The degree of core saturation of the transformer is related to the following factors:
1) Different core materials, the greater the magnetic flux of the material, the less likely it is to be saturated;
2) Core material The thickness of the iron core is preferably thin;
3) The assembly of the iron core is preferably dense;
4) The size and shape of the iron core;
5) The material and number of turns of the coil;
6) The corresponding positions of the primary coil and the secondary coil;
7) The size of the passing current;
8) Coil Assembly precision.
If the DC component is too high, resulting in magnetic bias, it cannot return to the initial state along the hysteresis loop, so it accumulates, saturates, the magnetic flux density drops sharply, and the transformer hangs up.
The magnetic flux density is too low and cannot withstand the high DC component. Same as above, the transformer will fail.
Extended information:
The reasons for the saturation of the switching power supply transformer are as follows:
Usually it is because a large DC component flows through the winding, especially when the pulse width is improperly adjusted. It is very easy to cause iron core (magnetic core) saturation. The method is to place a non-magnetic insulator of appropriate thickness between the iron core tongues, often a piece of paper, to increase the reluctance of the magnetic circuit and slow down the saturation speed of the iron core, so that the switching power supply transformer can obtain Good linearity. ?
Magnetic components (transformer saturation) thermal saturation (super Curie temperature), magnetic flux saturation (the designed Bm value is too high), voltage saturation (the input voltage is too high and exceeds the specified value), overload saturation (Overload), the flyback air gap of the switching power supply transformer is too small, causing the switching power supply transformer to be saturated.
Baidu Encyclopedia - Transformer