Solid-state transformers (SSTs) replace conventional magnetic transformers with power electronic converters—high-frequency switching circuits that provide voltage transformation, galvanic isolation, and power flow control. SSTs typically use wide-bandgap semiconductors (SiC, GaN) for high-frequency operation and reduced size. Applications include medium-voltage distribution grids, EV fast chargers, data center power, and renewable integration where bidirectional power flow, power factor correction, and fault isolation are valuable. Prototypes and pilot deployments exist; commercialization is advancing.
The power grid faces pressure for flexibility: bidirectional flow, voltage regulation, fault isolation, and integration of renewables and storage. SSTs offer programmable control not possible with conventional transformers. Challenges include cost—power electronics remain more expensive than magnetics—reliability under grid fault conditions, and electromagnetic compatibility. Research continues into higher-power, higher-voltage SSTs and grid-edge applications. As renewable and EV adoption grows, solid-state transformers may play an increasing role in distribution and conversion.