• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.507-510
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• 2003

This paper presents a novel prototype of tile three-phase bridge power block module type a auxiliary resonant AC link snubber circuit, which is effectively used for the three-phase voltage source type sinewave soft switching PWM inverter using IGBTs. Its operating principle Is described for current source load model, along with its practical design approach based on the simulation data. The performance evaluation of the three-phase voltage source type snewave soft switching PWM inverter incorporating a single three-phase bridge mo여le of active auxiliary resonant AC link snubber treated here Is illustrated, which is concerned with power duality efficiency power loss analysis. This inverter is discussed as compared with those of tile three-phase voltage source type sinewave hard switching PWM inverter. The power loss analysis of this soft switching PWM Inverter using IGBT power modules is evaluated on the basis of the measured v-i characteristics and switching power losses of IGBT, and antiparaliel diodes. The practical effectiveness of this inverter is proven by the power loss analysis for distributed power supply.

• 기술사
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• 제33권1호
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• pp.94-105
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• 2000

The purpose of this paper is to obtain the improved reliability and optimal control of the half-bridge inverter for induction heating system. Parasitic inductance components within the inverter circuit for induction heating including the loss-less turn-off snubber capacitor considerably affect stable operation and noise level of the system. This paper analyzes the effect of the inductance in detail and presents a new snubber configuration suitable for the half-bridge inverter to effectively reduce it. In the half-bridge inverter for induction heating the capacity of the loss-less snubber capacitor determines the switching losses because the zero voltage turn-on switching is used. However, the increase of the capacitor is limited by the system specifications, so that it is not easy work to reduce the switching loss. To effectively overcome the limitation, this paper introduces an active auxiliary resonant circuit suitable for the half-bridge inverter circuit, which operates actively according to the variation of load condition. It is also one of the most important study issues for the half-bridge inverter driven induction heater that the development of optimal control scheme considering varied load condition should be achieved. The control strategy ensures a very stable operation of overall inverter system and zero voltage turn-on switching irrespective of sensitive load parameter variations, in particular, even under the non-magnetic materials.

• Journal of Power Electronics
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• 제15권5호
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• pp.1235-1243
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• 2015

This paper presents a modified Space Vector Pulse Width Modulation Technique (SVPWM), which solves the well-known problem of voltage imbalance in the capacitors of a single-phase multilevel inverter. The proposed solution is based on the measurement of DC voltage levels at each capacitor of the inverter DC bus. The measurements are then used to adjust the size of the active vectors within the SVPWM algorithm to keep the voltage waveform sinusoidal regardless of any voltage imbalance on the DC link capacitors. When a voltage deviation exceeds a predetermined hysteresis band, the correspondent voltage vector is restricted to restore the voltage level to an acceptable threshold. Hence, the need for external voltage regulators for the voltage capacitors is eliminated. The functionality of the proposed algorithm is successfully demonstrated through simulations and experiments on a grid tied application.

• Journal of Power Electronics
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• 제17권5호
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• pp.1278-1287
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• 2017

Inverters are widely used in distributed power generation and other applications. However, their lack of inertia and variable impedance may cause system instability and power transfer inaccuracy. This paper proposes a control scheme for a single phase voltage-controlled inverter with some grid-friendly characteristics. The proposed control algorithm enables the inverter to function as a voltage source with an inner output impedance in both the islanded and grid-connected modes. Virtual inertia and rotor equations are embedded in the PLL part. Thus, the frequency stability can remain. The inner output impedance can be adjusted freely, which helps to accurately decouple and transmit the output active and reactive power. The proposed inverter operates like a traditional synchronous generator. Simulations and experiments are designed and carried out to verify the proposed control strategy.

• Journal of Power Electronics
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• 제16권6호
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• pp.2284-2293
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• 2016

With the rapid development of clean energy, photovoltaic (PV) generation has been utilized in the harmonic compensation of power systems. This paper presents a novel multi-function PV micro-inverter with three stages (pseudo-two-stage). It can inject active power and compensate harmonic currents in the power grid at the same time. In order to keep the micro-inverter working under the maximum allowable output power, an optimized capacity limitation strategy is presented. Moreover, the harmonic compensation can be adjusted according to the customized requirements of power quality. Additionally, a phase shedding strategy in the DC/DC stage is introduced to improve the efficiency of parallel Boost converters in a wide range. Compared with existing capacity limitation methods, the proposed strategy shows better performance and energy efficiency. Simulations and experiments verify the feasibility of the micro-inverter and the effectiveness of the strategy.

