore, magnetostatic calculations were performed in order to correlate the net magnetic charge of the Néel spike domain and domain-walls with the measured stray-field. It results that the measured magnetic field intensity nearby the Néel spike tip is compatible with a Bloch-to-Néel wall transition.
A. Napolitano; Carlo Stefano Ragusa; S. Guastella; S. Musumeci; P. Rivolo; Francesco Laviano. Visualization of stray-field distribution by charged domain-walls in rare-earth substituted iron garnets. Journal of Magnetism and Magnetic Materials 2020, 504, 166556 .
AMA StyleA. Napolitano, Carlo Stefano Ragusa, S. Guastella, S. Musumeci, P. Rivolo, Francesco Laviano. Visualization of stray-field distribution by charged domain-walls in rare-earth substituted iron garnets. Journal of Magnetism and Magnetic Materials. 2020; 504 ():166556.
Chicago/Turabian StyleA. Napolitano; Carlo Stefano Ragusa; S. Guastella; S. Musumeci; P. Rivolo; Francesco Laviano. 2020. "Visualization of stray-field distribution by charged domain-walls in rare-earth substituted iron garnets." Journal of Magnetism and Magnetic Materials 504, no. : 166556.
There is increasing interest in the optimization of non-oriented electrical steels for applications under excitation frequencies above 400 Hz. We discuss in this paper the possibility of a new manufacturing procedure, where skin-pass and subsequent heat treatment for recovery are applied as the two last stages of sheet processing. Samples from a commercial non-oriented 3 wt% silicon steel were submitted to 2.5% thickness reduction and were heat treated at temperatures ranging between 600 and 850 °C for 2 h. It is shown that, although the hysteresis loss increases with plastic deformation, the excess loss decreases in such a way that under increasing magnetizing frequencies the total energy loss of the deformed and recovered sample becomes lower than in the starting material. The higher the annealing temperature the lower the frequency at which crossover of the loss curves is observed, as long as full recrystallization does not occur. It is assumed that with the dislocation structures left in the deformed and partially recovered samples one achieves a condition of increased fragmentation of the magnetization process, that is, of increased number of concurring correlation regions (Magnetic Objects). The corresponding decrease of the excess loss component can eventually overcompensate the deterioration of the quasi-static magnetic properties, leading to lower total losses.
F.J.G. Landgraf; C. Ragusa; D. Luiz Rodrigues; Mateus Dias; O. De La Barrière; F. Mazaleyrat; F. Fiorillo; C. Appino; L. Martino; D. Luiz Rodrigues Junior. Loss decomposition in plastically deformed and partially annealed steel sheets. Journal of Magnetism and Magnetic Materials 2020, 502, 166452 .
AMA StyleF.J.G. Landgraf, C. Ragusa, D. Luiz Rodrigues, Mateus Dias, O. De La Barrière, F. Mazaleyrat, F. Fiorillo, C. Appino, L. Martino, D. Luiz Rodrigues Junior. Loss decomposition in plastically deformed and partially annealed steel sheets. Journal of Magnetism and Magnetic Materials. 2020; 502 ():166452.
Chicago/Turabian StyleF.J.G. Landgraf; C. Ragusa; D. Luiz Rodrigues; Mateus Dias; O. De La Barrière; F. Mazaleyrat; F. Fiorillo; C. Appino; L. Martino; D. Luiz Rodrigues Junior. 2020. "Loss decomposition in plastically deformed and partially annealed steel sheets." Journal of Magnetism and Magnetic Materials 502, no. : 166452.
This paper proposes a procedure for computing magnetic losses in coaxial magnetic gears. These magnetic structures are made of permanent magnets and ferromagnetic poles in relative motion transferring torque between two shafts in a contactless way. The loss computation in magnetic materials is crucial to define the system performance. The flux distribution inside the iron parts is computed by means of the finite element method and a model of iron losses taking into account the rotational nature of the flux loci is applied. The procedure highlights where the major loss sources are present and gives the opportunity to evaluate some corrective measures to reduce their effects. Particular attention is devoted to the 2D modeling in presence of permanent magnets segmentation.
