• ETRI Journal
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• 제28권3호
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• pp.389-392
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• 2006

In this letter, a laterally-driven bistable electromagnetic microrelay is designed, fabricated, and tested. The proposed microrelay consists of a pair of arch-shaped leaf springs, a shuttle, and a contact bar made from silicon, low temperature oxide (LTO), and gold composite materials. Silicon-on-insulator wafers are used for electrical isolation and releasing of the moving microstructures. The high-aspect-ratio microstructures are fabricated using a deep reactive ion etching (DRIE) process. The tandem-typed leaf springs with a silicon/gold composite layer enhance the mechanical performances while reducing the electrical resistance. A permanent magnet is attached at the bottom of the silicon substrate, resulting in the generation of an external magnetic field in the direction vertical to the surface of the silicon substrate. The leaf springs show bistable characteristics. The resistance of the pair of leaf springs was $7.5\;{\Omega}$, and the contact resistance was $7.7\;{\Omega}$. The relay was operated at ${\pm}0.12\;V$.

• 한국자기학회지
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• 제8권3호
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• pp.150-155
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• 1998

플라스틱 이방성 페라이트 자석에서 페라이트 분말함량 변화에 레올로지와 자기특성의 변화를 조사하였다. 분말함량 변화에 따른 상대점도의 측정값과 이론식을 비교하였다. 분말함량 증가에 따른 혼합물의 상대점도 증가경향과 플라스틱자석의 분말배향도의 감소경향은 정확히 일치하였다. 일정한 자장하에서 사출성형된 플라스틱 이방성 페라이트 자석에서 잔류자속밀도와 최대자기에너지적은 분말함량 증가에 따라 적선적으로 증가하다가 다시 감소하여 극대값을 나타냈으며, 극대값 이후의 자기특성 가소는 분말배향도의 급격한 감소에 기안하였다. 자기특성 극대값을 나타내는 분말한량은 사출형성시 자장의 세기와 결합체의 용융점도에 의존하며, 높은 자기특성을 위해서는 낮은 용융점도의 결합제 사용이 필요하다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.264-268
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• 2005

Most of the train brakes depends on friction between wheels and tracks. This requires braking force reduced in order not to cause wheel slides since the friction decreases as the train speed increases and consequently results in extension of braking distance. The braking system called 'Linear eddy current brake' or simply' Eddy current brake' is a braking system for making a brake independent from friction, which consists in creating electromagnet by coiling around shoes attached. to bogies; having the shoes above the tracks approached to the tracks upon acknowledgement of a braking command; and authorizing braking force that is irrelevant to friction through magnetic repulsion between electromagnet attached to the tracks and train set by the use of the electromagnet's magnet field characteristics. An electromagnetic attraction braking system that consists in pressing pole shoes attached to bogies against the tracks by using electromagnet's attraction force is called 'Electromagnetic track brake' or simply 'Track brake'. This paper has been prepared in purpose of studying technological tendencies of the eddy current brake and the track brake so that it can be utilized as fundamental data for commissioning Korean high-speed trains with the eddy current brake hereafter.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권8호
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• pp.557-564
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• 2000

A very simple control approach using neural network for the robust position control of a Permanent Magnet Synchronous Motor(PMSM) is presented. The linear quadratic controller plus feedforward neural network is employed to obtain the robust PMSM system approximately linearized using field-orientation method for an AC servo. The neural network is trained in on-line phases and this neural network is composed by a feedforward recall and error back-propagation training. Since the total number of nodes are only eight, this system can be easily realized by the general microprocessor. During the normal operation, the input-output response is sampled and the weighting value is trained multi-times by error back-propagation method at each sample period to accommodate the possible variations in the parameters or load torque. In addition, the robustness is also obtained without affecting overall system response. This method is realized by a floating-point Digital Signal Processor DS1102 Board (TMS320C31).

• 대한전기학회논문지:시스템및제어부문D
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• 제49권3호
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• pp.117-123
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• 2000

A new control method for precision robust position control of a PMSM (Permanent Magnet Synchronous Motor) using asymptotically stable adaptive load torque observer is presented in the paper. Precision position control is obtained for the PMSM system approximately linearized using the field-orientation method. Recently, many of these drive systems use the PMSM to avoid backlashes. However, the disadvantages of the motor are high cost and complex control because of nonlinear characteristics. Also, the load torque disturbance directly affects the motor shaft. The application of the load torque observer is published in [1] using fixed gain. However, the motor flux linkage is not exactly known for a load torque observer. There is the problem of uncertainty to obtain very high precision position control. Therefore, a model reference adaptive observer is considered to overcome the problem of unknown parameter and torque disturbance in this paper. The system stability analysis is carried out using Lyapunov stability theorem. As a result, asymptotically stable observer gain can be obtained without affecting the overall system response. The load disturbance detected by the asymptotically stable adaptive observer is compensated by feedforwarding the equivalent current which gives fast response. The experimental results are presented in the paper using DSP TMS320c31.

