The transformer core snubber （CS）, as one of the most important components in the EAST （experimental advanced superconducting tokamak） NBI （neutral beam injector） system, is designed to limit grid damage and pro...The transformer core snubber （CS）, as one of the most important components in the EAST （experimental advanced superconducting tokamak） NBI （neutral beam injector） system, is designed to limit grid damage and protect the ion source during periods of electrical breakdowns. A transformer core snubber is analyzed in detail in this paper. Several kinds of soft magnetic cores are presented and compared. With analysis and experiment on the basic characteristics of the cores, the most suitable materials are suggested. The circuit simulation code is established which could simulate faulty conditions with concentrated and distributed CS concepts. Based on the above work, an ion source CS is developed with series type of distributed topology. The CS has been subjected to experimental validation at 80 kV with a peak short-current of approximately 400 A in a real NBI system, which proves the accuracy of the adopted assumptions and the analysis method.展开更多
Feo.eCoo.^seHfTBsCu! nanocrystalline alloy obtained in isothermal annealing process from amorphous precursor was investigated as candidate of soft magnetic materials for high temperature applications. Co substitution ...Feo.eCoo.^seHfTBsCu! nanocrystalline alloy obtained in isothermal annealing process from amorphous precursor was investigated as candidate of soft magnetic materials for high temperature applications. Co substitution for Fe can enhance the curie temperature of amorphous alloy (Tc = 630 °C) and improve the magnetization of nanocrystalline alloy at high temperature ( = 1.56T at 550 °C). After annealing amorphous precursor at 550 °C for 1 hour, the optimum nanocrystalline alloy can be obtained which shows the local minimum coercivity ( = 16 A/m). The coercivity increases with the increase of annealing temperature corresponding to the formation of ferromagnetic phase in the secondary crystallization. Furthermore, additions of Hf and B elements reduce the melting temperature of the alloy studied comparing with the Fe-Co binary alloy.展开更多
基金supported by National Magnetic Confinement Fusion Science Program of China (Nos.2010GB108003, 2011GB113005-1)in part by the National Magnetic Confinement Fusion Science Program of China (No.2010GB108003)+1 种基金the State Basic Research Development Program of China (973 Program 2011GB113005-1)the Large Scientific Project of EAST Auxiliary Heating Upgrade
文摘The transformer core snubber （CS）, as one of the most important components in the EAST （experimental advanced superconducting tokamak） NBI （neutral beam injector） system, is designed to limit grid damage and protect the ion source during periods of electrical breakdowns. A transformer core snubber is analyzed in detail in this paper. Several kinds of soft magnetic cores are presented and compared. With analysis and experiment on the basic characteristics of the cores, the most suitable materials are suggested. The circuit simulation code is established which could simulate faulty conditions with concentrated and distributed CS concepts. Based on the above work, an ion source CS is developed with series type of distributed topology. The CS has been subjected to experimental validation at 80 kV with a peak short-current of approximately 400 A in a real NBI system, which proves the accuracy of the adopted assumptions and the analysis method.
基金supported by the 5^(th)framework Program of European Community,research project“Soft Magnetic.Nanomaterials for High Temperature and High Frequency Functional Application in Power Electronics",contract No.GSRD-CT-2001-03009.the key project of National Natural Science Foundation of China(50235030).
文摘Feo.eCoo.^seHfTBsCu! nanocrystalline alloy obtained in isothermal annealing process from amorphous precursor was investigated as candidate of soft magnetic materials for high temperature applications. Co substitution for Fe can enhance the curie temperature of amorphous alloy (Tc = 630 °C) and improve the magnetization of nanocrystalline alloy at high temperature ( = 1.56T at 550 °C). After annealing amorphous precursor at 550 °C for 1 hour, the optimum nanocrystalline alloy can be obtained which shows the local minimum coercivity ( = 16 A/m). The coercivity increases with the increase of annealing temperature corresponding to the formation of ferromagnetic phase in the secondary crystallization. Furthermore, additions of Hf and B elements reduce the melting temperature of the alloy studied comparing with the Fe-Co binary alloy.
