The difference between common mode inductance and differential mode inductance

The difference between common mode inductance and differential mode inductance
 

There are two types of inductors used to resist electromagnetic interference: common mode inductors and differential mode inductors.

Disturbance electromagnetic field generates differential mode current between lines, causing interference on the load, which is called differential mode interference; The disturbance electromagnetic field generates common mode current between the line and ground, which generates differential mode voltage on the load and causes interference, which is known as common mode ground loop interference.

The filtering inductance used to suppress common mode interference is called a common mode inductance [2]. The filtering inductance used to suppress differential mode interference is called differential mode inductance.
 

Common-mode inductors are two sets of coils with equal number of coils, equal wire diameter, and opposite winding directions wound around the same iron core. A differential mode inductor is a coil wound around an iron core.
 

The characteristic of a common mode inductor is that due to the opposite winding directions of two sets of coils on the same iron core, the iron core is not afraid of saturation. The most commonly used magnetic core material on the market is high conductivity ferrite material.
 

The characteristic of differential mode inductance is its application in high current situations. Due to the fact that a coil is wound around an iron core, when the current flowing into the coil increases, the iron core in the coil will become saturated. Therefore, the most commonly used iron core material in the market is metal powder core material. Especially the iron powder core material (due to its low price).