Solid-State Transformers (SSTs)
Solid-state transformers (SSTs) are electrical power conversion systems that combine semiconductor switches, electronic controls, and a transformer operating at a much higher frequency than the electricity grid. They change voltage levels while actively controlling how electricity flows between a power source and connected equipment. Depending on their design, they can provide alternating-current (AC) or direct-current (DC) outputs.
A conventional transformer changes AC voltage through electromagnetic induction at grid frequency, typically 50 or 60 hertz. An SST introduces power electronics that rapidly switch and process electricity. Operating its magnetic transformer at a higher frequency allows that component to be smaller and lighter. Despite the name, solid-state transformers generally still contain magnetic cores and windings. GridTechPedia
A common SST architecture works through three stages:
- Input conversion: A rectifier converts incoming AC electricity into DC.
- Voltage conversion and isolation: Electronic switches produce high-frequency AC, allowing a compact transformer to change voltage and electrically isolate the input from the output.
- Output conversion: Additional electronics deliver the required DC supply or convert it back into AC.
Architectures vary, and some combine or omit stages. Depending on configuration, SSTs can also regulate voltage, improve power quality, control reactive power, and support bidirectional electricity flows. These capabilities make them relevant to microgrids, renewable energy integration, battery storage, and other applications requiring flexible power management. energy.gov