• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2570-2578
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• 2010

This paper presents a digital-controlled single-phase power-factor correction (PFC) converter operating in critical current conduction mode. The proposed converter utilizes the DC-DC boost converter topology for the PFC and operates the inductor current in critical conduction mode. Because the proposed converter is controlled digitally using a micom, its control circuit is simplified and the converter operates more effectively. This paper first explains the operational principles of the proposed converter and then analyzes the converter circuit. And this paper explains the implementation method of proposed converter with a detail design example, which is divided into software and circuit design parts. Also, it is shown through the experimental results of the prototype converter by the designed circuit parameters that the proposed converter has good performance as a single-phase PFC converter.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2247-2255
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• 2017

Because the on-board charger (OBC) is installed in electric vehicles (EVs), high power density is regarded as a key technology. Among components of the OBC, inductors occupy more than 30% of the total volume. Thus, it is important to reduce the volume and the weight of inductors while maintaining thermal stability. Discontinuous conduction mode (DCM) can satisfy these requirements; however, only a few studies have adopted the DCM operation for OBCs because of the large inductor current ripple. In this paper, a design process is proposed for application of the DCM operation to OBCs. In order to analyze the inductor losses accurately, a numerical formula for the inductor current ripple is deduced based on a detailed analysis. Two inductors are fabricated using several ferrite cores and powder cores taking into consideration the inductor size, inductor losses, and temperature rise. In order to verify the analysis and design process, experimental results are presented that show that the designed inductors satisfy the requirements of the OBCs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.2
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• pp.9-17
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• 2002

A high-efficiency electronic ballast for HID lamps is presented. The ballast consists of a PFC and a resonant inverter. To reduce losses of the ballast, DC link voltage should be determined by taking into account the peak voltage of lamp and the maximum flux density should be kept 0.2[T] on all of inductors. AR inductor at bridge diode is employed in order to remove currant harmonics from PFC. An inductor is connected in series with an electrolytic capacitor at DC link to reject high-frequency current. The acoustic resonance is eliminated using the stead spectrum technique. The electronic ballast for 250[W] metal-halide discharge lamp is implemented and 96[%] efficiency, no acoustic resonance and low conducted EMI level are accomplished.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2000-2007
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• 2016

Generally, in order to implement the CRM(Critical Conduction Mode), the analog controller is used rather than a digital controller because the control is simple and uses less power. However, according to the semiconductor technology development and various user needs, digital control system based on a DSP is on the rise. Therefore, in this paper, the CRM bridgeless PFC converter based on a digital control is proposed. It is necessary to detect the inductor current when it reaches zero and peak value, for calculating the on time and off time by using the current information. However, in this paper, the on-time and off-time are calculated by using the proposed algorithm without any current information. If the switching-times are calculated through the steady-state analysis of the converter, they do not reflect transient status such as starting-up. Therefore, the calculated frequency is out of range, and the transient current is generated. In order to solve these problems, limitation method of the on-time and off-time is used, and the limitation values are varied according to the voltage reference. In addition, in steady state, depending on the switching frequency, the inductance is varied because of the resonance between the inductor and the parasitic capacitance of the switching elements. In order to solve the problem, inductance are measured depending on the switching frequency. The measured inductance are used to calculate the switching time for preventing the transient current. Simulation and experimental results are presented to verify the proposed method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.491-499
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• 2019

Recently, there has been increasing demand for power quality in power supply devices. The IEC 61000-3-2 standard requires that the AC / DC power supply for lighting meet the specifications for the power factor (PF) and total waveform distortion (THD). In addition, advanced countries in Europe are regulating the ripple rate as 15 ~ 30% for the flicker phenomenon caused by the change in the amount of foot energy due to the change in current of the output terminal. Therefore, domestic standards and regulations are being updated. This study adopted the Flyback converter to satisfy the PFC standard, and has the circuit first and second insulation function. To reduce the low frequency ripple of the LED current, Flyback, Coupled Inductor, LC parallel resonance filter, LLC resonance filter, and Cuk were simulated by PSIM to mimic each LED driving circuit. A coupled LC resonant circuit with a coupled inductor on the primary side and LC resonance on the secondary side was also proposed for output side ripple reduction.

