• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.48-56
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• 2009

This paper presents the power conversion system for TIG-welder using the fuel cell stack Generally, power supply for TIG-welder uses the front-ended diode bridge rectifier by common AC power source. In this case, power supply of TIG-welder increases in volume because of using bulky capacitor and diode-rectifier. Also, input current includes ripple and harmonics. Moreover, TIG-welder will be demand the power supply with lightweight and easy movement in the areas like as the islands and mountainous areas or the special environment are not use common AC power source. Thus, input power of the power conversion system for TIG-welder is used PEMFC(Polymer Electrolyte Membrane Fuel Cell), and the power conversion system is comprised of full-bridge converter with function of boost converter and inverter welding source, in this paper. The proposed power conversion system which is power supply for TIG-welder was verified by computer simulations and experiments.

• Journal of IKEEE
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• v.27 no.4
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• pp.450-455
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• 2023

Among single-phase photovoltaic inverters that can avoid excessive leakage current caused by the large parasitic capacitance of photovoltaic panels, a boost converter followed by a half-bridge inverter is the simplest and has the smallest leakage current. However, due to the high DC-link voltage, the rated voltage of the switching devices is high and the switching loss is large. This paper proposes a new circuit topology which can operate as a buck-boost inverter by adding two bidirectional switches to the output side of the half-bridge inverter instead of removing the boost converter. By reducing two stages of power conversion through the high-voltage DC-link to one stage, power loss can be reduced without increasing costs and leakage current. The feasibility of the proposed circuit topology is verified by computer simulation and power loss calculation.

• Journal of Energy Engineering
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• v.15 no.3 s.47
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• pp.181-187
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• 2006

This paper is proposed to a solar cell power system used in fire emergency equipment. Also it is designed with a high efficiency power converter in order to increase efficiency of power system. The controlling switches used in DC-DC booster chopper and DC-AC inverter are operated with soft switching, which is applied to resonant circuit method to reduce switching loss. The result is that the system gets to high efficiency. In this paper, A detection circuit of maximum power point of solar cell is described in this paper. And the performance evaluations for the photovoltaic power system of high efficiency are examined by the analysis of a new tracking controller with a maximum power $P_{max}$ detection of solar cell.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.179-184
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• 2019

In many countries, such as developing countries where electricity is scarce, small wind turbines in the form of Off Grid are an effective solution to solve power supply problems. In some countries, the expansion of power systems and the decline of electricity-intensive areas have led to the use of small wind power in urban road lighting, mobile communications base stations, aquaculture and seawater desalination. With this change, the size of the small wind power industry is expected to have greater potential than large-scale wind power. In the case of small wind power generators, the generator is controlled at a variable speed, and the voltage and current generated by the generator have many harmonic components. To solve this problem, the AC to DC converter to be studied in this paper is a three-phase step-up type converter with a single switch. The inductor current is controlled in discontinuous mode, and has a characteristic of having a unit power factor by eliminating the harmonic of the input current. The proposed converter is composed of LCL filter and three phase rectification boost converter at the input stage and a single phase full bridge for grid connection. It is a control system with energy storage system(ESS) that the system stabilization can be pursued against the electric power.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.450-452
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• 1996

In this paper, the authors propose a DC-DC boost converter of high efficiency by partial resonant switching mode, the switching devices in a proposed circuit are operated with soft switching and the control technique of those is simplified for switch to drive in constant duty cycle. The circuit has a merit which is taken to increase of efficiency, as it makes to a regeneration at input source of accumulated energy in snubber condenser without loss of snubber inconventional circuit. The proposed converter is deemed the most suitable for high power applications where the power switching devices are used.

• Journal of Power Electronics
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• v.8 no.1
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• pp.51-59
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• 2008

This paper addresses several issues concerning the analysis, design, modeling, simulation and development of single-phase, single-switch, power factor corrected AC-DC high frequency switching converter topologies with transformer isolation. A detailed analysis and design is presented for single-switch topologies, namely forward buck, flyback, Cuk, Sepic and Zeta buck-boost converters, with high frequency isolation for discontinuous conduction modes (DCM) of operation. With an awareness of modem design trends towards improved performance, these switching converters are designed for low power rating and low output voltage, typically 20.25W with 13.5V in DCM operation. Laboratory prototypes of the proposed single-switch converters in DCM operation are developed and test results are presented to validate the proposed design and developed model of the system.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.46-47
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• 2012

In the design of the battery charger it is important to limit the ripple current and voltage according to the manufacturer's recommendation for the reliable service and the extended life of the battery. However, it is often overlooked that these ripple components can cause internal heating of the battery, thereby reducing its service life. Thus the care must be taken in the design of the switching converter for the charge application through the accurate estimation of the output ripple values. In this research analysis on the output ripple of the dc-dc converter is detailed to provide a guideline for the design of the battery charger.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.341-344
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• 2001

In this paper, the characteristics of the proposed converter are show by simulation. As a result, the power factor is improved and the results show the usefulness of the proposed circuit. To improve the hard switching at turn-off of the basic circuit, the circuit using a current resonant switch is proposed. In the proposed circuit, THD of the input current is reduced to 1.8 of the basic circuit. The mechanism of the THD reduction is clarified. That is because the on period becomes shorter at the peak of the source voltage. Using the simulation, the characteristics of the output voltage, current flowing the switch, and THD of the input current are investigated by changing the resonant circuit parameters. Criteria for choosing resonant parameters of smaller THD are obtained.

• Journal of Fisheries and Marine Sciences Education
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• v.9 no.2
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• pp.209-221
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• 1997

This paper presents a soft switching unity power factor PWM rectifier, which features reduced conduction losses and soft switching with no auxiliary switches. The soft switching are achieved by using a simple commutation circuit with no auxiliary switches, and reduced conduction loses are achieved by employing a single converter, instead of a typical front end diode rectifier followed by a boost rectifier. Furthermore, thanks to good features such as simple PWM control at constant frequency, low switch stress and low VAR rating of commutation circuits, it is suitable for high power applications. The principle of operation is explained in detail, and major characteristics analysis and experimental results of the new converter also included.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.246-248
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• 1994

This paper describes a bidirectional Voltage Source PWM Converter for an elevator. From the study of boost rectifier, the control circuit desisted by full digital DSP technique. The characteristic of control circuit is that implements of space-vector PWM method and has feedback loop of DC side load current which reduce DC voltage flucturation.