• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.337-338
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• 2013

Combination the several type of single phase power conversion utilized simply topology are proposed in this paper. Totally four kind of converter are investigated, they are Boost AC/AC Converter, Buck AC/AC Converter, Boost AC/DC Converter, and Buck DC/AC Converter. Two types action mode are presented to determine the functional of circuit. First is AC chopper action mode, representation of the AC/AC converter. AC chopper action mode offered the sinusoidal current waveform, better power factor, faster dynamics, and smaller input/output filter. They present high robustness, offer safe commutation and have high efficiency. The second is full bridge action mode, determined the transformation AC to DC power and otherwise. Four switching devices and one magnetic contactor will establish the mode operation of circuit and manage the flow of power proceed in proper. The correction and advance of the kind of converter are verified by simulation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.32-33
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• 2011

This paper is about to the efficiency improvement of inverter for renewable energy. It is proposed the structure enhanced quality by using individually DC/DC converter for MPPT and only one inverter for DC/AC and the grid control algorithm for current control mode to the converter and inverter. The grid control algorithm is possible to setting the current reference to the dependent function of DC distribution voltage.

• Journal of Power Electronics
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• 제14권5호
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• pp.899-907
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• 2014

This paper proposes a single-phase bidirectional AC/DC converter topology applied in V2G systems, which consists of an inverter and a bidirectional non-inverting buck-boost converter. This topology can operate in four modes: buck charging, boost charging, buck discharging and boost discharging with high input current quality and unity input power factor. The inverter switches at line frequency, which is different from conventional voltage source inverters. A bidirectional buck-boost converter is utilized to adapt to a wider charging voltage range. The modulation and control strategy is introduced in detail, and the switching patterns are optimized to reduce the current ripple. In addition, the semiconductor losses are analyzed. Simulation and experimental results demonstrate the validity and effectiveness of the proposed topology.

• 한국항행학회논문지
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• 제18권5호
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• pp.483-489
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• 2014

제안된 회로는 교류 입력 전원부와 무손실 스너버 회로가 부가된 DC-DC 컨버터와 DC-AC 변환을 위한 인버터로 구성하였다. 변환된 등가회로를 이용하여 형광램프의 특성을 만족시킬 수 있는 최적의 회로상수를 결정해서 설계함으로써 기존의 인버터 직류측에서 발생되는 맥동주파수에 의한 왜형파 발생을 제거하고 인버터의 입력전류를 불연속이 되도록 하므로써 맥동율과 스위칭 손실을 현저히 감소시켰다. 이러한 모든 결과를 증명하기 위하여 40 W 직관형 형광램프를 대상으로 실험하여 고조파의 발생을 측정한 결과 제안된 전자식 안정기의 우수성을 확인하였다.

• 전자공학회논문지SC
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• 제44권4호통권316호
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• pp.21-26
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• 2007

본 논문에서는 광범위하게 적용되고 있는 단상 인버터 시스템에 대한 강인성을 향상시키기 위해 외란관측기 기반의 PI-제어기 설계 방법을 제안한다. 출력 단에 모터나 정류기와 같은 가변부하가 존재할 경우, 인버터의 출력 전압은 변동하기 쉬우며 바람직하지 않은 과도현상을 보일 수 있다. 본 논문에서는 가변부하에 의해 발생하는 출력 전압의 변화를 시스템의 외란에 의한 결과를 간주하여 부하 전류와 시스템의 불학실성에 의한 오차 (파라미터 변화나 잘못된 모델링과 같은)를 보상하는 외란관측기 기반 제어기를 설계한다. Matlab Simuink의 SimPowerSystem을 이용하여 단상 인버터 시스템에 대한 외란관측기 기반 제어기의 성능을 입증한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.505-511
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• 2008

when electric traction system used DC 1500V runs on decline of rail road track and slows down, dc voltage goes beyond regular voltage. In this case extra power is forcibly wasted by resister because rectifier of substation and electric train including power converter and so on are out of order. This paper described a DC electric railway system, which can generate the excessive DC power form DC bus line to AC source in substation for traction system. The purpose of this study was the development of the regenerative inverter system which suppress extra DC-line voltage and regenerate the energy instead of using a resister. That is Developed regenerative inverter system returns the regenerative energy from the DC line voltage to the utility. In addition, the inverter can be compensate the harmonics caused by the power conversion devices used in the DC traction system.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.337-340
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• 2007

In the dissertation, a power conversion system for fuel cell is composed of a PWM inverter with LC filter in order to convert fuel cell voltage to a single phase 220[V], In addition, new insulated DC-DC converters are proposed in order that fuel cell voltage is boosted to 380[V]. In this paper, it requires smaller components than existing converters, which makes easy control. The proposed DC-DC converter controls output power by the adjustment of phase-shift width using switch S5 and S6 in the secondary switch, which provides 93-97[%] efficiency in the wide range of output voltage. Fuel cell simulator is implemented to show similar output characteristics to actual fuel cell. Appropriate dead time td enables soft switching to the range where the peak value of excitation current in a high frequency transformer is in accordance with current in the primary circuit. Moreover, appropriate setting to serial inductance La reduces communication loss arisen at light-load generator and serge voltage arisen at a secondary switch and serial diode. Finally, TMS320C31 board and EPLD using PWM switching technique to act a single phase full-bridge inverter which is planed to make alternating current suitable for household.

• 전력전자학회논문지
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• 제18권1호
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• pp.54-62
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• 2013

This paper proposes a high-efficiency DC-DC converter with improved dynamic response characteristics for modular photovoltaic power conversion. High power efficiency is achieved by reducing switching power losses of the DC-DC converter. The voltage stress of power switches is reduced at primary side. Zero-current switching of output diodes is achieved at secondary side. A modified proportional and integral controller is suggested to improve the dynamic responses of the DC-DC converter. The performance of the proposed converter is verified based on a 200 [W] modular power conversion system including the grid-tied DC-AC inverter. The proposed DC-DC converter achieves the efficiency of 97.9 % at 60 [V] input voltage for a 200 [W] output power. The overall system including DC-DC converter and DC-AC inverter achieves the efficiency of 93.0 % when 200 [W] power is supplied into the grid.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.290-291
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• 2018

This paper proposed design method of DC link capasitor and leakage inductance of transformer with high voltage cascaded NPC H-bridge inverter. DC link capacitor is designed based on the ripple power between input AC power and output AC power, and leakage inductance of transformer is designed based on FFT table of unipola PWM with NPC H-bridge inverter. The proposed design method is verified by simulation results of 6.6[kV], 1.2[MW] Cascaded NPC H-bridge inverter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.647-650
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• 2005

The paper aims on an analysis for dc boost control using Z-source inverter. The modified space vector PWM method is used for controlling both the dc boost and ac output controls in the Z-source inverter. The capacitor voltage and the voltage stress of device with both the shoot-through time and modulation index are analyzed considering the zero state time of inverter. The theoretical analysis is verified with the simulation studies and experiments with 32-bit DSP.