• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1991년도 추계학술발표회논문집
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• pp.75-79
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• 1991

In this study, a new sinusoidal PWM inverter suitable for use with power MOSFETs is described. The output waveforms in the proposed OWM inverter are investigated both theoretically and experimentally. A modulating signal for the three-phase PWM inverter is obtained by adding 3nth harmonics to the conventional three-phase sine wave. By using the new modulating signal, the amplitude of the fundamental component is increased about 15 percent more than that of a conventional sine wave inverter and the commutation number of the inverter is decreased to two-thirds of a conventional one.

• 대한전기학회논문지
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• 제36권4호
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• pp.259-266
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• 1987

In order to drive motor control system precisely, the motor is to be controlled by mmfs and current with sinusoidal waveforms. In this paper the Delta Modulation (DM) Technique is used for generating PWM pulse with sinusoidal waveform. However the motor currents yet contain odd harmonics due to leakage inductances, speed and exitation. To reduce harmonics, the parameter adaptive control method is introduced. That is, Req.C parameter of Delta Modulator is controlled adaptively by parameter adaptor. The adaptive signal is achieved by the difference between motor current and reference waveform, and this signal is converted to the voltage commend signal by adaptive mechanism. The test reslts show that this system is operated smoothly over a wide range of motor speed and motor current is controlled to be sinusoidal waveform adaptively.

• International Journal of Aeronautical and Space Sciences
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• 제16권1호
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• pp.102-109
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• 2015

In Korea, Lunar exploration program has been prepared with the aim of launching in the 2020's. As a part of it, a lunar lander demonstrator was developed, which was the model for verifying the system such as structure, propulsion, and control system, before launching into the deep space. This paper deals with the path tracking performance of the lunar lander demonstrator with respect to the thruster controller based on Pulse Width Pulse Frequency Modulator (PWPFM) and Pulse Width Modulator (PWM). First, we derived equations of motion, considering the allocation of the thrusters, and designed the path tracking controller based on Euler angle. The signal generated from the path tracking controller is continuous, so PWPFM and PWM modulator are adopted for generating ON/OFF signal. Finally, MATLAB simulation is performed for evaluating the path tracking ability. We compared the path tracking performances of PWPFM and PWM based thrust controller, using performance measures such as the total impulse and the position error with respect to the desired path.

• 대한전기학회논문지
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• 제37권2호
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• pp.80-88
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• 1988

As a method to improve harmonics in the voltage source PWM inverter, 5 level stair case wave method is used. The complementary transistor inverter (CTI) bridge circuit has this characteristics. This circuit required synchronous type 3 level PWM signal. In this paper, the 3 phase PWM digital signals within about 10 modulation error of the natural sampling was caculated, and a ROM table out of it for the digital signal of the control system was made. According to this table, the digital control method was proposed, and DTI circuit operated by this method was reviewed. It was confirmed to make V/F control possible by the select modulation ratio to the frequency.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.179-181
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• 1998

In this paper, one chip PWM pattern generator which eliminates time delay of computations and improves utilization factor of voltage is proposed. Both amplitude of sinusoidal signal and triangular signal are directly controlled. Thus, time delay of computations can be eliminated, and it is possible to track accurately instantaneous current for a sudden change of load with microprocessor 80C196KC. In addition, setting dead-time is also possible for wide range. From experimental work with inverter system for driving induction motor, the validity of proposed one chip PWM pattern generator is verified.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.394-396
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• 1995

This paper present fuzzy control technique for the control of output voltage and improvement of UPS wave forms. General UPS has the harmonics in carrier because of output of PWM signal using analog circuit. Output voltage is controlled by selecting PWM data to improve these problems, PWM signal discreted is written on ROM and analog circuit is removed at the system and output voltage is controlled by selecting PWM data by fuzzy controller.

• 전력전자학회논문지
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• 제9권6호
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• pp.620-627
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• 2004

H-브릿지 멀티레벨 인버터는 여러 개의 단상 Power Cell을 직렬로 연결함으로써 저전압 전력용 반도체를 사용하여 고전압을 얻을 수 있고, 정현파에 가까운 출력전압 파형을 얻을 수 있는 멀티레벨 인버터 토폴로지이다. 본 논문은 산업현장에서 신뢰성을 인정받아 많이 사용되고 있는 직렬통신 방식의 일종인 CAN통신 인터럽터를 이용한 H-브릿지 멀티레벨 인버터 Power Cell의 PU 동기화 및 위상전이 방법에 관한 것이다. 제안된 방법의 주요 장점은 주제어기와 셀 제어기 사이에 직렬통신(CAN)을 사용함으로써 주제어기와 셀 제어기의 신호선의 단순화, 주제어기의 부담 감소, Power Cell의 모듈화, 셀 단위의 보호동작 용이, 확장성 향상 그리고 제어 신호 및 Power Cell의 신뢰성을 향상에 있다. 13레벨로 구성된 H-브릿지 멀티레벨 인버터 시험을 통해 제안된 방법의 타당성과 신뢰성을 입증하였다.

• 한국음향학회지
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• 제36권3호
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• pp.179-185
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• 2017

본 논문에서는 수중에서 운용하는 임베디드 능동 음향탐지 시스템에 적용하기 위한 광대역 송신 전력 증폭기 설계/제작/시험 과정에서 발생된 문제를 분석하고 해결방안을 제시한다. 최근 수중음향 분야에서도 탐지 성능을 향상시키기 위해 광대역 소나(Sound Navigation and Ranging, SONAR) 신호처리 연구가 진행되고 있으며 이를 위한 광대역 수중음향 송수신 장치 개발이 이루어지고 있다. 본 논문에서는 임베디드 시스템 특성상 복잡하지 않고 구현이 간단한 2 레벨 톱니파 형태의 Class D 급 PWM(Pulse Width Modulation) 신호 생성 방식을 사용하여 광대역 수중음향 신호를 생성한 이후에, 송신 증폭기를 통하여 다양한 형태의 송신 파형을 재생하고 수중에서 실험을 하는 과정에서 두가지 이상의 주파수를 가진 소나 신호를 동시에 재생한 경우, 원신호에 두 신호의 주파수 차의 정수배만큼 더해진 기생 주파수가 나타나는 현상이 발생하여 원하지 않은 송신 음원이 재생되는 문제가 있음을 발견하였다. 이러한 문제점의 원인을 분석하기 위해 MATLAB 및 Simulink를 이용하여 송신 하드웨어 및 PWM 제어 과정을 모델링하고 시뮬레이션 하였으며, 시뮬레이션을 통해 문제점을 재현하고 해결방안을 제시한다.

• Journal of Power Electronics
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• 제5권4호
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• pp.264-271
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• 2005

A new modified trapezoidal modulating signal for a pulse width modulation (PWM) inverter suitable for a permanent magnet synchronous motor (PMSM) drive is proposed in this paper. A new modulating signal for the PMSM drive is determined by the characteristic torque ripple of the motor with various electro-motive force (EMF). The proposed modulating signal is able to decrease the torque ripple even if the motor has sinusoidal EMF or non-sinusoidal EMF. By using the proposed modulating signal, the system reduced the torque ripple as well as achieved the effective utilization of the DC supply voltage for the inverter. Many improvements are accomplished by the PWM strategy adapting the modified trapezoidal modulating signal without a change in hardware.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.579-582
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• 2004

This paper presents controller design of a static var compensator using PWM Cuk AC-AC converter. The PWM Cuk AC-AC converter is modelled by using complex circuit DQ transformation and perturbed around the operating point whereby the small signal system characteristics is analytically obtained. Finally, the PSIM simulations show the validity of the modelling and analysis.