• Journal of Electrical Engineering and Technology
• /
• v.13 no.1
• /
• pp.345-351
• /
• 2018

This paper analyzes a resonant inverter to generate plasma. The resonant inverter consists of a full bridge converter, resonant network and reactor to generate a magnetic field for plasma generation. A plasma load has very distinct characteristics compared to conventional loads. The characteristics of plasma load are analyzed through experimental results. This paper presents the study on the resonant network, which was performed in order to determine how to achieve a constant current gain. Another important contribution of this study is the analysis of drop-out phenomenon observed in plasma loads which is responsible for unpredictable shutdown of the plasma generator that requires stable operation. In addition, the design process for the resonant network of a plasma generator is proposed. The validity of this study is verified through simulations and experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.1
• /
• pp.152-159
• /
• 2010

High power density and power conversion efficiency have been required in the power converters according to the rapid growth of industry. In this context, the next generation High Speed Train(HST) requires power converter which has high-efficiency, high-performance and high-density. In this paper, the new control technique for battery charger used for the next generation HST is proposed. The phase shift ZVZCS converter is classified according to a resonant circuit which is located in the primary or secondary side. In this paper, The PWM switching technique using all-pass filter is proposed to control ZVZCS converter which has resonant circuit in the secondary side. ATmega_128 micro controller based in all-pass filter in substitute for phase shift IC is presented to have digital control. To verify the proposed topology, the simulation and experiment are performed by using PSIM software and 1[kW] experimental set-up.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.18 no.2
• /
• pp.153-160
• /
• 2013

This research paper describes the development of battery charger with a variable output voltage capacity for charging the batteries used in electrical vehicles. The voltage and current accordingly is control via the buck converter that receives three phase current at primary side and fed to bridge rectifier which is comprised of full bridge converter and HFTR(High Frequency Transformer) for isolation and a square wave AC output. The transformer primary side is in series to divide certain charging current and the secondary side is comprised of six fix transformers so that they can generate certain amount of power and various output voltage through relay connection using 6 DC outputs. Moreover, all parallel connected full bridge serial resonant converter communicate together with upper(main) controller. The constructed structure is verified by conducting the test on PSIM as well as experimentally.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.3
• /
• pp.179-184
• /
• 2019

In many countries, such as developing countries where electricity is scarce, small wind turbines in the form of Off Grid are an effective solution to solve power supply problems. In some countries, the expansion of power systems and the decline of electricity-intensive areas have led to the use of small wind power in urban road lighting, mobile communications base stations, aquaculture and seawater desalination. With this change, the size of the small wind power industry is expected to have greater potential than large-scale wind power. In the case of small wind power generators, the generator is controlled at a variable speed, and the voltage and current generated by the generator have many harmonic components. To solve this problem, the AC to DC converter to be studied in this paper is a three-phase step-up type converter with a single switch. The inductor current is controlled in discontinuous mode, and has a characteristic of having a unit power factor by eliminating the harmonic of the input current. The proposed converter is composed of LCL filter and three phase rectification boost converter at the input stage and a single phase full bridge for grid connection. It is a control system with energy storage system(ESS) that the system stabilization can be pursued against the electric power.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.3 no.3
• /
• pp.298-304
• /
• 2014

In this paper, a novel topology for cascade multilevel converter is introduced, which has many levels with fewer number of power electronic components. Less number of the switches leads to the reduction of size, losses, simple control strategy and high efficiency. For proposed multilevel converter, a new algorithm for determination of dc voltage source values has been recommended. The performance and operation of the proposed multilevel converter has been evaluated with the simulation results of a cascade 25-level converter.

• Proceedings of the KIPE Conference
• /
• 2019.11a
• /
• pp.168-169
• /
• 2019

본 논문은 친환경자동차용 저전압 DC-DC 컨버터(Low-voltage DC-DC converter, LDC)의 고전력밀도 달성을 위한 스위칭 주파수 선정 및 구조 설계 방법을 소개한다. 위상천이 풀-브릿지(Phase-Shift Full-Bridge, PSFB) 컨버터의 손실 분석을 통해 스위칭 주파수 700kHz 선정하였으며, 냉각수 온도 65℃, 분당 8리터의 유량 기준으로 소자 온도가 110℃ 이내로 관리 되도록 고려하여 구조 설계를 수행했다. 온도 조건을 만족하면서 8kW/L의 높은 전력밀도를 달성하였으며 입력전압 200V-310V, 출력전압 12.8V-15.1V의 전압 범위를 만족하는 1.8kW 최종 시작품을 제작하여 실험으로 검증하였다.