Mattia Filippini; Piergiorgio Alotto; Vincenzo Cirimele; Maurizio Repetto; Carlo Ragusa; Luca DiMauro; Elvio Bonisoli. Magnetic Loss Analysis in Coaxial Magnetic Gears. Electronics 2019, 8, 1320 .
AMA StyleMattia Filippini, Piergiorgio Alotto, Vincenzo Cirimele, Maurizio Repetto, Carlo Ragusa, Luca DiMauro, Elvio Bonisoli. Magnetic Loss Analysis in Coaxial Magnetic Gears. Electronics. 2019; 8 (11):1320.
Chicago/Turabian StyleMattia Filippini; Piergiorgio Alotto; Vincenzo Cirimele; Maurizio Repetto; Carlo Ragusa; Luca DiMauro; Elvio Bonisoli. 2019. "Magnetic Loss Analysis in Coaxial Magnetic Gears." Electronics 8, no. 11: 1320.
CoO-doping is known to stabilize the temperature dependence of initial permeability and magnetic losses in Mn-Zn ferrites, besides providing, with appropriate dopant contents, good soft magnetic response at and around room temperature. These effects, thought to derive from the mechanism of anisotropy compensation, are, however, poorly assessed from a quantitative viewpoint. In this work, we overcome such limitations by providing, besides extensive experimental investigation vs frequency (DC–1 GHz), CoO content (0 ≤ CoO ≤ 6000 ppm), and temperature (−20 °C ≤ T ≤ 130 °C) of permeability and losses of sintered Mn-Zn ferrites, a comprehensive theoretical framework. This relies on the separate identification of domain wall motion and moment rotations and on a generalized approach to magnetic loss decomposition. The average effective anisotropy constant ⟨Keff⟩ is obtained and found to monotonically decrease with temperature, depending on the CoO content. The quasistatic energy loss Wh is then predicted to pass through a deep minimum for CoO = 3000–4000 ppm at and below the room temperature, while becoming weakly dependent on CoO under increasing T. The rotational loss Wrot(f) is calculated via the complex permeability, as obtained from the Landau-Lifshitz equation for distributed values of the local effective anisotropy field Hk,eff (i.e., ferromagnetic resonance frequency). Finally, the excess loss Wexc(f) is derived and found to comply with suitable analytical formulation. It is concluded that, by achieving, via the rotational permeability, value and behavior of the magnetic anisotropy constant, we can predict the ensuing properties of hysteresis, excess, and rotational losses.CoO-doping is known to stabilize the temperature dependence of initial permeability and magnetic losses in Mn-Zn ferrites, besides providing, with appropriate dopant contents, good soft magnetic response at and around room temperature. These effects, thought to derive from the mechanism of anisotropy compensation, are, however, poorly assessed from a quantitative viewpoint. In this work, we overcome such limitations by providing, besides extensive experimental investigation vs frequency (DC–1 GHz), CoO content (0 ≤ CoO ≤ 6000 ppm), and temperature (−20 °C ≤ T ≤ 130 °C) of permeability and losses of sintered Mn-Zn ferrites, a comprehensive theoretical framework. This relies on the separate identification of domain wall motion and moment rotations and on a generalized approach to magnetic loss decomposition. The average effective anisotropy constant ⟨Keff⟩ is obtained and found to monotonically decrease with temperature, depending on the CoO content. The quasistatic energy loss Wh is then predicted to pass ...
Cinzia Beatrice; Samuel Dobák; Vasiliki Tsakaloudi; Carlo Ragusa; Fausto Fiorillo. The temperature dependence of magnetic losses in CoO-doped Mn-Zn ferrites. Journal of Applied Physics 2019, 126, 143902 .
AMA StyleCinzia Beatrice, Samuel Dobák, Vasiliki Tsakaloudi, Carlo Ragusa, Fausto Fiorillo. The temperature dependence of magnetic losses in CoO-doped Mn-Zn ferrites. Journal of Applied Physics. 2019; 126 (14):143902.
Chicago/Turabian StyleCinzia Beatrice; Samuel Dobák; Vasiliki Tsakaloudi; Carlo Ragusa; Fausto Fiorillo. 2019. "The temperature dependence of magnetic losses in CoO-doped Mn-Zn ferrites." Journal of Applied Physics 126, no. 14: 143902.
