SSTs represent a transformative technology for the future of electrical grids, offering enhanced operational flexibility through the integration of advanced power electronics. By decoupling power system dynamics, SSTs significantly mitigate the risk of catastrophic failures that can cascade throughout the grid. The architecture of conventional SSTs involves complex configurations with multiple full-bridge and half-bridge stages, usually custom-designed for a specific location, that have long lead times and are extremely expensive to replace. Modular SSTs, unlike traditional transformers and custom-built SSTs, can be adapted to fit various power systems, promoting electrical infrastructure resiliency and efficiency. The widespread adoption of SSTs is expected to improve power quality and grid reliability while keeping costs manageable.
The project has three parallel tracks: Bidrectional switch (BiDFET) design and fabrication, passive materials development, and SST design and prototyping.
The design, development, and production of a monolithically integrated bidirectional BiDFET is an extension from an existing and proven MOSFET design. The use of the newly developed BiDFET will significantly reduce the needed component count, providing a reduction in overall topology size and complexity of SSTs. Additionally, the innovative BiDFET design provides reduced low voltage losses and reverse-transfer capacitances.
Passive material development for both high frequency (HF) magnetic materials use innovative magnetic core materials, developed at Sandia. The newly developed materials will provide long-term stress reliability compared to typical materials currently used in SST HF transformers.
The project is developing a modular AC:AC block topology that, provided the use of bidirectional switch elements, can be implemented using only six switches and no direct current bus. This innovation simplifies SST design and enhances efficiency, making it more viable for modern grid applications. Additionally, the block topology allows the combination of multiple SSTs in parallel and series for flexible usage in a variety of power system environments.
This research is in its final year and has led to the development of a start-up company partnering with Sandia, Public Service Company of NM, and Mitsubishi on an upcoming DOE-funded project focusing on utilizing the SST as a drop-in replacement for a single-phase pole-mount transformer in a fielded lighting circuit. Additional information.
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