• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.116-121
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• 2012

DC/DC switching power converters produce DC output voltages from different DC input sources. The converter is used in regenerative braking of DC motors to return energy back in the supply, resulting in energy savings for the systems containing frequent stops. The DC/DC converter is composed of a PWM-IC (pulse width modulation integrated circuit) controller, a MOSFET (metal-oxide semi-conductor field-effect transistor), an inductor, capacitors, and resistors, etc. PWM is applied to control and regulate the total output voltage. In this paper, radiation shows the main influence on the changes in the electrical characteristics of comparator, operational amplifier, etc. in PWM-IC. In the PWM-IC operation, the missing pulses, the changes in pulse width, and the changes of the output waveform are studied by the simulation program with integrated circuit emphasis (SPICE) and compared with experiments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.11
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• pp.886-897
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• 1990

This paper is proposed new optimal PWM scheme is based on a defined linear relationship between the successive pulsewidths of the PWM pattern. The calculation of the pulsewidths in the new PWM scheme is caried out without referring to the equations of CW and MW. With this scheme the PWM pattern for microprocessor controlled inverters can be composed easily by obtaining the optimal increment in sucessive pulsiwidths of the pattern. Furthmore, the harmonic level at the output of PWM inverter are always very low because this PWM pattern is selected on the basis of minimum THD. Theis scheme is applied to 1(Hp), three phase induction motor, and compared with conventional regular PWM scheme. The results of calculations and experiments show that new optimal PWM scheme could provide an effective generalized approach for minimization of harmonics in the VSI-PWM inverter.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.2
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• pp.194-204
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• 2002

In this paper, a new two-phase space vector RPWM(Random PWM) is proposed. In the proposed RPWM, each of two-phase PWM pulses is located randomly in each switching interval. Based on the space vector modulation technique, the duty ratio of the pulses is calculated. Along with the randomization of the PWM pulses, we can obtain the effects of spread spectra of inverter output voltage, d.c link current and audible switching acoustic noise as in the case of randomly changed switching frequency. To verily the validity of the proposed two-phase RPWM scheme, the experiment based on the Cl67 micro-controller was executed. The performance of the proposed scheme was compared with traditional PWM schemes experimentally.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.6
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• pp.525-537
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• 2001

In this paper a new space vector RPPWM(Random Position PWM) is proposed. In the propsed RPPWM each of three phase pulses is located randomly in each switching interval. Based on the Space vector modulation technique the duty ratio of the pulses is calculated Along with the randomization of the PWM pulses. we can obtain the effects of spread spectra of votlage, current as in the case of randomly changed switching frequency, To verify the validity of the proposed RPPWM simulation study was tried using Matlab/Simulink The main model described in Simulink block diagrams includes the space vector modulation block pulse position randomization block inverter block 3 phase induction motor block and so on By the simulation study, the harmonics of the output voltage and the current of inverter are predicted in different PWM methods- SVPWM, LLPWM proposed RPPWM.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.61-62
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• 2012

본 논문에서는 다중 반송파 정현 펄스폭 변조방식으로 제어되는 Cascaded H-bridge 멀티레벨 PWM 인버터의 스위칭 손실 저감을 위한 스위칭 패턴을 제안한다. 부하 담당 전력이 상대적으로 큰 H-bridge 모듈의 스위치는 저주파의 기본 출력 전압 레벨을 형성하도록 동작시키며, 부하 담당 전력이 상대적으로 작은 H-bridge 모듈의 스위치는 고주파의 PWM 파형을 기본파에 가감하여 출력전압 파형이 사인파에 가까워지도록 스위칭 패턴을 형성한다. 본 논문에서는 제안된 스위칭 패턴을 PD, APOD 방식의 다중 반송파 정현 펄스폭 변조방식으로 구현하여 Cascaded H-bridge 멀티레벨 PWM 인버터에 적용시키고 실험을 통해 기존의 스위칭 패턴에 비해 스위칭 손실이 개선됨을 증명한다.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.1
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• pp.92-97
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• 2005

This paper discusses an intelligent digital redesign technique for designing a fuzzy pulse-width-modulated (PWM) control. First when we are given a well-designed fuzzy analog control, the equivalent digital control is intelligently redesigned. Using the similar technique we intelligently redesign the fuzzy PWM control from the intelligently redesigned fuzzy digital control. A stabilizability of the intelligently redesigned PWM control is rigorously analyzed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.791-793
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• 2012

This paper describes development of the electric current pulse supply unit. This system is used to improve the problems of non-uniformed solidification structure, which is made in melting process of light weight alloy. The power supply switch of our system use MOSFET switch and gate control use PWM signal. We have simulated the designed circuit and made to PCB for the current pulse supply unit. The power circuits are simulated by a PSIM software. In the experiments, we have confirmed that the experiment results are follow the simulation results very well.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.45-52
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• 2021

The space vector control based voltage control method for a three-phase PWM rectifier requires a lot of effort to design an optimal switching pattern since a switching pattern for the switching section must be designed. In this study, a D-Q control based SPWM output voltage control algorithm was studied for the three-phase six-pulse CVS type rectifier. In the output voltage control algorithm, three-phase reference signals are obtained from the D-Q transformation based on the space vector representation method, instead of the switching pattern, SPWM method is used to generate rectifier switching control signals. Next, a three-phase six-pulse CVS PWM rectifier based on D-Q transformation and SPWM was modeled using EMTP-RV. Finally, the validity of the D-Q control-based SPWM voltage control algorithm was confirmed by comparing the output voltage waveform obtained through EMTP-RV simulation works with a reference value and confirming that the output voltage accurately follows the reference voltage.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.905_906
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• 2009

본 논문은 한전 전력연구원이 주관하고 명지대학교와 (주)효성이 참여하는 연구과제의 결과물로써 다중펄스 컨버터와 PWM 컨버터로 구성된 20MVA급 Back-to-Back STATCOM의 시스템 구성 및 제어 동작특성에 대하여 정리하였다. 한전 전력연구원과 (주)효성이 국책과제를 통해 순수 국내기술로 개발한 10MVA급 다중펄스 STATCOM의 활용방안으로 10MVA급 PWM STATCOM 1기를 추가하여 두 STATCOM 각각의 DC link단을 연계시킨 20MVA급 Back-to-Back STATCOM을 구성하고 제어 알고리즘을 개발하였다. 또한 PSCAD/EMTDC 소프트웨어를 이용하여 개발한 Back-to-Back STATCOM의 제어 및 동작특성을 분석하였다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.5
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• pp.67-73
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• 1997

인버터의 출력파형에 포함되는 고조파를 저감하기 위하여 소프트웨어에 의하여 W형태와 M형태의 펄스 폭변조 신호로 구동되는 3상 5레벨 PWM인버터를 구현하였고, 인버터의 출력전압의 종합 고조파 왜율은 비교 분석하였다. 제안한 M형 펄스 폭 변조 제어에 의하면 PWM 인버터의 종합 고조파가 크게 낮출 수 있어 인버터 응용 시스템의 성능을 향상시킬 수 있다. W형 및 M형의 펄스 폭 변조제어 3상 5레벨 PWM 인버터를 구현하여 인버터 출력전압의 종합 고조파 왜율을 5〔%〕이하로 유지됨을 입증하였다.