• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 추계학술대회
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• pp.111-112
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• 2017

This paper presents a novel three-port converter for the OnBoard Charger of Electric Vehicles by using an impedance control network. The proposed concept is suitable for charging a main battery and an auxiliary battery of an electric vehicle at the same time due to its power handling capability of the converter without additional switches. The power flow is managed by the phase angle (${\Theta}$) between the ports whereas voltage at each port is controlled by the asymmetric duty cycle and the phase shift (${\Phi}$) between the inverter lags controlled by the impedance control network. The proposed system has a capability of achieving zero voltage switching (ZVS) and zero current switching (ZCS) at all the switches over the wide range of input voltage, output voltage and output power. The feasibility of the proposed system is verified by the PSIM simulation.

• Journal of Power Electronics
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• 제17권3호
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• pp.756-765
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• 2017

The control of the power conversion system (PCS) in a battery energy storage system has a challenge due to the existence of grid impedance. This paper studies an impedance model of an LCL-based PCS in the d-q domain. The feature of a PCS connected to a weak grid is unveiled by use of an impedance model and a generalized Nyquist criterion. It is shown that the interaction between grid impedance and the PCS destabilizes the cascaded system in certain cases. Therefore, this paper proposes a novel control method that adopts virtual resistors to overcome this issue. The improvement in the control loop leads the PCS to a more stable condition than the conventional method. Impedance measurement is implemented to verify the correctness of the theoretical analysis. Experimental results obtained from a down-scaled prototype indicate that the proposed control method can improve the performance of the PCS under a weak grid.

• Journal of Power Electronics
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• 제10권5호
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• pp.538-547
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• 2010

This paper deals with a stand-alone wind energy conversion system (WECS) with an isolated asynchronous generator (IAG) and voltage and frequency (VF) control feeding three-phase four-wire loads. The reference generator currents are estimated using the instantaneous symmetrical component theory to control the voltage and frequency of an IAG system. A three-leg voltage source converter (VSC) with an isolated star/delta transformer is used as an integrated VSC. An integrated VSC with a battery energy storage system (BESS) is used to control the active and reactive powers of the WECS. The WECS is modeled and simulated in MATLAB using the Simulink and the Sim Power System (SPS) toolboxes. The proposed VF controller functions as a voltage and frequency regulator, a load leveler, a load balancer and a harmonic eliminator in the WECS. A comparison is made on the rating of the VSC with and without ac capacitors connected at the terminals of an IAG. Simulation and test results are presented to verify the control algorithm.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.1072-1079
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• 2014

This paper introduces a coordinated droop control for the stand-alone DC micro-grid, which is composed of photo-voltaic generator, wind power generator, engine generator, and battery storage with SOC (state of charge) management system. The operation of stand-alone DC micro-grid with the coordinated droop control was analyzed with computer simulation. Based on simulation results, a hardware simulator was built and tested to analyze the performance of proposed system. The developed simulation model and hardware simulator can be utilized to design the actual stand-alone DC micro-grid and to analyze its performance. The coordinated droop control can improve the reliability and efficiency of the stand-alone DC micro-grid.

• 전력전자학회논문지
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• 제5권5호
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• pp.467-474
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• 2000

본 논문에서는 배터리를 사용하는 유틸리티 차량용 컨트롤러 개발과 태양광 발전을 병행하여 차량의 운행시간을 보완하였다. 유틸리티 차량용 컨트롤러는 다른 컨트롤러와 호환성을 유지하고 저가격, 고성능을 위해 마이크로 프로세서를 이용하여 속도센서와 전류센서를 사용하지 않고 타여자 직류 전동기를 제어하였다. 태양광발전을 위해 DC-DC 컨버터를 이용하여 태양전지의 최대 전력점 추종 제어(MPPT)와 출력전류를 제어하여 태양전지와 배터리를 병렬운전하였다. 시스템의 타당성을 모의실험과 시제품의 실험을 통하여 검증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 추계학술대회
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• pp.131-132
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• 2018

The world market for BESS (Battery Energy Storage System) is growing rapidly, and battery technology is also developing. It is important to understand the battery characteristics and develop a control strategy to develop the optimal BMS (Battery Management System). In this paper, we compare and analyze the parameter characteristics of NCM LIB (Lithium Ion Battery) according to the temperature change.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.800-811
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• 2018

This paper presents a regenerative braking control scheme for Switched Reluctance Machine (SRM) drive in Electric Vehicles (EVs). The main purpose is to maximize the recovered energy during battery charging by taking into account the nonlinear physical characteristics of the Switched Reluctance Machine. The proposed regenerative braking method employs the back-EMF in the generation process as a complicated position-dependent voltage source. The proposed maximum power recovery (MPR) operation of the regenerative braking is first based on the maximization of the extracted power from the machine and then the maximization of the power transferred to the battery. The maximum power extraction (MPE) from SRM is based on maximizing the energy conversion ratio by the calculation of the optimum PWM switching duty cycle, turn-on, and turn-off angles. By using the impedance matching theorem that allows the maximum power transfer (MPT) of the MPE, the proposed MPR is achieved. The parametric averaged value modeling of the machine phase currents in the chopping control mode is used for MPR realization. By following this model, a nonlinear equivalent input resistance is derived for the battery internal resistance matching. The effectiveness of the proposed regenerative braking method is demonstrated through simulation results and experimental implementation.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 추계학술대회
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• pp.561-564
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• 2014

본 논문에서는 배터리 관리 기능을 갖는 빛 에너지 하베스팅 충전기 회로를 제안하였다. 제안된 회로는 MPPT(Maximum Power Point Tracking)를 통해 빛 에너지를 솔라 셀로부터 수확하고, 수확한 에너지를 외부 배터리 커패시터에 연결하여 충전한다. 배터리 관리회로(Battery Management)의 신호에 따라, 배터리 커패시터의 충전 상태를 조절한다. 제안된 회로는 0.35um CMOS 공정으로 설계하였으며, 모의실험을 통해 동작을 검증하였다. 설계된 회로의 최대효율은 84.8%이며, 칩 면적은 패드를 포함하여 $1350um{\times}1200um$이다.

• 한국정보통신학회논문지
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• 제25권11호
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• pp.1603-1611
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• 2021

본 연구에서는 에너지 저장장치인 배터리를 기존의 발전기 전력계통에 연계하기 위하여 양방향 전력의 흐름이 가능한 BDC(Bi-Directional Converter) 적용을 위해 모델링을 통하여 제어 프로세스를 설계하고, 해상 상황에 따라 변화하는 부하에 최적화된 전력 공급이 가능한 배터리의 충전 혹은 방전 메커니즘에 대하여 제안한다. 본 연구는 MATLAB/Simulink를 이용하여 BDC를 모델링 하였으며 부하 시나리오에 따라 배터리 충전 및 방전 시의 전류 제어 및 SOC(State Of Charge) 최적화를 시뮬레이션 하였다. 이를 통해 선내 운전되는 발전기가 최적운전 범위에 운전될 수 있도록 배터리와 전력 및 부하를 연동할 수 있도록 하였으며, 발전기가 높은 연료효율 범위에서 운전될 수 있도록 전력제어관리를 수행하였다.

• 전기학회논문지
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• 제61권4호
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• pp.574-579
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• 2012

In this paper, the battery charger developed which is satisfy by the characteristics of the rapid control and reduce the cost of the charger. analog-digital mixed mode controller developed with dedicated IC for PWM control and low-performance micro-processor is using for the operation control of charger. The low-cost NEV charger developed to verify the performance and usability is verified with charging battery experiment by of using developed charger.