Application And Prospect Of Amorphous And Nanocrystalline Soft Magnetic Materials in Solid-State Transformers

Jan 23, 2026

Introduction

Solid-State Transformers (SSTs) are revolutionary power conversion devices that integrate power electronics, magnetic components, and advanced control systems, offering advantages such as bidirectional power flow, reactive power regulation, and harmonic suppression. Amorphous and nanocrystalline soft magnetic materials, with their exceptional magnetic properties, have become the core material choice for SSTs, driving the transformation of power distribution systems toward high efficiency, miniaturization, and intelligence. This paper elaborates on their application advantages, typical scenarios, current challenges, and future prospects in SSTs.

Core Properties and Application Advantages

Key Magnetic Properties

Amorphous alloys feature a disordered atomic structure, while nanocrystalline alloys consist of nanoscale crystalline grains (typically 10-100 nm) embedded in an amorphous matrix. Both materials possess the following critical properties:

Low Core Loss: High resistivity and thin ribbon structure (typically 10-30 μm) minimize eddy current losses. Core losses are 60%-80% lower than traditional silicon steel, and no-load losses are reduced by over 40%.
High Permeability: Nanocrystalline materials, in particular, exhibit ultra-high permeability, enabling efficient energy transfer and reducing excitation current.
High Saturation Magnetic Induction: New nanocrystalline foils can reach a saturation magnetization of up to 1.9 T, supporting high-power density designs.
Excellent Thermal Stability: Heat treatment with niobium addition enhances thermal stability, making them suitable for high-temperature operating environments in power electronics.

Advantages in SSTs

Advantage	Description
High Power Density	High-frequency operation (1-20 kHz) reduces the size and weight of magnetic components by 50%-90% compared to conventional transformers.
Enhanced Efficiency	Core loss reduction improves SST efficiency to 98.5% or higher, critical for energy-intensive applications like data centers and renewable energy systems.
Compact Design	Smaller cores and windings enable integration into space-constrained applications such as electric vehicles (EVs) and subsea power grids.
Improved Reliability	Low loss reduces heat generation, extending component lifespan and enhancing system stability in harsh environments.

Typical Applications in SST Components

types of CNC machining

Amorphous and nanocrystalline cores are widely used in the isolation stage of SSTs. Nanocrystalline cores excel in the 1-20 kHz range, balancing loss and thermal performance. For example, offshore wind SSTs utilize nanocrystalline cores to achieve compact, lightweight designs for HVDC transmission. Amorphous cores are preferred for low-frequency, high-power applications due to their cost-effectiveness.

Inductors and Filter Components

These materials are applied in SST input/output inductors and EMI filters:

Common-Mode Inductors: High permeability suppresses electromagnetic interference, improving power quality.
Energy Storage Inductors: Low loss supports bidirectional energy flow in SSTs for grid stabilization.

Application Scenarios

Industry	Application	Material Benefits
Renewable Energy	PV inverters, wind converters	Higher efficiency, smaller size, enhanced reliability in extreme conditions.
Transportation	EV chargers, traction transformers	Lightweight, low noise, support for 800V high-voltage fast charging.
Smart Grids	Distribution SSTs, subsea power systems	Bi-directional flow, reactive power control, compact offshore substations.
Data Centers	800V DC power distribution	High efficiency, reduced cooling costs, miniaturized design.

Current Challenges and Solutions

Challenges

High Production Costs: Complex manufacturing processes for thin ribbons and heat treatment increase costs.
Brittleness: Nanocrystalline ribbons become brittle after annealing, complicating core assembly.
Market Adoption: Limited industrial awareness hinders large-scale commercialization.

Solutions

Process Innovation: Ultra-thin ribbon (≤12 μm) production reduces loss by over 50%, improving cost-performance ratio.
Design Optimization: New core structures (e.g., oval cores for EVs) enhance mechanical durability.
Standardization: Chinese teams lead the development of international power electronic transformer standards, promoting material acceptance.

Future Prospects

Market Growth

The global SST market is projected to expand rapidly, driven by smart grids, EVs, and renewable energy. Nanocrystalline materials are positioned to become the reference core material for medium-to-high-frequency SSTs. By 2030, amorphous/nanocrystalline SSTs could save over 50 billion kWh annually globally, reducing carbon emissions significantly.

Technological Trends

Material Upgrades: New alloys with higher saturation magnetization (≥1.9 T) and lower loss will emerge.
Integration with Emerging Technologies: Compatibility with superconductivity and AI-driven control systems will enhance SST performance.
Cost Reduction: Large-scale production and process automation will lower material costs by 30% or more, boosting market penetration.

Industrial Expansion

Applications will extend to aerospace, electric ships, and microgrids. For example, subsea SSTs with nanocrystalline cores will enable long-distance, platform-free DC transmission.

Conclusion

Amorphous and nanocrystalline soft magnetic materials are pivotal to SST advancement, offering unmatched efficiency, power density, and compactness. Addressing cost and brittleness issues through innovation will accelerate their adoption. As SSTs become mainstream in smart grids and clean energy systems, these materials will play a crucial role in shaping the future of energy conversion and distribution.