• Journal of Electrical Engineering and Technology
• /
• 제8권5호
• /
• pp.1078-1085
• /
• 2013

This paper presents a novel topology for cascaded transformer sub-multilevel converter. Eachsub-multilevel converter consists of two DC voltage sources with six switches to achieve five-level voltage. The proposed topology results in reduction of DC voltage sources and switches number. Single phase low frequency transformers are used in proposed topology and voltage transformation and galvanic isolation between load and sources are given by transformers. This topology can operate as symmetric or asymmetric converter but in this paper we have focused on symmetric state. The operation and performance of the suggested multilevel converter has been verified by the simulation results of a single-phase nine-level multilevel converter using MATLAB/SIMULINK.

• 전기학회논문지P
• /
• 제60권1호
• /
• pp.48-52
• /
• 2011

Over the years, traditionally, six-switch three-phase inverters have been widely utilized for variable speed alternating current motor drives. Recently, some efforts have been made on the application of four-switch three phase inverter for uninterruptible power supply and variable speed drives. This is due to some advantages of the four-switch three phase inverter over the conventional six-switch three-phase inverters such as reduced price due to reduction in number of switches, reduced switching losses, reduced number of interface circuits to supply logic signals for the switches, simpler control algorithms to generate logic signals, less chances of destroying the switches due to lesser interaction among switches, and less real-time computational burden. However such as slow di/dt and speed limitation, are the inherent characteristics and main drawbacks of the four-switch configuration. Those problems can be overcome in conjugation with Voltage-doublers which has additional advantage, such as unity power factor correction.

• 전력전자학회논문지
• /
• 제11권6호
• /
• pp.543-550
• /
• 2006

AC Plasma display panel(AC-PDP) 구동을 위한 Six-switch를 적용한 Three-level PDP Sustain 회로를 제안한다. 제안 회로는 기존 회로의 Sustain 스위치와 Clamp 다이오드의 내압이 절반이 되어 특성이 우수한 반도체 소자의 채택이 가능하며, 높은 전력 효율을 가지는 장점을 가지므로 AC-PDP 구동 회로 설계에 매우 적합하다. 본 논문에서는 기존 회로와 제안 회로의 비교 분석 및 시뮬레이션과 실험 결과를 보인다.

• Journal of Power Electronics
• /
• 제16권2호
• /
• pp.498-511
• /
• 2016

This paper presents a single-phase five-level inverter controlled by two novel pulse width modulation (PWM) switching techniques. The proposed PWM techniques are designed based on minimum switching power loss and minimum total harmonic distortion (THD). In a single-phase five-level inverter employing six switches, the first proposed PWM technique requires four switches to operate at switching frequency and two other switches to operate at line frequency. The second proposed PWM technique requires only two switches to operate at switching frequency and the rest of the switches to operate at line frequency. Compared with conventional PWM techniques for single-phase five-level inverters, the proposed PWM techniques offer high efficiency and low harmonic components in the output voltage. The validity of the proposed PWM switching techniques in controlling single-phase five-level inverters to regulate load voltage is verified experimentally using a 100 V, 500 W laboratory prototype controlled by dspace 1103.

• Journal of Power Electronics
• /
• 제18권2호
• /
• pp.604-614
• /
• 2018

This paper proposes a synchronous switching technique for a Vienna rectifier that uses carrier-based pulse width modulation (CB-PWM). A three-phase Vienna rectifier, similar to a three-level T-type converter with three back-to-back switches, is used as a PWM rectifier. Conventional CB-PWM requires six independent gate signals to operate back-to-back switches. When internal switches are operated synchronously, only three independent gate signals are required, which simplifies the construction of gate driver circuits. However, with this method, total harmonic distortion of the input current is higher than that with conventional CB-PWM switching. A reactive current injection technique is proposed to improve current distortion. The performance of the proposed synchronous switching method and the effectiveness of the reactive current injection technique are verified using simulations and experiments performed with a set of Vienna rectifiers rated at 5 kW.

