• Journal of Power Electronics
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• v.13 no.4
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• pp.636-646
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• 2013

A single-phase tapped-inductor boost converter has been proposed previously. However, detailed characterization and performance analysis were not conducted. This paper presents a detailed characterization, performance analysis, and design expressions of a single-phase tapped-coupled-inductor boost converter. Expressions are derived for average and RMS input current as well as for RMS input and output capacitor current ripple. A systematic approach for sizing the tapped-coupled inductor, active switch, and output diode is presented; such approach has not been reported in related literature. This study reveals that sizing of the inductor has to be based on current ripple requirement, turns ratio, and load. Conditions that produce discontinuous inductor current are also discussed. Analysis of a non-ideal converter operating in continuous conduction mode is also conducted. The expression for the voltage ratio considering the coupling coefficient is derived. The suitability of the converter for high-voltage step-up applications is evaluated. Factors that affect the voltage boost ratio are also identified. The effects of duty ratio and load variation on the performance of the converter are also investigated. The theoretically derived characteristics are validated through simulations. Experimental results obtained at a low power level are included to validate the analytical and simulation results. A good agreement is observed among the analytical, simulation, and experimental results.

• Journal of radiological science and technology
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• v.41 no.6
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• pp.603-610
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• 2018

This study examined the following: accuracy of the exposure conditions in the inverter device and three-phase device; output waveform over the exposure conditions; and average and standard deviation of the output waveform. After assessing whether the dose corresponding to the theoretical dose was presented, the following conclusions were obtained: 1. The accuracy of the tube voltage(kVp) and tube current(mA) exposure time(sec) was within the tolerable level prescribed in Korea's Safety Management Standards. In the error, Inverter device was large the tube voltage and exposure time, the three-phase device was large the tube current. 2. In terms of the output waveform of the exposure conditions and the average and standard deviation of the output waveform, the higher tube voltage and larger tube current resulted in greater standard deviation in pulsation. Moreover, the standard deviation of pulsation was shown to be greater in the inverter device than the three-phase device; there was also greater standard deviation in the inverter device considering the exposure time. 3. Regarding the exposure conditions over the output dose, all linearity showed the coefficient of variation which had an allowable limit of error within 0.05. Although the output dose ratio for the inverter device was 1.00~1.10 times no difference that of the three-phase device, there was almost no difference in dose ratio between the tube currents.

• Journal of Power Electronics
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• v.17 no.2
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• pp.323-333
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• 2017

This paper proposes a model-based optimal control algorithm for the clamp switch of a zero-voltage switching (ZVS) bidirectional DC-DC converter. The bidirectional DC-DC converter (BDC) can accomplish the ZVS operation using the clamp switch. The minimum current for the ZVS operation is maintained, and the inductor current is separated from the input and output voltages by the clamp switch in this topology. The clamp switch can decrease the inductor current ripple, switching loss, and conduction loss of the system. Therefore, the optimal control of the clamp switch is significant to improve the efficiency of the system. This paper proposes a model-based optimal control algorithm using phase shift in a micro-controller unit. The proposed control algorithm is demonstrated by the results of PSIM simulations and an experiment conducted in a 1-kW ZVS BDC system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.59-62
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• 2007

In this paper, we composed solar generation system with multi-phase interleaved boost converter Solar generated voltage is low, so it has need of the boost power conversion device for supply power to normal load. The multi-phase interleaved boost converter is easy to boost voltage and it can be reduced both input current ripple and output voltage ripple because it is composed with multi-phase. We simulated and tested multi-phase interleaved boost converter applied three-phase.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.280-286
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• 1998

In recent years, the interest in noise increases gradually and the low noise level becomes one of the important performances in electrical equipment for railway vehicle. In the auxiliary power supply, most of the noise is made by the current ripple of alternating current reactor(ACL) which filters the output voltage. And this current ripple results from the voltage harmonics across the ACL. So the noise can be reduced by eliminating the voltage harmonics across the ACL. This paper shows harmonic eliminating technique which is making gating signals of upper and lower inverter have a phase difference in the 12-step inverter type auxiliary power supply. This technique was proved by testing on the developed 180KVA auxiliary power supply using IGBT.

• Journal of Electrical Engineering and Technology
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• v.5 no.2
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• pp.290-298
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• 2010

This paper proposes an adaptive carrier-based pulse width modulation (PWM) method for a four-switch three-phase (4S3P) inverter under dc-link voltage ripple conditions. The proposed method guarantees balanced output currents despite of the existence of the voltage oscillations across two dc-link capacitors. And also, this new approach achieves a linear over-modulation with calculation time reduction. Simulation and experimental results are given to validate the feasibility of the proposed method.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.1
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• pp.99-106
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• 2012

For CMOS technology of 65 nm and beyond, the gate leakage current can not be negligible anymore. In this paper, the impact of the gate leakage current in ring voltage-controlled oscillator (VCO) on phase-locked loop (PLL) is analyzed and modeled. A voltage -to-voltage (V-to-V) circuit is proposed to reduce the voltage ripple on $V_{ctrl}$ induced by the gate leakage current. The side effects induced by the V-to-V circuit are described and optimized either. The PLL design is based on a standard 65 nm CMOS technology with a 1.8 V power supply. Simulation results show that 97 % ripple voltage is smoothed at 216 MHz output frequency. The RMS and peak-to-peak jitter are 3 ps and 14.8 ps, respectively.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.258-263
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• 1998

A comparative study of single-phase PWM converters having active filtering functions both on ac-input and dc-output sides have been carried out. Based on the function of the dc-output side active filter, two types of configurations, the RPM (ripple power managing) type and the APM (average power managing) type are compared to show their contrastive characteristics. The prototype system using DSP based control algorithms, i.e. deadbeet current control and voltage sensor-less technique using full-order observer, show the availability of the proposed system.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.370-372
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• 1996

A control scheme for the Voltage-sourced PWM converter based on space vector equations is introduced. The main advantages of this new control scheme are that sinusoidal line currents with nearly unity power factor, ripple-free DC voltage output are achevied without current sensors. The dynamical equations with battery model is derived. The proposed scheme is verified by computer simulation.

• Journal of Power Electronics
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• v.14 no.4
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• pp.649-660
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• 2014

A novel non-isolated bidirectional soft-switching SEPIC/ZETA converter with reduced ripple currents is proposed and characterized in this study. Two auxiliary switches and an inductor are added to the original bidirectional SEPIC/ZETA components to form a new direct power delivery path between input and output. The proposed converter can be operated in the forward SEPIC and reverse ZETA modes with reduced ripple currents and increased voltage gains attributed to the optimized selection of duty ratios. All switches in the proposed converter can be operated at zero-current-switching turn-on and/or turn-off through soft current commutation. Therefore, the switching and conduction losses of the proposed converter are considerably reduced compared with those of conventional bidirectional SEPIC/ZETA converters. The operation principles and characteristics of the proposed converter are analyzed in detail and verified by the simulation and experimental results.