How to form transformer eddy current

Transformer is an indispensable and important equipment in power system, which is mainly used for voltage up-and-down conversion to realize efficient transmission of electric energy. However, in the process of transformer operation, eddy current loss is one of the inevitable phenomena, which not only affects efficiency, but also leads to equipment heating and reduces service life. Therefore, it is of great significance to understand the formation mechanism of eddy current in transformer for optimizing design and improving operation efficiency.

Eddy current, also known as induced current, is a kind of annular current generated by changing magnetic field inside a conductor. Its formation principle is based on Faraday's law of electromagnetic induction and Lenz's law.

When the transformer works, alternating current passes through the primary winding, and alternating magnetic flux is established in the iron core. This alternating magnetic flux not only couples through the primary winding and the secondary winding, but also passes through the iron core itself. According to Faraday's law of electromagnetic induction, the changing magnetic flux will induce electromotive force (EMF) in the core material. Because the core material is usually conductive (such as silicon steel sheet), the induced electromotive force will form a closed loop current path inside the core, which is called eddy current.
　　he direction of eddy current follows Lenz's law, that is, the magnetic field it produces always hinders the change of the original magnetic flux that causes it. When eddy current flows in the iron core, Joule heat (IR loss) will be generated due to the resistance of materials, which is eddy current loss. Eddy current loss not only wastes electric energy, but also may cause the temperature of the core to rise, thus affecting the insulation performance and operation stability of the transformer.
　　n order to reduce the influence of eddy current, the transformer core is usually made of materials with high magnetic permeability and low conductivity, such as silicon steel, and the core is made of many laminated sheets. These sheets are separated by insulating layers, in order to increase the flow path resistance of eddy current, thus significantly reducing the size of eddy current and the resulting loss. This structure is called "laminated core" or "laminated core".

In addition, modern transformers may also use new materials such as amorphous alloy as iron core to further reduce eddy current loss and other iron losses and improve overall efficiency.
　　In a word, the eddy current in the transformer is formed by the annular current induced by the alternating magnetic field in the conductive core. Although eddy current phenomenon can't be completely avoided, its influence can be effectively suppressed and the energy efficiency and reliability of transformer can be improved by reasonable material selection and optimized structural design. With the development of power electronics technology and new materials, future transformers will continue to progress in the direction of lower loss and higher efficiency.