Fraunhofer Institute for Silicon Technology
Fraunhofer Institute for Silicon Technology

SST-based Smart Transformer

Solid-State Transformers (SSTs) are revolutionizing energy grids by replacing bulky 50 Hz transformers with compact, high-efficiency systems. Directly interfacing with medium-voltage grids, SSTs seamlessly interconnect AC and DC networks, offering a new degree of flexibility.

Through smart control, SSTs deliver critical grid services such as voltage/frequency regulation, fault protection, and dynamic load management. This supports the integration of renewables, fast EV charging, data centers, and battery storage.

With 10+ years of research in power converters, SSTs, and grid integration, ISIT provides real-world-ready solutions to build a more efficient, resilient, and sustainable energy future.

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  • MMC-based Active front end
  • Modular design and building blocks (PEBB)
  • Isolated DC/DC stage using conventional- and multiport- topologies
  • Advanced technologies for high efficiency and compactness:
    • SiC semiconductors
    • High power planar transformers
  • High availability solutions:
    • Embedded health monitoring
    • Lifetime extension strategies
    • Fault tolerance
  • Embedded communication – “Talkative power conversion”

We develop control approaches to deliver grid services:

  • Grid forming control (GFM)
  • Virtual inertia
  • Voltage and frequency support, power filtering
  • Islanding detection and operation – fault ride-through
  • Black start capability
  • Load balancing & energy management
  • AC- and DC- grid analysis and interoperability 

  • Medium-voltage laboratory for converter validation up to >1 MVA
  • Power Hardware in the loop (PHiL) testing under realistic emulated conditions:

Fast | low-cost | repeatable | safe

  • AC- and DC- microgrids for control validation, stability analysis, and interoperability studies