• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.400-401
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• 2019

본 논문에서는 전동기 제정수와 전압 및 전류제한 값에 따른 단상 영구자석 동기전동기의 능력곡선을 분석하였다. 역기전력 상수와 고정자 인덕턴스 및 전압 전류 제한값에 따라 영구자석 동기전동기의 능력곡선이 변하게 되며, 최대토크를 얻을 수 있는 인가전압의 크기 및 위상이 결정된다. 제안한 능력곡선의 분석방법을 통하여 얻은 최대토크에서의 인가전압을 컴퓨터 모의실험으로 검증하였다.

• Journal of applied mathematics & informatics
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• 제41권3호
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• pp.541-552
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• 2023

In 2005, Patterson studied lacunary statistical convergence of double sequences of real numbers and, in 2009, Mursaleen introduced notion of lacunary statistical convergence of single sequences in intuitionistic fuzzy normed space. The current work intends to investigate the lacunary statistical convergence of double sequences and some significant conclusions on the algebra of the lacunary statistical limit of double sequences in intuitionistic fuzzy normed space. In addition, we have studied some examples to support the definitions.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.751-760
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• 2017

This paper proposes a point of common coupling (PCC) voltage compensation algorithm using a current limitation strategy for use in distributed generation (DG). The proposed strategy maintains the PCC voltage by prioritizing currents when an output current reference is larger than the current capacity of the power condition system (PCS) of the DG. With this strategy, the DG outputs the active current, reactive current, and the negative sequence current. The DG uses the reactive current for maintaining the PCC voltage within a normal range; the negative sequence current is used for reducing the PCC voltage unbalance. The proposed method was verified using PSIM simulation and experimental results.

• 전기학회논문지P
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• 제63권4호
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• pp.236-240
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• 2014

Induction motor requires a rotating magnetic for rotation. Current required to generate the rotating magnetic field is magnetizing current. This magnetizing current is associated with the reactive power. This reactive power must be supplied from source side. Therefore, the power factor of the induction motor is low. So, the capacitor is installed on the motor terminals to compensate for the low power factor. Power supply company has recommended to maintain a high power factor to the customer. If the capacitor current is greater than the magnetizing current of the motor, there is a possibility that the self-excitation occurs. So it is necessary to calculate the optimal capacity capacitor current does not exceed the magnetizing current. In this study, we first compute the no-load current and the reactive power of the induction motor and then calculates the limit of the maximum power factor without causing self-excitation.

• Journal of Electrical Engineering and Technology
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• 제6권2호
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• pp.239-244
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• 2011

Industrial power distribution system includes many kinds of non-linear loads, which produce the harmonics during energy conversion transition. The single-tuned passive filter is widely used to absorb the harmonics and attenuate its undesirable effect in the distribution system. However, the passive filter might be severely stressed, and sometimes even damaged, due to the absorption of harmonics. There is voltage rise on the capacitor when the single-turned harmonic filter is applied. When the capacitor voltage rose above the allowable limit, the expected life of the capacitor will considerably deteriorate. On the other hand, the reactor can experience the spike voltage even if the voltage and current of the capacitor are within the allowable limit, and this accumulated voltage stress of the reactor causes its premature fault. In this paper, we analyzed and compared the harmonic voltage and current of the reactor and capacitor in a single-tuned harmonic filter through the EMTP software and verified them with the experimental results.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.353-356
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• 2007

This paper presents the thermal and electrical characteristics of ZnO arrester blocks under the AC voltages. The leakage currents of ZnO arrester blocks were measured as a function of time. The temperature distributions of ZnO arrester blocks were observed by the forward looking infrared camera The degradation and thermal runaway of ZnO arrester blocks were closely related with the temperature limit of ZnO arrester blocks which decided heat generation and dissipation As a result, the degradation and thermal runaway of ZnO arrester blocks depend on the temperature and leakage current of ZnO arrester blocks.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.190-192
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• 2002

The industrial power distribution system is a radial system and therefore usually protected with time delayed over current relays (OCR's). Proper time dial settings are provided at the OCR's. Meanwhile, the systems, where synchronous generator, or synchronous motors, or large induction motors are operating, can not be protected with only OCR's with time grading. This paper presents a technical limit and a suitable range of time delay in applying OCR's to clearing faults in the industrial power systems for maintaining stability. Dynamic simulations are made to show them employing a real power systems of a large petro-chemical complex.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.183-186
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• 2002

The paper is proposed intantaneous torque control of IPMSM for drive of wide speed range. The control scheme is based on the mathematical model of the motor and is applicable to the constant torque and field weakening operations The scheme allows the motor to be driven with maximum torque per ampere (MTPA) characteristic below base speed and it maintains the maximum voltage limit of the motor wide field weakening and the motor current limit under all conditions of operation accurately. For each control mode. a condition that determines the optimal d-axis current $i_d$ for maximum torque operation is derived. The proposed control algorithm is applied to PMSM drive system for drive of wide speed range, the operating characteristics controlled by maximum torque control are examined in detail by simulation.

• 한국산업정보학회논문지
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• 제6권2호
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• pp.74-79
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• 2001

로봇과 자동화기기에 범용으로 사용되는 Stewing Motor의 Driving을 위하여 unipolar 방식과 bipolar 방식의 Controller Circuit를 design 하였으며 특히 design시 Digital logic을 이용하여 Controller를 설계 제작하여 실험을 통해 그 응용성을 실험하였다. 또한 Motor의 효율 향상을 위하여 Motor의 Winding에 흐르는 전류를 제어하기 위하여 constant Current Limit Methode와 Constant Voltage Limit Methode를 분석하고 실재 회로 제작 시 응용하여 Motor의 효율을 향상시켰다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.176-181
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• 2006

Experiments of Counter-Current Flow Limit(CCFL or Flooding) is performed to improve the drawbacks of Wallis' Correlation which neglects the effects of channel size, channel length, injection method and the boundary conditions at the inlet of liquid and gas phase. In this study, CCFL is observed by changing shape of porous plate using air and water. Results show that as the size of porous increases, CCFL with round shape of the porous plate decreases. In the present study, a CCFL correlation is developed and the CCFL map is proposed based on the present experimental results. developed by this experimental study.