• Journal of Power Electronics
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• v.14 no.5
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• pp.815-826
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• 2014

An improved bridgeless interleaved boost power factor correction (PFC) rectifier to improve power efficiency and component utilization is proposed in this study. With combined conventional bridgeless PFC circuit and interleaved technology, the proposed rectifier consists of two interleaved and magnetic inter-coupling boost bridgeless converter cells. Each cell operates alternatively in the critical conduction mode, which can achieve the soft-switching characteristics of the switches and increase power capacity. Auxiliary blocking diodes are employed to eliminate undesired circulating loops and reduce current-sensing noise, which are among the serious drawbacks of a dual-boost PFC rectifier. Magnetic component utilization is improved by symmetrically coupling two inductors on a unique core, which can achieve independence from each other based on the auxiliary diodes. Through the interleaved approach, each switch can operate in the whole line cycle. A simple control scheme is employed in the circuit by using a conventional interleaved controller. The operation principle and theoretical analysis of the converter are presented. A 600 W experimental prototype is built to verify the theoretical analysis and feasibility of the proposed rectifier. System efficiency reaches 97.3% with low total harmonic distortion at full load.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.6
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• pp.465-471
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• 2007

The system efficiency of the proposed Buck-Boost AC-DC converter is increased by soft switching method. The converter includes to merit of power factor correction (PFC) from sinusoidal control of input current. The switching behavior of control switches operates with soft switching by partial resonance, and then the proposed converter has high system efficiency with decrement of switching power loss. The input current waveform in proposed converter is got to be a sinusoidal form of discontinuous quasi-pulse row in proportion to magnitude of AC input voltage under the constant duty cycle switching. Therefore, the input power factor is nearly unity. The output voltage of the converter is regulated by PWM control technique. The discontinuous mode action of current flowing into inductor makes to simplify control method and control components. The proposed PFC Buck-Boost converter is analyzed to compare with the conventional PFC Buck-Boost converter. Some computer simulative results and experimental results confirm to the validity of the analytical results.

• Journal of the Korea Society of Computer and Information
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• v.28 no.12
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• pp.231-238
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• 2023

For boost PFC (Power Factor Correction) converters, various control methods are being studied to achieve unity power factor and low THD (Total Harmonic Distortion) of AC input current. Among them, average current mode control, which controls the average value of the inductor current to follow the current reference, is the most widely used. However, nowadays, as advanced digital control becomes possible with the development of digital processors, predictive control of boost PFC converters is receiving attention. Predictive control is classified into predictive current mode control, which generates duty in advance using a predictive algorithm, and model predictive current control, which performs switching operations by selecting a cost function based on a model. Therefore, this paper simply explains the average current mode control, predictive current mode control, and model predictive current control of the boost PFC converter. In addition, current control under entire load and disturbance conditions is compared and analyzed through simulation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.9
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• pp.537-544
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• 2002

This paper describes a comparative analysis of soft switching boost converters through design, production and experiment. Soft switching boost converters are designed to satisfy the condition of input voltage 170-265Vac, output voltage 400Vdc, output current 5A, output power 20W-2000W and unit power factor. In addition, parameter values are designed so that system operation can be compared under this is similar conditions. The efficiency of the combined inductor soft switching boost converter was 97.63% with 1011 load better than that of other boost converter types. The combined inductor soft switching converter has simple circuit construction and low switching loss. EMI resulted by the switching noise, and harmonic distortion.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.5
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• pp.458-465
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• 2013

This paper proposes a novel soft-switched auxiliary resonant circuit to provide a Zero-Voltage-Transition at turn-on for a conventional PWM boost converter in a PFC application. The proposed auxiliary circuit enables a main switch of the boost converter to turn on under a zero voltage switching condition and simultaneously achieves both soft-switched turn-on and turn-off. Moreover, for the purpose of an intelligent multi-chip power module fabrication, the proposed circuit is designed to satisfy several design constraints including space saving, low cost, and easy fabrication. As a result, the circuit is easily realized by a low rated MOSFET and a small inductor. Detail operation and the circuit waveform are theoretically explained and then simulation and experimental results are provided based on a 1.8 kW prototype PFC converter in order to verify the effectiveness of the proposed circuit.