• Journal of Power Electronics
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• 제13권1호
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• pp.9-19
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• 2013

In this paper, a ripple input current embedded switched-inductor Z-source inverter (rESL-ZSI) and a continuous input current embedded switched-inductor Z-source inverter (cESL-ZSI) are proposed by inserting two dc sources into the switched-inductor cells. The proposed inverters provide a high boost voltage inversion ability, a lower voltage stress across the active switching devices, a continuous input current and a reduced voltage stress on the capacitors. In addition, they can suppress the startup inrush current, which otherwise might destroy the devices. This paper presents the operating principles, analysis, and simulation results, and compares them to the conventional switched-inductor Z-source inverter. In order to verify the performance of the proposed converters, a laboratory prototype was constructed with 60 $V_{dc}$ input to test both configurations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.205-207
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• 2001

In response to this inverter microwave oven has been developed to improve high speed cooking time & energy saving performance. The voltage resonating inverter has a defect in switching element that works at 5 or 6times higher than input voltage. Especially, it is very difficult to choose the switching device is very high for the 220 (V) commercial voltage. In this paper, it is proposed the optimum method to realize the turbo 1200(W) output power for microwave oven that is employed the 900(V) IGBT with decreasing operating voltage of the switching component by making the 220(V), 1000(W) inverter through the active clamp voltage resonating inverter.

• 전력전자학회논문지
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• 제4권4호
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• pp.342-348
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• 1999

본 논문에서는 간단한 제어회로와 반브릿지 PWM 인버터로 구성된 저가의 단상능동전력필터에 대해 기술하고 있다. 이 능동전력필터의 성능을 확인하기 위하여 EMTP 프로그램에 의한 시뮬레이션을 실시하고 프로토타입을 제작하여 실험을 실시하였는데, 그 결과 제안하는 능동전력필터는 단상비선형부하가 발생하는 고조파를 제거하는데 우수한 성능을 갖고 있음을 확인할 수 있었다. 제안된 시스템은 반브릿지 인버터와 단일 전류센서를 사용한 간단한 제어회로로 구성되었기 때문에, 하드웨어 비용이 저렴하고 프러그인 타입으로 제작 가능한 장점을 갖는다.

• 한국광학회지
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• 제4권3호
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• pp.294-300
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• 1993

표면광 마이크로 레잊, heterojunction phototransistor 그리고 저항을 단일 결정으로 성장시켜 집적시킨 NOR와 INVERTER 능동형 광 논리 소자에 대한 동작 특성을 조사하였다. 능동형 광 놀리 소자를 구성하는 개개 소자 중에서, 780 nm에서 발진하는 특정한 AlGaAs 초격자 마이크로 레이저의 미분 양자 효율은 15%로 나타났고, heterojunction phototransistor의 전류 이득은 에미터-컬렉터 전압이 4V이고, 입력 광의 세기가 $50{\mu}W$일 때 57으로 측정되었다. 직렬 저항이 370 ohm인 광 논리 소자의 출력은 입력광세기사 $47{\mu}W$일 때 $57{\mu}W$에서 $0{\mu}W$으로 감소하였다.

• 전력전자학회논문지
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• 제17권2호
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• pp.158-165
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• 2012

In this paper, the test bed using three-phase PWM converter connected with single phase inverter in series is set up to configure an active AC electric load. Since the two topologies, three-phase PWM converter and single-phase inverter, can be operated bidirectionally, the system not only re-generates surplus power to grid but also prevents power dissipation. However, the construction of system has a drawback. That is, ripple components two times of inverter operation frequency occur at DC-Link due to cascade connection, it can be cause of three phase unbalance Since the operational characteristic of the active AC electric load, the power frequency entered into the electric load can be varied, and the ripple of DC-Link is changed as well. In this paper, the three-phase PWM converter using a variable notch filter is proposed, and the reduction of three-phase current unbalance is presented. the validity of the proposed PWM converter using a variable notch filter is verified by the simulation and experimental results.