• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.134-139
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• 2005

This paper presents a cost effective quasi-resonant soft-switching PWM high frequency inverter with minimum circuit components. This inverter can achieve wider soft commutation, simpler power circuit configuration, smaller volumetric size, lower cost and wider power regulation range, higher-efficiency as compared with single ended quasi-resonant ZVS-PFM inverter and active voltage clamped quasi-resonant ZVS-PWM inverter. The operation principle of the proposed inverter is described on the basis of the simulation and experimental results, together with its operating performances in steady state. The operating performances of this unique proposed high frequency inverter based on ZVS and ZCS arms-related soft commutation principle is evaluated and discussed as compared with the active voltage-clamped ZVS-PWM inverter and a conventional single-ended ZVS-PFM inverter. The practical effectiveness of a novel type quasi-resonant soft-switching PWM high frequency inverter using IGBT is actually proved for consumer induction heated appliances as rice cooker, hot water producer, steamer and super heated steamer. The extended bidirectional circuit topology of quasi-resonant PWM high frequency inverter with minimum circuit components is demonstrated, which operate as the direct frequency changer.

• Journal of Magnetics
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• v.22 no.1
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• pp.69-77
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• 2017

To empower safe, economical and eco-friendly sustainable solution for enhancing oil and gas productivity from deep water reservoirs, new downhole technologies are recommended. Since electric machine plays leading role in the downhole application, it is a squeezing requirement for researchers to design and develop advanced electric machine. The Recent improvement in technology and uses of high-temperature magnets, permanent magnet flux switching machine (PMFSM) has become one of the appropriate contenders for offshore drilling but fewer designed for downhole due to ambient temperature. Therefore this comprehensive study deals with the design optimization and performance analysis of outer rotor PMFSM for the downhole application. Preliminary, the basic design parameters needed for machine design are calculated mathematically. Then the design refinement technique is implemented through deterministic method. Finally, initial and optimized performance of the machine is compared and as a result the output torque is increase from 16.39 Nm to 33.57 Nm while diminishing the cogging torque and PM weight up to 1.77 Nm and 0.79 kg, respectively. Therefore, it is concluded that purposed optimized design is suitable for the downhole application.

• International Commerce and Information Review
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• v.12 no.4
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• pp.363-382
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• 2010

It should be unthinkable to not provide water at survival of any living things. Water is too a basic element for development for a country. Currently, the global market of mineral water is growing rapidly. This study, I conceptualized mineral water as bottled water. In particularly, bottled water has seen huge global growth for the last few years. The annual growth rate of the market in the period 2005-2009 was 5.9%. Following a surge in obesity and subsequent health and wellness trends, many consumers are switching from sugary soft drinks to healthier alternatives. Therefore, the global bottled water market is one area which has big potential for growth, but price competition is getting intensified among multi-national and domestic firms. Korean providers too are faced with strong competition in growing domestic market. The bottled water market has presence of multinational provider like Nestle, Danone and Coca-Cola, which collectively account for 35.1% of the world market share in 2009. On the basis of a market orientation approach, this article looks at changing environments in the world mineral water industry and attempts to describe foreign market entry strategy of the Korean mineral water industry. The market orientation provides strong norms for learning from customers and competitors, is instrumental in creating a superior value for buyers, innovating successfully, and generating excellent firm performance. So firms should consider a strategic planning in basis on market orientation before they enter foreign markets. Some discussions were made about managerial implications for Korean bottled water providers.

• Journal of information and communication convergence engineering
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• v.6 no.3
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• pp.305-309
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• 2008

This paper presents an innovative prototype of a new conceptual electromagnetic induction eddy current based fluid heating appliance using voltage-fed quasi resonant zero voltage soft switching PWM high-frequency inverter using IGBTs, which can operate at a constant frequency variable power regulation scheme. The promising simple high efficient low noise inverter type electromagnetic induction eddy current based pipeline fluid heating appliance is proposed for saturated steam generator, superheated steam generator, hot water and hot air producer, metal catalyst heating for exhaust gas cleaning in engine. Under these technological backgrounds, a novel electromagnetic induction eddy current Dual Packs Heater(DPH) based pipeline fluid heating incorporates thin metal layer type package for continuous fluid heating appliances applying two types of voltage-fed quasi load resonant ZVS-PWM high frequency inverter. The unique features of a novel electromagnetic induction eddy current DPH based continuous pipeline fluid heating appliance is illustrated on the basis of simulation and discussed for the steady state operating characteristics and experimental results.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1416-1417
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• 2007

