• 전력전자학회논문지
• /
• 제17권2호
• /
• pp.158-165
• /
• 2012

In this paper, the test bed using three-phase PWM converter connected with single phase inverter in series is set up to configure an active AC electric load. Since the two topologies, three-phase PWM converter and single-phase inverter, can be operated bidirectionally, the system not only re-generates surplus power to grid but also prevents power dissipation. However, the construction of system has a drawback. That is, ripple components two times of inverter operation frequency occur at DC-Link due to cascade connection, it can be cause of three phase unbalance Since the operational characteristic of the active AC electric load, the power frequency entered into the electric load can be varied, and the ripple of DC-Link is changed as well. In this paper, the three-phase PWM converter using a variable notch filter is proposed, and the reduction of three-phase current unbalance is presented. the validity of the proposed PWM converter using a variable notch filter is verified by the simulation and experimental results.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2000년도 전력전자학술대회 논문집
• /
• pp.493-497
• /
• 2000

A battery is the device that transforms the chemical energy into the direct-current electrical energy without a mechanical process. Unit cells are connected in series to obtain the required voltage while being connected in parallel to organize capacity for load current. Because the voltage drop down in one set of battery is faster than in two one it may result in the low efficiency of power converter with the voltage drop and cause the system shutdown. However when the system being shutdown. However when the system being driven in parallel a circular-current can be generated,. It is shown that as a result the new batteries are heated by over-charge and over-discharge and the over charge current increases rust of the positive grid and consequently shortens the lifetime of the new batteries. The difference between the new batteries and old ones is the amount of internal resistance. In this paper we can detect the unbalance current using the microprocessor and achieve the balance current by adjusting resistance of each set, The internal resistance of each set becomes constant and the current of charge and discharge comes to be balanced by inserting the external resistance into the system and calculating the change of internal resistance.

• Journal of Power Electronics
• /
• 제16권2호
• /
• pp.786-797
• /
• 2016

This paper describes the design and development of a novel semiconductor-based solid-state switch for damped oscillating voltage test system. The proposed switch is configured as two identical series-connected switch stacks, each of which comprising 10 series-connected IGBT function units. Each unit consists of one IGBT, a gate driver, and an auxiliary voltage sharing circuit. A single switch stack can block 20 kV-rated high voltage, and two stacks in series are proven applicable to 30 kV-rated high voltage. The turn-on speed of the switch is approximately 250 ns. A flyback topology-based power supply system with a front-end power factor correction is built for the drive circuit by loosely inductively coupling each unit with a ferrite core to the primary side of a power generator to obtain the advantages of galvanic isolation and compact size. After the simulation, measurement, and estimation of the parasitic effect on the gate driver, a prototype is assembled and tested under different operating regimes. Experimental results are presented to demonstrate the performance of the developed prototype.

• 조명전기설비학회논문지
• /
• 제20권7호
• /
• pp.74-80
• /
• 2006

본 논문은 새로운 태양광 에너지 변환 기술에 의한 연계형 단상 인버터 제어기술을 나타내었다. 최대전력 점 추적제어는 두 부스터 컨버터의 MOSFET 스위치 제어 발생회로에 기초하고 단상 인버터는 풀 브리지의 4개 IGBT 스위치에 의해 전류 추종제어 된다. PV 모듈의 발생전력 제어회로는 PV 모듈의 출력 전압, 전류 검출에 의해 최대전력 점 제어한다. 결국 PV 모듈 양단은 인버터 입력전압으로 낮은 리플 전압을 유지하고 출력은 증가한다. 제안한 태양광 인버터 시스템의 효과가 시뮬레이션과 실험을 통하여 입증되었다.

