• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 연구회 합동 학술발표회 논문집
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• pp.60-63
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• 1998

The widely used power supply (Switched Mode Power Supply : SMPS) as a source in order to stabilize direct current for electronics or communication systems has merits, when it is compared to the existing source for stability, such as high efficiency, small size, light weight by means of switching process of the semiconductor device which controls the flow of power. However, due to existence of inductors and capacitors used for charging energy, the source part in electronic or communication systems hasn't reached the speed, that is supposed to get, for achieving smaller size and lighter weight. In order to get smallness in size, it is necessary to increase switching frequency. And that makes devices for measuring energy smaller. Nevertheless, the rise switching frequency brings increases in switching loss, inductor loss, and power loss. Also, the occurrence of surge and noise caused by high frequency switching is getting higher. The resonant converter has been considered as one of methods that give solutions for the problems of SMPS and that method have been paid attention as a source technology in electronics and communication.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.235-239
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• 2002

Combined generation system of photovoltaic and wind power is required backup system that such as a storage battery to supply energy, when not enough photovoltaic and wind power source for power supply equally and continually, because the energy source is changeable and stable through change of weather as irradiation, temperature, wind speed, wind speed, wind direction, seasons, etc..

• 한국초전도ㆍ저온공학회논문지
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• 제7권2호
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• pp.44-46
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• 2005

A SMES can be a perfect alternative energy storage device to the chemical batteries which are needed by most of the renewable energy supply systems. The chemical battery storage system is so expensive to maintain and causes another environmental problem because they are not recyclable. But, SMES has semi-permanent lifetime and no environmental problems cause it only need coolants which is non flammable, clean and recyclable gas. In order to verify the feasibility of a SMES for the renewable electrical power supply system, electrical characteristics of a test SMES coil with the photovoltaic power system were analyzed in this paper. Simulation results show that we can charge 40 amps of current in test SMES coil using solar power system. The experimental verification will be performed just after development of the peak power tracking system for the solar system.

• 조명전기설비학회논문지
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• 제29권5호
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• pp.86-93
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• 2015

Recently, ESS became efficient device to stabilize electric power supply system with the development SG related technology. In fact. there are some constraints to supply ESS, because of the high cost and required space, but rapid technology development for ESS will make it more useful soon. So, through this paper, we analyzed the benefit and demand effect when the battery is applied the building based on the measured energy consumption. After that, we got the conclusion that there is a volume limit in ESS application, in a benefit view point. And we realized that there is a demand violation, and the Cost-based BEMS is the best solution to enhance the effect of ESS application.

• 센서학회지
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• 제29권5호
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• pp.312-322
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• 2020

As the use of mobile devices increase, there is public interest in the utilization of the human motion generated mechanical energy. The human motion generated mechanical energies vary depending on the body region, type of motion, etc., and an appropriate device has to be designed to utilize them effectively. In this work, a device based on the principles of triboelectric generation and inertia was assessed in order to utilize the multi-axial mechanical energies generated by human motions. To improve the output performance we confirm the changes in the output that vary with the structural design, the reasons for such changes, and variations in performance based on the parts of the human body. In addition, the level of electrical energy generated based on motion type was measured; a maximum voltage of 30 V and a current of 2 ㎂ were generated. Finally, the proposed device was utilized in LEDs used for lighting, thus demonstrating that multi-axial mechanical energies can be harvested effectively. Based on the results, we expect that the developed device can be utilized as a sensor to detect mechanical energies, to sense changes in motion, or as a generator for auxiliary power supply for mobile devices.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 1995년도 제4회 학술강연회논문집
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• pp.171-175
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• 1995

Semiconductor diode lasers that can generate one watt or more of optical energy for tens of milliseconds (quasi continuous wave) are now readily available. Several researchers have demonstrated that this power level, when properly coupled, can reliably initiate pyrotechnic mixtures. This means that the initiator containing the pyrotechnic can be protected against inadvertent initiation from electromagnetic radiation or electrostatic discharge by a conducting Faraday cage surrounding the explosive. Only a small dielectric window penetrates the housing of the initiator, thereby eliminating the conductors necessitated by a bridgewire electroexplosive device. The diode laser itself, however, functions at a low voltage (typically 3 volts) and hence is susceptible to inadvertent function from power supply short circuits, electrostatic discharge or induced RF energy. The rocket motor arm-fire device de-scribed in this paper uses a diode laser, but protects it from unintentional function with a Radio Frequency Attenuating Coupler (RFAC).The RFAC, invented by ML Aviation, a UK company, transfers power into a Faraday cage via magnetic flux, thereby protecting the diode, its drive circuit and the pyrotechnic from all electromagnetic and electrostatic hazards. The first production application of a diode laser and RFAC device was by the Korean Agency for Defense Development.