O. De La Barriere; Carlo Ragusa; C. Appino; F. Fiorillo. Loss Prediction in DC-Biased Magnetic Sheets. IEEE Transactions on Magnetics 2019, 55, 1 -14.
AMA StyleO. De La Barriere, Carlo Ragusa, C. Appino, F. Fiorillo. Loss Prediction in DC-Biased Magnetic Sheets. IEEE Transactions on Magnetics. 2019; 55 (10):1-14.
Chicago/Turabian StyleO. De La Barriere; Carlo Ragusa; C. Appino; F. Fiorillo. 2019. "Loss Prediction in DC-Biased Magnetic Sheets." IEEE Transactions on Magnetics 55, no. 10: 1-14.
The magnetic properties of sintered Mn-Zn ferrites, Co $^{2+}$ enriched by addition of CoO up to 6000 ppm, have been measured in ring samples on a broad range of peak polarization values (2 mT – 200 mT) and frequencies (dc – 1 GHz). The results have been analyzed by separating the contributions to the magnetization process by the domain walls and the rotations and applying the concept of loss decomposition. By determining value and behavior of the rotational permeability $\mu_\text{rot}$ as a function of the CoO content, we obtain the average effective magnetic anisotropy and the related effects on the loss. We thus identify the hysteresis (quasi-static) W$_h$, rotational W$_text{rot}$, and excess W$_text{exc}$loss components and their dependence on CoO and we verify that the quasi-static loss W$_h$and the domain wall permeability μ$_\text{dw}$consistently pass, together with, through a minimum value for CoO = 3000 − 4000 ppm. An opposite trend is observed for μ$_text{rot}$. The rotational loss by spin damping W$_\text{rot,sd}$is then calculated by use of the Landau-Lifshitz equation, assuming distributed anisotropy field amplitudes. W$_\text{rot,sd}$covers the experimental loss behavior beyond about 1 MHz. W$_text{exc}$and W$_h$, both directly generated by the moving domain walls, share the dissipative response of the material at lower frequencies and show similar trends versus CoO content. It is concluded that the modulation of the magnetic anisotropy of Mn-Zn ferrites through Co$^{2+}$enrichment, leading to maximum magnetic softening for CoO = 3000 − 4000 ppm, can be assessed in terms of separate effects of domain wall motion and moment rotations and the related dissipative properties.
Samuel Dobak; Cinzia Beatrice; Fausto Fiorillo; Vasiliki Tsakaloudi; Carlo Ragusa. Magnetic Loss Decomposition in Co-Doped Mn-Zn Ferrites. IEEE Magnetics Letters 2018, 10, 1 -5.
AMA StyleSamuel Dobak, Cinzia Beatrice, Fausto Fiorillo, Vasiliki Tsakaloudi, Carlo Ragusa. Magnetic Loss Decomposition in Co-Doped Mn-Zn Ferrites. IEEE Magnetics Letters. 2018; 10 (99):1-5.
Chicago/Turabian StyleSamuel Dobak; Cinzia Beatrice; Fausto Fiorillo; Vasiliki Tsakaloudi; Carlo Ragusa. 2018. "Magnetic Loss Decomposition in Co-Doped Mn-Zn Ferrites." IEEE Magnetics Letters 10, no. 99: 1-5.
Efficient applications of magnetic cores in sensing and power electronics require low-loss and versatile soft magnetic materials, with excellent response on a wide range of frequencies. This objective is traditionally pursued with ferrite and Permalloy tape cores, available under a variety of properties. Comparable and even superior soft magnetic behavior can, however, be obtained with amorphous and nanocrystalline alloys, with the latter, in particular, combining flexible response to thermal treatments with high magnetic saturation. Broadband precise magnetic characterization of these materials, crucial to their use as inductive cores, is fully appreciated when associated with assessment by physical modeling. Comprehensive measuring approach and significant results obtained in sintered soft ferrites and nanocrystalline ribbons up to 1 GHz are highlighted in this paper. We show how broadband loss and permeability behaviors can be quantitatively interpreted in the framework of the loss separation concept, applied to eddy current and spin damping dissipation mechanisms.
