[技术文章]电感为什么难学？ [复制链接]

对于电感，尤其是磁性材料，无从下手，确实，很多人学电源，首先碰到的就是电感问题，相比电容都有很多的标准件，而稍大一点的电感，都需要自己做，尤其是变压器。而大学时期，电感方面的知识书本也只是讲了个皮毛，根本没法用，下面整理一下电感，变压器的难点所在。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> #i8] f{  
<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> rYp]RX>  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">电感的储能公式 W = 1/2*L*I^2。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> O,&nCxB]  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">这个公式，本质上讲跟电容的储能公式形式等价：W = 1/2*C*U^2。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> Y"x9B%e  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">再自己想想，大家会发现跟高中时期学的力学物体运动的动能公式形式也一样：E = 1/2*M*V^2。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> zNu>25/)(  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">既然有动能，那么就有势能，弹簧的势能，E = 1/2*K*X^2。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> )&Bf%1>  
<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> .ykCmznf*  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">以上四个公式中，前两者电容电感是电磁能的公式，后两者是物质机械能的公式。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> y@5{.jsr_  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">大家都知道机械能中，动能跟势能相互转换就是振动，动能跟势能同时转换就是机械波，比如水波、振动波、声音等等。波是能量传递的一种基本方式，可惜的是波的学习在大学物理中，很多二三线高校就没有深入的开展，所以导致很多人不了解波。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> ?!h jI;_&  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">跟物质机械能类似，电能的容器是电容，磁能的容器是电感(准确的名字应该是磁容)，电能与磁能的相互转换是LC振荡，电能与磁能同时转换就是电磁波。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> gJkk0wokC  
<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> *gq~~(jH  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">此外，大家要注意到，所有这些公式前面都有一个1/2，这个是很有意思的，比如，在恒定电压下，给电容充电，电容只能获得1/2供电端的能量，还有一半损失在电阻上了，这个规律在机械上也如此，典型的案例就是汽车起步时很耗油，匀速后油耗最低。起步时汽车速度为0，燃烧的气体对活塞做功，这些功几乎都转化为热能浪费了。所以要想降低损耗，需要降低档位，缓慢起步，让活塞运动速度与汽车速度的落差减少(这个中间有减速器和离合器，起步主要靠离合器实现速度落差阻尼匹配，类似RC充电电路的电阻，阻尼电压差)。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> }#~DX!Sj  
<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> 3C+!Y
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<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">电容常见的指标有容量、耐压两个，其次是损耗，频率特性，损耗跟频率特性，跟介质材料有极大关系。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> _I"T(2Au  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">那么电感同样也有类似的指标，电感量，耐流，其次是损耗，频率特性，同理也跟磁性材料有极大关系。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> yXuF<+CJ  
<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> iiWs]5  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">电感，之前讲了，应该属于磁容，容纳磁的东西，相比电容容纳电场，电感就是容纳磁场，根据安培环路定律，电流就是磁，因为有电流就会产生磁场，所以跟电容对应，电感存储的是磁，也就是电流。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> r34q9NFT5  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">电容的电荷量公式 Q = C*U，同理电感的磁通量公式 Φ = o
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L*I。(在多匝线圈中，要除以匝数，Φ = L * I / N)<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> o@&Hc bN^  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">电容的电荷量不能无限制的增加，若太多，电压升高，会导致介质击穿 E = U / d<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> m0: IFE($  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">电感的磁通量同样不能无限制的增加，若太多，磁压升高，会导致磁性材料的磁饱和，这是电感学习的难点，很多电感，都是围绕着电感量和磁饱和展开的，而电感量和磁饱和，是一对矛盾体，接下来核心讲这一对矛盾体。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> @Kx@ 2#~b  
<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> ~^&]8~m*d  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">我们以磁环电感为例来讲，<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> 5gdsV4DH$  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">电感量的公式：L = kN^2，k为系数，N为匝数，电感量跟线圈的匝数的平方成正比，注意，是平方成正比。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> @w%{yzr%  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">磁通量的公式：Φ = L*I/N = k*N*I。磁通量为电流与匝数成正比。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> Kzj9!'0R  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">电感量跟匝数平方成正比，而磁通量跟匝数成正比，确定形状后，不同的磁性材料，最大磁通量有一个极限，为了统一到材料上去，不考虑形状，一般用磁通量密度，也就是磁感应强度表示：B = Φ / S，也就是单位面积的磁通量。所以不同的材料，最大磁感应强度是不同的，比如铁氧体材料锰锌、镍锌最大磁饱和是0.5T，也就是5000高斯，一般取值小于0.3T，铁粉芯的磁饱和为1T。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> )L)jv
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<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">我们自己制作的电感，需要满足两个条件，1、电感量大小，2、磁感应强度不能达到饱和、3、体积、发热量。电感所有的问题基于这个展开。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> -^Pn4
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<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> Ewfzjc  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">设计电感，我们总是想用最小的磁环、最短的铜线达到目的，并且还没有发热量。若想实现这个，那么磁性的材料损耗必须要低，此外铜线短一些，铜的发热量也少，尤其在高频下，铜线因为趋肤效应发热量提高。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> "sM 3NY  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">基于上述条件，一般采用高磁导率低损耗的锰锌或者镍锌材料，锰锌常见的是PC40材料，磁导率为2500，镍锌适合更高的频率，但磁导率低一些，往往是800。高的磁导率，很容易得到高的电感，所以很适合做高频变压器。现在开关电源基本上工作在100KHz上，都是用锰锌来做变压器的。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> _'W en  
<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> }mZsK>  
<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">然而，在一些场合，比如变压器整流后输出，需要电感滤波，这个时候同时存在交流和直流电，很高的磁导率，很容易让直流导致磁饱和，类似一个喇叭，没声音的时候，应该在音圈振动的中心原点，而因为有直流存在，偏离中心点了，这样交流波动的范围就大大缩小。所以这个时候需要调整策略，首先要选择磁饱和大的磁芯，比如上面讲到，铁粉芯磁饱和可以达到1T，高于锰锌一倍，其次，铁粉芯磁导率较低，一般为60甚至更低，磁导率低了，绕的圈数就要多一些才能达到想要的电感量，或许大家会问，电感量低了，圈数绕多了，同样也要导致磁饱和啊，不知道大家注意到上面讲的一点没有，电感量跟圈数的平方成正比，而磁感应强度跟圈数成正比，也就是说，随着圈数的提高，电感量很快达到我们想要的值，而磁感应强度却没有达到饱和。利用电感量跟圈数的平方关系，而磁感应强度与圈数线性关系，实现了很好的平衡电感量与磁饱和，这一点非常关键。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> sPu@t&$  
<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> %\if
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<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">像现在的大功率电源前段都有PFC，也就是功率因数校准，都需要升压用的电感，这个电感流过的电都是交直流复合的，所以一般用铁粉芯材料，现在比较好的一种铁粉芯名叫铁硅铝，磁导率125附近，发热量较低。<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> MJ=(rp=YU9  
<br style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="word-wrap: break-word; color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);"> _a~
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<span style="word-spacing: 0px; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" .="color: rgb(68, 68, 68); font-family: Tahoma, Helvetica, SimSun, sans-serif; background-color: rgb(255, 255, 255);">可以这么讲，目前市面上大部分开关电源，变压器一般用高磁导率的铁氧体材料锰锌，而升压、降压滤波，带直流分量的都是用低磁导率的铁粉芯材料。

[ 此帖被shuszhao在2018-01-30 12:42重新编辑 ]