• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
• /
• pp.189-192
• /
• 2001

This paper proposed that an AC-DC converter system using multiple buck-chopper operates with four choppers connecting to a number of parallel circuits. To improve these, a large number of soft switching topologies included a resonant circuit have been proposed. And, some simulative results on computer are included to confirm the validity of the analytical results. The partial resonant circuit makes use of an inductor using step-down and a condenser of loss-less snubber. The result is that the switching loss is very low and the efficiency of system is high. And the snubber condenser used in a partial resonant circuit makes charging energy regenerated at input power source for resonant operation. The proposed conversion system is deemed the most suitable for high power applications where the power switching devices are used.

• Journal of Electrical Engineering and Technology
• /
• 제7권5호
• /
• pp.714-723
• /
• 2012

A new Z-source inverter (ZSI) topology is developed to improve voltage boost ability. The proposed topology is modified from the switched inductor topology by adding some more inductors and diodes into inductor branch to the conventional Z-source network. The modulation methods developed for the conventional ZSI can be easily utilized in the proposed ZSI. The proposed ZSI has an ability to obtain a higher voltage boost ratio compared with the conventional ZSI under the same shoot-through duty ratio. Since a smaller shoot-through duty ratio is required for high voltage boost, the proposed ZSI is able to reduce the voltage stress on Z-source capacitor and inverter-bridge. Theoretical analysis and operating principle of the proposed topology are explicitly described. In addition, the design guideline of the proposed Z-source network as well as the PWM control method to achieve the desired voltage boost factor is also analyzed in detail. The improved performances are validated by both simulation and experiment.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2005년도 춘계학술대회논문집
• /
• pp.174-177
• /
• 2005

Offline switching power supplies have high voltage and high current switching waveforms that generate Electromagnetic Interference(EMI) in the form of both conducted and radiated emissions. Consequently, all off-line power supplies must be designed to attenuate or suppress EMI emissions below commonly acceptable limits. Electrodeless fluorescent lamp's ballasts have AC/DC flyback converter, so we must control the EMI emissions.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.338-340
• /
• 2003

This paper proposes a stand-alone adjustable speed wind Power generation system using a cage-type induction generator. Indirect vector control is used, where the q-axis current controls the generator speed and the d-axis current controls the excitation level. The generator speed is adjusted according to the wind speed so as to produce the maximum output power. The generated power is charged in the battery bank through ac/dc PWM converter. The proposed scheme has been verified by the experimental results.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2007년도 추계학술대회 논문집
• /
• pp.118-120
• /
• 2007

일반적인 AC/DC변환 장치는 안정화된 직류 전원을 얻기 위해 대용량의 커패시터와 고속의 전력용 반도체 스위칭 소자를 사용한다. 하지만, 이러한 소자의 사용으로 인해 입력측의 고조파 손실 및 역률 저하의 문제점을 갖게 되고 고속 스위칭에 따른 스위칭 손실에 의한 효율이 저하되는 문제점을 갖게 된다. 따라서 본 논문에서는 역률개선이 가능하고 스위칭 손실이 저감되는 ZVS 방식을 이용한 새로운 형태의 역률개선용 소프트스위칭 방식의 부스트 컨버터를 제안한다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2009년도 정기총회 및 추계학술대회 논문집
• /
• pp.296-298
• /
• 2009

Ac-dc 싸이리스터 컨버터에서 전류기준값의 부호가 변화할 경우에 적분항 초기값을 통해 전류제어 과도특성을 개선하는 연구가 있었다. 이 논문에서는 전류기준값의 기울기에 변화가 있을 때 그 변화를 일으키기 위한 전압을 계산하고 그 값을 점호각 $\alpha$로 환산하여 시스템에 적용시켜 변곡점 부근에서의 전류제어 특성을 개선하는 방법을 제시하였다. 또한 전류기준값에 노이즈가 포함된 경우 LPF 유/무에 따른 특성변화와 노이즈가 포함되지 않은 경우 LPF 유/무에 따른 특성변화를 관찰하였다.

• Journal of Power Electronics
• /
• 제18권4호
• /
• pp.997-1006
• /
• 2018

This paper proposes a transformerless photovoltaic (PV) power converter system based on the DC/AC boost inverter, which can solve the leakage current and second-order ripple power issues in single-phase grid-connected PV inverters. In the proposed topology, the leakage current can be decreased remarkably since most of the common-mode currents flow through the output capacitor, by-passing parasitic capacitors, and grounding resistors. In addition, the inherent ripple power component in the single-phase grid inverter can be suppressed without adding any extra components. Therefore, bulky electrolytic capacitors can be replaced by small film capacitors. The effectiveness of the proposed topology has been verified by simulation and experimental results for a 1-kW PV PCS.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2017년도 추계학술대회
• /
• pp.199-200
• /
• 2017

ITER 초전도자석 전원공급장치의 통합제어를 위한 마스터제어기는 각 플랜트시스템(CCPS, TFPS, PFCS)에 대한 3개의 MCS로 구성되며, 전체 전원장치 I&C 시스템의 통합을 위하여 플랜트 레벨에서의 PSH 통합이 필요하다. ITER 제어시스템에서 제공하는 플랜트 시스템 I&C의 통합 기능을 이용하여 통합시 고려해야 하는 문제점 및 이슈들을 조사하여, 향후 마스터제어기의 통합 시험에 필요한 기능들을 사전에 점검하고, 통합오류를 최적화하여 마스터 제어기 제작 및 시험에 적용하고자 한다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2011년도 전력전자학술대회
• /
• pp.62-63
• /
• 2011

The wireless power transfer system using electromagnetic resonance is consists of PFC circuit, LLC resonant converter, high frequency DC-AC inverter and ECR devices for wirelessly transmitting the power. The output voltage of the module with free input voltage is 1MHz, 230Vp-p. As a experimental result, the wireless power transmission is confirmed and it is varified the validity of the experiment.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1992년도 하계학술대회 논문집 B
• /
• pp.1104-1107
• /
• 1992

Voltage controlled current regulated PWM(pulse width modulation) of VSI (voltage source inverter) is proposed. Adopting one degree of freedom, the voltage, the current controller shows much more improvement than conventional ones not using this method. The voltage controller or this proposal needs load's parameters, torque value, rotational speed. This voltage controller is located at converter part which links AC source and DC bus. With this proposed method, duty ratio of the inverter's switching is nearly unity for all speed and torque range. Hence, this method gets many advantages such as reducing current ripple, thermal loss, and noises and improving control performances. Theoretical approach to this voltage-current controller is performed, and the results are presented.