• Journal of Power Electronics
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• 제17권4호
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• pp.1117-1126
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• 2017

The main contribution of this paper is the use of sensorless active diodes to generate the gate signals for a three-phase boost-rectifier with a self-powered control scheme. The sensorless operation is achieved making use of the gate control signals generated by the active diode schemes on each of the switching devices using a pulse width half-controlled boost rectifier modulation technique (PWM-HCBR). The proposed scheme synchronizes the gate control signals with a three phase voltage supply. Autonomous operation is obtained making use of the output DC bus to feed the control circuitry, the active diodes and the driver circuitry. The three-phase boost-rectifier is supplied by a three-phase permanent magnet electric generator powered by a solar concentrator dish with variable voltage and variable frequency conditions. Experimental results report an efficiency of up to 94.6% for 25 W and an input of 3.6 V peak per phase with 450.

• 전력전자학회논문지
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• 제4권1호
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• pp.66-72
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• 1999

본 논문은 고주파 공진형 PWM 인버터식 X-선 장치의 인버터에 단상과 3상 전파정류방식 및 PSU 전원을 연결시켰을 때 나타나는 단시간 출력특성에 대해 분석하였다. X-선의 선질은 X-선관에 입력되는 DC 전압 파형에 의존한다. DC 출력전압 파형은 DC 전압전원의 고조파 왜곡에 의해 영향을 받는다. 이러한 관전압 파형의 왜곡은 X-선 출력의 직선성, 재현성 및 출력선질을 저하시킨다. 따라서 본 논문에서는 DC 출력전압 파형과 세 가지 형식의 DC 입력전원 형식에 따른 출력선량을 비교하였고 이에 따른 실험결과를 검토하였다.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권2호
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• pp.79-84
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• 2012

In this paper, a three-phase high-voltage converter (HVC), in which the main structure of each phase is composed of a cascaded PWM rectifier (CPR) and cascaded inverter (CI), is studied. A high-voltage grid is the input of the HVC. In order to ensure proper operation of the HVC, the control method should achieve output voltage sharing (OVS) among the rectifiers in the CPR, OVS among the inverters in the CI, and high power factor. Master-slave direct-current control (MDCC) is used to control the CPR. The ability of the control system to prevent interference is strong when using MDCC. The CI is controlled by three-loop control, which is composed of an outer common-output-voltage loop, inner current loops and voltage sharing loops. Simulation results show low total harmonic distortion (THD) in the HVC input currents and good OVS in both the CPR and CI.

• Journal of Power Electronics
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• 제12권2호
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• pp.249-257
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• 2012

An interleaved PWM converter is proposed to implement the features of zero voltage switching (ZVS), load current sharing and ripple current reduction. The proposed converter includes two ZVS converters with a common clamp capacitor. With the shared capacitor, the charge balance of the two interleaved parts is automatically regulated under input voltage and load variations. The active-clamping circuit is used to realize the ZVS turn-on so that the switching losses on the power switches are reduced. The ZVS turn-on of all of the switching devices is achieved during the transition interval. The interleaved pulse-width modulation (PWM) operation will reduce the ripple current and the size of the input and output capacitors. The current double rectifier (CDR) is adopted in the secondary side to reduce output ripple current so that the sizes of the output chokes and capacitor are reduced. The circuit configuration, operation principles and design considerations are presented. Finally experimental results based on a 408W (24V/17A) prototype are provided to verify the effectiveness of the proposed converter.

• Journal of Power Electronics
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• 제15권4호
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• pp.994-1005
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• 2015

This paper presents a novel power control strategy for PWM current-source rectifiers (CSRs) in the stationary frame based on the instantaneous power theory. In the proposed control strategy, a virtual resistance based on the capacitor voltage feedback is used to realize the active damping. In addition, the proportional resonant (PR) controller under the two-phase stationary coordinate is designed to track the ac reference current and to avoid the strong coupling brought about by the coordinate transformation. The limitations on improving steady-state performance of the PR controller is investigated and mitigated using a cascaded lead-lag compensator. In the z-domain, a straightforward procedure is developed to analyze and design the control-loop with the help of MATLAB/SISO software tools. In addition, robustness against parameter variations is analyzed. Finally, simulation and experimental results verify the proposed control scheme and design method.

• 한국산학기술학회논문지
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• 제5권5호
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• pp.413-420
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• 2004

본 연구에서는 인버터를 구동하는 용도의 직류전원장치에 대한 제어 알고리즘 개발을 목표로 하고 있으며, 구동과 회생기능을 갖는 전압형 PWM 컨버터에서 운전시 전원의 불평형을 보상하는 제어방법을 제안하고자 한다. 이를 위해 전력회생기능을 갖는 정류기에 대하여 기존 다이오드 및 SCR을 이용한 정류방식과의 비교를 통해 본 제어방식의 우수성을 시뮬레이션과 실험을 통해 입증하고자 한다. 전력변환기가 항상 평형상태를 유지하기 위해 전류제어 루프에 의하여 불평형 상태를 보상하는 방법을 사용하였으며, 통상적으로 전력변환기의 구성시 각상의 리액턴스가 같지 않은 누설변압기 등의 사용을 가능하게 하므로 제안된 전력변환기의 리액턴스가 불평형상태가 되어도 운전시 항상 평형상태로 유지되어 시스템을 안정적으로 구동 시킬 수 있는 제어기법의 설계를 통해 어떤 환경에서도 장치의 안정된 구동특성을 확인하고자 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.440-442
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• 1996

In this paper, characteristics of harmonic spectrum are studied for three phase PWM converter as the switching frequency variation and current control method changing. Especially, Differential Mode Noise which causes harmful effect on the other equipments is measured and compared with three phase diode rectifier.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.275-278
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• 2003

The pantograph contact can be disrupted due to irregularities in the motion. The pantograph detachment prohibits the current flow and makes the system uncontrollable. During the pantograph detachment period, the control error are accumulated by the integral property of the controller. The output of the controller, therefore, can be induced to be an extremely large value. When the pantograph is reattached, the extremely large output of the controllers causes a very high overshoot (or under-shoot) of the line current and the DC-link voltage. This work proposes a new method for detecting the pantograph bouncing conditions and designs a controller considering such conditions based on the pantograph bouncing detector.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.670-673
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• 2000

This paper describes a new inverter active inverter between a photovoltaic(PV) array and single-phase utility that avoid the bulky input(60Hz) transformer on the AC side. The interface employs a pwm boost converter on the DC side followed by a pwm boost converter on the DC side followed by a pwm current-forced single-phase rectifier for injecting the power from the PV array into the mains. The current waveform at the AC side remains sinusoidal and exactly in phase at all time. The circuit also has the advantage of requiring fewer switching device than high-frequency link system. This paper describes modeling of PV array and new system topology. Simulation results on the performance of the connection are also presented.

• 전력전자학회논문지
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• 제19권5호
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• pp.450-456
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• 2014

In HVDC converters that employ a line-commutated control, reactive power is absorbed by the rectifier and inverter terminals during AC/DC conversion. An AC filter usually consists of filters and large shunt capacitors to supply reactive power to the HVDC station. When STATCOM is used to supply reactive power to the HVDC system with AC filter, the low-order harmonics generated from STATCOM can result in a resonance between the shunt capacitor and AC network. Therefore, a control strategy based on selective harmonic elimination is adopted to minimize the low-order harmonics from STATCOM. The cancellation of harmonic instabilities is verified through simulations in PSCAD/EMTDC.