• Journal of the Microelectronics and Packaging Society
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• v.15 no.3
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• pp.19-25
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• 2008

In this paper, author proposes a novel step-up AC-DC chopper operated with power factor correction(PFC) and with high efficiency. The proposed chopper behaves with discontinuous current control(DCC) of input current. The input current waveform in the proposed chopper is got to be a discontinuous sinusoid form in proportion to magnitude of ac input voltage under the constant duty cycle switching. Therefore, the input power factor is nearly unity and the control method is simple. In the general DCC chopper, the switching devices are turned-on with the zero current switching, but turn-off of the switching devices is switched at current maximum value. To achieve a soft switching of the switching rum-off, the proposed chopper is used a new partial resonant circuit. The result is that the switching loss is very low and the efficiency of chopper is high.

• Journal of Power Electronics
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• v.18 no.2
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• pp.383-394
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• 2018

This paper presents an isolated power factor correction converter for general-purpose electric vehicle chargers with a wide output voltage range. The converter is based on an asymmetrical dual active bridge structure so that the voltage stress of switching devices can be eliminated by transferring the transformer leakage inductance to the circuit parameters. Harmonic and output controls are performed by secondary switches, and primary switches are only operated at a fixed frequency with a 50% duty ratio. A harmonic modulation technique is also adopted to obtain a near-unity power factor without input current monitoring. The feasibility of the proposed charger is verified with a 3.3 kW prototype.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1103-1104
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• 2008

In this paper, authors propose a novel step-up AC-DC chopper operated with power factor correction (PFC) and with high efficiency. The proposed chopper behaves with discontinuous current control (DCC) of input current. The input current waveform in the proposed chopper is got to be a discontinuous sinusoid form in proportion to magnitude of ac input voltage under the constant duty cycle switching. Therefore, the input power factor is nearly unity and the control method is simple. In the general DCC chopper, the switching devices are turned-on with the zero current switching, but turn-off of the switching devices is switched at current maximum value. To achieve a soft switching of the switching turn-off, the proposed chopper is used a new partial resonant circuit. The result is that the switching loss is very low and the efficiency of chopper is high.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.242-245
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• 1995

In this paper the multiple three rectifiers for the power factor correction are proposed, analyzed and designed. The multiple three phase rectifiers draw sinusoidal ac currents from the ac voltage sources with nearly unity input power factor and operate with PWM making the control circuit simple and system cost low. Outstandingly it reduces the rated power capacity of devices and the input filter size by reducing input current ripples. Moreover design rules can be obtained from input and output current equations. With the proposed rules, input power factor and output power capacity are determined approximately. Finally these design rules are verified with computer simulations.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.2
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• pp.121-128
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• 2018

This work proposes a simple control method of a buck-type active power decoupling circuit that can minimize the ripple values in the dc link voltage. The proposed method utilizes a simplified duty calculation method and an optimal compensation gain tracking algorithm with variable-step approach. Thus, the dc link voltage ripple can be effectively reduced through the proposed method along with rapid response in tracking the optimum compensation gain. Moreover, the proposed method has better dynamic responses in the load fluctuation or abnormal situation. MATLAB/Simulink simulation and hardware-in-the-loop-simulation(HILS)-based experimental results are presented to validate the effectiveness of the proposed control method.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.187-190
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• 1998

The values of physical components of the plants and controllers as well as the relevant environmental conditions change in time, thus the output performance can be deteriorated during the operating span of the system. Naturally the duty of calibration or the prevention of performance deterioration due to excessive component sensitivity should be provided to the control system. The proposed controller, whenever necessary, measures the open-loop and close-loop characteristics, and then calculates the offset and sensor gain correction values based on the prepared standard measurements It is applied to the control of a flexible link system with the gain and offset calibration problems in the light sensor module for position to show the applicability. In this paper, we propose a digital controller which has the capability of calibration gain and offset adjustment using fuzzy methods.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.160-161
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• 2017

기존의 단상 PFC(Power Factor Correction) 부스트 컨버터의 제어기는 부하전류와 듀티를 고려하지 않아 부하 변동시 출력전압을 일정하게 유지할 수 없다. 본 논문에서는 부하전류와 듀티를 보상하는 단상 PFC 부스트 컨버터 전압제어기 설계 방법을 제안한다. 인덕터 전류와 캐패시터 전류의 관계를 해석하여 제어기를 설계하고 모의 해석을 통해 입증한다.

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

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1416-1418
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• 2005

This paper presents a new hybrid control method of asymmetrical half-bridge converter(AHBC) with low voltage stresses of the diodes and interleaved PFC(power factor correction). The proposed new control scheme can observe variation of secondary diodes voltage stresses by variation of duty ratio and then decide the control portions which are asymmetrical control and PFM(Pulse Frequency Modulation). Therefore, the proposed control scheme has many advantages such as a low rated voltage of the secondary diodes, low conduction loss according to the low voltage drop and wide zvs range by load variation. Through simulation results, the validity of the proposed control scheme is demonstrated.

• The Transactions of the Korean Institute of Power Electronics
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• v.28 no.1
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• pp.8-14
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• 2023

This paper proposes a PFC converter with a double step-up function using an asymmetrical PWM scheme. For the conventional PWM scheme, the input voltage range, which maintains a double step-up function, is limited because the proposed converter has different voltage gains and characteristics when the duty ratio(D) is less than 0.5. The proposed converter has a constant voltage gain regardless of the magnitude of the input voltage and can achieve output voltage balancing by using the asymmetrical PWM scheme. A 1.6-kW prototype of the proposed converter was built and tested to verify the performance.