学术报告第160期—朱帮友 贺思芬论文投稿报告

时间：2022年4月27日  周三 14:30

地点：313会议室

论文投稿报告

报告人：朱帮友  研究生

题目：Frequency-domain Analysis-based Fault Diagnosis Algorithm for 3-phase Passive Rectifier in Acceleration Grid Power Supply

摘要：The acceleration grid power supply (AGPS) is a crucial part of Negative-ion Neutral Beam Injection (N-NBI) system of China Fusion Engineering Test Reactor (CFETR). The faults of 3-phase passive (diode) rectifier connected with Three-phase Three-level Neutral Point Clamped (TPTL-NPC) inverter under square-wave modulation and step-up transformer affect normal operation of fusion system even cause severe damages.

To diagnose and localize the faults of rectifier, firstly the paper analyzes time-domain expressions and spectral characters of output voltage of TPTL-NPC inverter-based power supply. Then frequency-domain analysis-based fault diagnosis (FAFD) and frequency-domain analysis-based sub-fault diagnosis (FASD) algorithms are proposed to diagnose open circuit (OC) fault of diode(s), which are benefiting from analysis of harmonics magnitude and phase-angle of output voltage. Only a fundamental period is needed to diagnosis and localize exact faults. And a strong Variable-duration Fault Detection Method (VFDM) is presented to separate acceptable ripple from OC faults. Detailed simulations and experimental results demonstrate the effectiveness, quickness and robustness of proposed algorithms, and it provides a significant method for fault diagnosis of other rectifiers and converters.

报告人：贺思芬  研究生

题目：Study of non-convergence problem of the integral method for polarizer design on the ECRH system

摘要：On the electron cyclotron resonance heating system, the integral method represents a class of classical mathematical methods for the polarizer design. However, the non-convergence problem caused by the Fredholm integral equation of the integral method. This usually leads to an incorrect result, sometimes may confuse the beginners. The simplified kernel function based on the infinitesimal approximation was presented in this paper, which effectively removing the non-convergence problem, making it easier to use and simplifying the code of calculation for beginners. A code is developed based on this method, then the calculation results are compared with the calculation results of the C-method, and the experimental results of the low power test platform. These results basically match, which indicates that this method can be used for polarizer design.