Spain, Zaragoza: The EU-funded SSTAR project has advanced solid-state transformer (SST) technology towards high-voltage grid applications, positioning it as a potential enabler for Europe’s energy transition.
Coordinated by CIRCE, the project focused on moving SSTs beyond low-voltage applications and demonstrating their viability for future power grids that need to be more flexible, digital and resilient.
Unlike conventional iron-core transformers, SSTs use high-frequency semiconductor switching and power electronics to manage energy conversion. This makes them relevant for grids with high shares of renewable generation and more complex operating conditions.
The project developed three main technology areas. These included a sustainable biobased dielectric fluid intended to improve insulation performance, a high-voltage SST module based on bidirectional inductive power transfer, and a decentralised cascade H-bridge control architecture.
SSTAR delivered a 200-litre sample of its vegetable-based dielectric fluid for use in the SST prototype. The IPT-based prototype achieved 76.7 kW power transfer at 1,500 V, with around 95 % efficiency under resonant operation.
The decentralised cascade H-bridge converter was validated with 28 series-connected modules at a simulated 66 kV grid voltage and 100 A RMS, corresponding to 660 kW per branch, without a central supervisory controller.
According to the project team, promising applications include industrial microgrids, data centres and offshore renewable energy installations.
The researchers said the project produced validated prototypes, sustainability assessment and a roadmap towards technical maturity, with further development now expected through industrial partnerships and funding opportunities.
Source: CORDIS / European Commission
