• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.51-52
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• 2012

Among the PV-AC module topologies, the flyback inverter have been occupied the attention due to its simplicities on configuration and control. Proposed switching control method changes the mode of operation in DCM and BCM alternatively. It is expected that the high performances in efficiency and extension of input voltage range can be achieved by the conduction mode change. Proposed switching technique is validated by PSIM simulation.

• 전기학회논문지
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• 제61권3호
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• pp.361-366
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• 2012

This paper analyzes the THD(Total Harmonics Distortion) according to output power fluctuation of photovoltaic(PV) systems using real time simulator. For being close to reality, the PV system including inverter and MPPT(Maximum Power Point Tracking) which composed of closed-loop using real-time simulator are modeled. The change of irradiance and temperature of PV module is modeled to consider the change of weather. The various simulations according to the weather conditions are performed and THD is calculated at each condition. In this paper, the results by off-line simulation are compared with the ones of real time simulation.

• Transactions on Electrical and Electronic Materials
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• 제17권1호
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• pp.21-24
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• 2016

A junction box used in a 3 kW photovoltaic power generation system plays a role in collecting and supplying the direct current voltage produced by photovoltaic modules to an inverter. It is also used for facilitating maintenance checks and protecting the module and inverter by keeping the voltage constant. As for the junction box, using it in a parallel connection creates a difference between the setup modules. In order to compensate, an inverse voltage diode is used. But the high-power created through the solar generator can be delivered to the inverter through the inverter regularly. Therefore, a component can break down due to excess heat. And consequently short circuits and electric leakage occurs. In this study, using a junction box that enabled the bypass of high electric power, it was possible to reduce heat generation by approximately 35℃ when compared to a standard junction box.

• 한국정보통신학회논문지
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• 제20권10호
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• pp.1949-1954
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• 2016

스마트 그리드(smart grid) 기술은 전력 공급자와 소비자 사이를 실시간으로 전력정보를 교환함으로써 전력의 효율성을 높이는 전력망 관리 기술이다. 최근에는 유지보수 및 설치가 용이한 태양광 발전시스템에 대한 적용이 늘고 있다. 그러나 태양광 발전 시스템은 고장진단이 어려우며, PV(PhotoVoltaics) 어레이 및 인버터(inverter) 등의 결함과 기타 잠재적인 출력저하 요소로 인하여 발전량이 감소하기도 한다. 이처럼 태양광 발전 시스템을 통하여 안정적인 에너지 포집과 관리 및 조속한 고장 검출이 필수 요구사항이라 할 수 있다. 본 논문에서는 태양광 발전 시스템을 대상으로 전력 생산량 및 이상 동작 현상을 모니터링하고 외부 환경을 계측하는 계측모듈을 개발하고, 계측된 정보 데이터를 전송할 수 있는 통신모듈을 통하여 원격지에서 태양광 발전 시스템의 동작 상태를 모니터링 하도록 설계하였다. 또한 스마트폰을 기반으로 구축된 태양광 발전 시스템을 실시간으로 관리하고 모니터링 할 수 있는 모바일 관리 시스템을 제시하고자 한다.

• 대한전기학회논문지:전력기술부문A
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• 제54권3호
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• pp.107-116
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• 2005

The paper addresses modeling and analysis of a grid-connected photovoltaic generation system (PV system). PSCAD/EMTDC, an industry standard simulation tool for studying the transient behavior of electric power system and apparatus, is used to conduct all aspects of model implementation and to carry out extensive simulation study. This paper is aimed at sharing with the PSCAD/EMTDC user community our user-defined model for PV system applications, which is not yet available as a standard model within PSCAD/EMTDC. An equivalent circuit model of a solar cell has been used for modeling solar array. A series of parameters required for array modeling have been estimated from general specification data of a solar module. A PWM voltage source inverter (VSI) and its current control scheme have been implemented. A maximum power point tracking (MPPT) technique is employed for drawing the maximum available energy from the PV array. Comprehensive simulation results are presented to examine PV array behaviors and PV system control performance in response to irradiation changes. In addition, dynamic responses of PV array and system to network fault conditions are simulated and analysed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
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• pp.204-207
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• 2004

The paper proposes a simulation model of grid-connected photovoltaic generation system (PV system) using on PSCAD/EMTDC, a reliable power system and apparatus transient analysis program. A equivalent circuit model of a solar cell is used for modeling solar array. A series of parameters required for array modeling are deduced from general specification data of a solar module. A PWM voltage source inverter (VSI) model is presented and current control scheme is implemented for VSI control. A maximum power point tracking (MPPT) technique is applied for controlling the PV system. Simulation case study provides V-I and V-P characteristics of solar array and PV system control performance for irradiation changes.

