• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.7 no.3
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• pp.27-33
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• 1993

This paper presents the &tal controller for driving high frequency voltage fed PWM inverter that carrier frequency is over 2OkHz.We analyzed the conventional PWM to select a proper PWM pattern. as the result, obtained PWM pattern of the controller in which asynchronus staircase sinusoidal waveform is used as reference signal, and variable carrier ratio method was used for PWM control. The PWM controller is designed by fully digital method. Especially, Thk proposed controller is consisted of 8 bit one-chip microprocessor and digital logic. the former is for arithmetic and data processing, and the latter is for PWM pattern synthesis. Therefore, The responsibility and controllability is improved. Also, Data processing capability is improved using proper program to output modulation index with 9 bits. Circuits configuration of digital controller are made up of one chip 8051 and EPLD, and its controllability is tested by operating voltage fed inverter. Harmonics and current waveform is evaluated and analyzed for the voltage fed inverter system.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.5
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• pp.490-498
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• 2002

In this paper, a design method of LCL filter at the AC input side of a voltage source PWM converter is proposed. Effective method to prevent pollution of the utility caused by high frequency current ripple is to use a AC input LCL filter, The C elements in the filter provide a low impedance path for the high frequency component, preventing them from entering the utility. The resistors In series with the capacitors are used for damping the resonance in the filter The design examples are shown and the validity of the proposed design method is verified through the PSIM simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.3
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• pp.254-260
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• 2000

일반적으로 3상 PWM AC/DC 컨버터는 정상상태에서의 효과적인 오차제거 및 빠른 과도응답 특성을 얻기 위해 동기좌표계상으로 모델링하여 제어한다. 그러나 이와 같은 제어기는 입력전압이 평형일 경우를 전제조건으로 하므로, 입력전압이 불평형일 경우 입력전류와 직류링크 전압에 2차 고조파 성분이 나타나게 된다. 본 논문에서는 불평형 입력전압 하에서 컨버터 시스템의 입력전류와 직류링크 전압에 발생하는 2차 고조파 성분을 최소화하기 위한 새로운 제어기법을 제안하였다. 입력측 역기전력 성분으로 간주할 수 있는 동기좌표계상의 전압을 입력전압의 상태에 따라 변동하였으며, 전류지령치를 무효전력과 2차 고조파 유효전력을 선택적으로 제거하도록 선정하였다. 입력전압의 분석은 동기좌표계상에서 수행되어지며, 각 상의 위상과 진폭의 검출이 불필요하다. 제안한 제어기법은 매우 간단하며 불평형 입력전압 상태에서 입출력 시스템의 고조파 왜란을 효과적으로 제어할 수 있다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.109-110
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• 2012

본 논문에서는 불평형 전원 전압 하에서 삼상 PWM 컨버터의 전류 보상 기법을 제안하였다. 전원 전압이 불평형인 경우 PLL(Phase Locked Loop)를 이용하여 추출한 위상각에는 왜곡 성분이 포함된다. 이러한 왜곡된 위상각으로 컨버터를 제어하는 경우 입력 전류에도 고조파가 포함되게 된다. 본 논문에서는 불평형 전원 전압 하에서도 입력 전류의 THD(Total Harmonic Distortion)를 IEEE Std. 519 규정인 5% 이내로 제한할 수 있도록 하는 전류 보상 기법을 제안하였다. 제안된 기법은 시뮬레이션을 통해 그 타당성을 검증하였다.

• Journal of the Korean Society of Radiology
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• v.4 no.3
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• pp.31-37
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• 2010

In this paper, a photovoltaic system is designed with PWM(Pulse Width Modulation) voltage source inverter. Proposed synchronous signal and control signal was processed by 56F8323 microprocessor for stable modulation. The PWM voltage source inverter using inverter consists of complex type of electric power converter to compensate for the defect, that is solar cell cannot be developed continuously by connecting with the source of electric power for ordinary use. It can cause the effect of saving electric power, from 10 to 20[%]. The PWM voltage source inverter operates in situation that its output voltage is in same phase with the utility voltage. In addition, I connected extra power to the system through operation the system voltage and inverter power in a synchronized way by extracting the system voltage so that the phase of the system and PWM voltage inverter can be synchronized. In the system of this research showed good results after being controlled in order to provide stable power to the load and the system through maintaining and low output power of harmonics.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.4
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• pp.677-684
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• 2024

In this paper, the design method of a step-up DC-DC converter based on PWM control was studied for solar power system application. The operating principle of the switching mode step-up type DC-DC converter was analyzed and the basic design method was studied. For photovoltaic system application, an output voltage feedback control algorithm based on PWM control was developed to enable the converter's output voltage to follow the target voltage under variable input conditions. As a procedure to verify the effectiveness of the proposed algorithm, a prototype of a step-up DC-DC converter with a single feedback output voltage was designed and made by boosting the input voltage DC 10V to DC 30V. In experiments with prototypes, it was confirmed that the output voltage of the oscilloscope and LCD accurately followed the target output voltage. In the performance evaluation test, it was confirmed that the output voltage of the oscilloscope and LCD accurately followed the target output voltage by showing an error rate within 1 [%] of the reference voltage.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.3
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• pp.268-274
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• 1999

The problem of power factor and hmmonics are occurred in convelter system which used to SCRs and diodes as p power semiconductor devices. IGBT power device with selh:ommutation type was solved that problem. maintain the l input line current with sinusoidal wave CUlTent of input power source voltage. It was estimated that improvement of t transient state characteristics with feedfolward compensator added in the diode rectifier with single phase voltage type i inverter was used to simulation load. As a results it was verified that the transient state characteristics with voltage t type PWM convelter control was improved.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2484-2486
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• 1999

본 논문에서는 PWM 승압형 컨버터/인버터를 사용한 교류전동기 구동시스템에서 커먼 모드 전압의 크기를 dc 버스 전압 1/3이하로 제한시키는 새로운 공간전압벡터 PWM 기법을 제안한다. Dc 버스 전압의 2/3에 해당하는 커먼 모드 전압 펄스가 발생하는 경우에 대하여 고찰하고 각각의 경우에 대한 인버터 스위칭 시점의 이동을 통한 제거 방법을 제안한다. 제안된 방법은 부가의 하드웨어를 요구하지 않고 소프트웨어적으로 손쉽게 구현될 수 있으며, 전력변환기의 제어성능에 영향을 미치지 않는다는 장점을 가진다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.3
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• pp.18-24
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• 2001

This paper deals with a three-phase Pulse width Modulation(PWM) voltage souse inverter-induction motor drive with a single-phase PWM converter. The single-phase system has the pulsating instantaneous power with twice the frequency of the ac source. The power pulsation generates the dc voltage pulsation of the converter. In result, the waveforms of the inverter output current and voltage are distorted. The steady-stare operations of the system are analyzed by employing a state-spare method Such everything confirmed it's validity throughout simulation and experiment.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.453-454
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• 2020

본 논문은 PWM에 의한 전압 고조파를 분석하여 LC 필터를 설계하는 방안을 제안한다. 전압형 인버터는 PWM 방식을 이용하여 출력전압을 합성하며, PWM에 의한 전압 고조파는 직류단 전압, Modulation index, Deadtime 등에 의해서 결정된다. 출력 전압 고조파와 PWM 전압고조파와의 관계를 풀어 LC 필터를 설계한다. 제안된 방법으로 설계된 LC 필터는 시뮬레이션을 통해 설계의 타당성을 확인하였다.