• Proceedings of the KIPE Conference
• /
• 2012.07a
• /
• pp.3-4
• /
• 2012

역률개선용 변환기는 입력전류를 교류전원과 동상으로 제어하여 다이오드 정류기에 비해 역률을 개선하고 THD를 저감시킬 수 있다. 본 논문에서는 단상 역률개선용 배전압 변환기를 IP 제어기와 Anti Wind-up Control을 사용하여 출력전압의 크기를 안정되게 제어하며 PI 제어기와 Anti Wind-up Control을 사용하여 입력전류가 입력전압과 동상이 되도록 제어한다. 또한 Duty-ratio Feed Forward Control을 사용하여 디지털 제어에 의한 진상현상을 저감시킨다. 본 논문에서는 소형화와 경량화가 가능하고 출력전압이 높은 역률개선용 단상 브리지리스 배전압 변환기를 구현한다.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.9
• /
• pp.1131-1136
• /
• 2014

Recently, power converters installed on the specialized vessels such as LNG Carrier and Icebreaker and offshore plants mainly use diode rectifier. However, such devices cause distortion of supply voltage waveform by involving much harmonics to input current of non linearity load in rectifying operation. Distortion of supply voltage waveform can be problems such as false operation of generator, transformer and load device and deterioration of power quality. This thesis is focusing with a view to producing accurate sinusoidal AC waveform with certain load through improvement of distortion of current waveform causing under operation of rectifier by using accurate circuit of DC shaping. The result of computer simulation proved that harmonics involved in current and voltage waveform of power system can be reduced.

• Proceedings of the KIPE Conference
• /
• 2020.08a
• /
• pp.136-138
• /
• 2020

본 논문은 일차측 순환전류를 제거할 수 있는 새로운 정류단을 갖는 위상천이 풀브리지 컨버터를 발표한다. 기존 센터탭 정류기를 갖는 위상천이 풀브리지 컨버터에서 출력 인덕터 대신 커플더 인덕터를 사용하고, 부품들을 재배치하여 기존 문제가 되었던 일차측 순환전류가 대폭 저감되는 효과를 달성하였다. 2차측 다이오드의 전압스트레스가 저감되는 것도 제안 위상천이 풀브리지 컨버터의 장점이다. 본 논문에서는 제안된 회로의 구조 및 동작원리를 설명하고, 입력 300-400V, 출력 50V, 1kW급 프로토타입 컨버터의 그 실험결과를 발표한다.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.18 no.4
• /
• pp.617-624
• /
• 2023

Recently, miniaturization and low power consumption of electronic products and improved efficiency and power factor improvement have become a matter of great interest. In this paper, an AC-DC converter based on PWM control was designed and made. The AC-DC converter is designed with a structure in which one rectifier circuit and one output voltage control circuit are connected in series. The rectifier circuit is a diode-based single phase full-wave current circuit and the output voltage control circuit is a DC-DC conversion circuit based on PWM control. Arduino was used as the main control device for PWM control, and LCD was configured at the output stage so that the control result could be checked. The error between the output voltage displayed on the oscilloscope and LCD and the target output voltage was confirmed through repeated experiments with the test circuit, and the validity of the proposed design methodology was confirmed by showing an error rate of about 5% based on the oscilloscope measurement value.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.7
• /
• pp.1124-1128
• /
• 2021

As regulations of emissions from ships become more stringent, electric propulsion systems have been increasingly used to solve this problem in vessels ranging from large merchant ships to small and medium-sized ships. Methods for improving the efficiency of the electric propulsion system include the improvement of power sources; the use of a system linked to environmentally friendly power sources, such as batteries, fuel cells, and solar power; and the development of hardware and control methodology for rectifiers, power conversion devices, and propulsion motors. The method using a phase-shifting transformer with diodes has been widely used for rectification. Power semiconductor devices with grid connection to an environmentally friendly power source using DC distribution, a variable speed power source, and the application of small and medium-sized electric propulsion systems have been developed. Accordingly, the demand for active front-end (AFE) rectifiers is increasing. In this study, a method using a neural network rather than a conventional proportional-integral controller was proposed to control the AFE rectifier. Tested controller data were used to design a neural network controller trained through MATLAB/Simulink. The neural network controller was applied to a rectification system designed using PSIM software. The results indicated the effectiveness of improving the waveform and power factor DC output stage according to the load variation. The proposed system can be applied as a rectification system for small and medium-sized environmentally friendly ships.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.13 no.3
• /
• pp.25-33
• /
• 1999

In this paper, the method of reducing hanmnics and correcting of power factor in single PWM converter associated with diode rectifier and boost converter is studied. In the general diode rectifier there are sorre problems that discontinuous current of reducing power factor and including distortion of hanmnics at the input current affects other sources. To solve the problems of performance degradation due to pulse wavefonn in the input current, the ac-dc converter in which the hanmnic distortion in the input current is reduced using a third-hanmnic-injected PWM is proposed. A lower power loss of switching and easy configuration of circuit are obtained by adopting discontinuous current mode. Simulation and experimental results of ac-dc converter with 5[kHz] switching frequency are presented and correction of power factor and reduction of total hanmnic distortion was established.lished.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.17 no.6
• /
• pp.105-112
• /
• 2003

Diode rectifier which can't be controlled output voltage and phase control converter as AC/DC converter have low power factor and harmonics of lower order in the line current. In this paper, three phase PWM(Pulse Width Modulation) AC/DC boost converter is studied to solve these problems. The characteristics of a proposed converter are to control the phase of current without current sensor as a very simple control algorithm using circuit parameters only and to apply sinusoidal PWM method with fixed switching frequency due to a difficult design of input filter and switching device. We simulate for the proposed algorithm that high power factor is achieved and DC link voltage has fast dynamic response without ripple in rectifying and regenerating operation. As a result of experiment with circuit parameter(inductor, capacitor) decided in simulation, the proposed converter had high power factor and reduction of low order harmonics as against diode rectifier.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.5 no.5
• /
• pp.413-420
• /
• 2004

In this paper, the control algorithm of DC source device for inverter starting is proposed and the control method for compensating unbalance system source on operating time in the voltage type PWM converter with driving and regenerative faculty is suggested. The maintaining method of balancing condition for converter of AC source is used the compensating unbalanced status by current control loop. In order to solve the problem which the unbalanced system control is used to leakage transformer not equaled reactance by each phase in rectifier system. The proposed H/W and control algorithm of rectifier system is contributed to minimize of device and rising efficiency.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.3
• /
• pp.223-227
• /
• 2016

Power supplies make the load compatible with its power source. DC power supplies are extensively used with most electrical and electronic appliances such as computers, television, and audio sets. The presence of non-linear loads results in a low power factor and higher harmonics in the power system. Several techniques for power-factor correction and harmonic reduction have been reported in the literature. This paper proposes a bridgeless boost converter that improves the power factor and reduces the harmonic content in input line currents as compared to full-bridge rectifiers. This bridgeless boost converter eliminates the need of a line-voltage bridge rectifier in conventional boost converter and thereby reduces conduction losses. The effectiveness of the proposed scheme is verified by computer simulations by using the PSIM software.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.6
• /
• pp.7-12
• /
• 2010

A semi-empirical organic schottky diode model is proposed for circuit simulation. We have set up a full custom design environment for organic schottky diode circuit using Spectre AHDL, which is widely used commercial EDA tool. We measured frequency response from fabricated rectifier, and it was compared to circuit simulation results using the AHDL model. The frequency response of the fabricated rectifier circuit is not sufficient for 13.56MHz RFID, however, it is enough for 135kHz-band RFID.