• 한국군사과학기술학회지
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• 제8권2호
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• pp.58-66
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• 2005

This paper presents miniaturized setback generators based on the conversion of mechanical energy into electrical energy for military applications, especially power supply for electronic fuzes. In order to minimize the volume of setback generators, a ring-shaped magnet enclosing a coil assembly is adopted. A mechanical safety system, shear plate, is used as a release mechanism of the setback generators to prevent the generators from operating accidentally. The setback generators are intended not to ignite an electrical detonator but to charge a capacitor which is capable of driving electronic circuit of fuze. We design the setback generators using the simulation results of an electromagnetic analysis tool, $Maxwell^{(R)}$ 2D. In experimental study, we perform safety tests of the shear plate and firing tests of the fabricated setback generators. The present setback generators show that the voltage of 14.2V is charged at the capacitor of $30{\mu}F$ within the charging time of 0.68msec and the critical acceleration for safety is 5,000G, thus verifying that the setback generators with a ring-shaped permanent magnet can be applicable to the power supply of small-caliber electronic fuze.

• 전력전자학회논문지
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• 제23권1호
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• pp.66-71
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• 2018

We propose an online parameter estimation method for surface-mounted permanent-magnet synchronous motor (SPMSM) using an affine projection algorithm (APA). The proposed method estimates parameters with two APAs based on the discrete-time model equation of SPMSM during motor operation. The first APA is designed to estimate inductance, and the second APA is designed to estimate resistance and flux linkage. However, in case when the d-axis current is controlled to 0A, the second APA cannot estimate resistance and flux linkage simultaneously because the matrix rank in APA becomes deficient. To overcome this problem, we temporarily inject a negative reference current input to the d-axis control loop, and the matrix in the APA then becomes full rank, which enables the simultaneous estimation of resistance and flux linkage. The proposed method is verified by PSIM simulation and an actual experiment, and the results reveal that SPMSM parameters can be estimated online during motor operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1005-1006
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• 2007

This paper analyzed the characteristics of the claw pole permanent magnet(PM) stepping motor by using 3D Finite element method(FEM). In this motor, magnetization is occurred along the z-axis, therefore it is necessary to apply 3D FEM for analysis of the claw pole motor. A phase difference of the two stacks's detent torque is 180 degrees. When the center of a permanent magnet is identical with the middle of a pole, small detent torque is produced in order to cancel each of detent torques. However, there are construction errors which are a discrepancy between one and the other phase section in the manufacturing process, thus the detent torque is increased. Moreover, it is confirmed that the proportion of the detent torque is considerably arisen according to the error. Analysis of the construction error is studied by changing the error $0^{\circ}$ to $3^{\circ}$.

• Journal of Power Electronics
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• 제19권6호
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• pp.1505-1514
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• 2019

The permanent magnet synchronous motor (PMSM) is widely used in various fields and the proportional-integral (PI) controller is popular in PMSM control systems. However, the motor parameters are usually unknown, which can lead to a complicated PI controller design and poor performance. In order to design a PI controller with good performance when the motor parameters are unknown, a control algorithm based on stability margin is proposed in this paper. First of all, based on the mathematical model of the PMSM and the least squares (LS) method, motor parameters are estimated offline. Then based on the estimation values of the motor parameters, natural angular frequency and phase margin, a PI controller is designed. Performance indices including the natural angular frequency and the phase margin are used directly to design the PI controller in this paper. Scalar functions of the d-loop and the q-loop are selected. It can be seen that the designed controller parameters satisfy Lyapunov large scale asymptotic stability theory if the natural angular frequencies of the d-loop and the q-loop are large than 0. Experimental results show that the parameter estimation method has good accuracy and the designed PI controller proposed in this paper has good static and dynamic performances.

• 한국자기학회지
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• 제9권2호
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• pp.121-126
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• 1999

친수성 철계 자성유체의 제조와 이 자성유체를 Nd-영구자석과 병용하여 기름 밀봉 장치의 개발을 목적으로 실험검토한 결과 다음과 같은 결론을 얻었다. 1)평균 입경 100$\AA$, 자화값 125.5emu/g, 대기중 15$0^{\circ}C$까지 산화 변질성이 없는 실리카 피착 철 초미립자의 표면에 오레인산 이온, D.B.S. 이온 및 T.M.A. 이온을 흡착한 후 ethylene glycol 용액중에 분산시켜 친수성 철 분말 자성유체를 제조할 수 있었다. 2)이상의 친수성 철 분말 자성유체[70%(g/ )Fe]를 영구자석(3200 Gauss)과 병용하여 기름 밀봉 장치에 응용한 결과 영구자석의 설치 개수를 영구자석 6단 그리고 구동축과 밀봉 장치 사이 간격 0.2mm의 조건에서 압력 7400g/$\textrm{cm}^2$까지 견딜 수 있는 우수한 내압 특성을 얻었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1230-1231
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• 2011