Enzo Ferrara; Fausto Fiorillo; Cinzia Beatrice; Samuel Dobák; Carlo Stefano Ragusa; Alessandro Magni; Carlo Appino. Characterization and assessment of the wideband magnetic properties of nanocrystalline alloys and soft ferrites. Journal of Materials Research 2018, 33, 2120 -2137.
AMA StyleEnzo Ferrara, Fausto Fiorillo, Cinzia Beatrice, Samuel Dobák, Carlo Stefano Ragusa, Alessandro Magni, Carlo Appino. Characterization and assessment of the wideband magnetic properties of nanocrystalline alloys and soft ferrites. Journal of Materials Research. 2018; 33 (15):2120-2137.
Chicago/Turabian StyleEnzo Ferrara; Fausto Fiorillo; Cinzia Beatrice; Samuel Dobák; Carlo Stefano Ragusa; Alessandro Magni; Carlo Appino. 2018. "Characterization and assessment of the wideband magnetic properties of nanocrystalline alloys and soft ferrites." Journal of Materials Research 33, no. 15: 2120-2137.
Accurate measurements of magnetic losses in laminations are a prerequisite for their theoretical assessment, as well as for satisfying calculations of energy dissipation in engineering systems. The standardized and universally applied measurement method, used as a reference for the definition of the material quality in the specification standards, is based on the Epstein test frame magnetizer. Its success relies on the reproducibility of the performed measurements. Its limitations come, on the one hand, from cumbersome sample preparation and, on the other hand, from a certain divergence of the measured loss figures from the true loss figures. Similar systematic differences between measured and true loss values are also observed with the standard single-sheet tester (SST) method. In both cases, measurements under bidimensional induction are or cannot be envisaged. The design of new measurement setups and magnetizers overcoming the drawbacks of the Epstein and SST methods and possibly becoming recognized standards in the future is welcome, but challenging. This paper is devoted to a comprehensive discussion of the state of the art in the alternating and 2-D measurements of energy losses in soft magnetic materials for electrical applications. We will summarize, in particular, measuring solutions proposed in the current literature, and we will discuss in detail recent developments achieved in the authors' laboratories regarding 1-D measurements with compensated permeameters and 2-D measurements at high inductions and high frequencies.
O. De La Barriere; C. Appino; C. Ragusa; F. Fiorillo; Martino Lo Bue; F. Mazaleyrat. 1-D and 2-D Loss-Measuring Methods: Optimized Setup Design, Advanced Testing, and Results. IEEE Transactions on Magnetics 2018, 54, 1 -15.
AMA StyleO. De La Barriere, C. Appino, C. Ragusa, F. Fiorillo, Martino Lo Bue, F. Mazaleyrat. 1-D and 2-D Loss-Measuring Methods: Optimized Setup Design, Advanced Testing, and Results. IEEE Transactions on Magnetics. 2018; 54 (9):1-15.
Chicago/Turabian StyleO. De La Barriere; C. Appino; C. Ragusa; F. Fiorillo; Martino Lo Bue; F. Mazaleyrat. 2018. "1-D and 2-D Loss-Measuring Methods: Optimized Setup Design, Advanced Testing, and Results." IEEE Transactions on Magnetics 54, no. 9: 1-15.
Magnetic losses under triangular symmetric and asymmetric induction waveforms, like the ones found in power electronics devices, have been measured over a broad range of frequencies and predicted starting from standard results obtained with sinusoidal induction. Non-oriented Fe-Si and Fe-Co sheets, nanocrystalline Finemet ribbons, and Mn-Zn ferrites have been investigated up to f = 1 MHz and duty cycles ranging between 0.5/f and 0.1/f. The intrinsic shortcomings of the popular approach to loss calculation of inductive components in power electronics, based on the empirical Steinmetz equation and its numerous modified versions, are overcome by generalized application of the Statistical Theory of Losses and the related concept of loss separation. While showing that this concept applies both to ferrites and metallic alloys and extracting the hysteresis (quasi-static), excess, and classical loss components, we relate in a simple way the magnetic energy losses under symmetric triangular induction (square wave voltage) and sinusoidal induction. The loss behavior under asymmetric triangular induction is directly retrieved from the symmetric one, by averaging the energy losses pertaining to the two different semi-periods. Good comparison with the experimentally measured energy loss versus frequency behavior is verified in all materials.
