N*******g 发帖数: 1089 | 1 如果一个flyback transformer, 我把两个windings并联起来, 作为primary side, 现
在primary side得inductance 是不是就使原来的1/2了?
一个Linear Tech得application engineer说,in the case of coupled inductors or
transformers placing windings in parallel results in the same inductance....
哪位能给分析一下?
谢谢! |
g******u 发帖数: 3060 | 2 If they are electronically connected then it is 1/2.
But if coupled, then does not change. |
N*******g 发帖数: 1089 | 3 What do you mean by "electronically connected"?
Actually the coupled transformer's primary side has two pins connected to
Vin and Vsw of a chip of LT1961....
【在 g******u 的大作中提到】 : If they are electronically connected then it is 1/2. : But if coupled, then does not change.
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g******u 发帖数: 3060 | 4 this has nothing to do with parallel windings, it's the terminals that are
paralleled.
coupling is connection via magnetic path, not electronically connceted.
【在 N*******g 的大作中提到】 : What do you mean by "electronically connected"? : Actually the coupled transformer's primary side has two pins connected to : Vin and Vsw of a chip of LT1961....
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p******h 发帖数: 577 | 5 If winded on the same leg of core, for example center leg, and the 100%
coupling can be assumed. Then it depends on whether it is coupling or
inverse coupling. If it is coupling, then the final inductance is same. If
it is inverse coupling, then ideally, the inductance becomes zero.
or
...
【在 N*******g 的大作中提到】 : 如果一个flyback transformer, 我把两个windings并联起来, 作为primary side, 现 : 在primary side得inductance 是不是就使原来的1/2了? : 一个Linear Tech得application engineer说,in the case of coupled inductors or : transformers placing windings in parallel results in the same inductance.... : 哪位能给分析一下? : 谢谢!
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N*******g 发帖数: 1089 | 6 Thanks you, gardenyu and pegasush
I am still confused with the difference between "coupling" and "
electronically connected". For the case I mentioned, I paralleled the two
single windings in the transformer as the primary side. Now the current goes
through these two paralleled windings. Are these two windings "coupled" or
electronically connected?
Why is the coupled windings' inductance kept same? |
g******u 发帖数: 3060 | 7 coupling是磁场偶合在一起,parallel connected是直接把两头接起来。这有什么不可
理解的呢?
goes
or
【在 N*******g 的大作中提到】 : Thanks you, gardenyu and pegasush : I am still confused with the difference between "coupling" and " : electronically connected". For the case I mentioned, I paralleled the two : single windings in the transformer as the primary side. Now the current goes : through these two paralleled windings. Are these two windings "coupled" or : electronically connected? : Why is the coupled windings' inductance kept same?
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N*******g 发帖数: 1089 | 8 两个电感并联起来没有耦合? 为什么有磁场耦合的并联电感, 电感不变?
【在 g******u 的大作中提到】 : coupling是磁场偶合在一起,parallel connected是直接把两头接起来。这有什么不可 : 理解的呢? : : goes : or
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g******u 发帖数: 3060 | 9 并联怎么耦合? 耦合是磁路,不是电路.
如果耦合电感其中一个开路,那这个电感有什么用?当然不变.
【在 N*******g 的大作中提到】 : 两个电感并联起来没有耦合? 为什么有磁场耦合的并联电感, 电感不变?
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N*******g 发帖数: 1089 | 10 你开始就没有明白我的问题。 我有个变压器, 这个变压器有三匝线圈, 他们肯定是
耦合的, 现在我把两匝线圈“并联”起来, 通电, 做输入边,这就是你说的
electronically connected, 现在我的问题是, 这两个并联的线圈的电感有没有变化? 如果没有, 为什么。
【在 g******u 的大作中提到】 : 并联怎么耦合? 耦合是磁路,不是电路. : 如果耦合电感其中一个开路,那这个电感有什么用?当然不变.
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N*******g 发帖数: 1089 | 11 oh, understood. I made a mistake in my calculation.
thanks!
【在 p******h 的大作中提到】 : If winded on the same leg of core, for example center leg, and the 100% : coupling can be assumed. Then it depends on whether it is coupling or : inverse coupling. If it is coupling, then the final inductance is same. If : it is inverse coupling, then ideally, the inductance becomes zero. : : or : ...
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m********e 发帖数: 585 | 12 It's easy: assume two equivalent batteries in parallel, the voltage is the
same as one battery. L*delta(I/2)/delta T *2 = L *deltaI/deltaT
or
...
【在 N*******g 的大作中提到】 : 如果一个flyback transformer, 我把两个windings并联起来, 作为primary side, 现 : 在primary side得inductance 是不是就使原来的1/2了? : 一个Linear Tech得application engineer说,in the case of coupled inductors or : transformers placing windings in parallel results in the same inductance.... : 哪位能给分析一下? : 谢谢!
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E*****a 发帖数: 757 | 13 并联的情况,和线粗一倍的情况,按说是一样的, inductance 按说不变的
【在 g******u 的大作中提到】 : If they are electronically connected then it is 1/2. : But if coupled, then does not change.
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I***a 发帖数: 174 | 14 匝比1:1的话方向没接反就是没变,应为你如果方向搞错了 你就把电路给短了。如果
没接错,绕圈数一样,gap一样,磁core一样,可能就少于几个百分点的变化吧,因为
两股parrelle的线之前有漏感,不过很小拉,你的K因该是90%以上吧,你用LT的应该没
有coupled L,不然被voltarra有专利,所以不会漏感太大。而且你Flyback的漏感大了
device的stress也大,或者snubber功耗大, 你那个算出来一半的L,忘记了两个线还
有coupling。这个一加就是L,一减就是0。
如果匝比不是1:1,是 n+1:1, 那你接反了的话,就是L*n^2/(n+1)^2. 那个共同的部
分就cancel掉了。
如果没接反的话,就相当于两个互感并联 (L+L/(n+1))//(L/(n+1)^2+L/(n+1)
). 记得一个参考公式:M=K*sqrt(L1*L2)。这里假设K=1了。不然就有漏感,会抵消一
点点。
or
...
【在 N*******g 的大作中提到】 : 如果一个flyback transformer, 我把两个windings并联起来, 作为primary side, 现 : 在primary side得inductance 是不是就使原来的1/2了? : 一个Linear Tech得application engineer说,in the case of coupled inductors or : transformers placing windings in parallel results in the same inductance.... : 哪位能给分析一下? : 谢谢!
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gr 发帖数: 2958 | 15 电流还是原来一样的么?
or
...
【在 N*******g 的大作中提到】 : 如果一个flyback transformer, 我把两个windings并联起来, 作为primary side, 现 : 在primary side得inductance 是不是就使原来的1/2了? : 一个Linear Tech得application engineer说,in the case of coupled inductors or : transformers placing windings in parallel results in the same inductance.... : 哪位能给分析一下? : 谢谢!
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