Silicon carbide

Voltage

Engineering

Metallurgy

Materials science

Galvanic isolation

Operating system

Computer science

Modular design

Transistor

Solid-state

Electronic engineering

Transformer

Converters

Optoelectronics

Electrical engineering

MOSFET

Engineering physics

IEEE Journal of Emerging and Selected Topics in Power Electronics

The advancements in wide-bandgap devices are enabling applications of power electronic converters coupled directly with medium-voltage (MV) grids that incorporate galvanic isolation within the converter using high-frequency solid-state transformers (SSTs). This paper presents analysis, design, and the characterization results of a 50-kVA modular soft-switched ac-ac SST using silicon carbide (SiC) MOSFET for MV (>6 kV ac) applications. The SST is comprised of two hard-switched ac-line interface bridges and a resonant dc-dc stage switched at approximately 180 kHz. To minimize the cost of switching elements per ampere and maximize the design flexibility, the design uses multiple discrete SiC devices of, readily available, 1700-V ratings. This paper covers the analysis of soft-switching operation, control architecture, converter design, and system-level integration.

A Modular SiC High-Frequency Solid-State Transformer for Medium-Voltage Applications: Design, Implementation, and Testing