Application areas of high-power switching transformers: mainly high-power switching power supplies, such as inverter DC welding machines; Electrolytic electroplating power supply; Laser power supply, communication equipment power supply, high-frequency induction heating power supply, etc., when the working frequency is increased to above 15KHZ, silicon steel can no longer meet the requirements; Although ferrite has low high-frequency losses, its saturation magnetic induction value (Bs) is low, and the volume and sag of the iron core are large, which is not conducive to the rational utilization of circuit board space. In addition, ferrite has a low Curie temperature and poor thermal stability. And nanocrystalline materials have excellent comprehensive magnetic properties, namely high magnetic induction, high magnetic permeability, low loss, and excellent temperature stability, quickly becoming the best choice for the iron core of inverter power transformers. In addition, the saturation magnetization of nanocrystals is three times that of ferrites, and the output power of iron cores with the same volume is twice that of iron gas. At the same time, they have greater resistance to overloading. The core loss is in the frequency range of 15KHZ-50KHZ, which is 1/2-1/5 of the ferrite loss. The magnetic permeability is more than 10 times that of ferrite, and the excitation power is small, thus reducing copper loss. The Curie temperature of iron-based nanocrystalline alloys is 570oC, which is three times that of iron gas.