The shape of the high-frequency core, what are the effects on the transformer?

Switching power supply in the high-frequency core is very common, when you face different shapes of high-frequency core, you can explain how they are different?

A high-frequency transformer is a device that transforms AC voltage, current and impedance. When there is AC current in the primary coil, the AC flux is generated in the iron core (or magnetic core), so that the voltage (or current) is induced in the secondary coil. The transformer consists of an iron core (or magnetic core) and a coil, which has two or more windings, of which the winding connected to the power supply is called the primary coil, and the rest is called the secondary coil. The magnetic core of the transformer includes tank core, RM core, E core, EC, ETD and EER core, PQ core, EP core, EP core, annular core and other magnetic cores, so how do these magnetic cores affect the work of the transformer?

1、 can 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 is in line with IEC standards, 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 than that of other types of magnetic cores of the same size; Because its shape is not conducive to heat dissipation, it is not suitable for use in high-power transformer inductors.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2 、RM type magnetic core

Compared with the tank type, the two symmetrical sides of the tank type are cut off, which is more conducive to heat dissipation and large-size lead extraction; Save about 40% of the installation space compared to the pot shape; The skeleton is needle-free or needle-inserted; A pair of clamps can be used for installation; The RM core can be made into a flat shape (suitable for today's flat transformers or directly mounted to a printed board circuit with already designed windings); Although the shielding effect is not as good as the can type, it is still good.

3、 Type E magnetic core

Compared with the tank core, the cost of the E core is much lower, coupled with the winding and assembly are relatively simple, this core shape is now the most widely used, but its disadvantage is that it can not provide self-shielding; The E core can be installed in different directions, and can also be superimposed to apply more power; This magnetic core can be made into a flat shape (which is a popular core shape for planar transformers now); It can also provide pin-free and pin type skeleton; Because its heat dissipation is very good and can be used in superposition, generally high-power inductors and transformers use magnetic cores of this shape.

4 、EC, ETD and EER cores

These types of core structures are between the E type and the can type. Like the E core, they can provide enough space for a large section of the lead lead (suitable for the current trend of low voltage and high current switching power supply); These shaped cores also dissipate heat very well; When the center column is cylindrical, compared with the cuboid of the same section, the length of the single-turn winding is shortened by 11%, which results in the copper loss is also reduced by 11%, and the magnetic core can provide a higher output power; At the same time, the center column is cylindrical, compared with the cuboid center column, it also avoids the hidden danger of destroying the insulation of the winding wire because the cuboid edges are wound.

5、 PQ magnetic core

The PQ core is specially designed for inductors and transformers for switching power supplies. The PQ shape is designed to optimize the ratio between core volume, surface area and winding area. This design, so that this design, in the smallest transformer volume and weight, to obtain the maximum output power, and occupy the smallest PCB installation space; Can use a pay clamp to install fixed; This effective design also makes the magnetic circuit cross-sectional area of the magnetic core more uniform, so this magnetic core structure also makes the design of the magnetic core structure has less hot spots than other magnetic core structure.

6、EP core

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

7、Toroidal core

For the manufacturer, the ring core is the most economical, and its cost is the lowest among the various magnetic cores that can be compared with it. Due to the use of the 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 the analysis of the influence of the magnetic core shape of the high-frequency transformer on the work of the transformer, and I hope it can help you.For more information, please contact us at sales@xfullstar.com