• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.288-291
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• 2006

The authors, R&D member of DAWONSYS and Soongsil University, are developing 5000kW smelting inverter system by 2007 under the sponsor from Korea Energy Management Corporation. As a part of the project, 2500kW inverter system has developed in 2005[6], and installed in real production site, and has been running for 7 months successfully. This report deals with the test result of 2500kW smelting inverter system and design for 5000kW smelting inverter system which is final target of this project.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.293-296
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• 2001

A conventional power supply to drive a microwave oven has ferro-resonant transformer and high voltage capacitor(HVC). Though it is simple, transformer is bulky, heavy and has low-efficiency. To improve this defect, a high frequency inverter type power supply has been investigated and developed in recent years. But, because of additional control circuit and switching device, inverter-type power supply is more expensive than conventional one. In this study, The design procedure of a novel HVC embedded high frequency transformer is proposed for down-sizing and cost reduction of Inverter-type power supply. Also, equivalent circuit mode] is derived by FEM analysis and impedance measurements. And the operation of proposed HVC embedded transformer is verified by simulations and experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.1
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• pp.107-113
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• 2001

This paper describes dynamic performance analysis of a STATCOM based on 3-level inverter. Major attention is focused on the controller design for 3-level inverter, including regulator design for voltage sharing across the dc link capacitors. A detailed simulation model was developed with Matlab and a scaled hardware model was built and tested to verify the proposed approach. Both simulation and experimental results confirm that the developed controller can regulate the reactive power. The developed controller could be effectively applied to the actual hardware system for STATCOM.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.11
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• pp.1079-1088
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• 2001

A dynamic simulation model was developed to analyse the transient characteristics of a multi-inverter heat pump. The programs included a basic air conditioning system such as a evaporator, condenser, compressor, linear electronic expansion valve (LEV) and by-pass circuit. The theoretical model was derived from mass conservation and energy conservation equations to predict the performance of the multi-inverter heat pump at various operating conditions. Calculated results were compared with the values obtained from the experiments at different operation frequencies of compressor, area of the LEV and configuration of indoor units operation. The results of the simulation model showed a good agreement with the experimental ones, so that the model could be used as an efficient tool for thermodynamic design and control factor design of air-conditioners.

• Journal of Information Display
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• v.13 no.4
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• pp.167-177
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• 2012

Cold cathode fluorescent lamps (CCFLs) are used to provide lighting for liquid crystal displays (LCDs). This paper presents a set of guidelines for measurement characterization and design to reduce the power consumption of CCFL LCD backlight inverters and panel electronics. The proposed methods aim to reduce the backlight power consumption by fine-tuning a back-light inverter for a specific LCD, using several methods. First, the authors describe their power measurement methodology; and next, they identify different areas for tuning a backlight inverter for a given display. The experiment results showed that power savings can range from 50 to 200mW if the backlight inverter is properly tuned. This paper also proposes an optimized configuration for light-emitting device (LED) panels to reduce power loss by selecting a LED with a specific input voltage and number of cells to help minimize power loss.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.345-351
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• 2018

This paper analyzes a resonant inverter to generate plasma. The resonant inverter consists of a full bridge converter, resonant network and reactor to generate a magnetic field for plasma generation. A plasma load has very distinct characteristics compared to conventional loads. The characteristics of plasma load are analyzed through experimental results. This paper presents the study on the resonant network, which was performed in order to determine how to achieve a constant current gain. Another important contribution of this study is the analysis of drop-out phenomenon observed in plasma loads which is responsible for unpredictable shutdown of the plasma generator that requires stable operation. In addition, the design process for the resonant network of a plasma generator is proposed. The validity of this study is verified through simulations and experimental results.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.228-230
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• 2009

Nowadays, the LCL-filter type becomes an attractive grid interfacing for grid-connected Voltage Source Inverter (VSI). LCL-filter can render the current harmonics attenuation around the switching frequency by using smaller inductance than L-filter. This paper presents a study about the LCL-filter design for single-phase grid-connected inverter in Photovoltaic (PV) system. According to the expected current ripple, the inductances of the filter can be determined. Based on the absorbed reactive power on capacitor, the capacitance can be calculated. Due to the theoretical analysis, a LCL-filter based single phase grid connected inverter control system are simulated. The studied simulation results are given to validate the theoretical analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.12
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• pp.1602-1610
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• 2018

Induction heating can convert electrical energy to thermal energy with high conversion efficiency and quick heating. Currently, a current source rectifier/inverter-fed parallel resonant circuit is widely used as an induction heating power supply for forging applications. However, the conventional induction heating power supplies composed of phase-controlled rectifier and SCR inverter have low efficiency and low power factor at input side, and require additional starting circuitry. So this paper proposes new induction heating power supply topologies for forging applications which have high power factor, high efficiency, and large output power. It also suggests detailed design guideline.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.6
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• pp.429-436
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• 2021

The design of a gate driver power supply for a three-phase inverter using a silicon carbide (SiC) MOSFET. The requirements for the power supply circuit of the gate driver for the SiC MOSFET are investigated, and a flyback converter using multiple transformers is used to make the four isolated power supplies. The proposed method has the advantage of easily constructing the power supply circuit in a limited space as compared with a multi-output flyback converter using a single core. The power supply circuit for the three-phase SiC MOSFET inverter for driving an AC motor is designed and implemented. The operation and validity of the implemented circuit are verified through simulations and experiments.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1318-1328
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• 2015

The photovoltaic (PV) power conditioning system for small-scale applications has gained significant interest in the past few decades. However, the standalone mode of operation has been rarely approached. This paper presents a two-stage multi-level micro-inverter topology that considers the different operation modes. A multi-output flyback converter provides both the DC-Link voltage balancing for the multi-level inverter side and maximum power point tracking control in grid connection mode in the PV stage. A modified H-bridge multi-level inverter topology is included for the AC output stage. The multi-level inverter lowers the total harmonic distortion and overall ratings of the power semiconductor switches. The proposed micro-inverter topology can help to decrease the size and cost of the PV system. Transient analysis and controller design of this micro-inverter have been proposed for stand-alone and grid-connected modes. Finally, the system performance was verified using a 120 W hardware prototype.