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Performance investigation of a low-power Hall thruster fed on iodine propellant

Plasma Science and Technology 2024年第6期26卷 140-148页

作者：徐宗琦王平阳蔡东升谭睿姜文静 Institute of Engineering Thermophysics School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China

The common propellants used for electric thrusters, such as xenon and krypton, are rare, expensive,and difficult to acquire. Solid iodine attracts much attention with the advantages of low cost,extensive availability, low vapor pressure, and ionization potential. The performance of a lowpower iodine-fed Hall thruster matched with a xenon-fed cathode is investigated across a broad range of operation conditions. Regulation of the iodine vapor's mass flow rates is stably achieved by using a temperature control method of the iodine reservoir. The thrust measurements are finished utilizing a thrust target during the tests. Results show that thrust and anode-specific impulse increase approximately linearly with the increasing iodine mass flow *** the nominal power of 200 W class, iodine mass flow rates are 0.62 and 0.93 mg/s, thrusts are7.19 and 7.58 m N, anode specific impulses are 1184 and 826 s, anode efficiencies are 20.8%and 14.5%, and thrust to power ratios are 35.9 and 37.9 m N/k W under the conditions of 250 V,0.8 A and 200 V, 1.0 A, respectively. The operating characteristics of iodine-fed Hall thruster are analyzed in different states. Further work on the measurements of plasma characteristics and experimental optimization will be carried out.

关键词： electric propulsion Hall thruster iodine propellant thrust measurement operating characteristics

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A Comparison of Technology Firms in Beijing and Shenzhen

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Frontiers of Economics in China-Selected Publications from Chinese Universities 2012年第3期7卷 434-464页

作者： Zhaoming Cui Leonard K.Cheng Lian Zhou School of Economics Shanghai University of Finance and EconomicsShanghai 200433China Department of Economics Hong Kong University of Science and TechnologyHong KongChina Guanghua School of Management Peking UniversityBeijing 100871China

Beijing and Shenzhen are both well known for their high-tech industries. This paper compares the financial performance of the two cities＇ technology firms and explores the effects of the firms＇ operating characteristics and strategy choices on their performance. We find that when comparable samples are used, the firms in Beijing performed better than those in Shenzhen. In addition, for firms both in Beijing and Shenzhen, the ratio of current asset to total asset had a significantly positive effect while both short-term and long-term debt-asset ratios had a significantly negative effect on the performance. The strategy variable sales expenses as a fraction of the cost of goods sold had a significantly positive effect on the performance of firms in Beijing, but the positive effect on firms in Shenzhen was not significant. R＆D inputs contributed significantly to the pre-tax profitability of Beijing firms, but bad no significant effect whatsoever on Shenzhen firms.

关键词： Chinese technology firms comparison of performance operating characteristics

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Magnetic Field and operating Performance Analysisof Conical-rotor Permanent Magnet Synchronous Motor

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CES Transactions on Electrical Machines and Systems 2018年第1期2卷 181-187页

作者： Jiabao Wang Shoudao Huang Chao Guo Yaojing Feng College of Electrical and Information Engineering Hunan UniversityChangsha 410082China

In order to accurately analyze the magnetic field of conical-rotor permanent magnet synchronous motor(CR-PMSM),the effectiveness of two methods was studied on handling of problems concerned with non-uniform distribution of magnetic field along axial direction in CR-PMSM,which were sectional calculation(SC)method and three-dimensional finite element(3-D FE)*** this basis,the influence of the axial displacement and dq-axis currents on the operating characteristics of axial magnetic force and torque is analyzed by using the 3-D FE *** results show that the axial magnetic force and torque decrease with the increase of axial displacement of the rotor,and the amplitude regularity of the axial magnetic force is affected by the d-axis current.A prototype machine is fabricated and tested,in order to validate the design theory.

关键词： Magnetic field of conical-rotor permanent magnet synchronous motor operating characteristics non-uniform of magnetic field 3-D FE method

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Electromagnetic field calculation of stator slot and operation simulation for salient pole synchronous machine

Electromagnetic field calculation of stator slot and operati...

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第三十九届中国控制会议

作者： Dazhuang Qiang Mingxing Yu Li Yang Department of information engineering Chaoyang Teachers College School of Equipment Engineering Shenyang Ligong University School of Mechanical Engineering and Automation Northeastern University

Salient pole synchronous machine is a kind of motive power machine with simple structure, rapid response and diversified control, which has been widely applied in constant-speed industrial drive system. Analysis of operation feature and electromagnetic field of salient pole synchronous machine has become an important research topic. In this study, a 500 kW salient pole synchronous machine was adopted as the research object, and the characteristic curve of such motor during excitation process and loading process was calculated using equivalent circuit method and field circuit coupling method. The calculation results were validated through comparing the simulation waveforms of electromagnetic torque, rotor speed and excitation current. Then, the magnetic field distribution and magnetic flux density distribution of feature parts under steady-state load were calculated. Simulation results showed that the steady-state speed and torque after excitation remained unchanged so did the steady-state excitation current and speed after loading. The rotor kept constant speed after loading, with steady-state power angle of 47°. The flux density amplitude of stator teeth was higher than that of intertooth part;normal flux density amplitude was significantly larger than tangential flux density amplitude. The maximum and minimum flux density amplitude were associated with stator slot number. 7 th-harmonic exerted great influence on the main flux density of magnetic field, which provides reference for fault diagnosis and operating characteristic analysis of various motors.

关键词： field circuit coupling synchronous motor operating characteristics mechanical characteristics flux track Simulation model

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