磁性材料術(shù)語(yǔ)解釋及計(jì)算公式

1、磁性材料術(shù)語(yǔ)解釋及計(jì)算公式起始磁導(dǎo)率“i初始磁導(dǎo)率是磁性材料的磁導(dǎo)率（B/H）在磁化曲線始端的極限值，即(AHt O)式中“O為真空磁導(dǎo)率（4ttx 07 H/m）H為磁場(chǎng)強(qiáng)度的變化率（A/m）AB磁感應(yīng)強(qiáng)度的變化率（T）有效磁導(dǎo)率“e在閉合磁路中，如果漏磁可忽略，可以用有效磁導(dǎo)率來(lái)表示磁芯的性能0式中L為裝有磁芯的線圈的電感量（H）N為線圈匝數(shù)Le為有效磁路長(zhǎng)度5）Ae為有效截面積（卅）飽和磁通密度Bs （T）磁化到飽和狀態(tài)的磁通密度。見(jiàn)圖1。圖1剩余磁通密度Br (T)從飽和狀態(tài)去除磁場(chǎng)后，剩余的磁通密度。見(jiàn)圖1。矯頑力He (A/m)從飽和狀態(tài)去除磁場(chǎng)后，磁芯繼續(xù)被反向磁場(chǎng)磁化，直至磁感

2、應(yīng)強(qiáng)度減為零，此時(shí)的磁場(chǎng)強(qiáng)度稱 為矯頑力。見(jiàn)圖1。損耗因子tan5損耗系數(shù)是磁滯損耗、渦流損耗和剩余損耗三者之和。tan”= tan d h + t an del tan dr式中tan o i.為磁滯損耗系數(shù)tan o e為渦流損耗系數(shù)tan d r為剩余損耗系數(shù)相對(duì)損耗因子 tan6/I i比損耗因子是損耗系數(shù)與與磁導(dǎo)率之比：tano /i (it用于材料) tano/zze (適用于磁路中含有氣隙的磁芯)品質(zhì)因數(shù)Q品質(zhì)因數(shù)為損耗因子的倒數(shù)：Q = 1/ tan5溫度系數(shù)a“( 1/K)溫度系數(shù)為T1和T2范圍內(nèi)變化時(shí)，每變化1K相應(yīng)的磁導(dǎo)率的相對(duì)變化量:a 口 = P 2-P 11Plt

3、2 -T式中“1為溫度為T1時(shí)的磁導(dǎo)率“2為溫度為T2時(shí)的磁導(dǎo)率相對(duì)溫度系數(shù)a “r(l/K)溫度系數(shù)和磁導(dǎo)率之比，即a /r =：. gt I減落系數(shù)DF在恒溫條件下，完全退磁的磁芯的磁導(dǎo)率隨時(shí)間的衰減變化，即DF =x(T2T1)“1為退磁后T1分鐘的磁導(dǎo)率“2為退磁后T2分鐘的磁導(dǎo)率居里溫度Tc (C)在該溫度時(shí)材料由鐵磁性(或亞鐵磁)轉(zhuǎn)變?yōu)轫槾判?，?jiàn)圖2。電阻率p(Q.m)具有單位截面積和單位長(zhǎng)度的磁性材料的電阻。密度 d (kg/m3)單位體積材料的重量，即d =W/V式中W為磁芯的重f (kg)V為磁芯的體積(於)功率損耗Pc (kW/ms)磁芯的高磁感應(yīng)強(qiáng)度下的單位體積損耗或單位

4、重量損耗.該磁通密度可表示為EBm =4.44 fNAe式中E為施加在線圈上的電壓有效值(V)Bin為磁感應(yīng)強(qiáng)度的峰值(T)f為頻率(Hz)N為線圈匝數(shù)Ae為有效截面積（m）電感系數(shù)AL （nH/N2）電感因數(shù)定義為具有一定形狀和尺寸的磁芯上每一匝線圈產(chǎn)生的電感量，即A l = L/N2式中L:為裝有磁芯的線圈的電感量（H）N:為線圈匝數(shù)Initial permeability, fiThe initial permeability “i is the limit value at the initial magnetization curves origin point and is giv

5、en by the following formula:ABi = Ko x T H(ah T o)Wherei o:Permeability of vacuum ( 4;rx10 7/y/,w )AH:Rate of change for magnetic field strength(A/m)E： Rate of change for Magnetic flux density(T)Effective permeab 訂 ity, “ eThis is usually defined as the permeability of a core forming a closed circui

6、t where leakage flux is negligibly smalLLcpe 二山 N? AeWhereL: Self-inductance of core with coil (H)N: Number of turnsLe: Effective magnetic path length (m)Ae: Effective cross-sectional area (m)Saturation flux density, Bs (T)The magnetic flux density at a magnetic field where his up to a approximate s

7、aturation magnetic field value (Fig.1)Remanence, Br (T)The value of density retained by the core when the magnetic field is reduced fromthe saturation magnetic flux density to zero. (Fig.1)Coactivity, He (A/m)The value of magnetic field strength where by the flux density becomes zero under the inten

8、sification, in the opposite direction, of the magnetic field (Fig.1)Loss factor , tan(5This is the sum of the hysteretic loss factor, eddy current loss factor and residual loss factortan(5= tan d h + tan + tan drWheretano h is the hysterias loss factor tanOc is the eddy current loss factor tano r is

9、 the residual loss factorRelative loss factor,tand/“iThis is the ratio of loss factor to permeability.tand/ii (for materials)tan5/e (for cores with gaps in the magnetic circuit)Quality factor, QThis is the reciprocal of the loss factor and is given byQ = 1/ tandTemperature coefficient, a fl (1/K)Thi

10、s is the fractional difference of permeability per IK in a temperature range of from T1 to T2.乜F I崗 T1 -TiWhere111: Permeability at temperature T1“2: Permeability at temperature T2Relative temperature coefficient, a fix (1/K)This is the temperature coefficient per unit permeability and is given by t

11、he following equation:completeWhereThisdemagnetizati 島thefactor-Ufactor771MDFPermeability0iofrepresentingOQ1thel JcoreXtheatvariation1aT1constantminutesof(T2permeabilityT1)temperature.afterthroughcompletetimeafterdemagnetization.crossEectonaThisisresistivelytheareaelectricalXof Qresistancem)2crossEe

12、ctonaThisisresistivelytheareaelectricalXof Qresistancem)2perunitx x critical statematerialI of temperaturethe )levelCurieferromagneticis tempera-turpTcthelengthcharfeswhichandtofhea magnetic core.Density, d (kg/ms)This is the weight per unit volume of a magnetic core as expressed below d =W/VWhereW:

13、 Weight of magnetic body (kg)V: Volume of magnetic body (in)Power loss, Pc (kW/ m3)Power loss denotes the loss by an electrical transformer, such as a switching power supply, under a magnetizaticm condition featuring a high frequency and large amplitude Operating magnetic flux density is given by the fol lowing equation.EBm =4.44 fNAeWhereE: voltage effective value applied to coilBin: peak value of magnetic flux density (T)f: Frequency (Hz)N: Number of tunesAe: Effective cross-sectional arum (i )In