Understand the influence of the number of coils of differential mode inductance
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  • 发布日期:2021-12-13 10:40:51
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Does it matter how many differential mode inductors there are? Many inductance manufacturers will be confused about this problem!
Does it matter how many differential mode inductors there are? Many inductance manufacturers will be confused about this problem!
So today Thursday, we will introduce the differential mode inductor to you for research and discussion!
1、 What role can differential mode inductance play?
The number of turns of differential mode inductance must be balanced. If it is unbalanced, there must be a problem. Common mode inductor is a common mode interference suppression device with ferrite as the magnetic core. It consists of two coils with the same size and the same number of turns symmetrically wound on the same ferrite ring magnetic core to form a four terminal device. It can suppress the large inductance of common mode signal, but it has little effect on the small leakage inductance of differential mode signal. The principle is that when the common mode current passes through the magnetic ring, the magnetic flux in the magnetic ring is superimposed with each other, so that the magnetic flux in the magnetic ring has a considerable inductance, which can suppress the common mode current; When two common mode currents pass through the differential mode current, the magnetic flux in the magnetic ring counteracts each other, and there is almost no inductance, so that the differential mode current will not decay when passing through. Therefore, the common mode inductance can effectively the common mode interference signal in the balance line, but has no effect on the differential mode signal normally transmitted by the line.
2、 The manufacturing of differential mode inductance shall meet the following requirements:
1. The wires wound on the coil magnetic core shall be insulated from each other to ensure that there is no breakdown or short circuit between turns of the coil under the action of instantaneous overvoltage.
(4) The coil shall be wound in a single layer as far as possible, which can reduce the parasitic capacitance of the coil and enhance the bearing capacity of the coil to instantaneous overvoltage.
2. When the coil flows through an instantaneous large current, the magnetic core shall not be saturated.
4) The magnetic core in the coil shall be insulated from the coil to prevent breakdown under the action of instantaneous overvoltage.
Common mode inductance
3、 Circuit diagram of common mode inductance and common mode inductance:
1. Cause interference on the load, which is differential mode interference; The disturbance electromagnetic field generates common mode current between line and ground, and the common mode current generates differential mode voltage on the load, which causes interference, which is common mode interference.
2. The filter inductor that suppresses common mode interference is called common mode inductor; The filter inductor for suppressing differential mode interference is called differential mode inductor.
3. Common mode inductors are two-wire and two-way; Differential mode inductors are unidirectional.
4、 3. The number of coils wound on the same core quotient is equal, the wire diameter is equal, and the common mode inductance of the two groups of coils with opposite windings; A differential mode inductor is a coil wound around an iron core.
5. Common mode choke is that two windings are connected to zero line and live line respectively, and the two windings go in and out at the same time to filter the common mode signal; Differential mode is a kind of filter inductance. Its winding is connected to zero line and live line respectively, which can only filter out differential mode interference.
6. Common mode signal: two identical signals on the zero line and the live line respectively, which are coupled and form a loop; Differential mode signal: it is the same loop as the useful signal.
7. Characteristics of common mode inductance: because the winding directions of two groups of coils on the same core are opposite, the core is not afraid of saturation. The most widely used magnetic core material on the market is high conductivity ferrite.
Differential mode inductors have properties for high current applications. Because the coil is wound on the iron core, when the current flowing into the coil increases, the iron core of the coil will be saturated, so the most commonly used iron core material in the market is metal powder core material. Especially iron powder core materials (due to low price).
Does it matter how many differential mode inductors there are? The answer is definitely influential. Just be appropriate!