• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.109-112
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• 1998

A step down chopper and PWM current source inverter is used for the connection between the PV array and the utility. This paper proposes chopper is controlled for the dc reactor decrease and PWM current source inverter is controlled to keep the output power at the maximum point for the PV. The PV current only is measured and employed for the power calculation combining the control parameter of the PWM current source inverter.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.179-185
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• 2005

This paper presents a novel circuit topology of a high efficiency single-phase power conditioner. This power conditioner is composed of time-sharing sinewave absolute pulse width modulated boost chopper with a bypass diode in the first power processing stage and time-sharing sinewave pulse width modulated full-bridge inverter in the second power processing stage operated by time-sharing dual mode pulse pattern control scheme. The unique operating principle of the two power processing stage with time-sharing dual mode sinewave modulation scheme is described with a design example. This paper proposes also a sinewave tracking voltage controlled soft switching PWM boost chopper with a passive auxiliary edge-resonant snubber. The new conceptual operating principle of this novel power conditioner related to new energy utilization system is presented and discussed through the experimental results.

• 전기의세계
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• v.28 no.9
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• pp.51-59
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• 1979

The forming and design method of D.C thyristor chopper circuit for DC Series motor control is suggested, ard the computation method of thyristor commutaing element's, value which makes it all the more important, is possible. Also the trigger circuit was dealt with. In this paper, in order to control the duty cycle, the duty time is kept on constancy and variable chopping frequency was adopted. By above mentioned circuit design method, the D.C thyristor chopper circuit was implemented and tested. In this circuit, the result of D.C motor control was good and reliable. The relation between the $K_{d}$ and the ratio of input-output current, or the characteristic of speed was varied lineary at the range 0.1 ~ 0.9 of duty cycle. This confirms the fact that D.C to D.C power conversion which is the merit of chopper control is operated most likely a transformer.ormer.

• Journal of Power Electronics
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• v.15 no.3
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• pp.660-669
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• 2015

This paper presents a control scheme with a focus on the combination of phase disposition pulse width modulation (PDPWM) and DC capacitor voltage control for a chopper-cell based modular multilevel converter (MMC) for the purpose of eliminating the time-consuming voltage sorting algorithm and complex voltage balancing regulators. In this paper, the convergence of the DC capacitor voltages within one arm is realized by charging the minimum voltage module and discharging the maximum voltage module during each switching cycle with the assistances of MAX/MIN capacitor voltage detection and PDPWM signals exchanging. The process of voltage balancing control introduces no extra switching commutation, which is helpful in reducing power loss and improving system efficiency. Additionally, the proposed control scheme also possess the merit of a simple executing procedure in application. Simulation and experimental results indicates that the MMC circuit together with the proposed method functions very well in balancing the DC capacitor voltage and improving system efficiency even under transient states.

• Journal of the Korean Institute of Telematics and Electronics
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• v.12 no.2
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• pp.43-46
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• 1975

In a chopper amplifier the input signal of the AC amplifier is a train of square-waves. In the rase of square-wave the operatiom of AC amplifier is much different from that of ordinary sinusoidal wave. In this paper for the purpose of contributing to the design of chopper amplifier destortions of waveforms in the amplifier were investigated. When the time constant of each stage is equal the waveform in each stave apppears as square wave whose top is exponentially decaying. And when each stave has different time constant the waveform in n-th stage is composed of n-square waves whose tops are exponentially decaying.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.417-422
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• 1997

This paper proposed that a AC-DC Converter topology of high power factor with soft switching mode operates with four chopper connecting a number of parallel circuit. To improve these, a large number of soft switching topologies included a resonant circuit have been proposed. And, some simulative results on computer is included to confirm the validity of the analytical results. The partial resonant circuit makes use of a inductor using step up and a condenser of loss-less snubber. The result is that the switching loss is very low and the efficiency of system is high. And the snubber condenser used in partial resonant circuit makes charging engergy regenerated at input power source for resonant operation. The proposed conversion system is deemed the most suitable for high power applications where the power switching devices are used.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.971-973
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• 2001

This paper shows how to design a Global control, using Field Orientation, avoiding to use the DC/DC converter, and finding the relationships among the DC magnitudes and AC ones. And This paper deals with water pumping system which economic and durable storage systems for sustained production of power and propose MPPT methods using $i_{qs}$ of BLDC motor without battery module and chopper circuit.

• Journal of the Korean Solar Energy Society
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• v.24 no.2
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• pp.89-96
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• 2004

PV system is easy to operate and maintain than the other power generating system since it generally contains no moving parts, operates silently and requires very little maintenance. A solar cell generates DC power from sunlight whose power is different at any instance according to condition of irradiation and temperature variables. In order to improve the system utility factor and efficiency of energy conversion, it is desirable to operate the PV system at maximum power point of solar cell under different condition This paper describes the experimental results of the PV system contain solar modules and a DC-DC converter(boost type chopper) using fuzzy controller. The experimental results show that the PV system always operates at maximum power point of solar cells having stabilized output voltage waveform with relatively small ripple component.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.951-954
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• 1998

This paper proposed that a high power AC-DC buck converter topology of high efficiency using loss-less snubber operates with four chopper connecting a number of parallel circuit. To improve these, a large number of soft switching topologies included a resonant circuit have been proposed. And, some simulative resutls on computer is included to confirm the validity of the analytical results. The partial resonant circuit makes use of a inductor using step-down and a condenser of loss-less snubber. The result is that the switching loss is very low and the efficiency of system is high. And the snubber condenser used in partial resonant circuit makes charging energy regenerated at input power source of rresonant operation. The proposed conversion system is deemed the most suitable for high power applications where the power switching devices are used.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.12-15
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• 2002

This propose a simple DC voltage sensor less single phase PFC(Power Factor Correction Circuit) converter by detecting a AC current sensors are not required to construct the control system. The DC voltage is directly controlled by the command input signal Kd($V_o/V_a$)for the boost chopper circuit. The DC voltage regulation is small because of the feed forward control for the AC line voltage VS and no dependence of the circuit parameters. The sinusoidal current waveform in phase with the AC input voltage can be obtained. These characteristics are confirmed by some experiment results.