Hanyu Zhao; Carlo Stefano Ragusa; Carlo Appino; Olivier De La Barriere; Youhua Wang; Fausto Fiorillo. Energy Losses in Soft Magnetic Materials Under Symmetric and Asymmetric Induction Waveforms. IEEE Transactions on Power Electronics 2018, 34, 2655 -2665.
AMA StyleHanyu Zhao, Carlo Stefano Ragusa, Carlo Appino, Olivier De La Barriere, Youhua Wang, Fausto Fiorillo. Energy Losses in Soft Magnetic Materials Under Symmetric and Asymmetric Induction Waveforms. IEEE Transactions on Power Electronics. 2018; 34 (3):2655-2665.
Chicago/Turabian StyleHanyu Zhao; Carlo Stefano Ragusa; Carlo Appino; Olivier De La Barriere; Youhua Wang; Fausto Fiorillo. 2018. "Energy Losses in Soft Magnetic Materials Under Symmetric and Asymmetric Induction Waveforms." IEEE Transactions on Power Electronics 34, no. 3: 2655-2665.
Mn-Zn ferrite samples prepared by conventional solid state reaction method and sintering at 1325 °C were Co-enriched by addition of CoO up to 6000 ppm and characterized versus frequency (DC – 1GHz), peak polarization (2 mT – 200 mT), and temperature (23 °C – 120 °C). The magnetic losses at room temperature are observed to pass through a deep minimum value around 4000 ppm CoO at all polarizations values. This trend is smoothed out either by approaching the MHz range or by increasing the temperature. Conversely, the initial permeability attains its maximum value around the same CoO content, while showing moderate monotonical decrease with increasing CoO at the typical working temperatures of 80 – 100 °C. The energy losses, measured by a combination of fluxmetric and transmission line methods, are affected by the eddy currents, on the conventional 5 mm thick ring samples, only beyond a few MHz. Their assessment relies on the separation of rotational and domain wall processes, which can be done by analysis of the complex permeability and its frequency behavior. This permits one, in particular, to calculate the magnetic anisotropy and its dependence on CoO content and temperature and bring to light its decomposition into the host lattice and Co2+ temperature dependent contributions. The temperature and doping dependence of initial permeability and magnetic losses can in this way be qualitatively justified, without invoking the passage through zero value of the effective anisotropy constant upon doping.
Cinzia Beatrice; Samuel Dobák; Vasiliki Tsakaloudi; Carlo Ragusa; Fausto Fiorillo; Luca Martino; Vassilis Zaspalis. Magnetic loss, permeability, and anisotropy compensation in CoO-doped Mn-Zn ferrites. AIP Advances 2018, 8, 047803 .
AMA StyleCinzia Beatrice, Samuel Dobák, Vasiliki Tsakaloudi, Carlo Ragusa, Fausto Fiorillo, Luca Martino, Vassilis Zaspalis. Magnetic loss, permeability, and anisotropy compensation in CoO-doped Mn-Zn ferrites. AIP Advances. 2018; 8 (4):047803.
Chicago/Turabian StyleCinzia Beatrice; Samuel Dobák; Vasiliki Tsakaloudi; Carlo Ragusa; Fausto Fiorillo; Luca Martino; Vassilis Zaspalis. 2018. "Magnetic loss, permeability, and anisotropy compensation in CoO-doped Mn-Zn ferrites." AIP Advances 8, no. 4: 047803.
Luca Boggero; Marco Fioriti; Carlo Stefano Ragusa; Sabrina Corpino. Trade off studies of hybrid-electric aircraft by Fuzzy Logic methodology. International Journal of Applied Electromagnetics and Mechanics 2018, 56, 143 -152.
AMA StyleLuca Boggero, Marco Fioriti, Carlo Stefano Ragusa, Sabrina Corpino. Trade off studies of hybrid-electric aircraft by Fuzzy Logic methodology. International Journal of Applied Electromagnetics and Mechanics. 2018; 56 (Preprint):143-152.
