学术报告第161期—李志恒 李丁晨论文投稿报告

时间：2022年5月5日 周四  15:00

地点：313会议室

论文投稿报告

报告人：李志恒 研究生

题目：The Equivalent Circuit Model and Analysis of Core Snubber

摘要：

Core snubber is a surge suppression protection device. When the breakdown of acceleration grid occurs, it can consum fault energy and limit the arc current. The simulation model with gyrator and the DC high voltage short circuit experiment platform are built in this paper. Firstly, the rationality of the model establishment hypothesis is verified. Then the equivalent magnetizing inductance expression is optimized. By comparing the simulated and measured results of a snubber prototype made by FINEMET, effectiveness of the equivalent circuit model is verified. The role of eddy current resistance and magnetization inductance model in the process of surge suppression and the optimization effect of the equivalent circuit model are analyzed. Finally, the dynamic response and the influence of system leakage inductance are analysed by the simulation model.

报告人：李丁晨 研究生

题目：Multi-point discharge model: Corona discharge study of needle electrode with double-tip in large-scale space

摘要：

Non-equilibrium plasma is widely used in many fields such as air purification, medical treatment and surface modification. Corona discharge is one of the effective means to obtain non-equilibrium plasma. In order to obtain high-concentration plasma, the study of multi-point corona discharge is necessary. However, the existing numerical simulation models used to study multi-point corona discharge are all calculations of small-scale space models, which cannot obtain the distribution of plasma (charged particles) in a large space. Based on our previous research, this paper proposes a hybrid model for studying the distribution of multi-point discharge plasma in large-scale spaces, which divides the computational domain and computes separately with the hydrodynamic fluid model and the ion mobility model. The calculation results are verified by the needle-ball electrode device. Firstly, the electric field distribution and plasma distribution of the needle electrodes with single tip and double tips are compared and discussed. Secondly, the plasma distribution of the needle electrode with double tip at different voltages was investigated. Both computational and experimental results indicate that the charged particle concentration and current of the double-needle electrode structure are both twice as high as those of the single-needle electrode structure. In addition, the calculated values of the current and negative ion concentration of the needle electrode with double tips are in good consistency with the experimental values, which verifies the accuracy of the multi-point discharge model in large-scale space. This model can extend the computational domain of the multi-point corona discharge model to the sub-meter (25 cm) or meter level, which provides an effective means to study the plasma distribution generated by multiple discharge points in the large-scale space.