• Journal of Magnetics
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• 제19권2호
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• pp.197-204
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• 2014

A transcranial magnetic stimulation device is a complicated appliance that employs a switching power device designed for discharging and charging a capacitor to more than 1 kV. For a simple transcranial magnetic stimulation device, this study used commercial power and controlled the firing angle using a Triac power device. AC 220V 60 Hz, the power device was used directly on the tanscranial magnetic stimulation device. The power supply device does not require a current limiting resistance in the rectifying device, energy storage capacitor or discharge circuit. To control the output power of the tanscranial magnetic stimulation device, the pulse repetition rate was regulated at 60 Hz. The change trigger of the Triac gate could be varied from $45^{\circ}$ to $135^{\circ}$. The AVR 182 (Zero Cross Detector) Chip and AVR one chip microprocessor could control the gate signal of the Triac precisely. The stimulation frequency of 50 Hz could be implemented when the initial charging voltage Vi was 1,000 V. The amplitude, pulse duration, frequency stimulation, train duration and power consumption was 0.1-2.2T, $250{\sim}300{\mu}s$, 0.1-60 Hz, 1-100 Sec and < 1 kW, respectively. Based on the results of this study, TMS can be an effective method of treating dysfunction and improving function of brain cells in brain damage caused by ischemia.

• 전기학회논문지
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• 제64권1호
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• pp.196-200
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• 2015

The switching noise in the power electronics of the power conversion equipment (Power Conditioning System) for large energy storage devices are generated. Since the burst-level transient noise from being generated in the power system at a higher power change process influences the control circuit of the low voltage driver circuit. Noise may cause the malfunction of the control device even if no dielectric breakdown leads to a control circuit. To overcome this, this paper proposes the installation of an additional nano-surge protection device on the power supply DC output circuit of the battery management unit.

• Journal of Advanced Marine Engineering and Technology
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• 제24권3호
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• pp.106-112
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• 2000

Since the oil crisis, we have been concerned about the energy saving techniques of electric generating systems. As a part of the effort to save energy, automatic electric load sharing device was developed. Usually, ship's electric generating system consists of two or three sets of generator. And, electric generating system is operated as single or parallel operation mode according to the demanded electric power. Therefore, it is important to investigate generators operating mode for the supply of required electric power in the ship in order to decrease the operating cost. So, this paper suggests the method to solve the optimal electric load distribution problem by dynamic programming. And, this thesis indicates that the proposed method is superior to the lagrange multiplier's method in obtaining optimal load distribution solution in the ship's electric generating system.

• 한국태양에너지학회 논문집
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• 제33권2호
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• pp.93-100
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• 2013

Two-step thermochemical cycle using ferrite-oxide($Fe_2O_4$) device was investigated. The $H_2O$(g) was converted into $H_2$ in the first experiment which was performed using a dish type solar thermal system. However the experiment was lasted only for 2 cycles because the metal oxide device was sintered and broken down. Another problem was that the reaction was taken place mainly on a side of the metal oxide device. The m-$ZrO_2$, which was widely known as a material preventing sintering, was applied on the metal oxide device. The ferrite loading rate and the thickness of the metal oxide device were increased from 10.67wt% to 20wt% and from 10mm to 15mm, respectively. The chemical reactor having two inlets was designed in order to supply the reactants uniformly to the metal oxide device. The second-experiment was lasted for 5 cycles, which was for 6 hours. The total amount of the $H_2$ production was 861.30ml. And cerium oxide($CeO_2$) device was used for increasing $H_2$ production rate. $CeO_2$ device had low thermal resistance, however, more $H_2$ production rate than $Fe_2O_4$ device.