• Journal of Electrical Engineering and Technology
• /
• 제6권3호
• /
• pp.328-333
• /
• 2011

A Distribution Automation System (DAS) is operated by monitoring and control of the field statesusing Feeder Remote Terminal Units (FRTUs) installed together withautomatic switches.An optimal placement of automatic switchescan enhanceefficiencyof the operation and restoration, and improve the power supply reliability ofa DAS.This paper proposes an algorithm to decide the optimal placement of automatic switches ina DAS.The proposed algorithm was developed ona DAS witha six sections and three links configuration. The proposed algorithm was provided inaneight-feeder power distribution system.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1993년도 하계학술대회 논문집 B
• /
• pp.1030-1034
• /
• 1993

A converter topology which is capable of four-quadrant(motoring and generation) operation is proposed for the variable speed constant frequency(hereafter referred as VSCF) power conversion scheme. The new converter topology for the VSCF power conversion scheme is made of two functional stages. One is converting stage which consists of six switches and six diodes and it interfaces a three-phase 60Hz at supply and a single-phase variable-frequency ac source. The other is the commutating stage though which each phase-winding is energized.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2006년도 전력전자학술대회 논문집
• /
• pp.384-386
• /
• 2006

본 논문에서는 AC Plasma display panel(AC-PDP) 구동을 위한 Six-switch를 적용한 Three-level PDP Sustain 회로를 제안한다. 제안 회로는 기존 회로의 Sustain 스위치와 Clamp 다이오드의 내압이 절반이 되어 특성이 우수한 반도체 소자의 채택이 가능하며, 환류 전류가 저감되어 높은 전력 효율을 가지는 장점을 가지므로 AC-PDP 구동 회로 설계에 매우 적합하다. 본 논문에서는 기존 회로와 제안 회로의 전도 손실 계산 및 시뮬레이션과 실험 결과를 보였다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1997년도 전력전자학술대회 논문집
• /
• pp.276-279
• /
• 1997

본 논문은 통신용전원장치와 같은 대용량의 DC 전원 장치에 적용하기 위하여 3상용 6 Switch로 구성된 Bridge로써 대용량 DC-DC converter에 적합한 Topology에 관한 것이다. 기본 동작은 기존의 Phase shifted ZVS PWM 방식을 사용하며, Bridge의 바깥쪽 양쪽암의 펄스폭을 제어하는데, 같은 펄스를 동시에 주는 방식과 각각 별도로 제어하는 방식, 두암의 위상을 지연시키는 방식에 관하여 연구하였다. 제안된 Topology들은 컴퓨터 시뮬레이션을 수행하여 그 동작특성을 확인하였고, 대용량에 적용할 수 있음을 확인하였다. 장치의 용량은 출력 500[A]/30[V] 회로를 구성하여 각각의 경우에 대하여 컴퓨터 시뮬레이션 결과를 제시하였다.

• 전자공학회논문지SC
• /
• 제42권2호
• /
• pp.49-58
• /
• 2005

새롭게 개발되어진 소프트 스위칭 3상 PM 정류기는 간단한 회로 구성과 고효율을 가지고 있다. 제안한 회로는 ARCP 컨버터의 한 종류이다. 기존의 ARCP 컨버터는 3상 보조 리액터와 소프트 스위칭 보조 회로를 6개의 보조 스위치, 각 스위치의 게이트 구동 회로, 제어회로가 필수적이나 결과적으로 이 회로는 높은 손실을 가지고 있다. 본 논문에서 제안한 주 회로는 두 개의 보조 리액터와 두 개의 스위치와 각각의 다이오드로 구성되는 보조 소프트 스위칭 회로이다. 부가적으로 두 개의 주 스위치와 간단한 보조 스위치의 제어회로는 PWM 제어 회로로 만들어지며, 공통으로 사용하였다. 소프트 스위칭 보조 회로의 작용을 의미하며, 주 스위치는 WS로 동작되고, 보조스위치는 ZCS로 동작된다. 본 논문에서 제안한 회로의 구성과 동작 원리를 설명하였으며, 실험결과에 의해서 증명하였다 용랑5[kW]의 시작품을 사용하여 변환효율은 최대$98.8[\%]$과 역률$99[\%]$를 얻었다.