Development of a Superconducting Inverter Based on Magnetic Field Triggered Dynamic Resistance

This work investigates a new application of high-temperature superconductors (HTS) as switches for power electronics, in particular through the design and demonstration of a fully superconducting H-bridge inverter. The switch itself uses the dynamic resistance that builds up in HTS tapes subjected to an alternating magnetic field while carrying a dc transport current. This enables lossless current transmission in the on-state and a switchable resistance in the off-state of the switch. At the start, an introduction to HTS materials, including their operational constraints and the mechanisms and models of dynamic resistance are given.
Preliminary experiments were conducted to characterize the dynamic behavior of such switches under various magnetic field amplitudes and frequencies, with experimental results supported by analytical and numerical models. The dynamic behavior of two parallel superconducting switches was also examined more closely. These results were incorporated into the design of an inverter. It has been shown that the conversion of dc current to ac current can be successfully achieved and that the conversion is stable over a long period of time. ... mehrIn addition, the leakage current was reduced.
A SPICE-based model allowed the extrapolation of scaling laws, revealing material requirements and efficiency trade-offs for higher power applications. Strategies such as the use of wider superconducting tapes and alternative substrate materials were evaluated to reduce the amount of superconducting tape required. In addition, a novel stack assembly for efficient magnetization of long HTS tapes based on the rectangular disk-up-down assembly (rDUDA) principle was developed and experimentally validated.
The results represent an initial proof of concept, establishing feasibility and providing tools for future optimization and scaling. The technology is currently at Technology Readiness Level (TRL) 3–4. Further research will focus on improving switch design, minimizing losses, refining manufacturing processes, and designing large-scale demonstrators to move towards practical applications in low-voltage, high-current scenarios.