Two major advancements in the field of wide-bandgap semiconductors were recently announced in China: a 15 kV bidirectional-blocking SiC power device developed by Dr. Xing Huang’s team at Pinejade, and a 10 kV SiC MOSFET jointly released by Zhanxin Electronics and Zhejiang University.
These achievements mark China’s entry into the international leading tier of kV-class SiC technology and are expected to significantly accelerate the commercialization of solid-state transformers (SSTs) in smart grids, AI data centers, and renewable energy systems.
Breaking the Technical Bottleneck of High-Voltage SSTs
As next-generation equipment for future energy systems, SSTs promise high efficiency, compact size, and flexible energy management. However, their industrialization has long been constrained by the performance limitations of high-voltage power devices.
Traditional silicon IGBTs cannot meet SST requirements for high voltage, high switching frequency, and low loss. SiC, with ten times the breakdown field strength of silicon and inherently lower switching and conduction losses, has emerged as the ideal material for kV-class high-voltage applications.
Recent breakthroughs in 10–15 kV SiC devices significantly improve SST efficiency, simplify system architecture, and reduce cost-laying the foundation for medium-voltage SST deployment.
15 kV Bidirectional-Blocking SiC Device Simplifies Medium-Voltage Topologies
Developed by Dr. Xing Huang during his tenure at the FREEDM Systems Center, North Carolina State University, the 15 kV SiC device targets long-standing challenges in medium-voltage distribution networks.
Commercial SiC devices below 3 kV require multi-level cascaded H-bridge configurations to connect to 10–35 kV grids.
This leads to:
a large number of devices,
increased control complexity,
reduced system reliability.
The new 15 kV device-with true bidirectional blocking capability and 15 kV breakdown voltage-can directly interface with medium-voltage grids without multi-stage cascading, reducing SST cascading levels by over 80%.
A novel bidirectional terminal design, combined with extensive studies of short-circuit behavior, avalanche breakdown, and high-temperature aging, enables full reliability characterization and supports demanding scenarios such as DC fault isolation and HVDC systems.
10 kV SiC MOSFET: Large Chip Area, High Current, and Mass-Production Ready
At ISPSD 2025, Zhanxin Electronics and Zhejiang University unveiled a 10 kV SiC MOSFET addressing two major industry challenges: large-area wafer fabrication and high-voltage conduction loss.
Key performance highlights:
chip size: 10 mm × 10 mm, one of the largest publicly reported;
conduction current: ~40 A;
breakdown voltage: >12 kV;
specific on-resistance (Ron.sp): <120 mΩ·cm², approaching theoretical SiC limits;
manufactured on a 6-inch SiC platform with scalable mass-production capability.
The device leverages high-energy ion implantation and a narrow JFET design to resolve the inherent trade-off between high voltage and low resistance, while optimized terminal structures improve yield for large-area chips.
Enabling Upgrades Across Smart Grids, AI Data Centers, and Renewables
The maturation of kV-class SiC power devices is expected to accelerate SST adoption across multiple sectors:
Smart Grids
SSTs utilizing medium-voltage SiC devices enable efficient AC–high-frequency–DC conversion, improving grid flexibility and distributed energy integration.
AI Data Centers
kV-class SiC devices make medium-voltage direct supply architectures feasible.
Single-rack power density can reach 1 MW.
PUE can drop below 1.1.
Annual energy savings for hyperscale data centers can reach tens of millions of kWh.
Renewable Energy
Thanks to high-frequency performance:
PV inverters and wind converters can reduce filter size by 50%.
system cost decreases by ~20%;
Reliability improves under harsh environmental conditions.
Outlook: Higher Voltage, Lower Cost, and Wider Deployment
kV-class SiC devices are expected to evolve toward:
higher breakdown voltages (15 kV+), higher current ratings, and lower loss through trench-gate and advanced packaging technologies;
lower cost via 8-inch SiC wafers and yield improvements;
deeper integration with SSTs to enable innovative topologies for smart grids, AI computing clusters, and renewable energy bases.
These breakthroughs demonstrate strong momentum in China’s high-voltage SiC ecosystem and signal a critical window for rapid SST industrialization.
