[Beginner] The main losses caused by high-frequency transformer winding

吾妻思萌

[Beginner] The main losses caused by high-frequency transformer winding [Copy link]

The main losses of high-frequency transformers are: leakage inductance, skin effect, and proximity effect.

The main method to reduce leakage flux in high-frequency transformers is to reduce the magnetic potential difference between any two points. Therefore, it is very important to analyze the magnetic potential distribution in the transformer. In other words, the magnetic induction intensity should not be too large, as shown in the figure below, so H is large.

Magnetic potential caused by transformer winding

The leakage of high-frequency magnetic core coils can lead to serious consequences:

1. Leakage inductance causes electromagnetic interference in surrounding circuits

2 Leakage flux causes loss in surrounding circuits

3. Leakage flux causes eddy current in the copper foil coil conductor, reducing the effective cross-sectional area of the conductor, positive conductor loss, or causing local overheating of the conductor.

Skin effect: Studies have shown that the current density in the wire decreases exponentially from the surface to the center of the wire, the effective cross-sectional area of the wire decreases and the resistance increases, as shown in the following figure

Skin Effect

Proximity Effect

In multi-layer coils, the loss caused by the proximity effect is much greater than the loss caused by the skin effect. Therefore, special attention should be paid to the proximity effect in multi-layer winding. Generally, try to use multiple strands in parallel, such as φ0.21, φ0.18