Fast charging stations are stretching the limits of traditional power grids. High-power chargers, drawing 350 to 500 kW or more, create megawatt-scale demand that strains medium-voltage distribution lines, especially when clustering in urban or highway locations. Conventional line-frequency transformers (LFTs), with heavy iron cores and copper windings, are reliable but bulky, inefficient, and unsuited to the flexible handling of local energy flows.
A promising alternative is the solid-state transformer (SST), tells IEEE Spectrum. Unlike passive LFTs, SSTs rely on high-frequency switching (using semiconductor devices like SiC or GaN) and active control to manage power flow dynamically. They can replace multiple components, transforming voltage, regulating output, and integrating with local storage or renewables, all in a smaller, more adaptable unit.
However, SSTs have faced barriers. Previous multiport designs required extra components (such as battery buffers or balancing circuits) and complex insulation, making them far more expensive, often five to ten times the cost of conventional transformers. A recent study from the Indian Institute of Science and Delta Electronics proposes a cascaded H-bridge (CHB) multiport SST that removes many of those trade-offs. Their prototype delivered over 95% efficiency without needing auxiliary battery storage.
In that design, a multiwinding transformer is placed on the low-voltage side, avoiding expensive insulation at medium voltage. Each DC output port operates independently, so each EV charger can get its optimized voltage and current without affecting neighboring stations. The approach also allows load sharing and avoids power imbalance issues.
While still in the lab stage, SSTs hold potential to reshape how charging infrastructure is built. By cutting size, integrating control, and removing the need for extra storage, they could make ultra-fast EV hubs more grid-friendly, more modular, and more economical. And their value isn’t limited to EV charging; they could serve data centers, industrial DC systems, or renewable grids that demand compact, smart power conversion.