Converter Design for High Temperature Superconductive Degaussing Coils

Converter Design for High Temperature Superconductive Degaussing Coils

Wikkerink, D.P. (TU Delft High Voltage Technology Group)
Mor, A. R. (TU Delft DC systems, Energy conversion & Storage; Universitat Politécnica de Valencia)
Polinder, H. (TU Delft BUS/TNO STAFF)
Ross, Robert (TU Delft High Voltage Technology Group)

2022

Detection of the magnetic signature of ships can be avoided by using a degaussing system; a set of on-board copper coils that compensates for the magnetic signature. High temperature superconductors (HTS) are currently investigated as a replacement for copper degaussing coils. By using HTS, we have to deal with higher currents and therefore with higher power supply losses. Also, large current leads are needed which introduces extra losses. This paper investigates different possible solutions to minimize these losses. Four H-bridge-based MOSFET topologies are presented that were designed to reduce the power supply and current lead losses. The first topology uses an H-bridge configuration so that the degaussing current can freewheel through the low-resistance MOSFETs. The second topology places the H-bridge inside the cryostat so that the current leads can be made smaller. The third topology includes a smoothing capacitor in the cryostat so that the current leads and input current are even smaller. The fourth topology uses a transformer so that the current leads can be eliminated. Measurements were done to determine the MOSFETs and capacitor performance in liquid nitrogen. The simulated losses of the four topologies are compared to determine the most energy-efficient option for supplying current to the HTS coils. It was found that by submerging multiple parallel MOSFETs in liquid nitrogen, the on-state resistance is decreased and the current supply can be made more efficient. Also, by placing a smoothing capacitor inside the cryostat, the current lead losses can be minimized significantly. The benefits of using a transformer do not outweigh the transformer losses.

Capacitors
Coils
Converter
Converters
cryocooled electronics
cryostat
degaussing
High-temperature superconductors
HTS
magnetic signature
MOSFET
parallel MOSFETs
Resistance
Topology

http://resolver.tudelft.nl/uuid:f82c2435-cc0e-4118-87ec-99d78c983d6d

https://doi.org/10.1109/ACCESS.2022.3227508

2169-3536

IEEE Access, 10, 128656-128663

Institutional Repository

journal article

© 2022 D.P. Wikkerink, A. R. Mor, H. Polinder, Robert Ross