Fault diagnosis algorithm for 3-phase passive rectifiers based on frequency-domain analysis for acceleration grid power supply in CFETR NBI system

The acceleration grid power supply (AGPS) is a crucial part of the Negative-ion Neutral Beam Injection system in the China Fusion Engineering Test Reactor, which includes a 3-phase passive (diode) rectifier. To diagnose and localize faults in the rectifier, this paper proposes a frequency-domain analysis-based fault diagnosis algorithm for the rectifier in AGPS. First, time-domain expressions and spectral characteristics of the output voltage of the TPTL-NPC inverter-based power supply are analyzed. Then, frequency-domain analysis-based fault diagnosis and frequency-domain analysis-based sub-fault diagnosis algorithms are proposed to diagnose open circuit (OC) faults of diode(s), which benefit from the analysis of harmonics magnitude and phase-angle of the output voltage. Only a fundamental period is needed to diagnose and localize exact faults, and a strong Variable-duration Fault Detection Method is proposed to identify acceptable ripple from OC faults. Detailed simulations and experimental results demonstrate the effectiveness, quickness, and robustness of the proposed algorithms, and the diagnosis algorithms proposed in this article provide a significant method for the fault diagnosis of other rectifiers and converters.     

DC active power filter based on model predictive control for DC bus overvoltage suppression of accelerator grid power supply

The China Fusion Engineering Test Reactor plans to build a 200 k V/25 A acceleration grid power supply(AGPS) for the negative-ion-based neutral beam injector prototype system. The AGPS uses a rectifier-inverter-isolated step-up structure. There is a DC bus between the rectifier and the inverter.In order to limit DC bus voltage ripple and transient fluctuations, a large number of capacitors are used, which degrades the reliability of the power supply and occupies a large amount of space. This wor...     

一种新型磁涡流节能供热装置研制

风能储量大、分布区域广,是一种开发利用潜力巨大的可再生清洁能源。作者提出将风能直接就地转化成热能为建筑物供暖,聚焦提高风力磁涡流致热和换热效率研究。采用海尔贝克阵列磁极排列建立单边磁场,增大定子涡流,较表贴式磁极结构的致热功率提升28.27%;采用昆虫翅脉结构仿生流道设计发热体,增大换热面积,较传统螺旋形流道换热效率提高18.7%。在致热和换热设计性能仿真基础上,采用SolidWorks完成风力磁涡流制热装置的机械设计,并制作了一台5 kW原理样机,开展整机台架致热效果试验,结果表明平均致热效率可达55.82%。提出的新型磁涡流节能供热装置,可实现海岛、农村和边疆等电网难以达到地区建筑物绿色供暖,有着广阔的应用前景。     

Design and control of the accelerator grid power supply-conversion system applied to CFETR N-NBI prototype

The acceleration grid power supply (AGPS) rated 200 kV/25 A is a key component devoted to supply the acceleration grids of the China fusion engineering test reactor negative-ion-based neutral beam injector (N-NBI) prototype system. This paper focused on the design and control of the AGPS conversion system (AGPS-CS), with emphasis on the requirement of the wide range output voltage and rise time. A voltage regulation switch at the front of step-down transformer is applied to optimize the grid current and DC-link voltage. Moreover, a new feedforward control strategy with piecewise PI compensator is proposed to improve the characteristics of AGPS. The simulation results of the proposed AGPS-CS are presented, proving the performance of the power supply to achieve the desired requirements.