How to calculate the loss of the transformer in the power adapter

Issue Time:2019-05-14
Transformer is a very important component in the power adapter, which functions as power transmission, voltage conversion and insulation isolation. However, in the daily use of the power adapter, the transformer will cause some loss. The transformer loss includes core loss and winding loss. . The core loss is referred to as iron loss, and the winding loss is referred to as copper loss. The iron loss of the transformer can be calculated according to the core loss curve given by the core manufacturer. Below, Shenzhen Intermodal Electronics will briefly introduce the factors affecting copper consumption and the calculation method of copper consumption.

In low-frequency transformers, the copper loss is obtained by (Irms) 2Rdc, where Rdc is the DC resistance of the winding, calculated according to the length, radius and resistivity of the wire (as checked by the wire table), Irms is the rms current, calculated according to the waveform . In the high-frequency transformer, the winding copper loss ratio (Irms) 2Rdc is larger due to the skin effect and the proximity effect. Both the skin effect and the proximity effect are caused by eddy currents induced by changes in the internal magnetic field of the coil. The skin effect is caused by eddy currents induced by the magnetic field generated by the current flowing through the wire itself in the wire. The proximity effect is caused by eddy currents induced in the wires by magnetic fields generated by current flowing through adjacent wires or coils.

The skin effect causes the current of the wire to flow only over a thin surface of the wire. The thickness of the surface layer or the annular conductive region is inversely proportional to the square root of the frequency. Thus, as the frequency increases, the conductive area of ​​the wire decreases, the AC resistance increases, and the copper loss also increases. Accurate calculation of the loss of the power adapter transformer can provide some reference data for the design of the power adapter. With reasonable improvement, the power adapter can be more efficient and more durable.

Shenzhen Lianyunda Electronics Co., Ltd. transformer adopts TDK PC40 imported magnetic core; 3 layers of insulated wire; and shielded copper foil; secondary flying wire; EMC standard; high voltage test up to 4000V. Shenzhen Lianyunda electronic first-class power adapter brand manufacturers, focusing on power adapter products for 12 years, with a strong R & D team and production capacity, finely crafted, superior quality, you can rest assured to choose.

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