이 논문은 전차원 상태 관측기 기반의 EEMF(Extended Electro-Motive Force) 모델을 이용한 IPMSM(Interior Permanent Magnet Synchronous Motor:매입형 영구 자석 동기 전동기)센서리스 제어 기술을 제안한다. 임의의 ${\gamma}-{\delta}$축 상에서 IPMSM 상태 방정식을 전개하고 이를 전차원 상태 관측기로 구현해 Extended EMF(역기전력)성분을 추정한다. 추정 성분을 이용해 제어각의 오차를 구하고 PI제어기를 사용해 제어각의 오차를 0으로 수렴시켜 전동기 회전 속도를 추정한다. 추정 속도를 적분해 제어각을 얻고, IPMSM 센서리스 제어를 수행한다. 제안한 알고리즘은 실험을 통해 그 타당성을 검증한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1051-1052
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• 2007

In this paper, as a clean lift, a maglev(magnetic levitation) clean lift is designed and described. The maglev clean lift, which is superior to conventional lifts in vibration, noise, clean class and speed characteristics, consists of magnets, guide rails, guide rollers, magnet module frame, cage, guidance controller, sensors, etc. As design specifications, the maximum value of vibration is 0.2G, the maximum value of noise is 60dB, and the clean class is #10. The design results for the maglev clean lift are shown and discussed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.83-84
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• 2012

본 연구는 3상 농형 유도전동기 보다 많은 특성을 가지는 다상 교류전동기의 구동 시스템 연구를 위하여 개발된 5상 3.0Kw 내부장착 영구자석 릴럭턴스 동기전동기(PMA-RSM)의 설계 및 제작에 대한 내용이다. 전동기 설계에는 Maxwell 2D/3D와 Simplorer의 EM Package 및 전동기 해석 프로그램을 활용하였다. 설계된 5상 PMA-RSM의 고정자와 회전자 구조의 특성과 제작된 전동기의 형태를 보여준다. 또한 고정자 권선방법으로 채택된 집중권에 대한 자계의 FEM 해석 결과와 기초적인 운전특성을 보여 준다.

• 한국정밀공학회지
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• 제21권5호
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• pp.174-181
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• 2004

This paper presents the development of a magnetostrictive microactuator. The structural and functional requirements are as follows: it must be a millimeter structure and must achieve controllable displacement with nanometer resolution. Finite Element Analysis(FEA) is used to determine the structure with the most uniform and highest magnetic flux density along the Terfenol-D rod. The microactuator prototype 1 is designed and made based on the FEA. It is observed that the microactuator show some level of hysteresis and that it produces 25 newton in force and 3 ${\mu}{\textrm}{m}$ in displacement with 1.5 amperes of current, and resolution of 250 nm per 0.1 amperes. To improve the performance of the microactuator prototype 1, microactuator prototype 2 is made again with a permanent magnet (PM). It is observed that the microactuator prototype 2 gene.ates 3.3 ${\mu}{\textrm}{m}$ in displacement with 0.9 amperes of current. It means that the microactuator prototype 2 performs better than the microactuator prototype 1.

• 한국자기학회지
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• 제23권6호
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• pp.179-183
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• 2013

최근에 발견된 $d^0$ 반쪽금속성을 가지는 호이슬러 화합물 $N_2KCa$와 $O_2KCa$이 합금을 이루었을 때 그 반쪽금속성과 자성을 제일원리 방법을 이용하여 연구하였다. 계산을 통해 얻은 상태밀도와 총 자기모멘트를 통해 고려의 대상인 $N_{1.5}O_{0.5}KCa$, NOKCa, $N_{0.5}O_{1.5}KCa$ 등 세 가지 화합물 모두 반쪽금속성 나타냄을 알 수 있었다. 이들 화합물에서 N 원자와 O 원자의 자기모멘트는 순수물질에 비해 상당히 증가하였으며, K 원자의 자기모멘트는 상당히 큰 음의 값을 가졌다. 각 원자들의 자기모멘트와 계산된 원자별 상태밀도를 연관시켜 자성과 반쪽금속성을 논의하였다.