• The Transactions of the Korean Institute of Power Electronics
• /
• v.3 no.2
• /
• pp.92-98
• /
• 1998

With the development of semiconductor devices, adoption of microcontroller prevails in industrial area. But in are welding industry, there has not been much progress in adoption of microcontroller technology. Therefore, this paper shows the application of digital control technology to welding machine. This paper presents the design of microcontroller that is appropriate for three phase $CO_2$ gas metal are welding machine. By using microcontroller in $CO_2$ gas metal are welding machine, the overall cost can be reduced compared to analog comtroller. Also TMS370C850 microprocessor is used as overall microcontroller for the are welding machine.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.16 no.3
• /
• pp.274-282
• /
• 2011

The ultra slim U-I and W-I primary and pick-up coils for OLEV (On-Line Electric Vehicles) are proposed. With the proposed structures, the amount and the cost of the core are dramatically reduced. Not only air gap but also the lateral displacement are improved. The proposed structures are applied to the OLEV bus and SUV, which achieve 83% efficiency at 17cm air gap with more than 60kW output power, and the construction cost is lower than ￦300M/km. The proposed coil structures are verified with simulations and experiments.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.38 no.7
• /
• pp.524-538
• /
• 1989

A new bilateral series resonant inverter and its control method are proposed. The proposed inverter consists of zero current switched cycloconverter. Output voltage is regulated by modulating the average magnitude of resonant current sinusoidally. Cycloconverter synthesizes low frequency output voltage from high frequency resonant current pulses. In the proposed inverter, bidirectional power flow in possible and isolation transformer is miniaturized. The proposed control method is verified through simulation and experiment. The proposed inverter will satisfy the small size and low cost requirements of small Uninterruptible Power Supply (UPS) of less than 1 KVA suitable for micro-computers and electronic equipments used in office and home automation.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.5
• /
• pp.1198-1206
• /
• 2011

In this paper, we proposed a home network integrated dimmer switch using Z-wave Mesh Network. The dimmer switch come with wired and wireless network-based intelligent lighting switch that can be installed in a apartments with home network technologies. This switch is ease to install and operate. Furthermore, it provide power saving through efficient control of light using motion detect sensor and light intensity sensor. In order to evaluate the performance of our developed home network integrated dimmer switch, we performed a load performance test and from our result, it showed excellent performance in terms of lighting control and communication speed.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38B no.1
• /
• pp.46-53
• /
• 2013

Recently, intensive research has been performed for reducing video decoder energy consumption, especially based on DVFS (Dynamic Voltage and Frequency Scaling) technique. Our previous work [1] has proposed the optimal DVFS algorithm for energy reduction in video decoders. In spite of the mathematical optimality of the algorithm, the precondition of known frame decoding cycle/complexity limits its application to some realistic scenarios. This paper overcomes this limitation by frame data size-based estimation of frame decoding complexity. The proposed decoding complexity estimation method shows over 90% accuracy. And with this estimation method and buffer underflow margin of around 20% of frame size, almost same power consumption reduction performance as the optimal algorithm can be achieved.

• Journal of Advanced Navigation Technology
• /
• v.22 no.5
• /
• pp.420-428
• /
• 2018

In this paper, represented uninterruptible power supply (UPS) equipment maintaining constant output voltage, the proposes a photovoltaic system constructed with a step up boosting chopper and single phase pulse width modulation (PWM) voltage source inverter. as power source disconnection, voltage variation and output current variation with load variation. This system is driven by being synchronized voltage fed inverter and AC source, and in the steady state of power source charge battery connected to DC side with solar cell using a Photovoltaic that it was so called constant voltage charge. It can be results of saving electric power, and through a normal operation of energy storage system (ESS), the system operated the LED a calling on signal changes at the airport in an efficient manner. In addition, better output waveform was generated because of PWM method, and it was proved to test by experiment maintained constant output voltage regardless of AC source disconnection, load variation, and voltage variation of AC power source.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.54 no.8
• /
• pp.107-114
• /
• 2017

In this paper, a novel power factor compensation system based on voltage-controlled method is proposed for 3-phase 4-wire power system. The proposed voltage-controlled power factor compensation system generates a reactive power required for compensation by applying a variable output voltage by a slidac to a capacitor. In conventional power factor compensation system using the capacitor bank method, the power factor compensation error occurs depending on the load condition due to the limited capacity of the capacitors. However, the proposed system compensates the power factor up to 100% without error. In this paper, we have developed a voltage-controlled power factor compensation system and a control algorithm for 3-phase 4-wire power system, and verify its performance through simulation and experiments. If the proposed power factor compensation system is applied to an industrial field, a power factor compensation performance can be maximized. As a result, it is possible to reduce of electricity prices, reduce of line loss, increase of load capacity, ensure the transmission margin capacity, and reduce the amount of power generation.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.6
• /
• pp.17-23
• /
• 2012

In this paper, we were proposed a new LED light device lighting control algorithm for optimal energy saving. The propose lighting control algorithm be to the LED lights devices lighting control by measuring illuminance into multi sensors. And it be to lighting control by inverting of octagon pattern during set-up time. All the LED is lighting when detecting motion by the motion sensor. And, it was designed enable remote management control by communicate with central monitoring center using Zigbee wireless network to measured data from sensors at real time. In this paper, a proposed lighting control algorithm was measured power consumption about the lighting status of LED lighting device using the lighting control program for demonstrate of energy savings effect. The measured result, the lighting method applying proposed algorithm were proved energy savings effect of more 40% more compared to the existing lighting method.

• Journal of the Korea Society of Computer and Information
• /
• v.20 no.4
• /
• pp.11-16
• /
• 2015

Data center, not only the development of globally of cloud-based IT solutions, As the big data, education, use of development electronic equipment of communication means is increased, Demand of domestic and international data center has increased steadily. Due to the increase of data center demand, heat generation of server rack due to the development of IT equipment is also increasing continuously. Calculating heat value of the data center, because more than 99% of the power usage of IT server is converted into heat, the calorific value as the size and capacity of the server is larger will increase. In this paper, to center the cooling system of air-cooled, and research and development of air conditioning systems for energy reduction of data center, through performance analysis and simulation, it has been analyzed that there is energy savings.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.6
• /
• pp.4260-4266
• /
• 2015

In this study, the optimal control method for minimizing of energy consumption for central cooling system with proper occupant comfort level is researched by simulation. The optimal control method is that the optimal set temperatures such as the condenser water temperature, supply air temperature, and chilled water temperature with environment variable change such as outdoor air dry-bulb and wet-bulb temperatures are obtained by suggested optimal control algorithm with maximum and part building load. The TRNSYS program is used for system modeling and the control performances with the suggested optimal control method are compared with the existing control method of fixed set points. The suggested optimal control method shows better responses in energy consumption in comparison with existing control ones.