• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1528-1538
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• 2018

In this paper, configuration of $1-{\phi}$ seven-level boost DC-link cascade based reversing voltage multilevel inverter (BDCLCRV MLI) is proposed for uninterrupted power supply (UPS) applications. It consists of three level boost converter, level generation unit and full bridge circuit for polarity generation. When compared with conventional boost cascaded H-bridge MLI configurations, the proposed system results in reduction of DC sources, reduced power switches and gate drive requirements. Inverter switching is accomplished by providing appropriate switching angles that is generated by any optimization switching angle techniques. Here, round modulation control (RMC) method is taken as the optimization method and switching angles are derived and the same is compared with various switching angles methods i.e., equal-phase (EP) method, and half-equal-phase (HEP) method which results in improved quality of obtained AC power with lowest total harmonic distortion (THD). Reduction in DC sources and switch count makes the system more cost effective. A simulation and prototype model of $1-{\phi}$ seven-level BDCLCRV MLI system is developed and its performance is analyzed for various operating conditions.

• Journal of Power Electronics
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• 제9권1호
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• pp.109-116
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• 2009

This paper addresses the output control of a utility-connected double-fed induction machine (DFIM) for wind power generation systems (WPGS). DFIM has a back-to-back converter to control outputs of DFIM driven by the wind turbine for WPGS. To supply commercially the power of WPGS to the grid without any problems related to power quality, the real and reactive powers (PQ) at the stator side of DFIM are strictly controlled at the required level, which in this paper is realized with the Fuzzy PI controller based on the field orientation control. For the Sinusoidal Pulse Width Modulation (SPWM) converter connected to the rotor side of DFIG to maintain the controllability of PQ at the state side of DFIM, the DC voltage of the DC link capacitor is also controlled at a certain level with the conventional Proportion-Integral (PI) controller of the real power. In addition, the power quality at the grid connected to the rotor side of DFIM through the back-to-back converter is maintained in a certain level with a PI controller of the reactive power. The controllers for the PQ at the stator side of DFIM, the DC link voltage of the back-to-back inverter and the reactive power at the grid connected to the rotor side of DFIM are designed and simulated in the PSIM program, of which the result verifies the performance of the proposed controllers.

• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.905-914
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• 2016

This paper proposes a new phase current reconstruction technique for interleaved three-phase bidirectional dc-dc converters using a single current sensor. In the proposed current reconstruction algorithm, a single current sensor is employed at the dc-link, and the dc-link current information is sampled at either the peak or valley point of the pulse-width modulation (PWM) carriers regularly. From the obtained current information, all phase currents are reconstructed in a single PWM cycle. After that, the digital current controller is applied to achieve current balancing in each phase. Compare to the previous multiple current sensor method, the proposed strategy reduces the number of the current sensors in the interleaved three-phase bidirectional converter as well as reducing potential current sensing error caused by non-ideal characteristics of the multiple current sensors. The effectiveness of the proposed method is verified from the experiments based on a 3kW three-phase bidirectional converter prototype for the automotive battery charging application.

• Journal of Power Electronics
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• 제17권4호
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• pp.923-932
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• 2017

This paper proposes a novel scheme which can compensate the common-mode voltage (CMV) for five-level active neutralpoint clamped (5L-ANPC) inverters, which is based on modifying the space vector pulse width modulation (SVPWM) and adding an auxiliary leg to the inverter. For the modified SVPWM, only the 55 voltage vectors producing low CMV values among the 125 possible voltage vectors are utilized, which varies over the three voltage levels of $-V_{dc}/12$, 0 V, and $V_{dc}/12$. In addition, the compensating voltage, which is injected into the 5L-ANPC inverter system to cancel the remaining CVM through a common-mode transformer (CMT) is generated by the additional NPC leg. By the proposed method, the CMV of the inverter is fully eliminated, while the utilization of the DC-link voltage is not decreased at all. Furthermore, all of the DC-link and flying capacitor voltages of the inverter are well controlled. Simulation and experimental results have verified the validity of the proposed scheme.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.412-415
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• 1999

