The dependences of the power loss per cycle on frequency have been investigated in the ranges of 100 Hz≤ f ≤25000 Hz and 0.1 T ≤ B_m ≤ 1.0 T for three main original magnetic states in five sorts of Fe-based nanocr...The dependences of the power loss per cycle on frequency have been investigated in the ranges of 100 Hz≤ f ≤25000 Hz and 0.1 T ≤ B_m ≤ 1.0 T for three main original magnetic states in five sorts of Fe-based nanocrystalline soft magnetic alloys. The measured and calculated results showed that the total power loss per cycle clearly exhibited a nonlinear behavior in the range below 3 kHz-5 kHz depending on both the magnetic state and the value of B_m, whereas it showed a quasi-linear behavior above this range. The total loss was decomposed into hysteresis loss, classical eddy current loss and excess loss, the obvious nonlinear behavior has been confirmed to be completely determined by the dependence of the excess loss on frequency. It has been indicated that the change rate of the excess loss per cycle with respect to frequency sharp decreases with increasing frequency in the range below about 3 kHz-5 kHz, wherease the rate of change slowly varies above this range, thus leading to the quasilinear behavior of the total loss per cycle. In this paper, some linear expressions of the total loss per cycle has been given in a wider medium-frequency segment, which can be used for roughly estimating the total loss.展开更多
To fully release the potential of wide bandgap(WBG)semiconductors and achieve high energy density and efficiency,a carbonyl iron soft magnetic composite(SMC)with an easy plane-like structure is prepared.Due to this st...To fully release the potential of wide bandgap(WBG)semiconductors and achieve high energy density and efficiency,a carbonyl iron soft magnetic composite(SMC)with an easy plane-like structure is prepared.Due to this structure,the permeability of the composite increases by 3 times(from 7.5 to 21.5)at 100 MHz compared with to the spherical carbonyl iron SMC,and the permeability changes little at frequencies below 100 MHz.In addition,the natural resonance frequency of the composite shifts to higher frequencies at 1.7 GHz.The total core losses of the composites at 10,20,and 30 m T are80.0,355.3,and 810.7 m W/cm^(3),respectively,at 500 k Hz.Compared with the spherical carbonyl iron SMC,the core loss at500 k Hz is reduced by more than 60%.Therefore,this kind of soft magnetic composite with an easy plane-like structure is a good candidate for unlocking the potential of WBG semiconductors and developing the next-generation power electronics.展开更多
The chaotic behaviour exhibited by a typical ferroresonant circuit in a neutral grounding system is investigated in this paper.In most earlier ferroresonance studies the core loss of the power transformer was neglecte...The chaotic behaviour exhibited by a typical ferroresonant circuit in a neutral grounding system is investigated in this paper.In most earlier ferroresonance studies the core loss of the power transformer was neglected or represented by a linear resistance.However,this is not always true.In this paper the core loss of the power transformer is modelled by a third order series in voltage and the magnetization characteristics of the transformer are modelled by an 11th order two-term polynomial.Extensive simulations are carried out to analyse the effect of nonlinear core loss on transformer ferroresonance.A detailed analysis of simulation results demonstrates that,with the nonlinear core loss model used, the onset of chaos appears at a larger source voltage and the transient duration is shorter.展开更多
CW-CO2 laser nitriding technique was applied to improve the properties (such as aging property and the core loss) of grain oriented silicon steel. The samples were nitrided with regular space. Laser power density and ...CW-CO2 laser nitriding technique was applied to improve the properties (such as aging property and the core loss) of grain oriented silicon steel. The samples were nitrided with regular space. Laser power density and scanning speed were chosen as 7.8×105W·cm-2 and 100mm·min-1. By some laser irradiation, Fe4N and Fe3N were formed in the nitrided zone. The nitrided samples were annealed at the temperatures ranged from 100 to 900°C. The core loss of some interested samples was tested. The results show that the core loss of the nitrided samples with different thickness of 0.23 and 0.30mm decreased by 14.9% and 9.4% respectively, and the aging property were improved up to 800°C. The mechanism of laser nitriding to improve the properties of grain oriented silicon steel is discussed.展开更多
In order to check the traditional core loss formula, the core loss spectrum P(f) of Co-based amorphous soft magnetic alloy with constant permeability has been studied. It is found that within a high frequency range fr...In order to check the traditional core loss formula, the core loss spectrum P(f) of Co-based amorphous soft magnetic alloy with constant permeability has been studied. It is found that within a high frequency range from 10 kHz to 200 kHz and at Bm = 0. 1 T,the P(f) has the fractal structure P (f) = Po, and with the increasing of induced anisotropy energy Ku, the fractal dimension Dfrises, thus the total power loss at high frequency increases and the frequency characteristic of P(f) becomes worse.展开更多
