• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.233-240
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• 1998

This paper presents a high efficiency low switching PWM technique for the propulsion system of Electric car. In order to achieve the continuous voltage control to six-step and a low harmonics with low switching frequency under 500㎐, the synchronous technique is combined with a space vector overmodulation and implemented by using DSP. Improved performance and a validation of proposed method is shown by the experimental results using a 1.65MVA IGBT VVVF inverter and inertia load equivalent to 160 tons electric cars.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1084-1087
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• 2002

This paper presents an improved fuzzy logic-based adaptive PWM technique. A fuzzy logic- based adaptive PWM technique determines the optimal output voltage vector which takes into account both direction of back-emf and direction of current error vector. This technique has a simple structure and a good level of stability, but it has disadvantages. The longer sampling period, the larger current error. Because there is no considerations of the current error magnitude of each phases. The proposed method improves the control performance by selecting the optimum switching pattern in which the magnitudes of current errors are considered introducing space vector concept. Simulation results using Matlab/Simulink show that the proposed control method reduces current error keeping the merit of previous one.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.321-324
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• 2005

This paper describes the application of newly developed conducted EMI reduction technique of SVPWM in induction motor drive. The newly developed common mode voltage reduction SVPWM technique doesn't any zero-voltage vector states for inverter control. Hence it can restrict the common mode voltage better than conventional PWM technique. The proposed technique is verified through simulation and experimental results. And by applying vector-controled system, the proposed technique have superior ability of reducing EMI and equal control performance comparing conventional SVPWM technique.

• Journal of Power Electronics
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• 제12권4호
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• pp.548-558
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• 2012

In this paper, a novel offset-based single-state pulse width modulation (PWM) method for achieving zero common-mode voltage (CMV) and reducing switching losses in multilevel inverters is presented. The specific active switching state of the zero common-mode (ZCM) voltage that approximates the reference voltage can be deduced from the switching state sequence of the reduced CMV phase disposition PWM (CMV PD PWM) method. From the reference leg voltages for the zero common-mode voltage, an N-to-2-level transformation defines a virtual two-level inverter and the corresponding nominal leg voltage references. The commutation process of the reduced CMV PD PWM method in a multilevel inverter and its outputs can be simply followed in a nominal switching time diagram for the virtual inverter. The characteristics of the reduced CMV PD PWM and the single-state PWM for zero common-mode voltage are analyzed in detail in this paper. The theoretical analysis of the proposed PWM method is verified by experimental results.

• 전력전자학회논문지
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• 제9권4호
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• pp.356-363
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• 2004

본 논문에서는 무정전 전원장치와 같이 일정전압 일정주파수(constant voltage and constant frequency; CVCF) 운전에 사용되는 단상 PWM 인버터의 정밀 전압제어 기법을 다루었으며 정상상태에서 전압 오차를 최소화하기 위해 phase-locked loop(PLL) 기법을 이용한 새로운 전압 제어 방법을 제안하였다. 제안된 제어기법에서는 출력 커패시터 전압과 전류를 이용하여 PLL 보상기를 구성하였으며 주제어기에 PLL 보상기를 추가하여 출력 전압의 정상상태 성능을 개선하였다. 제안된 방법의 타당성을 검증하기 위하여 시뮬레이션과 실험을 수행하였으며, 그 결과 기존의 방법에 비해 정상상태 전압제어 성능과 Total Harmonic Distortion(THD)이 현저히 개선됨을 입증할 수 있었다.

• 전력전자학회논문지
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• 제7권1호
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• pp.1-10
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• 2002

본 논문에서는 2상 인버터용 공간전압벡터 PW 방식을 제안하였다. 제안된 2상 공간전압벡터 PWM 방식은 2상 유도전동기에 적용할 수 있다. 2상 공간전압벡터 방식을 사용하는 2상 인버터는 4개의 공간 전압벡터를 발생하나 영 전압 벡터는 만들 수 없다. 2상 인버터에서는 4개의 공간 전압벡터를 조정하여 기본 전압벡터를 실현한다. 또한, 2상 공간전압벡터방식에 의해 최적의 PWM 전압파형을 만들기 위한 대칭변조방식이 제안되었다. 제안된 2상 공간 전압벡터방식에 대한 타당성을 확인하기 위해 시뮬레이션과 실험이 실행되었다.

• 전력전자학회논문지
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• 제9권5호
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• pp.507-515
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• 2004

고속 스위칭 소자의 출현과 함께 높은 전압 상승률(dv/dt)은 PWM 인버터에 EMI 노이즈 및 축 전압 그리고 베어링 누설전류 등의 문제 등을 발생시키고 있다. 본 논문에서는 유도전동기 시스템에서의 새롭게 개발된 전도성 EMI 저감 SVPWM 기법의 응용에 대하여 기술한다. 새롭게 개발된 커먼모드 전압제거 SVPWM 기법은 인버터 제어에 있어서 영벡터 상태를 사용하지 않고 종래의 PWM 기법에 비하여 커먼모드 전압의 감소가 가능하다. 소프트웨어 접근에 의한 제안된 기법의 타당성은 시뮬레이션과 실험적 결과를 통하여 확인하였다.

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

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.535-539
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• 1989

A high-frequency asymmetrical PWM control technique is proposed which can improve the input power factor of ac chopper and also suppress its harmonic contents of currents at both its input and load sides and the acoustic noises by its switching semiconductor devices. The ideal switching function for the proposed technique is derived and hence converted into asymmetrical PWM pattern for practical implementation of ac voltage regulator. Also the various power circuits of three phase AC choppers are suggested. The theoretical characteristics of the proposed PWM technique are investigated by digital simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.541-543
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• 1997

In this paper, a proposed resonant PWM switching technique makes the boost AC/DC converter to high input power factor and less switching loss. Also, the switching control scheme is used which minimize harmonic components employing novel PWM technique. In addition, an employment of resonant circuit for switching makes zero current switching(ZCS) and zero voltage switching(ZVS) for control switches without switching losses. The result shows that high power factor is still for varying load and switching loss is very low.