• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.384-387
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• 2000

In this paper Power factor correction circuit of single-phase three-level boost converter is proposed. The advantage of the proposed control scheme for three-level boost converter are low blocking voltage of each power device low THD(Total Harmonic Distortion) and high power factor. The control scheme is based on the current comparator capacitor compensator and region detector, In simulations the proposed system is validated.

• Journal of Power Electronics
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• v.14 no.4
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• pp.712-721
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• 2014

This paper introduces a simple grid-voltage-sensorless control scheme for single-phase power factor correction (PFC) boost converters. The grid voltage waveform is obtained based on the dc output voltage, the switching duty ratio, and a phase-lead compensator. In addition, the duty ratio feedback is utilized to obtain the unity input power factor and the zero harmonic current. The proposed control scheme is designed and mathematically analyzed based on a small-signal model of PFC boost converters. To verify the effectiveness of the proposed control scheme, several simulations and experiments are carried out in two applications: an industrial power system with a 60 Hz grid frequency and a commercial aircraft application with a 400 Hz grid frequency.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.1
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• pp.53-60
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• 2014

Redundant handovers cause degraded quality of service to passengers in vehicle. This paper proposes a handover scheme suitable for users traveling in vehicles, which enables continuous learning of the handover process using a discrete-time Markov chain (DTMC). Through AdaBoost machine learning algorithm, the proposed handover scheme avoids unnecessary handover trials when a short dwell time in a target cell is expected or when the target cell is an intermediate cell through which the vehicle quickly passes. Simulation results show that the proposed scheme reduces the number of handover occurrences and maintains adequate throughput.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.677-687
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• 2018

This paper presents a novel power decoupling control scheme with the bidirectional buck-boost converter for primary-side regulation photovoltaic (PV) micro-inverter. With the proposed power decoupling control scheme, small-capacitance film capacitors are used to overcome the life-span and reliability limitations of the large-capacitance electrolytic capacitors. Then, an improved flyback PV inverter is employed in continuous conduction mode with primary-side regulation for the PV power conditioning. The proposed power-decoupling controller shares the reference for primary side current regulation of the flyback PV inverter. The decoupling controller shapes the input current of the bidirectional buck-boost converter. The shared reference eliminates the phase-delay between the input current to the bidirectional buck-boost converter and the double frequency current at the PV primary current. The elimination of the phase-delay in dynamic response enhances the ripple rejection capability of the power decoupling buck-boost converter even with small film capacitor. With proposed power decoupling control scheme, the additional advantage of the primary-side regulation of flyback PV inverter is that there is no need to have an extra current sensor for obtaining the ripplecurrent reference of the decoupling current-controller of the power-decoupling buck-boost converter. Therefore, the proposed power decoupling control scheme is cost-effective as well as the size benefit. A new transient analysis is carried out which includes the source voltage dynamics instead of considering the source voltage as a pure voltage source. For verification of the proposed control scheme, simulation and experimental results are presented.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.2
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• pp.122-129
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• 2011

In this paper, a new power factor correction circuit(PFC) based on a soft-switched boost scheme is proposed. Except for some soft-switching transition intervals, it operates exactly like the conventional boost scheme. Thus the desirable features of both high efficiency and easy control can be obtained. The design guidelines are suggested to achieve high efficiency. To verify the superior performance of the proposed circuit, experiment and simulation is carried out.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.2
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• pp.149-158
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• 2006

A soft-switching scheme for the PWM boost converter, ZCT (Zero current transition : ZCT) boost converter Is newly proposed to obtain the desirable features of both the conventional BWM boost and resonant converters such as easy of control, reduced switching losses and stresses, an4 low EMI. In order to achieve the soft-switching action, the proposed scheme employs an auxiliary circuit, which is added to the conventional boost converter and used to achieve soft-switching for both the main switch and the output diode while not incurring any additional losses due to auxiliary circuit itself. The basic operations, in this paper, we discussed and design guidelines are presented. Through a 100kHz, 60-W prototype, the usefulness of the proposed scheme is verified.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.1
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• pp.54-60
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• 2020

A digital current control scheme using virtual d-q transformation for a boost single-phase power factor correction (PFC) converter is proposed. The use of virtual d-q transformation in single-phase power converters is known to improve current control performance. However, the conventional virtual d-q transformation-based digital current control scheme cannot be directly applied to the boost single-phase PFC converter because the current and average voltage waveforms of the inductor used in the converter are not sinusoidal. To cope with this problem, this study proposes a virtual sinusoidal signal generation method that converts the current and average voltage waveform of the inductor into a sinusoidal waveform synchronized with the grid. Simulation and experimental results are provided to show that the virtual d-q transformation-based digital current control is successfully applied to the boost single-phase PFC converter with the aid of the proposed virtual sinusoidal signal generation method.

• Journal of Power Electronics
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• v.10 no.2
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• pp.132-137
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• 2010

Interleaving techniques are widely used to reduce input/output ripples and to increase the power capacity of boost converters operating in critical conduction mode. Two types of phase-shift control schemes are studied in this paper, the turn-on time shifting method and the turn-off time shifting method. It is found that although the turn-off time shifting method exhibits better performance, it suffers from sub-harmonic oscillations at high input voltages. To solve this problem, an intensive quantitative analysis of the sub-harmonic oscillation phenomenon is made in this paper. Based upon that, a novel modified turn off time shifting control scheme for interleaved boost converters operating in critical conduction mode is proposed. An important advantage of this scheme is that both the master phase and the slave phase can operate stably in critical conduction mode without any oscillations in the full input voltage range. This method is implemented with a FPGA based digital PWM control platform, and tests were carried out on a two-phase interleaved boost PFC converter prototype. Experimental results demonstrated the feasibility and performance of the proposed phase-shift control scheme.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.1934-1936
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• 1998

This paper proposes a new control scheme for enhanced power factor in the boost type AC/DC rectifier. The control scheme is to generate duty-cycle pattern without instantaneous measurement of the input line current. With a very simple controller structure the line current is forced to trace a sinusoid in phase with input voltage. The simulation results show the validity of the proposed control scheme.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.414-416
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• 2005

In this paper, a new scheme of current programmed control for three phase PWM AC-AC converter is presented. By considering only the magnitude components, a similar scheme in the DC-DC converter can be extended to the three phase PWM AC-AC converter. The proposed current programmed control will be well adopted into various converter topologies though three phase PWM AC-AC boost converter is treated as an example. The converter analysis is carried out by applying the vector DQ transformation to obtain physical insight into the converter operation. Finally, the experiment result shows the validity of the proposed scheme.