• 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.

• Journal of Biomedical Engineering Research
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• v.2 no.1
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• pp.55-64
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• 1981

The important parameters of DC amplifier, which is widely use4 for the medical and engineering fields, are input offset voltage and temperature drift. Chopping amplifier reduces approximately 10% the parameters changing than monolithic operational amplifier. In this study, a chopping amplifier with semiconductor chopper is designed and tested, this chopper is realized by CMOS analog switch and timing circuits. The test results approve that designed amplifier is suitable for precision instrument DC amplifier.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.4
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• pp.349-356
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• 1990

In order to control DC motors for electric cars by chopper system, four quadrant operations - forward powering, forward regenerative braking, reverse powering, reverse regenerative braking - are needed. For the four quadrant operations, the separately - excited DC motors are used in this study. The conversion of each quadrant operation has been obtained by 1) adopting the two phase chopper system with combined output for the armature control, and 2) the single phase chopper system for the field control.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.2
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• pp.63-68
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• 2017

This paper proposes a new non-isolated DC conversion circuit topology of the voltage source coupled inductor series resonant high-frequency PFM controlled boost chopper type DC-DC power converter using two in one IGBT power module, which can efficiently operate under a principle of zero current soft switching for wide output regulation voltage setting ranges and wide fluctuation of the input DC side voltage as well as the load variation ranges. Its steady state operating principle and the output voltage regulation characteristics in the open-loop-based output voltage control scheme without PI controller loop are described and evaluated from theoretical and experimented viewpoints. Finally, in this paper the computer-aided simulation steady-state analysis and the experimental results are presented in order to prove the effectiveness and the validity of voltage regulation characteristics of the proposed series resonant zero current soft switching boost chopper type DC-DC power converter circuit using IGBTs which is based on simple pulse frequency modulation strategy more than, 20kHz.

• 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.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.370-373
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• 1997

In this paper, we compose of the stepdown chopper and the current source inverter. Because dc side current of the current source inverter pulse with twice frequency of utility, we control that modulation factor of chopper is pulsed twice frequency. Therefore if voltage across the dc reactor equal to zero, it tis decreased. And we control modulation factor of the chopper to operate at maximum power point around of solar cell.

• 전기의세계
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• v.25 no.4
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• pp.28-31
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• 1976

Thyristor는 많은 전력기기와 결합되어 전기기기 전반의 양상을 크게 변화시키고 있다. 예를 들면 변압기의 불꽃없는 탭이나 회전기의 정류자에 대치되는 무정류자전동기와 그리고 개폐기, 차단기의 대용등을 생각할 수 있다. 전력변환장치로서는 (1)직류전력을 조정하는 목적으로 Thyristor를 일종의 스위치로써 직류전압을 단속시켜 직류평균전력을 제어하는 DC Chopper (2)교류전원에 두개의 Thyristor를 역병렬접속하여 교류전류의 통전기간을 위상제어에 의하여 교류를 제어하는 AC Chopper (3)직류를 교류로 변환하는 자여식 inverter등이 있다. 본 해설에서는 지면관계상 D.C Chopper방식에 대한 기본회로와 그의 이용만을 취급한다.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1400-1408
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• 2013

This paper proposes a new grid-tied power converter for battery energy storage, which is composed of a 2-stage DC-DC converter and a PWM inverter. The 2-stage DC-DC converter is composed of an LLC resonant converter connected in cascade with a 2-quadrant hybrid-switching chopper. The LLC resonant converter operates in constant duty ratio, while the 2-quadrant hybrid-switching chopper operates in variable duty ratio for voltage regulation. The operation of proposed system was verified through computer simulations. Based on computer simulations, a hardware prototype was built and tested to confirm the technical feasibility of proposed system. The proposed system could have relatively higher efficiency and smaller size than the existing system.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.484-486
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• 1997

In this paper, we compose of the utility phovoltaic system with the stepdown chopper and the current source inverter to reduce pulsation of dc current and dc reactor. We study that control several ways(twice frequency of utility voltage square pulse and without the chopper) of chopper part. Therefore if voltage across the dc reactor equal to zero, it is decreased. And we control modulation factor of the chopper to operate at maximum power point around of solar cell.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.547-551
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• 1987

New chopper circuits for decoupled operation of the dc series motor are presented. These new choppers are capable of controlling field current completely separately, while offering capability of bidirectional armature energy flow. To develop the chopper circuit, with minimum number of switching elements, the complete family of possible conduction circuits are systematically investigated. Then one or two quadrant chopper circuits which offer the desired operations are synthesized from the resulting conduction circuits. Finally, the developed chopper circuits are completely analyzed. The details of operation of the chopper circuits are also fully described.