High-frequency transformer is a device to transform AC voltage, current and impedance, when the primary coil through the AC current, the iron core (or magnetic core) will produce AC flux, so that the secondary coil induced voltage (or current).

The transformer is composed of an iron core (or a magnetic core) and a coil. The coil has two or more windings, among which the windings connected to the power supply are called primary coils, and the remaining windings are called secondary coils.

Transformer cores include tank cores, RM cores, E cores, EC, ETD and EER cores, PQ cores, EP cores, EP cores, ring cores and so on. How do these cores affect transformer operation? Please look at the specific analysis below.

1. Tank core

The skeleton and winding are almost all wrapped by the magnetic core, resulting in a very good shielding effect on EMI; The size of the tank core conforms to IEC standard, and the interchangeability is very good during manufacturing. Simple frame (without pins) and PCB board mounting frame (with pins) are available;

Due to the design of the tank shape, the cost is higher compared with other types of magnetic cores of the same size; Because its shape is not conducive to heat dissipation, it is not suitable for high power transformer inductors.

2. RM core

Compared with the tank type, the two symmetrical sides of the tank type are cut off. This redesign is more conducive to heat dissipation and large size lead extraction. Compared with the tank shape, it saves about 40% of the installation space; Skeleton needle-free and needle-inserted; A pair of clips can be used for installation;

The RM core can be made into a flat shape (suitable for current flat transformers or directly assembled into a printed board circuit with designed windings); It's not as well shielded as the canister, but it's still good.

3. E-core

Compared with the tank core, the cost of E-core is much lower, and the winding and assembly of E-core are relatively simple. This core shape is now widely used, but its disadvantage is that it cannot provide self-shielding.

The E core can be installed in different directions, and can also be stacked for more power. The core can be made into a flat shape (a popular core shape for planar transformers today);

Needle-free and needle-inserted frames are also available; Because of its excellent heat dissipation and its ability to be used superimposed, this shape of core is commonly used in high-power inductors and transformers.

4. EC, ETD and EER cores

These types of core structures are intermediate between E-type and tank type. Like E-cores, they can provide enough space for large section leads (suitable for the current trend of switching power supply low voltage and high current);

Cores of these shapes also dissipate heat very well; Compared with a cuboid with the same cross section, the length of the winding with single turn is shortened by 11%, which reduces the copper loss by 11% and makes the magnetic core provide a higher output power. At the same time, the center column is cylindrical, compared with the center column of the cuboid, it also avoids the hidden danger that the winding wire insulation will be damaged when the edges and corners of the cuboid are wound.

5. PQ core

PQ cores are specially designed for inductors and transformers used in switching power supplies. The design of PQ shape optimizes the ratio between core volume, surface area and winding area. This design, so that this design, in a small transformer volume and weight, to obtain a larger output power, and occupy a small PCB installation space;

A pair of clamps can be used for installation and fixation; This effective design also makes the cross-sectional area of the magnetic circuit of the magnetic core more uniform, so this magnetic core structure also makes it less hot spots than other magnetic core structure design.

6, EP type magnetic core

EP type magnetic core circular center column three-dimensional structure, except the end of contact with PCB board, completely wrapped winding, shielding is very good; This unique shape minimizes the effect of the air gap formed at the contact surface when the two cores are assembled, and provides a greater volume and proportion of the total space utilization.

7. Ring core

For the manufacturer, the ring core is more economical, in comparison with the various cores, it is the lowest cost; Due to the use of skeleton, the additional and assembly costs are equal to zero; When suitable, the winding machine can be used for winding; Its shielding is also very good.

The above is a summary of the analysis of the influence of the shape of the magnetic core of the high-frequency transformer on the work of the transformer. I hope it can help you.