Chicago/Turabian StyleLuca Boggero; Marco Fioriti; Carlo Stefano Ragusa; Sabrina Corpino. 2018. "Trade off studies of hybrid-electric aircraft by Fuzzy Logic methodology." International Journal of Applied Electromagnetics and Mechanics 56, no. Preprint: 143-152.
Enzo Ferrara; Carlo Appino; Luciano Rocchino; Carlo Ragusa; Olivier de la Barrière; Fausto Fiorillo. Effective versus standard Epstein loss figure in Fe-Si sheets. International Journal of Applied Electromagnetics and Mechanics 2017, 55, 105 -112.
AMA StyleEnzo Ferrara, Carlo Appino, Luciano Rocchino, Carlo Ragusa, Olivier de la Barrière, Fausto Fiorillo. Effective versus standard Epstein loss figure in Fe-Si sheets. International Journal of Applied Electromagnetics and Mechanics. 2017; 55 (Preprint):105-112.
Chicago/Turabian StyleEnzo Ferrara; Carlo Appino; Luciano Rocchino; Carlo Ragusa; Olivier de la Barrière; Fausto Fiorillo. 2017. "Effective versus standard Epstein loss figure in Fe-Si sheets." International Journal of Applied Electromagnetics and Mechanics 55, no. Preprint: 105-112.
The Pulse Width Modulation (PWM) technique is commonly used to supply modern high-speed electrical machines. The fundamental frequency is typically in the kilohertz range, with switching frequencies of several tens of kilohertz, as determined by the new SiC or GaAs based power transistors modules. Switching introduces minor loops in the major hysteresis cycle, with durations of the order of 100 μs or lower, with the resulting magnetization dynamics influenced by strong skin effect. However, since these minor loops have relatively small amplitude, their constitutive equation may be described by an equivalent permeability (real or complex), depending on the mean slope of the minor loop and its static energy loss. By retrieving this permeability, the classical loss is straightforwardly calculated by analytical solution of the Maxwell’s equations. In this work, we measure and calculate, according to the quasi-linear approximation for the minor loops, the magnetic energy losses of 0.194 mm thick non-oriented Fe-Si 3.2% sheets subjected to PWM induction waveform. Minor loop peak amplitudes ranging between 50 mT and 0.2 T and frequencies up to 10 kHz are investigated. The results are consistent with the proposed model, to within 5%.
Hanyu Zhao; Carlo Stefano Ragusa; Olivier De La Barriere; Mahmood Khan; Carlo Appino; Fausto Fiorillo. Magnetic Loss Versus Frequency in Non-Oriented Steel Sheets and Its Prediction: Minor Loops, PWM, and the Limits of the Analytical Approach. IEEE Transactions on Magnetics 2017, 53, 1 -4.
AMA StyleHanyu Zhao, Carlo Stefano Ragusa, Olivier De La Barriere, Mahmood Khan, Carlo Appino, Fausto Fiorillo. Magnetic Loss Versus Frequency in Non-Oriented Steel Sheets and Its Prediction: Minor Loops, PWM, and the Limits of the Analytical Approach. IEEE Transactions on Magnetics. 2017; 53 (11):1-4.
Chicago/Turabian StyleHanyu Zhao; Carlo Stefano Ragusa; Olivier De La Barriere; Mahmood Khan; Carlo Appino; Fausto Fiorillo. 2017. "Magnetic Loss Versus Frequency in Non-Oriented Steel Sheets and Its Prediction: Minor Loops, PWM, and the Limits of the Analytical Approach." IEEE Transactions on Magnetics 53, no. 11: 1-4.
The concept of loss separation is physically assessed and solidly validated by the Statistical Theory of Losses (STL) [1], which provides complete and accurate description of the frequency dependence of the energy losses in magnetic steel sheets under both sinusoidal and non-sinusoidal flux.
C. Ragusa; H. Zhao; M. Khan; O. De La Barriere; C. Appino; F. Fiorillo. Magnetic losses versus frequency in non-oriented steel sheets and their prediction: The limits of the analytical approach. 2017 IEEE International Magnetics Conference (INTERMAG) 2017, 1 -2.
