• 전기학회논문지
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• 제65권7호
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• pp.1204-1210
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• 2016

The phase currents must be accurately measured to achieve the instantaneous torque control of AC motors. In general, those are measured using the current sensors. However, the measured current signals can include the offset errors and scaling errors by several components such as current sensors, analog amplifiers, noise filter circuits, and analog-to-digital converters. Therefore, the torque-controlled performance can be deteriorated by the current measurement errors. In this paper we have analyzed the influence caused by vector control of 2-phase induction motor when two errors are included in measured phase currents. Based on analyzed results, the compensation method is proposed without additional hardware. The proposed compensation method was applied vector-controlled inverter for 2-phase induction motor of 360[W] class and verified through computer simulations and experiments.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권6호
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• pp.262-270
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• 2003

In this paper, the characteristics of single-phase line-start permanent magnet synchronous motor driven by constant voltage are analyzed on d-q axis vector diagram and compared with that of current controlled motor. The coupled method of symmetrical coordinates and d-q axis voltage equation are applied to the analysis method like the analysis of single-phase induction motor. From the result of the analysis, it is seen that motors driven by constant voltage source have effects on not only the amplitude of current and torque but also current and current phase angle, so overall characteristics such as power factor and load angle are affected by circuit parameters. For precise analysis and design of single-phase line-start synchronous motor, its characteristics should be analyzed on d-q axis vector plan in consideration of the variation of circuit parameters.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권6호
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• pp.629-633
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• 2015

An active balun using current steering for phase correction is presented. The proposed active balun is constructed with two different unit balun structures based on current steering to reduce phase and amplitude errors. This type of topology can be compared with the conventional phase and amplitude correction techniques which do not incorporate the current steering. Designed and fabricated active balun in $0.18{\mu}m$ CMOS process operates over 0.95 - 1.45 GHz band, showing input reflection coefficient under -15 dB, phase error of $11^{\circ}$ and gain error of 0.5 dB. Gain is measured to be 0.3 dB maximum and power consumption of 7.2 mW is measured.

• Journal of Multimedia Information System
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• 제5권2호
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• pp.139-142
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• 2018

This work presents a novel architecture of phase locked loop (PLL) with the current compensating scheme to improve phase noise characteristic. The proposed PLL has two charge pumps (CP), main-CP (MCP) and sub-CP (SCP). The smaller SCP current with same time duration but opposite direction of UP/DN MCP current is injected to the loop filter (LF). It suppresses the voltage fluctuation of LF. The PLL has a novel voltage controlled oscillator (VCO) consisting of a voltage controlled resistor (VCR) and the three-stage ring oscillator with latch type delay cells. The VCR linearly converts voltage into current, and the latch type delay cell has short active on-time of transistors. As a result, it improves phase noise characteristic. The proposed PLL has been fabricated with $0.35{\mu}m$ 3.3 V CMOS process. Measured phase noise at 1 MHz offset is -103 dBc/Hz resulting in 3 dBc/Hz phase noise improvement compared to the conventional PLL.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.399-402
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• 1999

The single sensor technique reconstructing phase currents from the dc-link current without phase current sensors in proposed. When the duration of active vector is too short for the snubber current to reduce, the dc-link current including the snubber current gives large detection error. The solution is presented by analyzing the snubber current and modifying the switching sequences. This scheme is simple, requires only one sampling a period and has good results for detecting the phase currents.

• 전력전자학회논문지
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• 제17권1호
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• pp.1-7
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• 2012

This paper describes the performance comparison results for current controller of a single-phase PFC converter with 1-switch voltage doubler strategy for single-phase double-conversion UPS(Uninterruptible Power Supply). A single-phase PFC converter with 1-switch voltage doubler strategy needs a diode bridge and one bidirectional active switch. Thus it is possible to reduce the material cost. However, the study results of current controller design and comparison of current control method has not been known after the converter circuit was proposed. For the performance comparison of current control, single-phase 3 kVA double-conversion UPS was tested. The performance of PI and PR current controller is experimentally confirmed with followings - input current reference tracking, input power factor correction and input current THD suppression.

• 조명전기설비학회논문지
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• 제22권12호
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• pp.157-163
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• 2008

다상 교호 컨버터에서 인덕턴스가 불일치 할 때 첨두전류 제어기를 사용하는 경우에 각 상의 평균 전류는 동일하지 않다. 본 논문에서는 각 상의 인덕턴스가 불일치한 경우에 첨두전류 모드에서 평균전류가 동일해지는 전류분배 제어기를 제안한다 제어기는 과도상태에서도 전류의 평형이 잘 이루어질 수 있도록 설계한다. 제안된 방법을 2상과 4상 교호 승압컨버터에 적용시켰으며, 실험 결과를 통해 인덕턴스가 불일치한 경우에도 첨두전류 모드에서 전류평형이 잘 이루어짐을 보인다.

• 전력전자학회논문지
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• 제11권4호
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• pp.307-312
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• 2006

본 논문에서는 직류링크전류를 기반으로 SRM의 상전류를 추정하였고 이를 이용한 SRM 에 대한 속도제어법을 제안하였다. 또한 직류링크전류검출회로를 제안하여 전류검출분해능을 높일 수 있었으며 오프셋에 의한 영향을 최소화시킬 수 있는 장점을 가지고 있다. 상전류 정보를 이용한 SRM 구동방식과 직류링크전류정보를 이용한 SRM 구동방식을 실제실험을 통하여 비교함으로서 본 논문에서 제안한 상전류 추정알고리즘과 이에 관련된 직류링크전류 검출회로에 대한 유효성이 검증되었고 직류링크전류를 이용한 SRM 속도제어시스템은 속도응답이 3 상 전류정보를 이용한 시스템만큼 빠른 응답특성이 있음을 확인하였다.

• 전력전자학회논문지
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• 제27권1호
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• pp.33-39
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• 2022

A multi-phase brushless direct current (BLDC) motor is widely used in large-capacity electric propulsion systems such as submarines and electric ships. In particular, in the field of military submarines, the polyphaser motor must suppress torque ripple in various failure situations to reduce noise and ensure stable operation for a long time. In this paper, we propose a polyphaser current control method that can improve efficiency and reduce torque ripple by minimizing the increase in stator winding loss at maximum output torque by controlling the phase angle and amplitude of the steady-state current during open circuit failure of the stator winding. The proposed control method controls the magnitude and phase angle of the healthy phase current, excluding the faulty phase, to compensate for the torque ripple that occurs in the case of a phase open failure of the motor. The magnitude and phase angle of the controlled steady-state current are calculated for each phase so that copper loss increase is minimized. The proposed control method was verified using hardware-in-the-loop simulation (HILS) of a 12-phase BLDC motor. HILS verification confirmed that the increase in the loss of the stator winding and the magnitude of the torque ripple decreased compared with the open phase fault of the motor.

• 전력전자학회논문지
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• 제1권1호
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• pp.38-46
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• 1996

The commutation operation of the current source converter for switched reluctance motor drives is analyzed in this paper. The commutation operation in the current source converter consists of two modes. At turn-off of phase switch, the phase current decreases sinusoidally, and the sum of two phase currents during commutation period is constant. At this time, the capacitor voltage increases quickly with changing polarity and decreases slowly when another phase switches turn on or off. Frequency of step-down DC chopper in the current source converter is low because of the dump such as BJTs and GTOs are possible as phase switches instead of Power MOSFET and IGBTS. They may result in reductions of conduction losses and manufacturing cost in the current source converter comparing to the voltage source converter of SRM.