• 디지털산업정보학회논문지
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• 제17권1호
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• pp.1-6
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• 2021

In this paper, to expand the use of standalone street lights, an algorithm for controlling LED energy consumption was proposed. The proposed method uses an LED module of a standalone street light divided into n zones. This is a method of reducing total power consumption by preventing the increase in power consumption due to high heat generation by weakly operating the entire LED according to the illuminance. When the amount of sunlight decreases, the whole LED operates weakly and then brightens, and unlike streetlight that act as streetlight, a method of dividing LEDs by area and limiting the number of LEDs operating according to illumination intensity was proposed. This is a way to use a lot of time with limited battery capacity by reducing the generation of heat that consumes the most power in streetlight. It is also a method of continuously changing the initial usage area to improve the total usage time of the LED substrate. As a result of the experiment, it was found that the proposed method extends the service time because it generates less heat than the conventional stand-alone streetlight.

• Journal of Power Electronics
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• 제17권4호
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• pp.1027-1036
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• 2017

The brushless doubly-fed induction generator (BDFIG) is a new type of dual stator winding induction generator. In such a generator, both the power winding (PW) and the control winding (CW) are housed in the stator. This paper presents the performance characteristics of a stand-alone BDFIG operation system. A new T-type steady-state model of a BDFIG is proposed. This model is more suitable for the performance analysis of stand-alone BDFIGs than the conventional Π-type steady-state model and the simplified inner core steady-state model. The characteristics of the power flow and CW current are analyzed by detailed mathematical derivations on the basis of the proposed T-type steady-state model. The analysis results are verified by experiments, which are carried out on a prototype BDFIG. The results of the performance analysis contribute to simplifying the control circuit, improving the control performance, and selecting an appropriate BDFIG for actual industrial applications.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.206-209
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• 2003

This paper deals with stand-alone PV power generation system with charge and discharge controller for the LED road sign. Main power source of PV system are generally solar cell and battery. Therefore PV system can be classified into variable types in accordance with connection type between battery and solar sell. Mainly used on of them is direct connection type which has advantage such as simple structure and simple controller. To verify the proposed PV generation system for the LED road sign, the detail simulation and experiment results indicate that operating characteristics are verified by experiment with a laboratory prototype in this paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 F
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• pp.1942-1944
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• 1997

This paper presents a 10kW stand-alone photovoltaic power generation system with uninterruptible power system facility and its simple topology. The system s based on a DC/DC converter for a photovoltaic energy conversion, a four switch IGBT PWM inverter, a battery, and DSP controller.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.338-340
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• 2003

This paper proposes a stand-alone adjustable speed wind Power generation system using a cage-type induction generator. Indirect vector control is used, where the q-axis current controls the generator speed and the d-axis current controls the excitation level. The generator speed is adjusted according to the wind speed so as to produce the maximum output power. The generated power is charged in the battery bank through ac/dc PWM converter. The proposed scheme has been verified by the experimental results.

• Journal of Power Electronics
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• 제13권6호
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• pp.1070-1079
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• 2013

This paper develops an enhanced harmonic voltage compensator which is implemented with the aid of two repetitive controllers (RCs) in order to improve the output voltage performance of stand-alone distributed generation (DG) systems. The proposed harmonic voltage compensator is able to maintain the DG output voltage sinusoidal regardless of the use of nonlinear and/or unbalanced loads in the load side. In addition, it can offer good steady-state performance under various types of loads and a very fast dynamic response under load variations to overcome the slow dynamic response issue of the traditional RC. The feasibility of the proposed control strategy is verified through simulations and experiments.

• 전력전자학회논문지
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• 제9권1호
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• pp.73-80
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• 2004

본 논문에서는 농형유도발전기를 이용한 독립형 풍력발전시스템의 최대전력 추종제어기법을 제안한다. 농형 유도발전기는 벡터제어 방식으로 동작되는데 d-축 전류에 의해 여자가 제어되고 q-측 전류에 토크가 제어된다. 이 토크제어에 의해 발전기는 풍속의 변화에 따라 최대전력을 발생하도록 가변속 제어된다. 발전된 전력은 ac/dc PWM 컨버터에 의해 직류 출력단 배터리뱅크로 충전된다. 제안된 기법은 M-G세트로 구성된 터빈시뮬레이터를 이용하여 실험적으로 검증된다.

• 디지털산업정보학회논문지
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• 제12권2호
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• pp.1-6
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• 2016

Several efforts to replace the use of existing fossil energy resources have already been made around the world. As a result, a new industry of renewable energy has been created, and efficient energy distribution and storage has been promoted intensively. Among the newly explored renewable energy sources, the most widely used one is solar energy generation, which has a high market potential. An energy storage system (ESS) is a system as required. In this paper, the design and implementation of an ESS for the efficient use of power in stand-alone street lights is presented. In current ESS applied to stand-alone street lights, either 12V~24V DC (from solar power) or 110V~220V AC (from commercial power) is used to recharge power in systems with lithium batteries. In this study, an ESS that can support both solar power and commercial power was designed and implemented; it can also perform emergency recharge of portable devices from solar powered street lights. This system can maximize the scalability of ESSes using lithium batteries with efficient energy conversion, with the advantage of being an eco-friendly technology. In a ripple effect, it can also be applied to smart grids, electric vehicles, and new, renewable storage markets where energy storage technology is required.

• 한국전자통신학회논문지
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• 제10권4호
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• pp.527-532
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• 2015

국내 섬지역의 전력 수급은 계통 연계가 어려워 일반적으로 디젤 발전기에 의존하고 있어 관리 비용이 매우 높다. 이러한 문제를 해결하기 위해 최근 계통 독립형 마이크로그리드 기술에 대한 연구 및 실증이 활발히 진행 중이다. 본 논문은 에너지 자립섬을 위한 계통 독립형 마이크로그리드 통합 모니터링 시스템을 제안한다. 먼저 태양광, 풍력, 디젤 발전설비, 송 배전망의 상태 및 부하, 그리고 에너지 저장 시스템의 모니터링을 위한 소프트웨어 시스템 아키텍처를 설계한 후 관리자가 쉽게 파악할 수 있는 모니터링 소프트웨어를 구현한다. 구현된 모니터링 소프트웨어는 발전설비의 상태 및 오류를 실시간으로 시각화함으로써 관리자의 신속한 의사 결정이 가능하다.

• 전력전자학회논문지
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• 제12권2호
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• pp.131-138
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• 2007

본 논문은 출력단에 LC필터를 갖는 3상 PWM 인버터의 출력전압을 일정전압/일정주파수로 제어하기 위한 새로운 비선형 제어기법을 제안한다. 출력 LC필터를 포함한 비선형 모델을 궤환선형화(feedback linearization) 이론을 통하여 선형화하고 선형 제어이론에 기초하여 제어기를 설계한다. 이 제어기는 LC 출력필터를 갖는 PWM 인버터를 사용하는 독립형 풍력발전 시스템에 적용된다. 제안한 제어기법은 정상상태와 부하변동의 과도상태에 대한 실험을 통하여 검증된다.