AMA StyleC. Ragusa, H. Zhao, M. Khan, O. De La Barriere, C. Appino, F. Fiorillo. Magnetic losses versus frequency in non-oriented steel sheets and their prediction: The limits of the analytical approach. 2017 IEEE International Magnetics Conference (INTERMAG). 2017; ():1-2.
Chicago/Turabian StyleC. Ragusa; H. Zhao; M. Khan; O. De La Barriere; C. Appino; F. Fiorillo. 2017. "Magnetic losses versus frequency in non-oriented steel sheets and their prediction: The limits of the analytical approach." 2017 IEEE International Magnetics Conference (INTERMAG) , no. : 1-2.
Finemet type alloys have been investigated from DC to 1 GHz at different induction levels upon different treatments: as amorphous precursors, as ribbons nanocrystallized with and without an applied saturating field, as consolidated powders. The lowest energy losses at all frequencies and maximum Snoek's product are exhibited by the transversally field-annealed ribbons. This is understood in terms of rotation-dominated magnetization process in the low-anisotropy material. Intergrain eddy currents are responsible for the fast increase of the losses with frequency and for early permeability relaxation of the powder cores. Evidence for resonant phenomena at high frequencies and for the ensuing inadequate role of the static magnetic constitutive equation of the material in solving the magnetization dynamics via the Maxwell's diffusion equation of the electromagnetic field is provided. It is demonstrated that, by taking the Landau-Lifshitz-Gilbert equation as a constitutive relation, the excellent frequency response of the transverse anisotropy ribbons can be described by analytical method.
Cinzia Beatrice; Samuel Dobák; Enzo Ferrara; Fausto Fiorillo; Carlo Ragusa; Ján Füzer; Peter Kollár. Broadband magnetic losses of nanocrystalline ribbons and powder cores. Journal of Magnetism and Magnetic Materials 2016, 420, 317 -323.
AMA StyleCinzia Beatrice, Samuel Dobák, Enzo Ferrara, Fausto Fiorillo, Carlo Ragusa, Ján Füzer, Peter Kollár. Broadband magnetic losses of nanocrystalline ribbons and powder cores. Journal of Magnetism and Magnetic Materials. 2016; 420 ():317-323.
Chicago/Turabian StyleCinzia Beatrice; Samuel Dobák; Enzo Ferrara; Fausto Fiorillo; Carlo Ragusa; Ján Füzer; Peter Kollár. 2016. "Broadband magnetic losses of nanocrystalline ribbons and powder cores." Journal of Magnetism and Magnetic Materials 420, no. : 317-323.
The statistical theory of losses (STL) provides a simple and general method for the interpretation and prediction of the energy losses in soft magnetic materials. One basic application consists, for example, in the prediction of the loss under arbitrary induction waveform, starting from data available from conventional measurements performed under sinusoidal flux. There are, however, persisting difficulties in assessing the loss when the induction waveform is affected by a dc bias, because this would require additional experimental data, seldom available to machine designers. In this paper, we overcome this problem applying, with suitable simplifications, the dynamic Preisach model. Here, the parameters of the STL model are obtained exploiting preemptive conventional measurements only. By this new simplified method, analytical expressions for the loss components are obtained under general supply conditions, including dc-biased induction waveforms.
Olivier De La Barriere; Carlo Stefano Ragusa; Carlo Appino; Fausto Fiorillo. Prediction of Energy Losses in Soft Magnetic Materials Under Arbitrary Induction Waveforms and DC Bias. IEEE Transactions on Industrial Electronics 2016, 64, 2522 -2529.
AMA StyleOlivier De La Barriere, Carlo Stefano Ragusa, Carlo Appino, Fausto Fiorillo. Prediction of Energy Losses in Soft Magnetic Materials Under Arbitrary Induction Waveforms and DC Bias. IEEE Transactions on Industrial Electronics. 2016; 64 (3):2522-2529.
Chicago/Turabian StyleOlivier De La Barriere; Carlo Stefano Ragusa; Carlo Appino; Fausto Fiorillo. 2016. "Prediction of Energy Losses in Soft Magnetic Materials Under Arbitrary Induction Waveforms and DC Bias." IEEE Transactions on Industrial Electronics 64, no. 3: 2522-2529.
