• Journal of Power Electronics
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• 제17권6호
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• pp.1402-1412
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• 2017

This paper presents a new high step-up dc/dc converter for renewable energy systems in which a high voltage gain is provided by using a coupled inductor. The operation of the proposed converter is based on a charging capacitor with a single power switch in its structure. A passive clamp circuit composed of capacitors and diodes is employed in the proposed converter for lowering the voltage stress on the power switch as well as increasing the voltage gain of the converter. Since the voltage stress is low in the provided topology, a switch with a small ON-state resistance can be used. As a result, the losses are decreased and the efficiency is increased. The operating principle and steady-states analyses are discussed in detail. To confirm the viability and accurate performance of the proposed high step-up dc-dc converter, several simulation and experimental results obtained through PSCAD/EMTDC software and a built prototype are provided.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.143-144
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• 2016

The circulating current control within the phase legs is one of the main control objectives in a modular multilevel converter (MMC) under different operating conditions. This paper proposes a control strategy of circulating currents in the MMC under unbalanced voltage by using a proportional-resonant (PR) controller. Under the unbalanced voltage, the circulating currents in the MMC consists of three components such as positive-sequence, negative-sequence, and zero-sequence circulating currents. With the PR controller, all components of the circulating current will be directly controlled in the stationary reference frame without decomposing into positive- and negative-sequence components. Thus, the ripples in the circulating currents and the DC current are suppressed under the unbalanced voltage. The effectiveness of the proposed method is verified by simulation results based on PSCAD/EMTDC simulation program.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.232-233
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• 2016

본 논문은 계통과 연계된 3상 전압원 인버터를 기반으로 한 BESS의 능동 단독 운전 검출 방법을 제안한다. 제안하는 기법은 PR제어기와 필터를 가지고 기본파 전류와 2차 고조파 전류를 이용해 수행하였다. 단독운전은 BESS로부터 정격전류의 1% 2차 고조파를 주입하기 때문에 PCC점에서의 2차 고조파 전압 변화량을 검출 할 수 있다. 제안하는 기법은 모든 조건하에 정확하고 빠르게 검출 할 수 있다. IEEE와 UL1741에서 제시하는 단독 운전 기준 시험 회로를 구성하여 PSCAD/EMTDC 소프트웨어를 통한 시뮬레이션과 5kW 하드웨어 장치를 통해 제안된 단독 운전 검출 방법을 검증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 추계학술대회
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• pp.248-249
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• 2010

This paper describes development of hardware simulator for the PMSG(Permanent Magnet Synchronous Generator) wind power system, which was designed using real wind data. The simulator consists of a realistic wind turbine model using anemometer, vector drive, induction motor. The turbine simulator generates torque and speed signals for a specific wind turbine with respect to given wind speed. This torque and speed signals are scaled down to fit the input of 3kW PMSG. The PMSG-side converter operates to track the maximum power point and the grid-side inverter controls the active and reactive power supplied to the grid. The operational feasibility was first verified by computer simulations with PSCAD/EMTDC. The feasibility of real system implementation was confirmed through experimental works with a hardware set-up.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 추계학술대회
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• pp.32-33
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• 2010

This paper describes a droop control method for the autonomous operation of DC distribution system using distributed generations and energy storage. The method suppress the circulating current, and each unit could be controlled autonomously without communication system. Detailed model of wind power generation, photo-voltaic generation, fuel-cell generation and battery was implemented with the user-defined model of PSCAD/EMTDC software that is coded with C-language. The simulation and experimental results confirms that the proposed DC distribution system make it feasible to provide power to the load stably and verify effectiveness of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.267-269
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• 2004

Recently, due to increasing the application of power electronic equipment, harmonics generated from the non-liner load are fairy produced. Harmonics can cause a distribution problems such as the overheating of distribution transformer, the breakdown of device and communication interference. Interest about power quality decline of distribution system is very increased. In this paper, we are measured the harmonic voltage and current of distribution system to analyze harmonic characteristics, and it is analyzed Total Harmonic Distortion(HTD). Also, we are modeled distribution system using PSCAD/EMTDC. And it is analyzed harmonic voltage and current in steady-state. The study result have been indicated the utility about harmonics analysis and modeling for distribution system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.283-285
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• 2004

Modern power systems are very complex and to model them completely is impractical for electromagnetic transient studies. Therefore areas outside the immediate area of interest must be represented by some form of frequency dependent equivalent. This paper presents the formulation for developing 1 & 2 port Frequency Dependent Network Equivalent (FDNE) with the instantaneous term in S-domain and illustrates its use. This 1 & 2 Port FDNE have been applied to the CIGRE Benchmark Rectifier test AC system. The electromagnetic transient package PSCAD/EMTDC is used to assess the transient response of the 1 & 2 port (FDNE) developed with Norton Equivalent network.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.388-390
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• 2004

디지털 보호계전기의 성능 검증에 있어서 RTDS(Real Time Digital Simulator)와 같은 디지털 시뮬레이터를 사용하는 경우가 점점 증가하고 있다. 특히 보호계전기의 동특성(Dynamic Performance) 시험에 있어서는, 디지털 시뮬레이터를 이용한 성능 검증이 거의 필수적이다. 본 논문에서는 디지털 보호계전기 중 거리계전기의 Reach Test에 있어서 성능 검증에 사용할 계통 모델 선정 방안을 PSCAD/RTDS에서의 구현 관점에서 기술하고 있다. 양단 전원을 가지는 4모선 2회선 송전선로를 Bergeron 모델을 이용하여 모델링하고, 모델의 유효성을 귀납적인 방법을 사용해서 검증하는 방안을 제시하고 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.214-216
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• 2004

Power quality has become concern both utilities and their customers with wide spread use of electronic and power electronic equipment. This paper deals with the use of a multiresolution analysis and a discrete wavelet transform to detect interruption, sag, swell, transients and etc. The simulation system is constructed by using PSCAD/EMTDC. To show the effectiveness of the proposed method, a various case studies are simulated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.217-219
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• 2004

The installation of small sized dispersed generation(DG) units operating in parallel with the utility supply presents several technical problems for the protection and control of the system. One of the critical concerns is the occurrence of islanding. Hence, this paper propose the Digital Universal Relay(DUR) including anti-islanding function as DG interconnection interface. The existent islanding detection algorithms are examined. And the most effective and reliable method of those is modified for DUR application. The modified algorithm is evaluated through the modeling of the test system by PSCAD/EMTDC.