In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux densi...In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.展开更多
A full-frequency instant core-loss equation built from the induction physical model of magnetic materials, where the iron loss, eddy loss, and hysteresis loss no longer have an integral term, and this new equation pro...A full-frequency instant core-loss equation built from the induction physical model of magnetic materials, where the iron loss, eddy loss, and hysteresis loss no longer have an integral term, and this new equation provides high simulation accuracy and performs dynamic core loss analysis on non-sinusoidal or pulse magnetic fields. The simulation examples use a high-grade electrical steel sheet 65CS400 by Epstein experimental data covering magnetic field 0.1 - 1.8 T and frequency 50 - 5000 Hz, and the average error of the simulated core loss is less than 4%. Since the simulation is converged by magnetic physical parameters, so the physical relevance of the similar laminated materials can be compared with the coefficient results. .展开更多
The effects of Sn addition on core loss and texture of non-oriented electrical steels were investigated.Experiments revealed that the core loss of non-oriented electrical steels could be obviously decreased and the in...The effects of Sn addition on core loss and texture of non-oriented electrical steels were investigated.Experiments revealed that the core loss of non-oriented electrical steels could be obviously decreased and the intensity of {111} texture and {112} texture of final annealed specimens could be markedly reduced by Sn addition.The reasons for reducing core loss and the intensity of unfavorable texture were analyzed.展开更多
Amorphous magnetic alloy powders were prepared from bulk metallic glasses Fe74Cr2Mo2Sn2P10Si4B4C2 with supercooled liq-uid region of 32 K by water atomization.Amorphous magnetic powder core precursor was produced from...Amorphous magnetic alloy powders were prepared from bulk metallic glasses Fe74Cr2Mo2Sn2P10Si4B4C2 with supercooled liq-uid region of 32 K by water atomization.Amorphous magnetic powder core precursor was produced from a mixture of the amorphous alloy powder with addition of insulation and bonding materials by mold compacting at room temperature.After annealing the core precursor,the amorphous magnetic core exhibits superior magnetic properties as compared with molypermalloy powder core.The initial permeability up to 1 MHz was about 80,the flux density at 300 Oe was 1.06 T and the core loss at 100 kHz for Bm=0.1 T was only 329 kW/m3.The ultra-low core loss is attributed to the combination of relatively high resistivity and the amorphous structure of the Fe-based amorphous powder.Besides the outstanding magnetic properties,the Fe-based amorphous magnetic powder core had a much lower cost which renders the powder cores a potential candidate for a variety of industrial applications.展开更多
The correlation between microstructure and magnetic properties of Fe73.5Cu1Nb3Si15.5B7 alloy annealed at 360°C—620°C has been investigated. The best static and dynamic soft magnetic properties have been obt...The correlation between microstructure and magnetic properties of Fe73.5Cu1Nb3Si15.5B7 alloy annealed at 360°C—620°C has been investigated. The best static and dynamic soft magnetic properties have been obtained after annealing at 500°C and 550°C for 1 h, respectively. The dependence of annealing temperature on coercivity has shown three magnetic hardenings for the studied alloys annealed at 460°C, 530°C and 620°C, respectively. And the plot of core loss as a function of annealing temperature manifests a peak at 530℃, and this peak increases with increasing magnetic induction at low frequencies. This effect can probably be attributed to the precipitation of a new phase.展开更多
As well known, high initial permeability μ_i of the order of 10~4 and low coercivity H_c not more than 0.8 A/m have been obtained on nearly zero magnetostrictive Co-based amorphous alloys. It is naturally expected th...As well known, high initial permeability μ_i of the order of 10~4 and low coercivity H_c not more than 0.8 A/m have been obtained on nearly zero magnetostrictive Co-based amorphous alloys. It is naturally expected that such high μ_i and low H_c will be obtained on Fe-based amorphous alloys because of the higher cost of Co. If so, amorphous alloys展开更多
Widely used soft magnetic alloy 1J79 is a magnetic material with high permeability.Generally, it works under the conditions of frequency f=100—10000 Hz and magnetic induction B_m=0.1—0.7 T; thus the total core loss ...Widely used soft magnetic alloy 1J79 is a magnetic material with high permeability.Generally, it works under the conditions of frequency f=100—10000 Hz and magnetic induction B_m=0.1—0.7 T; thus the total core loss P is an important index reflecting its magnetic properties. In engineering applications, when a soft magnetic alloy which has a permeability of μ【5000 works in a frequency of f【100Hz and at a B_m=0.2—1.5T, its P can be described by the following empirical formula:展开更多