In this paper, we describe an implementation of the B-Link bus interface logic for a directory controller and a remote access cash controller in the SCI-based CC-NUMA multimedia server developed by ETRI . The CC-NUMA multimedia server is composed of a number of Pentium III SHV nodes and a SCI interconnection network. To communicate with remote nodes, each node has a CC-Agent which consists of a processor bus interface(PIF). a directory controller(DC), a remote access cash controller(RC), and two SCI 1ink controllers(LCs). The B-Link bus interface logic is developed for a directory controller and a remote access cash controller in order to communicate with a SCI link controller on a B-Link bus. It consists of a sending master controller a receiving slave controller, and asynchronous data buffers. And It performs a self-arbitration, a data packet transmission, a queue allocation, an early terminal ion. and a cut-through data path.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2000년도 봄 학술발표논문집 Vol.27 No.1 (A)
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• pp.45-47
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• 2000

본 연구는 심볼릭 모델 체커 중의 하나인 SMV(Symbolic Model Verifier)를 이용하여 한국전자통신연구원(ETRI)에서 개발한 CCA(Cache Coherent Agent) 보드를 위한 I-Link Bus(Inside Bus)의 몇 가지 특성(property)들을 검증하여 I-Link Bus의 요구사항(requirement)이 만족됨을 보인다. 이 검증에서는 I-Link Bus의 모델을 SMV 입력 언어로 명세하며, 검증할 특성들을 시제 논리(temporal logic)를 이용하여 나타낸다. 검증을 통해서 I-Link Bus와 PIF(Processor Interface), DC(Directory Controller), RC(Remote access cache Controller)모듈들이 중재기 우선 순위, send 우선 순위, 중재 요청 신호의 관리, liveness등의 특성들을 만족한다라는 것을 검증하였다.

• 전기전자학회논문지
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• 제23권4호
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• pp.1280-1287
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• 2019

계통 연계 형 양방향 PCS 기술은 분산 형 신재생 에너지 스마트 그리드를 구현하기 위한 기술이며, 방대한 스마트 그리드 시스템 중 태양광 모듈로부터 수집된 전력 및 상용 계통전원을 이용하여 상시 전력을 충전하였다가 필요시 저장된 전력을 저압 계통 측으로 방출할 수 있도록 하는 하이브리드형 에너지 저장 장치이다. 이를 위해 MPPT 기능이 포함된 PV입력 전력변환기와 배터리 충·방전을 위한 양방향 전력변환기 및 DC Link 전압을 3상 380V AC 계통으로 출력하고 필요할 경우 계통전력을 AC/DC변환하여 양방향 DC/DC컨버터를 통해 배터리로 충전기능을 수행하는 인버터로 구성된 3개의 전력변환기 구조를 갖는 PCS를 설계 및 개발하였다. 현재 이 시스템을 정전 및 화재사고에 취약한 제주의 사이트에 적용하여 실증 및 운영하고 있다.

• 제어로봇시스템학회논문지
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• 제13권2호
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• pp.154-162
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• 2007

In this paper, we propose a new AC-DC converter control method to comply with harmonics regulation(IEC 61000-3) effective for the inverter system of an air conditioner whose power consumption is less than 2,500W. There are many different ways of AC-DC converter control, but this paper focuses on the converter control method that is adopting an input reactor with low cost silicon steel core to strengthen cost competitiveness of the manufacturer. The proposed control method controls input current every half cycle of the line frequency to get unit power factor and at the same time to reduce switching loss of devices and acoustic noise from reactor. This kind of converter is known as a Partial Switching Converter(PSC). In this study, theoretical analysis of the PSC has been performed using Matlab/Simulink while a 16-bit micro-processor based converter has been used to perform the experimental analysis. In the theoretical analysis, electrical circuit models and equations of the PSC are derived and simulated. In the experiments, micro-processor controls input current to keep the power factor above 0.95 by reducing the phase difference between input voltage and current and at the same time to maintain a reference DC-link voltage against voltage drop which depends on DC-link load. Therefore it becomes possible to comply with harmonic regulations while the power factor is maximized by optimizing the time of current flow through the input reactor for every half cycle of line frequency.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.155-158
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• 2001

In this paper, the Load Current Observer Design for 3-phase Voltage Type PWM Converter with DC Meter Load. The sinusoidal input current and unity input power factor are realised based on the estimated source voltage performed by the Load Current Observer using actual currents and DC link voltage.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.470-471
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• 2012

본 논문은 루엔버거 관측기를 이용하여 직류링크 전압을 추정하고 추정치와 측정치를 비교하여 전압센서의 고장을 진단하는 방법을 제안한다. 또한 전압센서 고장 시에 추정치를 이용하여 제어함으로써 전압센서 고장 허용제어가 가능함을 보인다. 제안된 알고리즘은 시뮬레이션을 통해 그 타당성이 검증된다.