Low Voltage DC-Grids with Galvanic Isolation: System Discussion, Efficiency and Performance Comparison to AC - Feeding

Low voltage DC-grids have shown to increase efficiency and performance compared to AC-grids. This paper provides an overview of different feeding configurations for low voltage DC-grids. Their advantages and disadvantages are compared in terms of both efficiency and performance. To prove the considerations, a test machine is evaluated under both DC and AC feeding. It is shown that losses of an exemplary industrial machine are reduced by up to 18.6 % when switching to bidirectional DC feeding with galvanic isolation and by up to 9.6 % without galvanic isolation.