Insulated underground cables have the potential to reduce power outages, maintenance costs, and transmission losses compared to overhead lines.</span><span style="font-family:""> </span&g...Insulated underground cables have the potential to reduce power outages, maintenance costs, and transmission losses compared to overhead lines.</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">On the other hand, they are exposed to several risks and physical damages, since they are buried in the ground. Though the cables are armoured in order to provide mec</span><span style="font-family:Verdana;">hanical protection and achieve tensile strength, and also to provide effective conductance of earth fault currents.</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">The main purpose of this paper is to introduce insulated underground cables, armouring process, and to analyze the induced currents in metallic parts such as sheath and armour </span><span style="font-family:Verdana;">that causeohmic losses which are categorized mainly in two groups as circulating current and eddy current. This paper presents a review on analytical techniques used to analyze the effect of magnetic fields, andcalculate the losses in </span><span style="font-family:Verdana;">the armour of the cables,</span><span style="font-family:""> </span><span style="font-family:Verdana;">besides providing the strategies and solutions used for armour loss reduction.展开更多
The paper describes a simulated experiment that focuses on the numeric computation of magnetic loss in the laminated core of a single-phase power transformer. The students’ laboratory work is part of the library of e...The paper describes a simulated experiment that focuses on the numeric computation of magnetic loss in the laminated core of a single-phase power transformer. The students’ laboratory work is part of the library of experiments of the Electrical Machines virtual laboratory and makes use of the two-dimensional open-access electromagnetic field analysis software Finite Element Method Magnetics. The idea of the simulated exercise is to demonstrate how the magnetic loss caused by time-varying excitations affects the magnetic permeability, <em>μ</em>, of the laminated core and the terminal quantities of the energizing winding. A parametric analysis employing different values for the electrical conductivity and maximum hysteresis-induced angle of the laminated material yields five different field problems with increasing magnetic loss. Electric circuits characterized by the (<em>I-V</em>) operating point and reflected impedance of the energizing winding provide the information required to compute the changes in real power Δ<em>P</em>, reactive power Δ<em>Q</em> and magnetically stored energy Δ<em>W</em><sub>m</sub> between successive problems characterized by increasing magnetic loss. The concept of reflected impedance helps to explain the physical meaning of the changes in power dissipation and energy storage in the laminated core.展开更多
文摘The dependences of the power loss per cycle on frequency have been investigated in the ranges of 100 Hz≤ f ≤25000 Hz and 0.1 T ≤ B_m ≤ 1.0 T for three main original magnetic states in five sorts of Fe-based nanocrystalline soft magnetic alloys. The measured and calculated results showed that the total power loss per cycle clearly exhibited a nonlinear behavior in the range below 3 kHz-5 kHz depending on both the magnetic state and the value of B_m, whereas it showed a quasi-linear behavior above this range. The total loss was decomposed into hysteresis loss, classical eddy current loss and excess loss, the obvious nonlinear behavior has been confirmed to be completely determined by the dependence of the excess loss on frequency. It has been indicated that the change rate of the excess loss per cycle with respect to frequency sharp decreases with increasing frequency in the range below about 3 kHz-5 kHz, wherease the rate of change slowly varies above this range, thus leading to the quasilinear behavior of the total loss per cycle. In this paper, some linear expressions of the total loss per cycle has been given in a wider medium-frequency segment, which can be used for roughly estimating the total loss.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11574122 and 51731001)Joint Fund of Equipment Pre-Research and Ministry of Education,China(Grant No.6141A02033242)。
文摘To fully release the potential of wide bandgap(WBG)semiconductors and achieve high energy density and efficiency,a carbonyl iron soft magnetic composite(SMC)with an easy plane-like structure is prepared.Due to this structure,the permeability of the composite increases by 3 times(from 7.5 to 21.5)at 100 MHz compared with to the spherical carbonyl iron SMC,and the permeability changes little at frequencies below 100 MHz.In addition,the natural resonance frequency of the composite shifts to higher frequencies at 1.7 GHz.The total core losses of the composites at 10,20,and 30 m T are80.0,355.3,and 810.7 m W/cm^(3),respectively,at 500 k Hz.Compared with the spherical carbonyl iron SMC,the core loss at500 k Hz is reduced by more than 60%.Therefore,this kind of soft magnetic composite with an easy plane-like structure is a good candidate for unlocking the potential of WBG semiconductors and developing the next-generation power electronics.
