Solid-state transformer

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A solid-state transformer (SST), power electronic transformer (PET), or electronic power transformer is actually an AC-to-AC converter, a type of electric power converter that replaces a conventional transformer used in AC electric power distribution. It is more complex than a conventional transformer operating at utility frequency, but it can be smaller and more efficient than a conventional transformer because it operates at high frequency. The main types are "true" AC-to-AC converter (with no DC stages) and AC-to-DC-to-DC-to-AC converter (in which an active rectifier supplies power to a DC-to-DC converter, which supplies power to a power inverter). A solid-state transformer usually contains a transformer, inside the AC-to-AC converter or DC-to-DC converter, which provides electrical isolation and carries the full power; this transformer is much smaller because it operates at high frequency. A solid-state transformer can actively regulate voltage and current. Some can convert single-phase power to three-phase power and vice-versa. Variations can input or output DC power to reduce the number of conversions, for greater end-to-end efficiency. As a complex electronic circuit, it must be designed to withstand lightning and other surges. Solid-state transformer is an emerging technology.


  • "Are Solid-State Transformers Ready for Prime Time?".
  • "Solid State Transformer For Power Distribution Applications" (PDF).