• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1030-1032
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• 2003

Single phase SRM(switched reluctance motor) can not be start by itself because positive torque is generated in limited section. Therefore single phase SRM need starting device which is place the rotor in positive torque section when motor is begun to start. The prototype of salient pole rotor type single phase SRM, fabricated in previous research, has permanent magnet starting device. It is installed in bottom of the rotor for starting by itself. But, it is affected the motor when driving and cause the decrease of torque and speed. On this paper, average torque of the prototype was measured according to installation of the starting device or not. And influence of the staring device on average torque was confirmed by comparison of the results.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.933-935
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• 2003

The single-phase line start permanent magnet motor(LSPM) have a rotor cage bar for induction starting and permanent magnets, providing synchronous torque. So, LSPM is vary complex and difficult to analysis transient characteristics and rotor design. In this paper, F.E.M analysis about single-phase line start permanent magnet motor and compare of the single-phase line start permanent magnet synchronous motor's transient characteristics by size and position of rotor bar.

• Journal of the Korean Society of Safety
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• v.15 no.3
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• pp.14-22
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• 2000

A numerical analysis has been performed on the two-dimensional rectangular gallium melting problem using the enthalpy method. The major advantage of this method is that the physical domain is discretized with fixed grids without transforming variables and the interface conditions of phase change are accounted for the definition of suitable source terms in the governing equations. But in the fixed method, there is some ambiguity in defining the porosity constant which has no physical interpretation. If the velocity correction is included in the momentum equation, for the appropriate range of porosity constant, the realistic predictions are obtained. The object of the present work is to predict the phase change within the molten steel with thin riser slab using the modified enthalpy-porosity method. The computational procedures for predicting velocity and temperature are based on the finite volume method and the non-staggered grid system. The influence of natural convection on the melting process is considered. A comparison with the experimental results shows that the modified method is better than the previous one.

• The Transactions of the Korean Institute of Power Electronics
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• v.1 no.1
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• pp.20-26
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• 1996

The common drive method of the single phase induction motor(SPIM) is to install a start capacitor and a centrifugal switch in series with the auxiliary winding. In this paper, the phase angle voltage sequence controller is proposed to eliminate a start capacitor and a centrifugal switch of SPIM. In comparison with the capacitor start system of SPIM, the proposed control system shows that it contributes to saving the starting current about 57% and to improving of the starting efficiency of SPIM. The proposed starting characteristics of the SPIM is obtained with this strategy through simulation and experimental results.

• Journal of Magnetics
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• v.17 no.3
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• pp.196-199
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• 2012

This paper presents the analytical calculation of winding inductance for a single-phase brushless DC machine based on the magnetic circuit concept. The machine is used in the low power range of applications, such as ventilation fans, due to its simplicity and low cost. Since flux linkage is proportional to inductance, the calculation of winding inductance is of central importance. By comparison with experimental and analytical values, it is shown that proposed analytical expression is able to effectively predict the winding inductance of single-phase brushless DC machines at the design stage.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.56-57
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• 2013

불평형 및 왜곡 상태에서 정상분 추출은 기존 여러 가지 방법이 제시되어 있다. 여기에 PLL(Phase Locked Loop) 방식에 따라 다양한 특성이 나타나게 된다. 본 논문에서는 4가지 정상분 추출 방법과 2가지 PLL 방법을 적용하여 각각의 성능을 시뮬레이션 및 실험을 통해 비교 분석하였다.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.111-114
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• 2000

Harmonics and fundamental reactive power of nonlinear loads in serious unbalanced power condition are compensated by current synchronous detection(CSD) theory which is also acceptable for single phase power system, but the CSD theory is not suitable any more in case of controlled independently harmonics and reactive component. Therefore a new algorithm the extended current synchronous detection (ECSD)theory for a three phase active power filter based on decomposition of fundamental reactive distorted components is proposed in this paper. The proposed ECSD theory is simulated and tested comparison with a few power theories under asymmtrical condition in power system.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.54.3-54
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• 2001

This paper presents a controller design technique for standard 2nd-order system satisfying user-specified phase margin. A simple method is presented to meet stability margin for the 2nd-order system, which is important since the 2nd-order plant models are frequently encountered in the practical plant models such as actuators of the optical drive systems. Through the comparison of the specified stability margin and achieved stability margin, it is shown in the simple example that the proposed technique is useful in the initial design of control systems with stability margin specifications.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.1
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• pp.8-14
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• 1999

The active devices used at microwave frequency have the different phase shift according to input power. Especially, The difference of the phase shift is large in the saturation region of the amplifier. In this paper, we disigned the phase control system for fixing the different phase shift at device. With the high frequency nonlinear amplifier, we fabricated such system that the phase shift to be fixed automatically using the varible phase shifter. The variable phase shifter fixed total phase variation of the circuit using the information that was obtained from the comparison of imputsignal phase with output signal phase. Even though the input signal is 2-tone or FM type, we could estimate and also fix the phase variation on DUT Dynamic range is about 10dB. It has been experimented at 1960MHz using Teflon (H=31mil, ${\varepsilon}r$=3.2)

• Journal of the Korean Society of Safety
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• v.17 no.2
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• pp.8-15
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• 2002

In order to investigate the vibration characteristics of fluid-structure interaction problem, we modeled two identical rectangular plates coupled with fluid. A commercial computer code, ANSYS was used to perform finite element analysis and FEM solutions were compared with the experimental results to verify the finite element model. As a result, comparison of FEM and experiment showed good agreement, and the transverse vibration modes, in-phase and out-of-Phase, were observed alternately in the fluid-coupled system. The effect of fluid gap size on the fluid-coupled natural frequency were investigated. It was shown that the mode numbers increased, the normalized natural frequencies monotonically increased. And it was also found that an increase of the fluid gap reduced the coupled natural frequencies for the in-phase modes but increased the coupled natural frequencies for the out-of phase modes, and eventually converged to the results of an infinite fluid gap.