Improving efficiency is a common requirement in today's power supplies and electronic equipment. Traditional transformers can no longer meet today's efficiency requirements. High-frequency transformers can not only improve efficiency, but also save power resources. Its service life is much longer than that of ordinary transformers, and it has dual social and economic benefits of energy conservation and environmental protection.

Judging from the current domestic high-frequency transformer products, none are made of flat copper strips. If you use a flat copper strip, it needs to be very flat, which is very difficult in terms of manufacturing technology. Otherwise, the eddy current loss of the conductor will be very large at high frequencies. At present, high frequencies basically use Litz wire to avoid eddy current losses at high frequencies.

Advantages of high-frequency transformers over traditional transformers

This is because the magnitude of the induced electric potential of the transformer depends on the change of the magnetic flux per unit time. That is to say, the faster the magnetic flux changes, the greater the induction The greater the potential. Although the magnetic core of the high-frequency transformer is small and the maximum magnetic flux is not large, it operates at high frequency and the magnetic flux changes rapidly. Therefore, when the magnetic core is small and the number of coil turns is small, sufficient electric potential can be generated, while the opposite is true for low frequency.

As the name suggests, a transformer is a power electronic instrument that changes voltage. It is a device that uses Faraday's electromagnetic induction principle to change AC voltage. It is mainly composed of a primary coil, an iron core and a secondary coil. It can achieve matching conversion of input and output current, voltage, and impedance, and can also achieve primary physical isolation. According to different primary voltages, they can be divided into step-down transformers, step-up transformers, isolation transformers, etc.

The design calculation of the transformer shows that under the same power condition, the higher the frequency, the smaller the core and the fewer turns per volt. Designing a high-frequency transformer should start with the magnetic core. The transformer cores of switching power supplies are mostly soft magnetic materials used under low magnetic fields, with high magnetic permeability, low coercivity and high resistivity. The magnetic permeability is high, and under a certain number of coil turns, it can withstand a high external voltage through a small excitation current, so under a certain output power requirement, the volume of the magnetic core can be reduced.

Advantages: Very suitable for use on windings of one or two turns, high space utilization, small leakage inductance, and high current resistance.

Disadvantages: high cost, not suitable for multiple turns, poor versatility, and difficult process.

Calculation: The length times the height is the area, which is equivalent to the sum of the cross-sectional areas of all Litz lines.

Flat copper tape cannot be used at high frequencies because the skin effect will be more obvious if the frequency is too high, and winding is very inconvenient. It is suitable for large currents. The opposite is true for the Leeds Line. High frequency has advantages and winding is easy. However, overloading is easy to occur when the current is large.