From Research to Deployment: The Innovation Leap in the UK's Solid-State Transformer Development

I. Overview of Solid-State Transformers (SST)

A Solid-State Transformer (SST) is an advanced power conversion device that integrates power semiconductors, high-frequency transformers, and control circuits.

Compared with traditional transformers, SST supports AC/AC, AC/DC, and DC/DC conversions, and features advantages such as bidirectional power flow, intelligent control, and a compact design.Its main topologies include single-stage, two-stage (with LVDC or HVDC links), and three-stage structures, each suitable for specific application scenarios.

II. Advantages of SST

• Compact size and lightweight: High-frequency operation reduces volume by up to 80%.

• High efficiency: Fewer conversion stages and support for direct DC connection.

• Smart grid compatibility: Enables real-time monitoring, voltage regulation, reactive power compensation, and fault isolation.

• Integration with renewable energy and energy storage: Directly connects solar, wind, and battery systems.

• Suitable for high-growth markets: Such as EV fast charging, data centers, and rail transit.

III. Application Fields

• Power Grid: Enhances grid flexibility, supports bidirectional power flow, and integrates distributed energy resources.

• Electric Vehicle (EV) Charging: Enables ultra-fast charging (350kW+), Vehicle-to-Grid (V2G) functionality, and direct integration of renewable energy.

• Rail Transit: Replaces traditional traction transformers, reducing weight and improving efficiency.

• Data Centers: Improves energy efficiency, reduces cooling requirements, and supports the integration of renewable energy.

• Marine and Aviation: Drives electrification transformation and reduces carbon emissions.

IV. Technical Challenges

• High Cost: The cost of SST is 5–10 times that of traditional transformers.

• Reliability Issues: Weak short-circuit withstand capacity, and semiconductor devices are susceptible to voltage stress.

• EMI Interference: High-frequency switching causes electromagnetic interference, requiring complex filter design.

• Insulation and Thermal Management: The performance of insulating materials under high frequencies has not been fully mastered.

• Gate Driving and Protection: The design is complex, requiring isolation and high-precision control.

V. Market Opportunities in the UK

• Grid Modernization: The UK has approximately 585,000 substations, among which 230,000 distribution substations can benefit from SST.

• Renewable Energy Targets: The 2030 targets include 50GW of offshore wind power and 47GW of solar energy.

• EV Charging Infrastructure: It is estimated that 300,000 public charging piles will be needed by 2030, and the ultra-fast charging market has huge potential.

• Rail Electrification: Approximately 2,880 diesel locomotives are to be replaced, and the SST market potential exceeds £30 million.

• Data Center Growth: Power demand continues to rise, and SST can improve energy efficiency and flexibility.

VII. The Role of CSA Catapult

• Provides full-chain technical support for SST, including design, simulation, and prototype verification.

• Leads projects such as ASSIST to promote the development of the UK's domestic high-voltage Si device supply chain.

• Possesses core capabilities including multi-objective optimization, advanced packaging, and thermal management.