Dr. Pengbo Zhou, Southwest Jiaotong University, China
During PHD, I performed a pioneering study on completing the theory of frequency dependence of HTS ac losses. Through the numerical simulation considering all the layers of HTS coated conductors and the applied frequency up to 15 kHz, it is found that there is a transition frequency, above which the ac losses per cycle no longer increase with the frequency as the theory predicts. This is mainly due to the fact that the losses in the metallic layers is not the commonly defined eddy current losses, but transport current loss. The underlying mechanism is that the current flowing through the metallic layers is transport current driven by the power supply and the coupled magnetic field rather than eddy current. (https://doi.org/10.1063/1.5094727). Later, using simulation, it is found that the geometry, especially the width of copper stabilizers strongly affects transport ac losses: wider copper stabilizers would bring about much higher losses due to the inhomogeneous current distribution among the copper stabilizers (https://doi.org/10.1109/TASC.2019.2904204). These findings are valuable for the design and optimization of HTS CC-based power devices. Due to these studies, I have been awarded the 2018 ASC Best Student Paper in Seattle.
