• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.2
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• pp.121-128
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• 2018

This work proposes a simple control method of a buck-type active power decoupling circuit that can minimize the ripple values in the dc link voltage. The proposed method utilizes a simplified duty calculation method and an optimal compensation gain tracking algorithm with variable-step approach. Thus, the dc link voltage ripple can be effectively reduced through the proposed method along with rapid response in tracking the optimum compensation gain. Moreover, the proposed method has better dynamic responses in the load fluctuation or abnormal situation. MATLAB/Simulink simulation and hardware-in-the-loop-simulation(HILS)-based experimental results are presented to validate the effectiveness of the proposed control method.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.2
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• pp.116-123
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• 2014

In this paper, a soft-switching scheme for the PWM interleaved buck converter(IBC) is newly proposed to obtain the advantages of both the conventional PWM interleaved buck and resonant converters such as ease of control, reduced switching losses and stresses, and low EMI. To obtain the soft-switching action, the proposed scheme employs an auxiliary circuit, which is added to the conventional interleaved buck converter and used to achieve soft-switching for both the main switches and the output diodes while not incurring any additional losses due to the auxiliary circuit itself. In this paper, the basic operations are discussed and design guidelines are presented. And through the experimental results, the usefulness of the proposed converter is verified.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.269-272
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• 1988

This paper introduces a method to reduce the reactive power required by electronic converters. The instantaeous reactive power is calculated and compensated by the current controlled PWH voltage source converter connected parallel between the power lines and the converter. A high performance current control technique which is based on the current deviation vector is used for the PWM converter as compensator of reactive power. Accurate compensation of the reactive power and t control system ensuring fast response to the sudden change of loaf are attained. The converter structure and control scheme are discussed. Simulation of the system is performed.

• 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.1
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• pp.189-197
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• 2017

This paper elaborates two novel proposed topologies (type-I and type-II) of the high step-up DC-DC converter using switched inductor and voltage multiplier cell. The advantages of these proposed topologies are the less voltage stress on semiconductor devices, low device count, high power conversion efficiency, high switch utilization factor and high diode utilization factor. We analyze the Type-II topologies operating principle and mathematical analysis in detail in continuous conduction mode. High-intensity discharge lamp for the automotive application can use the derived topologies. The proposed converters give better performance when compared to the existing types. Also, it is found that the proposed type-II converter has relatively higher voltage gain compared to the type-I converter. A 40 W, 12 V input voltage and 72 V output voltage has developed for the type-II converter and the performances are validated.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.5
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• pp.786-791
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• 2017

In this paper, the run time of Li-polymer secondary cell with and without Active Balancing BMS is analyzed. The Active Balancing System using Flyback Converter with two-way power control facility, his designed for optimal characteristics of balancing. The run time of Li-polymer secondary cell is drastically increased employing the Flyback Convert Active Balancing BMS. The run time performance of Li-polymer secondary cell with or without Flyback Converter Active Balancing BMS is analyzed with the discharging and charging experiment of Li-polymer secondary cell.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.2
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• pp.235-245
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• 2014

This paper presents an envelope tracking power amplifier using a standard CMOS process for the 3GPP long-term evolution transmitters. An efficiency of the CMOS power amplifier for the modulated signals can be improved using a highly efficient and wideband CMOS bias modulator. The CMOS PA is based on a two-stage differential common-source structure for high gain and large voltage swing. The bias modulator is based on a hybrid buck converter which consists of a linear stage and a switching stage. The dynamic load condition according to the envelope signal level is taken into account for the bias modulator design. By applying the bias modulator to the power amplifier, an overall efficiency of 41.7 % was achieved at an output power of 24 dBm using the 16-QAM uplink LTE signal. It is 5.3 % points higher than that of the power amplifier alone at the same output power and linearity.

• Journal of Electrical Engineering and Technology
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• v.5 no.3
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• pp.435-442
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• 2010

This paper proposes an 18-step back-to-back (BTB) voltage source converter using four sets of 3-Level converter modules with auxiliary circuits to increase the number of steps. The proposed BTB voltage source converter has the independent control capability of active power and reactive power at the interconnected ac system. The operational feasibility of the proposed BTB converter was verified through many simulations with PSCAD/EMTDC software. The feasibility of hardware implementation was verified through experimental results with a scaled hardware prototype. The proposed BTB converter could be widely applied for interconnecting the renewable energy source to the power grid.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.9
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• pp.869-876
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• 2016

In the Phase Shifted Full Bridge(: PSFB) converter, there are several design factors including power switches, power switches' driving circuits, transformer and inductor, and rectifier stage, etc. Among them, a key factor influencing an optimal performance of the PSFB converter is the design of transformer. Especially, its effect becomes more important in low voltage and high power applications. In this paper, a study on an optimal design of transformer in the PSFB converter is presented. The design equations for the transformer are derived and analyzed in details, and an example design of the transformer for a 12V, 1200W server power supply application is showed as the result of analysis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.1
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• pp.68-75
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• 2012

This paper presents a comparative analysis of the parallel operation of different switches in a DC/DC converter. In high power applications, multi-switch PWM power conditioners may be preferred despite a higher component count, due to the absence of low frequency filters, reduced switching losses and fault tolerance. The paper demonstrates how current sharing (CSH) and time sharing (TSH) lead to the reduction of switching stress in the parallel operation of switches in any converter. The solutions proposed in this study can be applied on different scales to other power conditioners for DC/DC converter systems. Discussions of the concepts, hypotheses and computer simulations are verified by 1 kW experimental results.