At present, the R&D of solid-state transformers (SSTs) in China is progressing in sync with global developments, marking a critical period to seize opportunities, vigorously advance, and gain a competitive edge. On May 15th, experts from domestic research institutes, universities, leading enterprises, and industry associations gathered in Yancheng, Jiangsu Province, bringing their teams' latest research findings to engage in in-depth discussions on the key technical issues surrounding the application of amorphous/nanocrystalline cores in solid-state transformers.

A solid-state transformer (SST) is a power device based on semiconductor components (such as MOSFETs, IGBTs) for electrical energy conversion. By replacing the traditional iron-core coil structure with high-frequency electromagnetic induction technology, it can flexibly regulate voltage, frequency, and power characteristics. SSTs offer core advantages such as high energy conversion efficiency, compact size, light weight, low noise, and the potential for integrated smart control functionalities. Their development and breakthroughs represent crucial technical support for the robust advancement of new power systems.

From the perspective of material innovation, amorphous/nanocrystalline materials possess a "dual character": the amorphous phase provides high resistivity to reduce eddy current losses, while the nanocrystalline phase imparts excellent soft magnetic properties. This gives them a more pronounced application advantage in SSTs compared to other magnetic materials under equivalent magnetic flux density conditions.

The conference revealed that replacing traditional soft magnetic materials like ferrites with amorphous/nanocrystalline materials could reduce SST manufacturing costs by 30% and lower carbon emissions. By 2030, this technology is projected to contribute over 50 billion kWh in annual global energy savings, positioning it as one of the key technologies driving the green energy transition. Currently, domestically produced ultra-thin nanocrystalline materials with thicknesses below 12 micrometers have achieved losses more than 50% lower than conventional nanocrystalline materials. Thus, breakthroughs in the R&D of amorphous/nanocrystalline cores are expected to further catalyze the transformation of materials required for new power systems.

From the viewpoint of technological breakthrough, SSTs are high-frequency power electronic conversion devices. Therefore, the high-frequency isolation transformer is the core component of an SST. Key technical bottlenecks include limited capacity, high loss density, challenges in designing high-capacity units, system complexity, and high costs. In the domain of high-frequency transformers, amorphous/nanocrystalline materials offer more stable temperature characteristics, making them suitable for high-frequency transformers operating at elevated temperatures, though effective thermal management is essential. Additionally, amorphous/nanocrystalline technology enables the manufacture of larger-sized cores, providing higher power density under equivalent design magnetic flux density, aligning with the trend toward high-capacity, compact power electronic equipment.

The conference highlighted that traditional ferrites exhibit losses over three times greater than those of amorphous materials in the 10 kHz frequency band. Domestically, a 20-centimeter wide core has been developed with losses as low as 56,000 watts per kilogram. This achievement not only maintains ultra-low losses but also solves the problem of magnetic domain distortion caused by uneven stress distribution in wide-format materials. Concurrently, applications in projects like the Xiong'an New Area and the Zhangjiakou Winter Olympics demonstration have verified the stability advantages of amorphous/nanocrystalline cores under high-frequency operating conditions.

From the standpoint of standards leadership, domestic teams are currently leading the formulation of international standards for power electronic transformers, which have entered the final review stage. Standards signify industry leadership, marking China's first instance of securing standard-setting authority in this field. The conference also noted that a domestic team is advancing the "Technical Specification for Medium- and High-Frequency Isolation Transformers for Flexible DC Systems," filling a domestic gap. This specification sets a loss limit for the above-10 kHz frequency band that is 15% stricter than current EU standards.

In terms of application expansion, amorphous-core transformers have already surpassed the single-unit capacity limit of 10 MVA. A domestic team is applying a developed three-phase transformer in a photovoltaic project in Xinjiang, which is expected to reduce land occupation by 60% compared to traditional solutions. In the rail transit sector, the use of a 3 kHz amorphous-core traction transformer on Shenzhen Metro Line 16 has resulted in a 7.2% reduction in energy consumption and a 12 dB noise reduction. Of particular note is the application in offshore wind power. Deep-sea transformers currently under testing employ epoxy vacuum casting technology, tripling insulation lifespan in salt-fog corrosive environments, thereby providing critical equipment support for DC power transmission from far-offshore wind farms.

In summary, material breakthroughs are reshaping the technological pathways of power equipment. Amorphous/nanocrystalline core technology not only drives the upgrade of SSTs but also provides foundational material support for emerging fields such as hydrogen energy electrolysis and maglev power supply. With the vigorous advancement of the "Dual Carbon" goals, China's high-frequency transformer market is projected to reach 120 billion yuan by 2030, ushering in a significant period of development opportunity for amorphous/nanocrystalline technologies.