文摘The chaotic behaviour exhibited by a typical ferroresonant circuit in a neutral grounding system is investigated in this paper.In most earlier ferroresonance studies the core loss of the power transformer was neglected or represented by a linear resistance.However,this is not always true.In this paper the core loss of the power transformer is modelled by a third order series in voltage and the magnetization characteristics of the transformer are modelled by an 11th order two-term polynomial.Extensive simulations are carried out to analyse the effect of nonlinear core loss on transformer ferroresonance.A detailed analysis of simulation results demonstrates that,with the nonlinear core loss model used, the onset of chaos appears at a larger source voltage and the transient duration is shorter.
基金supported by the National Natural Science Foundation of China(No.50174020).
文摘CW-CO2 laser nitriding technique was applied to improve the properties (such as aging property and the core loss) of grain oriented silicon steel. The samples were nitrided with regular space. Laser power density and scanning speed were chosen as 7.8×105W·cm-2 and 100mm·min-1. By some laser irradiation, Fe4N and Fe3N were formed in the nitrided zone. The nitrided samples were annealed at the temperatures ranged from 100 to 900°C. The core loss of some interested samples was tested. The results show that the core loss of the nitrided samples with different thickness of 0.23 and 0.30mm decreased by 14.9% and 9.4% respectively, and the aging property were improved up to 800°C. The mechanism of laser nitriding to improve the properties of grain oriented silicon steel is discussed.
文摘In order to check the traditional core loss formula, the core loss spectrum P(f) of Co-based amorphous soft magnetic alloy with constant permeability has been studied. It is found that within a high frequency range from 10 kHz to 200 kHz and at Bm = 0. 1 T,the P(f) has the fractal structure P (f) = Po, and with the increasing of induced anisotropy energy Ku, the fractal dimension Dfrises, thus the total power loss at high frequency increases and the frequency characteristic of P(f) becomes worse.
文摘In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.
文摘A full-frequency instant core-loss equation built from the induction physical model of magnetic materials, where the iron loss, eddy loss, and hysteresis loss no longer have an integral term, and this new equation provides high simulation accuracy and performs dynamic core loss analysis on non-sinusoidal or pulse magnetic fields. The simulation examples use a high-grade electrical steel sheet 65CS400 by Epstein experimental data covering magnetic field 0.1 - 1.8 T and frequency 50 - 5000 Hz, and the average error of the simulated core loss is less than 4%. Since the simulation is converged by magnetic physical parameters, so the physical relevance of the similar laminated materials can be compared with the coefficient results. .
文摘The effects of Sn addition on core loss and texture of non-oriented electrical steels were investigated.Experiments revealed that the core loss of non-oriented electrical steels could be obviously decreased and the intensity of {111} texture and {112} texture of final annealed specimens could be markedly reduced by Sn addition.The reasons for reducing core loss and the intensity of unfavorable texture were analyzed.
