High-frequency transformers are power transformers operating at frequencies exceeding the intermediate frequency (10kHz). They are primarily used in high-frequency switching power supplies, and also in high-frequency inverter power supplies and high-frequency inverter welding machines. Based on operating frequency, they can be categorized into several levels: 10kHz-50kHz, 50kHz-100kHz, 100kHz-500kHz, 500kHz-1MHz, and above 1MHz. For high-power applications, IGBTs are generally used. Due to the tailing effect of IGBT turn-off current, their operating frequency is relatively low. For lower-power applications, MOSFETs can be used, allowing for higher operating frequencies.
With the increasing demand for artificial intelligence (AI) computing power and the advancement of energy transition, the application of high-frequency transformers has expanded to power supply systems for AI data centers, supercomputing clusters, and other computing infrastructure, and is also being applied in areas such as renewable energy integration and grid upgrades.
The world's first 10 kV flexible switchgear based on a single megavolt-ampere nanocrystalline high-frequency transformer has commenced construction in Qingpu, Shanghai. The project demonstrates the application of a single 1 megavolt-ampere power electronic transformer and includes a 750V DC bus for convenient connection to distributed photovoltaic systems, DC charging piles, and energy storage systems. Future plans for the project include leveraging the advantages of power electronic transformers in multi-voltage power supply and clustered regulation and control to create a "demonstration of AC/DC distribution networks based on high-frequency transformers using novel soft magnetic materials."
