• Journal of IKEEE
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• v.23 no.4
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• pp.1280-1287
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• 2019

Grid-connected bidirectional PCS(Power Conditioning System) technology is a technology for implementing distributed renewable energy smart grid. And it is always charged by using power collected from solar modules and commercial grid power among vast smart grid systems, and stored when needed.It is a hybrid energy storage device that allows power to be released into the low voltage system. To this end, a PV input power converter with MPPT function, a bidirectional power converter for battery charging and discharging, and a DC Link input are output to a 3 phase 380V AC system, and if nessary, the bidirectional DC/DC converter We designed and developed a PCS with three power converter structures composed of inverters that perform battery charging. Currently, this system is applied to the site of Jeju, which is vulnerable to power outages and fire accidents.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.4
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• pp.102-108
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• 2010

The photovoltaic system changes solar energy into DC by solar cell and this DC is inverted into AC which is used in general houses by inverter. Recently, the use of power of the photovoltaic system is increased. Therefore, the study of 3 phase solar system to transmit large power is very important. This paper proposes a method that finds simply faults and diagnoses the switch open faults of 3-phase pulse width modulation (PWM) inverter of grid-connected photovoltaic system. The proposed method in $\alpha\beta$ plane uses the patterns of trajectory image as the characteristic parameters and differenciates a normal state and open states of switches. Then, the result is made into tree. The tree is composed of 21 fault patterns and the parameters to classify faults are a shape, a trajectory area, a distributed angle, and a typical vector angle. The result shows that the proposed method diagnosed fault diagnoses, classified correctly them, and made a pattern tree by fault patterns.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.89-90
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• 2011

본 논문에서는 스마트그리드 시스템의 안정적인 운전을 위한 핵심적인 요소인 고압의 에너지저장장치를 충방전 할 수 있는 BESS 시스템을 제안한다. 제안한 BESS 시스템용 전력변환장치는 배터리 밸런싱 회로를 적용하여 저압의 배터리 모듈을 직렬로 구성하여 양방향 DC/DC 컨버터 없이 양방향 DC/AC 인버터만으로 BESS 시스템을 구성할 수 있다. 제안한 BESS 시스템의 충방전 시 특성을 살펴보고 50kW급 BESS 시스템을 통해 유용성을 확인한다.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.971-973
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• 2001

This paper shows how to design a Global control, using Field Orientation, avoiding to use the DC/DC converter, and finding the relationships among the DC magnitudes and AC ones. And This paper deals with water pumping system which economic and durable storage systems for sustained production of power and propose MPPT methods using $i_{qs}$ of BLDC motor without battery module and chopper circuit.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.185-187
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• 2006

본 논문은 신 발전 방식들 중 하나인 용융탄산염형 연료전지 발전시스템의 국산화연구와 관련하여, 연료전지로부터 생성된 전력을 전력계통에 안정되게 변환, 주입하기 위한 계통연계형 전력변환기를 제작하고 단위기기별 성능 시험을 수행한 결과이다. 250kW급 전력변환기의 구조 설계와 단위기기 설계는 250kW급 용융탄산염형 연료전지 시스템의 정격 사양 및 스택의 운전 형태를 시뮬레이션 하여 진행되었으며, 크게 DC/DC 컨버터부와 DC/AC 인버터부의 회로로 구성된다.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.147-148
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• 2018

본 논문에서는 SiC를 이용한 신재생 에너지용 다중입력 PCS를 개발하였다. 제안하는 PCS는 풍력, 태양광, 배터리를 포함하는 다중입력 구조를 갖고 2단 방식으로 비절연 DC-DC 컨버터가 전압, 전류 및 양방향 제어를 하고 DC-AC 인버터가 단상 계통연계, 독립운전을 지원한다. 또한 SiC Mosfet을 사용하여 수동소자 크기를 최소화 하고 고효율 동작을 달성하였다. 제안하는 PCS의 동작모드를 제시하고 시작품을 통해 본 논문의 타당성을 검증하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1796-1801
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• 2008

In this paper, a new current based maximum power point tracking (CMPPT) method is proposed for a single phase photovoltaic power conditioning system and the current based MPPT modifies incremental conductance method. The current based MPPT method makes the entire control structure of the power conditioning system simple and uses an inherent current source characteristic of solar cell array. In addition, digital phase locked loop using an all pass filter is introduced to detect phase of grid voltage as well as peak voltage. Controllers about dc/dc boost converter, dc-link voltage, dc/ac inverter is designed for a coordinated operation. Furthermore, PI current control using a pseudo synchronous d-q transformation is employed for grid current control with unity power factor. 3kW prototype photovoltaic power conditioning system is built and its experimental results are given to verify the effectiveness of the proposed control schemes.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.254-256
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• 2007

The Solar energy is either used as a solar thermal energy or converted to electrical power through power conversion system. The latter method is defined as a solar cell changing the solar energy into the direct electric energy or power conversion that convert the dc power into ac power.For the solar cell to be a practical alternative energy, the study should be focused not only on the solar cell ,but also the power conversion system for common power source. In this study, we get the suitable power to common load ,using Ag Grid DSC(Dye-sensitized solar cell). Our purpose is to achieve the common solar cell power generation system ,using converter and PWM(Pulse width modulation) inverter system controled by DSP.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.45-50
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• 1998

In recent year, inverters and cycloconverters system are widely used for fed induction motor drives. Motor drives by cycloconverter is possible to frequency have been directly changed without AC/DC converter, so that circuits is simpler than inverter. A aims of this paper is the control strategy and hardware design for vector control system by cycloconverter fed induction motor drives. In this paper, Algorithm of vector control is derivlid from the model of controlled current source-fed induction motor. Vector control system is implemented using these algorithm and a pulse width controled cycloconverter using a SCR. Cycloconverter of vector control system is controlled by pulse width of SCR's trigger signal. pulse width is controlled primary command current $li_1l$ and frequency TEX>$\omega_1$..

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1515-1522
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• 2011

This paper proposes the algorithm for the output AC voltage control of Z-source inverter by the detection of the input DC voltage and Z-network capacitor voltage. The actual modulation index of the proposed method is detected by the capacitor voltage in Z-network and input DC voltage of three-phase Z-source inverter. Control modulation index for the output voltage control is calculated by the detected actual modulation index and reference modulation index. And, calculated control modulation index is applied to the modified space vector modulation (SVM) for control the output voltage of Z-source inverter. To verify the validity of the proposed method, PSIM simulation was achieved and a DSP controlled 1[kW] three-phase Z-source inverter was producted. The simulation and experiment were performed under the condition that the load was changed in case of the constant input DC voltage and the input DC voltage was changed in case of the load was constant. As a result, we could know that the output phase voltage of Z-source inverter followed to the reference voltage 70[VRMS] despite the load or the input DC voltage were suddenly changed.