• Proceedings of the KIPE Conference
• /
• 2007.07a
• /
• pp.132-134
• /
• 2007

하이브리드 차량 및 전기차량 구동 모터의 권선저항에 의한 손실 및 모터의 크기를 줄이기 위해 고효율, 고승압형 DC-DC 컨버터 사용이 요구된다. 기존의 부스트 컨버터는 기생저항 성분에 의해 고승압이 불가능하여 변압기를 사용하여 승압비를 향상시킨 current-fed push-pull, current-fed full bridge, dual inductor-fed 부스트 컨버터 등으로 변형되어 사용되어 왔다. dual inductor-fed 부스트 컨버터의 경우 동일조건하에서 앞서 기술된 2가지 컨버터보다 2배의 승압비를 얻을 수 있으며 1차측 전류 스트레스가 낮은 장점을 가지고 있어 대전력, 고승압 응용에 적합하다. 하지만 변압기의 누설인덕턴스에 의한 써지성 전류/전압을 제한하기 위한 부가적인 snubber회로의 사용으로 효율을 떨어뜨리게 되는 단점을 가지고 있다. 본 논문에서는 이러한 단점을 보완할 수 있는 새로운 2개의 인덕터와 1개의 변압기를 갖는 DC-DC 컨버터를 제안한다. 제안된 컨버터의 동작원리와 모드해석을 실시하고 최종적으로 400W, 42Vdc (Battery)/400Vdc (Electric Motor) 실험결과를 통해 이를 검증한다.

• Proceedings of the KIPE Conference
• /
• 2012.07a
• /
• pp.183-184
• /
• 2012

본 논문에서는 출력 인덕터 리플과 2차 측 정류기의 공진 전압을 저감할 수 있는 다중 위상천이 풀 브리지 컨버터를 제안한다. 제안된 회로는 총 8개의 스위치가 사용되며, 각 4개의 스위치가 하나의 위상천이 풀 브리지 인버터 부를 구성하는 구조이다. 기존 위상천이 풀 브리지 컨버터의 경우, 진상레그와 지상레그의 위상차이를 조절하여 출력전압을 제어하는데 반해, 제안된 회로는 진상레그와 지상레그의 위상차이 뿐만 아니라 각 풀 브리지 인버터 부의 위상차이를 동시에 조절하여 출력전압을 제어하는 것이 특징이다. 이를 통하여 제안회로는 출력 인덕터 전류 리플 및 2차 측정류기의 공진 전압을 크게 저감시킬 수 있어 고 효율화에 유리하다. 본 논문에서는 제안된 회로의 이론적 해석 및 PSIM 모의실험을 수행하며, 450W급 시작품을 제작하여 제안회로의 타당성을 검증하였다.

• Proceedings of the KIPE Conference
• /
• 2012.07a
• /
• pp.335-336
• /
• 2012

본 논문에서는 출력 인덕터 전류의 리플을 저감할 수 있는 새로운 방식의 위상천이 풀 브리지 컨버터를 제안한다. 제안된 회로는 2개의 풀 브리지 인버터가 연결된 구조로 되어 있으며 하나의 풀 브리지 인버터가 고정 위상($0^{\circ}$)으로 동작할 때, 다른 풀 브리지 인버터의 위상을 조절하여 출력 전압을 제어하는 방식이다. 정상 동작 시, 제안회로는 기존 위상천이 풀 브리지 컨버터에 비해 출력 인덕터 전류 리플이 매우 작고, 2차 측 정류기의 공진 전압도 작아져 출력 LC 필터의 소형화 및 고효율화가 가능하여 대전류 사양에 매우 적합한 장점을 갖는다. 본 논문에서는 제안된 회로의 이론적인 특성을 분석하고, 450W 전원장치를 시작품으로 제작하여 그 우수성을 확인하였다.

• Journal of IKEEE
• /
• v.26 no.4
• /
• pp.584-589
• /
• 2022

For DC-AC power conversion from a high-voltage photovoltaic panel to a single-phase grid, the two-stage transformerless inverter with a buck-boost converter followed by a full-bridge inverter is widely used. To avoid an excessive leakage current due to the large parasitic capacitance of the photovoltaic panel, the full-bridge inverter can only adopt the bipolar PWM which results in much higher power loss compared to the unipolar PWM. In order to overcome such a poor efficiency, this paper proposes a new topology in which an IGBT and a diode for circuit isolation are added to the buck-boost converter. The proposed circuit isolation method allows the unipolar PWM in the full-bridge inverter without any increase in the leakage current so that the overall efficiency can be improved. The validity of the proposed solution is verified by computer simulation and power loss calculation.