• Proceedings of the KIPE Conference
• /
• 2019.11a
• /
• pp.218-219
• /
• 2019

본 논문은 모드 유지 알고리즘이 적용된 직류 배전용 에너지 저장 장치(Energy Storage System, ESS)의 모듈형 운전 제어 기법에 관해 제안한다. 모드 유지 알고리즘은 설정된 방전 깊이(Depth of Discharge, DoD) 내에서 계통의 전력 수요 및 공급의 변화가 생긴 경우에 수시로 변화하는 충/방전 모드의 변경을 제한하는 알고리즘이다. 이를 통해 ESS의 가용 용량을 최대한 사용 가능하며, 계통의 전력 공급 및 부하 수요에 따라 계통의 동작 상태를 결정할 때 도움을 줄 수 있다. 제안한 알고리즘은 PSIM 시뮬레이션을 통해 검증하였다.

• Proceedings of KOSOMES biannual meeting
• /
• 2017.11a
• /
• pp.42-42
• /
• 2017

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.53 no.5
• /
• pp.248-252
• /
• 2004

Since DC ground resistance, which is a good index of the performance of a grounding system in low frequency. does not show the performance in transient state. We measured ground impedances in frequency domain ranging from 0.1 Hz to 900 KHz maximum to quantify the transient grounding performance of 4 types of grounding system. Transfer function was derived from the measured frequency-dependant ground impedance of a grounding grid. A simulation has been performed to verify the transfer function using EMTP (Electro-Magnetic Transient Program).

• Journal of Power Electronics
• /
• v.7 no.3
• /
• pp.203-212
• /
• 2007

In this paper, a proposed approach to improve the power factor of three-phase rectifiers and to stabilize the output voltage against load change is presented. The elements of the given control strategy are small size, low cost, high performance, and simplicity. The proposed control strategy of switches is based on a prototype of three bi-directional switched consisting of four diodes and one IGBT. A control technique and operational procedure are also developed, both theoretically and experimentally. The experimental results clearly verify the theoretical analysis from the prototype connected to grid unity.

• Proceedings of the KIPE Conference
• /
• 2017.07a
• /
• pp.329-330
• /
• 2017

본 논문에서는 계통 연계 단상 인버터의 양방향 모드 전환을 위한 새로운 제어 기법을 제안하였다. 일반적으로 DC 측과 AC 측 사이의 전력 흐름은 d-q 동기 회전 좌표계에서 계통 연계 인버터의 전류 지령치에 의해 제어된다. 따라서 전력 흐름의 방향이 변경되면 전류 지령치를 반전하는 것이 일반적이다. 그러나 전류의 급격한 변화를 초래하고 과도상태가 길어지는 등 AC 측의 전력 품질을 악화시킨다. 따라서 본 논문에서는 동기 회전 좌표계에서의 원활한 모드 전환을 위한 향상된 제어 기법을 제안한다. 이론적 분석과 시뮬레이션 결과로 제안된 제어 기법의 타당성을 입증한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.1
• /
• pp.36-44
• /
• 2014

The conventional central photo voltaic inverters have several problems. First, shadow problem in each solar panel, and high DC voltage problem from each panel because of concentration to one central inverter. Therefore, module integrated inverter is proposed to solve these problems. The inverter should be small and cost effective. The cost and size in the inverter depend on the inductor. So the switching frequency should be increased to reduce the inductor and total size, but there is a problem in efficiency because of the losses in turn-on and turn-off. In the paper, the critical conduction mode(CRM) switching method is adopted to reduce the switching loss and interleaving method is proposed to increase the efficiency in Flyback converter. Finally, the validity of the proposed scheme is investigated with simulated and experimental results for a prototype system rated at 200W.

• Journal of Power Electronics
• /
• v.15 no.4
• /
• pp.1035-1046
• /
• 2015

This study presents a practical implementation of a multi-mode two-phase interleaved boost converter for fuel cell electric vehicle application. The main operating modes, which include two continuous conducting modes and four discontinuous conducting modes, are discussed. The boundaries and transitions among these modes are analyzed with consideration of the inductor parasitic resistance. The safe operational area is analyzed through a comparison of the different operating modes. The output voltage and power characteristics with open-loop or closed-loop operation are also discussed. Key performance parameters, including the DC voltage gain, input ripple current, output ripple voltage, and switch stresses, are presented and supported by simulation and experimental results.

• Proceedings of the KIPE Conference
• /
• 2012.07a
• /
• pp.313-314
• /
• 2012

In this paper presents study of T-Type multi level inverter for utility interactive photo voltaic inverter. In order to increase efficiency and performance of utility interactive photo voltaic (UIPV) system, we propose multi level PCS topology, such as T-type inverter. The control algorithm for utility interactive inverter is implemented by simulation and experimentation, which includes dc-bus and midpoint voltage controller, ac-grid current controller and PLL algorithm.

• Proceedings of the KIPE Conference
• /
• 2015.11a
• /
• pp.199-200
• /
• 2015

본 논문에서는 Online UPS system에 계통 연계가 가능하며, 피크 전력을 저감 할 수 있는 기능을 추가한 UPS를 제안한다. 제안한 UPS는 계통 연계와 피크 전력 저감을 위하여 AC/DC PWM 컨버터와 배터리 단에 양방향 Buck-Boost 컨버터를 적용하였으며 역률 0.98 이상과 THD를 3%이하의 조건을 만족하고 IGBT의 신뢰성 확보를 위한 발열 및 방열을 검토한다.

• Proceedings of the KIPE Conference
• /
• 2010.11a
• /
• pp.276-277
• /
• 2010

This paper describes the control of a utility-connected doublefed induction machine (DFIM) for wind power generation systems (WPGS). Real and reactive powers (PQ) at the stator side of DFIM are strictly controlled to supply the power to the grid without any problems. In this paper the control is realized using Fuzzy PI controller based on the stator-flux orientation control.