The electronic transformer has an electronic device that converts the AC voltage of the mains into DC, and then forms a high-frequency AC voltage output through semiconductor switching devices, electronic components and high-frequency transformer windings. It is a new type of electric energy conversion equipment. It not only has the basic functions of voltage conversion, electrical isolation and energy transfer that traditional power transformers have, but also can realize other additional functions such as power quality regulation, system power flow control and reactive power compensation.