The concept of loss separation based on the statistical theory of losses (STL) provides complete and accurate description of the frequency dependence of the energy losses in non-oriented soft magnetic sheets under the assumption of uniform magnetization reversal through the sheet cross-section. This assumption, implying a simple standard formulation for the classical loss component, has been recently challenged in the literature, in favor of a non-uniform reversal mechanism, expected to prevail in highly non-linear materials, where saturation magnetization wavefronts are deemed to symmetrically propagate across the sheet thickness (saturation wave model, SWM). Different conclusions regarding the dynamic loss analysis and its decomposition into the classical and excess loss components correspondingly emerge. In this letter, we discuss detailed investigations on the broadband energy loss versus frequency behavior in different non-oriented Fe-Si and low-carbon steel sheets. The experiments can be fully and consistently described by the STL. This occurs, in particular, for high-induction values and near-squared hysteresis loops, a predictable condition for adopting the SWM, which, however, fails to account for the experiments.
Carlo Stefano Ragusa; Hanyu Zhao; Carlo Appino; Mahmood Khan; Olivier De La Barriere; Fausto Fiorillo. Loss Decomposition in Non-Oriented Steel Sheets: The Role of the Classical Losses. IEEE Magnetics Letters 2016, 7, 1 -5.
AMA StyleCarlo Stefano Ragusa, Hanyu Zhao, Carlo Appino, Mahmood Khan, Olivier De La Barriere, Fausto Fiorillo. Loss Decomposition in Non-Oriented Steel Sheets: The Role of the Classical Losses. IEEE Magnetics Letters. 2016; 7 ():1-5.
Chicago/Turabian StyleCarlo Stefano Ragusa; Hanyu Zhao; Carlo Appino; Mahmood Khan; Olivier De La Barriere; Fausto Fiorillo. 2016. "Loss Decomposition in Non-Oriented Steel Sheets: The Role of the Classical Losses." IEEE Magnetics Letters 7, no. : 1-5.
We present a new method for the accurate characterization of soft magnetic sheets using a permeameter based on the precise compensation of the magnetomotive force (MMF) drop in the flux-closing yoke. It has been developed in order to overcome the systematic uncertainty affecting the value of the magnetic field strength in single sheet testers when obtained, according to the standards, through the measurement of the magnetizing current. This phenomenon is more critical to high-permeability materials, because of the reduced MMF drop across the sample. While additional sensors and auxiliary windings have been proposed in the literature, a novel approach is demonstrated here, based on the use of the permeameter upper half yoke as the MMF drop sensor and of an auxiliary winding on the lower half yoke, implementing compensation. This solution, dispensing one from dealing with the usually small signal levels of the conventional MMF drop sensors (e.g., Chattock coils), provides the best results with the introduction of wedge-shaped magnetic poles, in order to accurately define the magnetic path length. The method is validated by the measurements of power loss, apparent power, and hysteresis cycles on non-oriented and grain-oriented Fe-Si steel sheets, which are compared with local measurements performed on the same samples using H-coil and B-coil across a uniformly magnetized region.
Olivier De La Barriere; Carlo Stefano Ragusa; Mahmood Khan; Carlo Appino; Fausto Fiorillo; Frederic Mazaleyrat. A Simple Compensation Method for the Accurate Measurement of Magnetic Losses With a Single Strip Tester. IEEE Transactions on Magnetics 2016, 52, 1 -4.
AMA StyleOlivier De La Barriere, Carlo Stefano Ragusa, Mahmood Khan, Carlo Appino, Fausto Fiorillo, Frederic Mazaleyrat. A Simple Compensation Method for the Accurate Measurement of Magnetic Losses With a Single Strip Tester. IEEE Transactions on Magnetics. 2016; 52 (5):1-4.
Chicago/Turabian StyleOlivier De La Barriere; Carlo Stefano Ragusa; Mahmood Khan; Carlo Appino; Fausto Fiorillo; Frederic Mazaleyrat. 2016. "A Simple Compensation Method for the Accurate Measurement of Magnetic Losses With a Single Strip Tester." IEEE Transactions on Magnetics 52, no. 5: 1-4.