• 한국산학기술학회논문지
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• 제16권1호
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• pp.634-638
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• 2015

2상 유도전동기의 벡터제어를 위해서는 전동기로 입력되는 상전류를 실시간으로 측정해야 한다. 일반적으로 전동기의 상전류는 인버터의 출력단에 2개의 홀전류센서를 삽입하여 측정한다. 그러나, 홀전류센서는 가격이 비싸고, 2상 유도전동기용 벡터제어 인버터는 주로 시스템의 가격이 낮은 저전력 응용분야를 대상으로 연구가 진행되고 있으므로 홀전류센서를 사용하는 것은 경제성 측면에서 부적합하다. 따라서, 본 논문에서는 인버터의 출력단에 고가의 홀전류센서 대신 션트저항을 삽입하고, 이것의 양단 전압을 차동 증폭기로 증폭하여 모든 운전영역에서 정밀하게 상전류를 측정하는 방법을 제안한다. 이를 220[V]/360[W]급의 2상 유도전동기 벡터제어 인버터에 적용하였으며, 제안된 방법의 유효성은 컴퓨터 시뮬레이션과 실험을 통하여 검증하였다.

• 전기학회논문지P
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• 제55권4호
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• pp.196-201
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• 2006

A electrical fault that may generate an electrical disaster is defined as any abnormal condition caused by reduction in the insulation strength. To find out the abnormal condition, periodical inspections have being performed every 3 years. Recently, the number of empty houses during normal working hours is rising by dramatic increase in the number of nuclear families and double income families. To define the potential risk of the electric installation, measurement of zero phase current has been being considered. But the measured value could not be adapted to an absolute reference to the installation because the measured zero phase current value also contained capacitive leakage current. Therefore, in this paper, the correlation between the condition of the electrical installation and the zero phase current was analyzed. The result focuses on to detect them in a cost efficient way.

• Journal of Power Electronics
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• 제12권1호
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• pp.113-119
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• 2012

This paper describes the design and control of a phase shift full bridge converter with a current doubler, which can be used for the on-board charger for the lead-acid battery of electric forklifts. Unlike the common resistance load, the battery has a large capacitance element and it absorbs the entire converter output ripple current, thereby shortening the battery life and degrading the system efficiency. In this paper a phase shift full bridge converter with a current doubler has been adopted to decrease the output ripple current and the transformer rating of the charger. The charge controller is designed by using the small signal model of the converter, taking into consideration the internal impedance of the battery. The stability and performance of the battery charger is then verified by constant current (CC) and constant voltage (CV) charge experiments using a lead-acid battery bank for an electric forklift.

• 전력전자학회논문지
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• 제11권5호
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• pp.447-453
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• 2006

본 논문은 전류 제어기를 가지는 마이크로 스텝 제어를 통하여, 뛰어난 5상 스텝 모터 구동드라이버를 제안하였다. 시스템의 최소화 구성을 위하여 아날로그 전류 제어기를 제안하였다. 이로 인해 가격 절감 효과를 가지고 왔으며, 기존 상용 제품과 비교하여 소음 및 발열의 감소도 확인하였다. 본 시스템을 위치 제어 로봇에 적용하여 위치제어 적용 가능성 및 제안된 아날로그 제어기와 구동 드라이버의 타당성을 검증하였다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권1호
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• pp.42-47
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• 2017

This paper proposes a new series-coupled voltage-controlled oscillator (VCO). The proposed VCO consists of four current-reuse Armstrong VCOs (CRA-VCOs) coupled by four transformers. The series-coupling, current-reuse, and Armstrong topologies improve the phase noise performance by increasing the negative-Gm of the VCO core with half the current consumption of a conventional differential VCO. The proposed VCO consumes 6.54 mW at 9.78 GHz from a 1-V supply voltage. The measured phase noise is -115.1 dBc/Hz at an offset frequency of 1 MHz, and the FoM is -186.5 dBc/Hz. The frequency tuning range is from 9.38-10.52 GHz. The core area is $0.49mm^2$ in a $0.13-{\mu}m$ CMOS process.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.871-875
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• 1998

A DSP-based source current control for power conditioner is presented to compensate current harmonics and asymmetries of three-phase four-wire emergency generators caused by nonlinear and/or unbalanced loads. There-phase voltage type converter with split-dc-capacitor is adopted as the power circuit and a new direct source current control method is suggested, which simplifies the controller. The proposed control method shapes the generator current sinusoidally inphase with the voltage and allows the generator to supply maximum power even to single phase loads. An IGBT base lookVA prototype with the controller realized with a DSP (TMS320C32) is built and tested to verify the performance of the power conditioner.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.124-126
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• 2001

A reliable fault type identification (phase selection) plays a very important role in transmission line protection, particularly in Extra High Voltage(EHV) networks. The conventional fault type identification algorithm used the phase difference between positive and negative sequence current excluding load current. But, it is difficult to pick out only fault current since we can not know when a fault occurs and identify the fault type in weak-infeed conditions that dominate zero-sequence current in phase current. The proposed algorithm can identify the accurately fault type using the sum of unit vectors which are calculated by positive-sequence votage and negative-sequence voltage.

• 전력전자학회논문지
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• 제21권2호
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• pp.144-149
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• 2016

This paper presents a power control method of high-speed single-phase BLDC motor. Most electric appliances require a power factor corrector (PFC) to mitigate grid current harmonics. However, the reactive components and power semiconductors in the PFC increase system cost and dimension. In this paper, a new motor drive system for a high-speed single-phase BLDC motor is proposed, which can decrease grid current harmonics without PFC by directly manipulating motor power and eliminating bulky electrolytic dc-link capacitor. Given that the proposed motor power control method does not require motor current controller, no current sensor is necessary. Moreover, the proposed algorithms can be easily implemented using a low-cost micro-controller. The effectiveness of the proposed power control method is verified by experiments.

• Journal of Power Electronics
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• 제13권1호
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• pp.77-85
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• 2013

This paper proposes a new dead time compensation method of independent six-phase permanent magnet synchronous motors (IS-PMSM). The current of the independent phase machines contains odd-numbered harmonics because of the dead time and the nonlinear characteristics of the switching devices. By using the d-q-n three-dimensional vector analysis, these harmonics can be extracted at the n-axis current. Thus, the current distortion can be compensated by controlling the n-axis current of the IS-PMSM to zero. The proposed method is simple and can be easily implemented without additional hardware setup. The validity of the proposed compensation method is verified with simulations and several experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1151-1154
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• 2000

Phase angle control ac drives system gains a high popularity due to their simple implementation despite the disadvantage of their poor input power factor especially for large values of phase delay angle. Furthermore it generates subharmononic current at specific phase angle. As input current of do drive systems are sinusoidal, the power factor and subharmonic current characteristics are improve. This paper presents the application of a PWM control technique of do chopper system to reduce the subharmonic current and its characteristics using single-phase dc chopper drive system of universal motor.