The high-frequency chain inverter technology replaces the bulky power frequency transformer in the traditional inverter with a high-frequency transformer, which greatly reduces the volume and weight of the inverter. In the hardware circuit design of the high-frequency chain, the high-frequency transformer is an important part. High-frequency transformers are power transformers whose operating frequency exceeds the intermediate frequency (10kHz). power transformer.


  High-frequency transformers are non-standard parts, with various specifications and specifications, and there is no naming standard. The so-called model is just a symbol marked by the manufacturer for distinguishing classification. Custom machining usually has to be designed in-house.

  Designing a high frequency transformer should start with the magnetic core. The cores of switching power supply transformers are mostly soft magnetic materials used in low magnetic fields, which have high permeability, low coercivity, and high resistivity. The magnetic permeability is high, and when a certain number of turns of the coil is used, it can withstand a high applied voltage with a small excitation current. Therefore, the volume of the magnetic core can be reduced under the requirement of outputting a certain power. The core coercivity is low, the hysteresis area is small, and the iron loss is also small. High resistivity, the eddy current is small, and the iron loss is small. The ferrite material is a composite oxide sintered body with high resistivity and is suitable for use at high frequencies, but the Bs value is relatively small and is often used in switching power supplies.

Generally speaking, two methods are used in the design of high-frequency transformers: the first is to first obtain the product AP of the magnetic core window area AW and the magnetic core effective cross-sectional area Ae (AP=AW×Ae, called the magnetic core area product), According to the AP value, look up the table to find out the number of the required magnetic material;

The second is to first obtain the geometric parameters, look up the table to find out the core number, and then design.

In the process of high frequency transformer design, attention should be paid to:

1) During the transient process, the leakage inductance and distributed capacitance of the high-frequency chain will cause inrush current, peak voltage and pulse top oscillation, which will increase the loss and cause damage to the switch tube in severe cases. At the same time, when the output winding has many turns and layers, the influence of distributed capacitance should be considered, and reducing the distributed capacitance is beneficial to suppress the interference of high-frequency signals to the load. It is difficult to reduce the distributed capacitance and leakage inductance at the same time for the same transformer, and appropriate capacitance and inductance should be ensured according to different work requirements.

2) In the design, at the time of maximum output power, the magnetic induction intensity in the magnetic core should not reach saturation to avoid distortion in large signals.

The above is the introduction of common methods of high-frequency transformer design summarized by Xiaobian for you. I hope it can help you. If you want to know more information about high-frequency transformers, click on high-frequency transformer information!