The high frequency pulsed power system is widely available for use in high frequency generator applications. We designed and fabricated our own high frequency pulsed power system to obtain very sort pulse width and high peak value and investigated microbe removal characteristics using it. This paper introduces a simple high voltage high frequency pulsed power system for removing various bacteria caused by dirty water. This system include power supply circuit, switching MOSFET, and flyback converter. We can also control the switching using a PIC one chip microprocessor. As a result, we can obtain good removing characteristics of various bacteria by adjusting the charging voltage, the pulse repetition rate and the electrical field inducing time.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1364-1367
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• 2005

In this paper, a novel prototype topology of soft switching PWM controlled high frequency AC power conversion circuit without DC voltage smoothing chemical capacitor filter link from the voltage grid of utility frequency AC power supply source with 60Hz-100V or 60Hz-200V is proposed and introduced for innovative consumer induction heating(IH) boiler applications as hot water producer, steamer and super heated vapor steamer.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.11
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• pp.23-29
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• 2008

This paper presents a new conceptual electromagnetic induction eddy current based stainless steel plate spiral type heater for heat exchanger or dual packs heater in hot water system boiler steamer and super heated steamer, which is more suitable and acceptable for new generation consumer power applications. In addition, an active clamping quasi-resonant PWM high frequency inverter using trench gate IGBTs power module can operate under a principle of zero voltage soft commutation with PWM is developed and demonstrated for a high efficient induction heated hot water system and boiler in the consumer power applications. This consumer induction heater power appliance using active clamping soft switching PWM high frequency inverter is evaluated and discussed on the basis of experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.1
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• pp.27-34
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• 2010

To dissipate the heat generated from the switching devices in the inverter system of HEV, the water cooling structure is proposed. The bolt type cooling structure has a problem such as water leakage for high pressure of water, therefore the proposed cooling structure applied pipe structure in the heat sink. The heat dissipation characteristics for various structures of water channel and distance between heat source and water channel was analyzed through the simulation. heat dissipation effect for two types of water cooling structures was investigated. Based on the simulation results, two types of water cooling system for 30kW inverter system of HEV were manufactured and the heat dissipation effect was verified.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.1
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• pp.35-40
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• 1999

We selected horse mackerel Trachurus japonicus, mackerel Scomber japonicus and arrow squid Todarodes pacificus, to use in the experiment. These fishes migrate to the Cheju coast and were caught by set-net. We studied the leading effect on the fish schools using the attracting lamps in an outdoor water tank at the Marine Research Institute in Cheju National University. The results obtained are summarized as follows; 1. The attracting rate of fish schools was increasing as the time between switching on and off each lamp was getting longer when each of the attracting lamps was switched on and off in order. However, the attracting rate of mackerel school showed a tendency to be higher than that of the other two species. 2. The attracting rate of fish schools was increasing as the time of switching off the lamps was getting longer when the attracting lamps which had been switched on were switched off in order. However, the attracting rate of mackerel school showed a tendency to be higher than that of the other two species. 3. The attracting rate of fish schools was decreasing as the speed of moving the attracting lamp was getting faster when the attracting lamp was moving. However, the attracting rate of mackerel school showed a tendency be higher than that of the other two species. 4. To determine the distance between the attracting lamps, there would be two methods. One is switching on and off the attracting lamps in order, and the other is switching off the attracting lamps in order which had been switched on. The methods showed that the attracting rate of fish schools were decreasing as the distance between the attracting lamps were getting longer. However, the attracting rate of mackerel school showed a tendency to be higher than that of the other two species.

• Journal of Korean Society of Rural Planning
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• v.25 no.4
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• pp.35-45
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• 2019

Korean agriculture experienced rapid changes in its production structure to respond fluctuations on external conditions, and these changes have increased the dependence between agricultural resources and negative environmental externalities from agricultural production. As a tool for managing agricultural resources and reducing negative environmental effects from agricultural production, this study employs water-energy-food nexus for integrated resource management. To show the necessity of an integrated approach, this study evaluated three policy scenarios including changes in capital interest, water capacity, and energy cost. The results show that three scenarios have unintended consequences for farmers' incomes and their use of resources. Also the unintended consequences of government policies also affected farms' vulnerability to environmental changes. In particular, the expansion of financing for the establishment of non-circulating water curtain facilities did not have a significant effect on the crop switching of farms. In addition, increasing the amount of available water through the aquifer recharge project leads to the installation of non-circulating water curtain facilities in zucchini farm. It raises dependence on groundwater in agricultural production, thereby increasing farmers' vulnerability to groundwater shortages. These results imply that the agricultural sector needs to consider the interrelationship between agricultural resources when designing or evaluating policies.