• Title/Summary/Keyword: Small Hall

Search Result 182, Processing Time 0.023 seconds

Development of Sub-200 W Laboratory Model Hall Thrusters for Small and Micro Satellites (소형 및 초소형위성 활용을 위한 200 W 이하 저전력 홀 전기추력기 랩모델 연구개발)

  • Lee, Dongho;Kim, Holak;Doh, Guentae;Kim, Youngho;Park, Jaehong;Lee, Jaejun;Choe, Wonho
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.26 no.2
    • /
    • pp.40-46
    • /
    • 2022
  • Hall thrusters are one of the electric propulsion, where ions are accelerated to generate thrust and are widely utilized in space missions due to their high specific impulses. Recently, as the utilization of small and micro satellites with the mass of similar or less than 100 kg is highly increasing, the importance of research and development of the low-power electric propulsion is also raised. In this study, we developed two sub-200 W or less class, laboratory model Hall thrusters and measured the thrust and analyzed the discharge characteristics. Consequently, we obtained 2.5-9.0 mN of thrust, 600-1,150 s of specific impulse, and 15-28% of anode efficiency at 50-175 W of anode power.

전자가 도핑된 $Sr_{0.9}$$La_{0.1}$Cu$O_2$초전도체의 홀 효과

  • Kim, Hyun-Jung;W. N. Kang;Kim, Kijoon H. P.;Lee, Sung-Ik;S. Karimoto
    • Progress in Superconductivity
    • /
    • v.4 no.1
    • /
    • pp.32-36
    • /
    • 2002
  • We have measured the Hall effect in infinite-layer Sr/sub 0.9/La/sub 0.1/$CuO_2$ thin films grown by molecular beam epitaxy. We do not observe $T^{2}$ dependence of the cotangent of Hall angle, which is commonly observed in other cuprate High-Tc superconductors. Therefore, this result cannot be interpreted within two different scattering mechanism based on charge-spin separation theory. The mixed-state Hall effect shows no sign anomaly, implying that tile hydrodynamic contribution of vortex core is negligibly small.

  • PDF

Performance Improvement of Position Estimation by Double-PLL Algorithm in Hall Sensor based PMSM Control (Double-PLL을 이용한 홀 센서 기반 PMSM 제어의 위치 추정 성능 개선)

  • Lee, Song-Cheol;Jung, Young-Seok
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.22 no.3
    • /
    • pp.270-275
    • /
    • 2017
  • This paper proposes a double-phase-locked-loop (PLL) to improve the performance of position estimation in hall sensor-based permanent magnet synchronous motor control. In hall sensor-based control, a PLL is normally used to estimate the rotor position. The proposed Double-PLL consists of two PLLs, including a reset type integrator. The motor control is more accurate and has better performance than conventional PLL, such as a small estimated position ripple. The validity of the proposed algorithm is verified by simulations and experiments.

Development of Xenon feed system for a 300 W Hall-effect Thruster (300 W급 홀 추력기를 위한 제논연료공급장치 개발)

  • Kim, Youn-Ho;Seon, Jong-Ho;Kang, Seong-Min;Wee, Jung-Hyun;Yoon, Ho-Sung;Choe, Won-Ho;Lee, Jong-Sub;Seo, Mi-Hui
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.37 no.4
    • /
    • pp.419-424
    • /
    • 2009
  • A Xenon feed system has been developed for a 300 W Hall-effect thruster intended for orbit maintenance of small satellite. The system can store about 2 kg of xenon gas at 150 bar and is capable of controlling the mass flow rate of the gas at 0.5 SCCM resolution. The performance of the system is verified with a laboratory experiment. It is confirmed that the operation of the feed system is successful at a pressure level of $1.0{\times}10^{-6}$ torr in the vacuum chamber.

Development of BioRobot System Based on Mobile Agent for Clinical Laboratory (임상병리검사를 위한 모바일 에이전트 기반의 바이오로봇 시스템 개발)

  • Choi, Byung-June;Jin, Sung-Moon;Sin, Seung-Hun;Koo, Ja-Choon;Kim, Min-Chul;Kim, Jin-Hyun;Son, Woong-Hee;Ahn, Ki-Tak;Chung, Wan-Kyun;Choi, Hyouk-Ryeol
    • The Journal of Korea Robotics Society
    • /
    • v.2 no.4
    • /
    • pp.317-326
    • /
    • 2007
  • Recently, robotic automation in clinical laboratory becomes of keen interest as a fusion of bio and robotic technology. In this paper, we present a new robotic platform for clinical tests suitable for small or medium sized laboratories using mobile robots. The mobile robot called Mobile Agent is designed as transfer system of blood samples, reagents, microplates, and any instruments. Also, the developed mobile agent can perform diverse tests simultaneously based on its cooperative and distributed ability. The driving circuits for the mobile agent are embedded in the robot, and each mobile agent communicates with other agents by using Bluetooth communication. The RFID system is used to recognize patient information. Also, the magnetic hall sensor is embedded to remove and compensate the cumulated error of locomotion at the bottom of mobile agent. The proposed mobile agent can be easily used for various applications because it is designed to be compatible with general software development tools. The Mobile agents are manufactured, and feasibility of the robot and localization of the agents using magnetic hall sensor are validated by preliminary experiments.