• 전기학회논문지
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• 제60권3호
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• pp.632-638
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• 2011

In this paper, a nonlinear controller is proposed to track the desired velocity and to cancel sinusoidal disturbances. The proposed method consists of a velocity tracking controller and internal model principles (IMPs). For the design of the velocity tracking controller, mechanical and electrical dynamic controllers are independently designed. For the mechanical dynamics, the velocity tracking controller generates the desired quadrature current to track the desired velocity. The current tracking controller is designed to guarantee the desired quadrature current and to regulate the direct current. Therefore, the proposed velocity tracking controller has a field-oriented control. Since the controllers of the mechanical and electrical dynamics are independently designed, the stability of the closed-loop system is demonstrated using passivity. Since both the cogging torque and DC current errors act as sinusoidal disturbances in PMSM, we use four add-on type IMPs that preserve the merits and performance of the pre-designed controller without sacrificing the closed-loop stability. The performance of the proposed method is validated via simulations.

• 조명전기설비학회논문지
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• 제13권4호
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• pp.160-169
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• 1999

리니어 펄스 모터(LPM, Linear Pulse Motor)는 고정자와 가동자 사이의 공극에 미세한 치 피치로 되어 있기 때문에 고정밀의 유연한 선형운동을 필요로 하는 분야에 적합하다. 리니어 펄스모터의 힘과 위치는 치 피치, 공극 영구자석 및 여자전류에 의해서 민감하게 영향을 받는다. 따라서 LPM은 힘 특성을 해석하는 것이 매우 중요하다. 본 논문은 공극에서 힘 계산을 위하여 퍼미언스법을 적용하였다. LPM의 공극은 공압베어링에 의해서 발생된 압력으로 부상된다. 간단한 공압과 퍼미언스법은 일정 조건에서 공극을 계산하는 데 사용되었다. 따라서 최대로 이용할 수 있는 힘은 공극의 가변에 대한 자기수반 에너지법으로부터 구하였으며, 또한 수직력과 선형 추력은 미세 변위 1[mm]로부터 얻을 수 있었다.

• Transactions on Electrical and Electronic Materials
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• 제5권1호
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• pp.11-14
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• 2004

An rf triode magnetron sputtering system is designed and installed its construction in vacuum chamber. In order to calibrate the rf triode magnetron sputtering for thin films deposition processes, the effects of different glow discharge conditions were investigated in terms of the deposition rate measurements. The basic parameters for calibrating experiment in this sputtering system are rf power input, gas pressure, plasma current, and target-to-substrate distance. Because a knowledge of the deposition rate is necessary to control film thickness and to evaluate optimal conditions which are an important consideration in preparing better thin films, the deposition rates of copper as a testing material under the various sputtering conditions are investigated. Furthermore, a triode sputtering system designed in our team is simulated by the SIMION program. As a result, it is sure that the simulation of electron trajectories in the sputtering system is confined directly above the target surface by the force of E${\times}$B field. Finally, some teats with the above 4 different sputtering conditions demonstrate that the deposition rate of rf triode magnetron sputtering is relatively higher than that of the conventional sputtering system. This means that the higher deposition rate is probably caused by a high ion density in the triode and magnetron system. The erosion area of target surface bombarded by Ar ion is sputtered widely on the whole target except on both magnet sides. Therefore, the designed rf triode magnetron sputtering is a powerful deposition system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.41-43
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• 2009

This paper deals with determination of parameters of permanent magnet linear synchronous machine(PMLSM) for high thrust and improvement of speed performance. To satisfy these characteristics, PMLSM with double-sided PM mover and slotless ring-winding stator is presented. And using multilaver method, this paper analyzes the electromagnetic field phenomena and estimates parameters such as back-EMF and thrust constant. These parameters are used to derive DC link voltage of voltage source inverter with space vector pulse width modulation(SVPWM) using a digital signal processor and encoder pulse signal. The DC link voltage is one of the most important factor for accurate design. It enables to determinate dynamic operating range of system. Hence, performance evaluation is performed through dynamic modeling. Finally, in this paper, dynamic characteristics according to DC link voltage are presented as experiment result.

• 한국자동차공학회논문집
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• 제23권1호
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• pp.25-33
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• 2015

This paper presents the d-q axis equivalent circuit model of an interior permanent magnet (IPM) which includes the iron loss resistance. The model is implemented to be able to run in real-time on the FPGA-based HIL simulator. Power electronic devices are removed from the motor control unit (MCU) and a separated controller is interfaced with the real-time simulated motor drive through a set of proper inputs and outputs. The inputs signals of the HIL simulation are the gate driver signals generated from the controller, and the outputs are the winding currents and resolver signals. This paper especially presents iron loss prediction which is introduced by means of comparing the torque calculated from d-q axis currents and the desired torque; and minimizing the torque difference. This prediction method has stable prediction algorithm to reduce torque difference at specific speed and load. Simulation results demonstrate the feasibility and effectiveness of the proposed methods.