基金supported by the National Hi-Tech Research and Development Program (Grant No.2001AA327030)Science and Technology Program of Beijing (Grant No.D0405003040121)
文摘Amorphous magnetic alloy powders were prepared from bulk metallic glasses Fe74Cr2Mo2Sn2P10Si4B4C2 with supercooled liq-uid region of 32 K by water atomization.Amorphous magnetic powder core precursor was produced from a mixture of the amorphous alloy powder with addition of insulation and bonding materials by mold compacting at room temperature.After annealing the core precursor,the amorphous magnetic core exhibits superior magnetic properties as compared with molypermalloy powder core.The initial permeability up to 1 MHz was about 80,the flux density at 300 Oe was 1.06 T and the core loss at 100 kHz for Bm=0.1 T was only 329 kW/m3.The ultra-low core loss is attributed to the combination of relatively high resistivity and the amorphous structure of the Fe-based amorphous powder.Besides the outstanding magnetic properties,the Fe-based amorphous magnetic powder core had a much lower cost which renders the powder cores a potential candidate for a variety of industrial applications.
基金supported by the Beijing Municipal Science and Technology Project (Grant No. D405003040121)supported by National Amor-phous and Nanocrystalline Alloy Engineering Research Center, Beijing Central Iron and Steel Research Institute
文摘The correlation between microstructure and magnetic properties of Fe73.5Cu1Nb3Si15.5B7 alloy annealed at 360°C—620°C has been investigated. The best static and dynamic soft magnetic properties have been obtained after annealing at 500°C and 550°C for 1 h, respectively. The dependence of annealing temperature on coercivity has shown three magnetic hardenings for the studied alloys annealed at 460°C, 530°C and 620°C, respectively. And the plot of core loss as a function of annealing temperature manifests a peak at 530℃, and this peak increases with increasing magnetic induction at low frequencies. This effect can probably be attributed to the precipitation of a new phase.
文摘As well known, high initial permeability μ_i of the order of 10~4 and low coercivity H_c not more than 0.8 A/m have been obtained on nearly zero magnetostrictive Co-based amorphous alloys. It is naturally expected that such high μ_i and low H_c will be obtained on Fe-based amorphous alloys because of the higher cost of Co. If so, amorphous alloys
文摘Widely used soft magnetic alloy 1J79 is a magnetic material with high permeability.Generally, it works under the conditions of frequency f=100—10000 Hz and magnetic induction B_m=0.1—0.7 T; thus the total core loss P is an important index reflecting its magnetic properties. In engineering applications, when a soft magnetic alloy which has a permeability of μ【5000 works in a frequency of f【100Hz and at a B_m=0.2—1.5T, its P can be described by the following empirical formula:
文摘Insulated underground cables have the potential to reduce power outages, maintenance costs, and transmission losses compared to overhead lines.</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">On the other hand, they are exposed to several risks and physical damages, since they are buried in the ground. Though the cables are armoured in order to provide mec</span><span style="font-family:Verdana;">hanical protection and achieve tensile strength, and also to provide effective conductance of earth fault currents.</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">The main purpose of this paper is to introduce insulated underground cables, armouring process, and to analyze the induced currents in metallic parts such as sheath and armour </span><span style="font-family:Verdana;">that causeohmic losses which are categorized mainly in two groups as circulating current and eddy current. This paper presents a review on analytical techniques used to analyze the effect of magnetic fields, andcalculate the losses in </span><span style="font-family:Verdana;">the armour of the cables,</span><span style="font-family:""> </span><span style="font-family:Verdana;">besides providing the strategies and solutions used for armour loss reduction.
文摘The paper describes a simulated experiment that focuses on the numeric computation of magnetic loss in the laminated core of a single-phase power transformer. The students’ laboratory work is part of the library of experiments of the Electrical Machines virtual laboratory and makes use of the two-dimensional open-access electromagnetic field analysis software Finite Element Method Magnetics. The idea of the simulated exercise is to demonstrate how the magnetic loss caused by time-varying excitations affects the magnetic permeability, <em>μ</em>, of the laminated core and the terminal quantities of the energizing winding. A parametric analysis employing different values for the electrical conductivity and maximum hysteresis-induced angle of the laminated material yields five different field problems with increasing magnetic loss. Electric circuits characterized by the (<em>I-V</em>) operating point and reflected impedance of the energizing winding provide the information required to compute the changes in real power Δ<em>P</em>, reactive power Δ<em>Q</em> and magnetically stored energy Δ<em>W</em><sub>m</sub> between successive problems characterized by increasing magnetic loss. The concept of reflected impedance helps to explain the physical meaning of the changes in power dissipation and energy storage in the laminated core.
