Power transformer, as an indispensable component in the power system, plays a key role in transmitting AC power from one circuit to another and changing the voltage and current by electromagnetic induction. From power plants to household appliances, from transmission lines to electronic devices, power transformers are everywhere and play a vital role.

The working principle of the power transformer is based on Faraday's law of electromagnetic induction. It mainly consists of two windings (primary winding and secondary winding) and a magnetic core. When the AC current passes through the primary winding, an alternating magnetic field is generated in the core, which passes through the secondary winding and generates an induced electromotive force in it, thereby realizing the transmission of electric energy and voltage conversion.

The magnetic core is usually made of silicon steel sheets with high magnetic permeability and low magnetic resistance to reduce leakage loss. The primary winding is connected to the input power supply, while the secondary winding is connected to the output load. Depending on the ratio of the number of turns of the winding, the transformer can achieve step-up or step-down functions. When the number of turns of the secondary winding is more than that of the primary winding, the output voltage is higher than the input voltage, and the voltage is increased; otherwise, the voltage is decreased.

The main functions of the power transformer include voltage conversion, current conversion, electrical isolation and coupling. Through voltage conversion, the transformer can provide appropriate voltage supply according to different needs, thereby meeting the operating requirements of various equipment and systems. Current conversion enables the transformer to play the role of current matching and power transmission in the power system.

Electrical isolation is another important feature of the power transformer. Through the insulated core and windings, the transformer completely isolates the input circuit and the output circuit, providing safety and protection to prevent current and noise from propagating to other circuits. The transformer can also be used to couple two circuits to achieve signal transmission and impedance matching.

Power transformers are widely used in various fields. In power plants and transmission lines, transformers are used to increase and decrease voltage to efficiently transmit electrical energy. In substations, they are used to distribute and regulate voltage. In electronic devices, such as power adapters, electronic transformers, etc., power transformers are used to provide appropriate voltage and current supply. In addition, power transformers also play an important role in the fields of new energy, electric vehicles and rail transportation.

With the continuous growth of energy demand and the focus on energy efficiency, power transformers are developing towards high efficiency, low loss and high power density. The use of new core materials, optimized winding design and improved manufacturing processes can effectively improve the conversion efficiency of transformers and reduce energy losses. At the same time, high-frequency technology and integrated design are also widely used to increase power density and reduce volume.

Environmental protection and sustainability are important directions for the development of power transformers in the future. The use of environmentally friendly materials, reduction of energy consumption and carbon dioxide emissions will become important considerations in transformer design and manufacturing.