• Journal of Power Electronics
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• 제13권2호
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• pp.313-321
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• 2013

This paper describes the operation analysis results of a communication-based DC micro-grid using a hardware simulator developed in the lab. The developed hardware simulator is composed of distributed generation devices such as wind power, photovoltaic power and fuel cells, and energy storage devices such as super-capacitors and batteries. Whole system monitoring and control was implemented using a personal computer. The power management scheme was implemented in a main controller based on a TMS320F28335 chip. The main controller is connected with the local controller in each of the distributed generator and energy storage devices through the communication link based on a CAN or an IEC61850. The operation analysis results using the developed hardware simulator confirm the ability of the DC micro-grid to supply the electric power to end users.

• 제어로봇시스템학회논문지
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• 제22권5호
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• pp.315-319
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• 2016

This paper proposes a simple adaptive sliding mode control algorithm for controlling a permanent magnet synchronous generator (PMSG) of a MW-class direct-driven wind turbine system. The proposed adaptive sliding mode controller does not require accurate knowledge of the PMSG parameter or turbine torque values. The proposed controller can accurately track the reference angular speed computed by the maximum power point tracking(MPPT) algorithm. Finally, this paper gives Matlab/Simulink simulation results to verify the practicality and effectiveness of the proposed adaptive sliding mode controller.

• 조명전기설비학회논문지
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• 제25권8호
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• pp.48-59
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• 2011

This paper presents a new gain scheduling speed controller of permanent magnet synchronous generators(PMSG) for MW-class direct-driven wind turbine systems. The proposed gain scheduling speed controller performs the speed tracking at more than one operating point, and the first-order torque observer estimates the turbine torque which is needed to precisely control the speed of PMSG. The proposed speed controller verifies that the PMSG can successfully follow the reference speed which is determined via the maximum power point tracking(MPPT) control and pitch control under turbulent wind conditions. The proposed speed control algorithm is simulated using Simulink and its performance is confirmed through comparison with the results by PI control method.

• 한국산학기술학회논문지
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• 제7권5호
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• pp.963-969
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• 2006

본 연구에서는 태양광 발전시스템의 최대전력추종을 위해 퍼지 이론을 도입한 디지털 퍼지제어기를 설계하였다. 그리고 퍼지제어기의 디지털 설계를 위해 소용량 태양광 발전시스템의 각 부분을 구성하고 이를 적용하여 기존의 제어기와 비교 실험하였다. FPGA로 구현된 제어기는 기존의 마이크로프로세서로 구현된 제어기에 비해 일사량 변화에도 출력전압의 변동이 적은 안정적인 동작특성을 보였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.261-264
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• 2006

In this paper, doubly-fed induction-type wind power generation system simulation model for grid connection is developed. The simulation model is based on PSCAD/EMTDC and consists of rotor-blade, blade controller, generator power converter and generator controller Blade controller controls the blade pitch angle for starting, peak power limiting and emergency condition. Generator controller controls the generator output power to maximize the system efficiency. Simulation results are shown for the variable wind speed conditions. The simulation model can be utilized for study of actual interaction between wind turbine and grid for reliable operation and protection of power system.

• 전기전자학회논문지
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• 제20권1호
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• pp.45-53
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• 2016

본 논문에서는 진동에너지 수확을 위한 MPPT (Maximum Power Point Tracking) 제어 기능을 갖는 CMOS 인터페이스 회로를 설계하였다. 간단한 구조와 적은 비용으로 출력을 안정화시키기 위해 전력변환기인 DC-DC 부스트 변환기의 출력 단에 PMU (Power Management Unit)를 이용하는 구조를 제안하였다. 또한, 진동소자로부터 최대전력을 수확하여 시스템의 효율을 향상시키기 위해 FOC (Fractional Open Circuit) 방식의 MPPT 제어회로를 설계하였다. 진동소자 (PZT)에서 출력되는 AC 신호는 AC-DC 변환기를 통해 DC 신호로 변환되며, DC-DC 부스트 변환기를 거쳐 승압되고, PMU에 의해 듀티 (duty)를 갖는 안정화된 신호로 변환되어 부하로 공급된다. AC-DC 변환기는 효율 특성이 좋은 능동 다이오드를 이용한 전파정류기를 사용하였으며, DC-DC 부스트 변환기는 제어회로가 간단한 쇼트키 다이오드를 이용한 구조를 사용하였다. 제안된 회로는 $0.35{\mu}m$ CMOS 공정으로 설계되었으며, 설계된 칩의 면적은 $915{\mu}m{\times}895{\mu}m$이다. 설계된 회로의 성능을 검증한 결과 전체회로의 최대 전력효율은 83.4%이다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.173-174
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• 2016

This paper proposes a comparison of Voltage Oriented Control (VOC) and Direct Power Control (DPC) under command mode transition for PMSG Wind Turbines (WT). Based on a neutral point clamped three level back to back type Voltage Source Converter (VSC), proposed control scheme automatically control the generated output power to satisfy a grid requirement from the hierarchical wind farm controller. Automatic command mode transition based on the dc-link voltage error provides a command mode changing between grid command and MPPT mode. It is confirmed through PLECS simulations in Matlab. Simulation result shows that proposed control scheme of VOC and DPC achieves a much shorter transient time of generated output power than the conventional control scheme of MPPT with optimal torque control and VOC under a step response. The proposed control scheme makes it possible to provide a good dynamic performance for PMSG wind turbines in order to generate a high quality output power.

• 전기학회논문지P
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• 제66권4호
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• pp.267-273
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• 2017

In recent years, there is an increasing demand for DC microgrid because the digital load due to DC increases and the efficiency of the distribution system increases due to loss of conversion losses and conversion stages due to reactive power compared to AC distribution. Currently, with the support of the KEPRI, the development of an electronic large-capacity circuit breaker for DC distribution protection, which has been underway since 2016, is proceeding. In this paper, as a part of this project, we modeled the DC microgrid connected with PV using PSCAD. The converter station, AC/DC converter control, PV and MPPT controller are designed. In order to evaluate the performance of the modeled DC microgrid, it is examined whether the voltage is adjusted according to the load variation.

• 신재생에너지
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• 제1권2호
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• pp.11-18
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• 2005

A modular photovoltaic PCS with high-frequency isolation is proposed. The proposed system consists of a SEPIC converter and a full-bridge inverter Using the power slope versus voltage of the PV array, the MPPT controller is proposed that produces a smooth transition to the maximum power point. The dc current of the PV array is estimated without using a dc current sensor The disturbance of the line voltage is detected using a fast sensing technique. Experimental results obtained on a 500W prototype show high performance such as almost unity power factor, $90\%$ power efficiency, $3.6\%$ THD.

• 전기학회논문지
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• 제59권10호
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• pp.1845-1849
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• 2010

We have proposed and fabricated a Buck-Boost DC to DC Converter for Thermoelectric generator (TEG) with constant output voltage suitable for battery chargers or constant voltage supplies in the range of several watt. The experimental and simulation results have shown that the proposed method allows stable operation with maximum 86% power transfer efficiency. The proposed circuit has a merit in cost and miniaturization of a system compared to conventional MPPT algorithms, because the proposed method adopts only analog circuit without DSP or micro controller unit for calculating peak power point by iterative methods.