• KEPCO Journal on Electric Power and Energy
• /
• 제5권4호
• /
• pp.343-347
• /
• 2019

When referring to weight, volume, and efficiency, a SuperConducting Synchronous Generator (SCSG) is definitely superior to conventional generators as a large-scale wind power generation system. The SCSG is connected to a full power converter that transmits the energy from the SCSG to the power grid. To reduce the current stress and system cost, the SCSG which has nine-phase armature windings with three converters is used. This paper deals with a comparative analysis of 10 MW superconducting wind power generators with three-phase and nine-phase armature windings. The stator windings of SCSGs are of various types. Using the finite element method, SCSGs are analyzed and compared in terms of the weight and volume of SCSGs, the total length of the superconducting wire, harmonics, torque performance, and efficiency. The analyzed results will be effectively utilized to design large-scale superconducting generators for wind power generation systems.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2009년도 추계학술대회 논문집
• /
• pp.285-289
• /
• 2009

In this paper, we propose to research the dynamic Matlab/Simulink model of supercapacitor bank(SCB) for a microgrid application. We demonstrated that this model id sufficient to design the control system of entire power storage system, SCB, the chopper and grid connected converter. The proposed dynamic model is simulated with the help of Matlab/$Simulink^{TK}$ in the MTG/PC/SCB hybrid energy system. The study results show that SCB have a good performance to curb power fluctuation in building microgrid application.

• Journal of Power Electronics
• /
• 제8권1호
• /
• pp.81-90
• /
• 2008

This paper presents an investigation of a voltage and frequency controller for an isolated asynchronous generator (IAG) driven. by a wind turbine and supplying 3-phase 4-wire loads to the isolated areas where a grid is not accessible. The control strategy is based on the indirect current control of the VSC (voltage source converter) using the frequency PI controller. The proposed controller consists of three single-phase IGBT (Insulated Gate Bipolar Junction Transistor) based VSC, which are connected to each phase of the IAG through three single phase transformers and a battery at their DC link. The controller has the capability of controlling reactive and active powers to regulate the magnitude and frequency of the generated voltage, harmonic elimination, load balancing and neutral current compensation. The proposed isolated system is modeled and simulated in MATLAB using Simulink and PSB (Power System Block-set) toolboxes to verify the performance of the controller.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2011년도 전력전자학술대회
• /
• pp.186-187
• /
• 2011

3상 PWM 컨버터에서 LCL필터 필름 커패시터는 Self-healing 메커니즘에 의해 열화가 진행되며, 이는 시스템의 필터성능과 역률 저하로 이어진다. 따라서 계통측 커패시터의 고장을 판단하고 교체시기를 결정하는 것이 필요하다. 본 논문에서는 정전용량의 80%에 해당하는 공진주파수를 한 주기 동안 주입하였을 때 나타나는 응답의 변화를 통해 커패시터의 열화고장진단 알고리즘을 제안하였다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2011년도 전력전자학술대회
• /
• pp.553-554
• /
• 2011

환경오염의 의한 지구온난화가 세계적 이슈가 되고 있으며 화석연료의 고갈 등으로 기존의 자동차들이 점점 설 자리를 잃어 가는 게 현재 상황이다. 따라서 화석연료 자동차를 대체해야하는 많은 새로운 형태의 자동차가 제시 되고 있는데 그중에 현재 가장 경쟁력과 경제성을 가진 전기자동차가 대두되고 있는 시점에 이를 충전하기 위한 여러 장치들이 나오고 있다. 그중에 우리는 3상계통 인버터와 고효율 DC-DC 컨버터로 구성 된 충전기를 소개하고자한다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.494_495
• /
• 2009

This paper presents a study of DFIG wind power generation system for real-time simulation. For real-time simulation, the real-time digital simulator (RTDS) and its user friendly interface simulation software (RSCAD) are used. 2.2MW grid-connected variable speed DFIG wind power generation system is modeled and analyzed in this study. Stator-flux oriented vector control scheme is applied to stator, rotor side converter control, and back-to-back PWM converters are implemented for the decoupled control. The real-wind speed signal extracted by an anemometer is used for realistic and accurate simulation analysis. Block diagrams for DFIG and control scheme of stator, rotor-side are introduced. Real-time simulation cases are carried out and analyzed for the validity of this work.