  • PDF

Hall Effect and Resistivity of Amorphous $Fe_{83-x}Zr_{7}B_{10}Nb_{x}$ Alloys

  • Lee, Soo-Hyung;Yu, Seong-Cho;Xu, Jun-Hau;Rao, K.V.;Noh, Tae-Hwan;Kang, Il-Koo;Rhie, Kungwon
    • Journal of the Korean Magnetics Society
    • /
    • v.5 no.5
    • /
    • pp.841-845
    • /
    • 1995
  • The effect of small addition of Nb on the electrical resistivity and Hall coeffcient of the amorphous $Fe_{83}Zr_{7}B_{10}$ alloy and annealed ones ones below the crystallization temperature were investigated, which has been considered to be suitable for high frequency core material. At room temperature, their resistivities $\rho$ and the spontaneous Hall coeffcients $R_{s}$ are $~1.6\;{\mu}{\Omega}m$ and $~3{\times}10^{-8}m^{3}/As$, respectively. $R_{s}$ and $\rho$ are decreased with increasing temperature from 100 K to room temperature. Side-jump effect was adopted to analyze the effect of the small variation of conentration and annealing. The quantity of $R_{s}/{\rho}^{2}$ at room temperature, which is directly related to the electronic structure of the mother alloy, remained almost a constant except as quenched one as it can be predicted from the side-jump effect. The unexpected temperature dependence of $R_{s}/{\rho}^{2}$ measured at low fields much below Tc is left as a question.

  • PDF

HALL EFFECT AND RESISTIVITY OF AMORPHOUS $Fe_{83-x}Zr_{7}B_{10}Nb_{x}$ ALLOYS

  • Lee, Soo-Hyung;Yu, Seong-Cho;Xu, Jun-Hau;Rao, K.V.;Noh, Tae-Hwan;Kang, Il-Koo;Rhie, Kungwon
    • Journal of the Korean Magnetics Society
    • /
    • v.5 no.5
    • /
    • pp.772-777
    • /
    • 1995
  • The effect of small addition of Nb on the electrical resistivity and Hall coefficient of the amorphous $Fe_{83}Zr_{7}B_{10}$ alloy and annealed ones below the crystallization temperature were investigated, which has been considered to be suitable for high frequency core material. At room temperature, their resistivities $\rho$ and the spontaneous Hall coefficients $R_{s}$ are $~1.6\;{\mu}{\Omega}m$ and $~3{\times}10^{-8}m^{3}/As$, respectively. $R_{s}$ and $\rho$ are decreased with increasing temperature from 100 K to room temperature. Side-jump effect was adopted to analyze the effect of the small variation of concentration and annealing. The quantity of $R_{s}/{\rho}^{2}$ at room temperature, which is directly related to the electronic structure of the mother alloy, remained almost a constant except as quenched one as it can be predicted from the side-jump effect. We suggested the temperature dependence of $R_{s}/{\rho}^{2}$ can be compared to Ms{T}.

  • PDF

Numerical simulation of a hall thruster for orbit transfer and correction of small satellites (소형위성의 궤도 천이 및 보정을 위한 홀 방식 전기추력기의 수치모사)

  • Seon Jong-Ho;Lee Jong-Sub;Lim Yu-Bong;Choe Won-Ho;Lee Hae-June
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2006.05a
    • /
    • pp.66-69
    • /
    • 2006
  • A two-dimensional Particle-In-Cell (PIC) simulation of a Hall thruster is presented. The thruster is being developed for orbit transfer and correction of a small satellite. Preliminary investigation of the simulation result finds well separated acceleration and ionization layers. The simulation further shows that collisional ionization of the xenon neutrals allows sufficient acceleration of the ionized plasmas that is adequate for the intended correction and transfer of small satellite orbits. Anticipated performance of the thruster based upon the present results will be calculated.

  • PDF

A VIEW PLASMA MOTION OF HALL EFFECT THRUSTER WITH PARTICLE SIMULATION (입자모사를 통한 HALL EFFECT THRUSTER의 플라즈마 운동 이해)

  • Lee, J.J.;Jeong, S.I.;Choe, W.;Lee, J.S.;Lim, Y.B.;Seo, M.H.;Kim, H.M.
    • Bulletin of the Korean Space Science Society
    • /
    • 2007.10a
    • /
    • pp.139-143
    • /
    • 2007
  • Electric propulsion has become a cost effective and sound engineering solution for many space applications. The success of SMART-1 and MUSES-C developed by European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) each proved that even small spacecraft could accomplish planetary mission with electric propulsion systems. A small electric propulsion system which is Hall effect thruster like SMART-1 is under development by SaTReC and GDPL (Glow Discharge Plasma Lab.) in KAIST for the next microsatellite, STSAT-3. To achieve optimized propulsion system, it is very necessary to understand plasma motions of Hall effect thruster. In this paper, we try to approach comprehensive plasma model with the particle simulation complementary to Particle In Cell (PIC) simulation. We think these two different approaches will help experimenters to optimize Hall effect thruster performances.

  • PDF