• Journal of Power Electronics
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• 제19권6호
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• pp.1403-1412
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• 2019

A coupled inductor-dual boost-inverter (CIDBI) with a differential structure has been presented for application to a micro-inverter photovoltaic module system due to its turn ratio of a high-voltage level. However, it is difficult to design a CIDBI converter with a conventional PI regulator to be stable and achieve good dynamic performance, given the fact that it is a high order system. In view of this situation, a sliding mode control (SMC) strategy is introduced in this paper, and two different sliding mode controllers (SMCs) are proposed and adopted in the left and right side of two Boost sub-circuits to implement the corresponding regulation of the voltage and current. The schemes of the SMCs have been elaborated in this paper including the establishment of a system variable structure model, selection of the sliding surface, determination of the control law, and presentation of the reaching conditions and sliding domain. Finally, the mathematic analysis and the proposed SMC are verified by experimental results.

• 한국정보전자통신기술학회논문지
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• 제14권1호
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• pp.56-69
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• 2021

상용계통과 연계한 PV 시스템은 인버터의 특성과 더불어 소형, 고 역률, 낮은 고조파 출력, 고 신뢰성, 최대출력 운전, 저비용 등의 장점이 요구된다. 태양광발전시스템의 PV 에너지를 계통과 부하로 전달하기 위해 양방향의 PCS가 요구되어 진다. 본 논문에서는 태양광 발전의 ESS를 고려한 PCS를 제안하여 부하평준화를 통한 전력의 안정적인 공급을 확인하고자 한다. 이를 위해 일사량과 부하량에 따른 5단계의 동작 모드 알고리즘을 제안하고, 충/방전 제어를 위한 제어기를 설계 하였다. 양방향의 효율적인 에너지 전달을 위해 DC-link단에 양방향 컨버터 및 배터리를 연결하고, 연계형 인버터를 통해 DC-link 전압 및 인버터 출력전압을 제어하였다. 제안된 시스템의 타당성을 입증하기 위해 PSIM을 사용한 시뮬레이션을 수행하여 타당성과 안정성을 검토하였으며, 이를 확인하기 위해 3[kW] PCS를 제작하여 실험하였다. 실험결과를 통해 제안된 시스템에 요구되어지는 특성을 검증하였으며 기존 시스템에 비해 강인한 시스템을 구성하였다.

• Journal of Power Electronics
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• 제17권1호
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• pp.222-231
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• 2017

In this paper, a new architecture for a cost-effective power conditioning systems (PCS) using a single-sourced asymmetric cascaded H-bridge multilevel inverter (MLI) for photovoltaic (PV) applications is proposed. The asymmetric MLI topology has a reduced number of parts compared to the symmetrical type for the same number of voltage level. However, the modulation index threshold related to the drop in the number of levels of the inverter output is higher than that of the symmetrical MLI. This problem results in a modulation index limitation which is relatively higher than that of the symmetrical MLI. Hence, an extra voltage pre-regulator becomes a necessary component in the PCS under a wide operating bias variation. In addition to pre-stage voltage regulation for the constant MLI dc-links, another auxiliary pre-regulator should provide isolation and voltage balance among the multiple H-bridge cells in the asymmetrical MLI as well as the symmetrical ones. The proposed PCS uses a single-ended DC-DC converter topology with a coupled inductor and charge-pump circuit to satisfy all of the aforementioned requirements. Since the proposed integrated-type voltage pre-regulator circuit uses only a single MOSFET switch and a single magnetic component, the size and cost of the PCS is an optimal trade-off. In addition, the voltage balance between the separate H-bridge cells is automatically maintained by the number of turns in the coupled inductor transformer regardless of the duty cycle, which eliminates the need for an extra voltage regulator for the auxiliary H-bridge in MLIs. The voltage balance is also maintained under the discontinuous conduction mode (DCM). Thus, the PCS is also operational during light load conditions. The proposed architecture can apply the module-integrated converter (MIC) concept to perform distributed MPPT. The proposed architecture is analyzed and verified for a 7-level asymmetric MLI, using simulation results and a hardware implementation.

• 한국수소및신에너지학회논문집
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• 제17권3호
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• pp.338-346
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• 2006

In this paper, the test results of medium-size(120 kW class) PV system which was installed in the Taeahn thermal power station of Korea Western Power Co., Ltd., were summarized for developing the practical technology to applicate high voltage grid connection PV system. The 120 kW photovoltaic system which was consisted of 1,300 modules, PCS, and 150 kVA transformer station has been operated since Aug. 05, 2005. For verifying the modeling results of PV system, the operation data was compared with modeling results which was executed commercial PSCAD/EMTD and Psim tools. An equivalent circuit model of a solar cell has been also used for solar array modeling. A series of parameters required for array modeling have been estimated from general specification data of a solar module. A PWM voltage source inverter(VIS) and its current control scheme have been analyzed by using P&O (perturbation and Observation) MPPT algorithms technique.