• Proceedings of the KIPE Conference
• /
• 2010.07a
• /
• pp.297-298
• /
• 2010

산업용 인버터 시장은 부하의 운전 조건에 따라 고성능, 다기능, 단순 기능 분야로 구분된다. 당사는 고성능, 다기능 분야에 대응이 가능한 N700V 모델을 개발하여 영업 활동을 하고 있으나, 단순기능 분야에는 기능의 복잡성과 높은 가격 등으로 경쟁력이 저하되었다. 이에 당사는 단순기능 분야에 대응이 가능하도록 기능은 단순하고 가격경쟁력이 있는 맞춤형 인버터를 새로이 개발하게 되었다. 본 논문에서는 당사가 산업용 인버터 제품의 이원화를 위해 새로이 개발된 단순 기능형 인버터 N700E(5..5kW ~ 350kW) 시리즈에 대한 주요기능 및 성능에 대해 소개하고자 한다.

• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.505-511
• /
• 2008

when electric traction system used DC 1500V runs on decline of rail road track and slows down, dc voltage goes beyond regular voltage. In this case extra power is forcibly wasted by resister because rectifier of substation and electric train including power converter and so on are out of order. This paper described a DC electric railway system, which can generate the excessive DC power form DC bus line to AC source in substation for traction system. The purpose of this study was the development of the regenerative inverter system which suppress extra DC-line voltage and regenerate the energy instead of using a resister. That is Developed regenerative inverter system returns the regenerative energy from the DC line voltage to the utility. In addition, the inverter can be compensate the harmonics caused by the power conversion devices used in the DC traction system.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.490-493
• /
• 2005

In order to reduce the harmonics in invertor output of the DVR system, typically LC filter is employed. In designing the LC filter, it is required to consider the gild impedance and the characteristic of the harmonics. In this paper, problems in the conventional way of designing the LC filter is analyzed and new LC fitter design technique is proposed. In the proposed technique, parameters of the LC filter are calculated considering grid impedance, THD, DC link voltage and phase lag. The validity and feasibility of the proposed method is verified through the simulations experiments. The DVR system with the proposed LC filter is being built and tested.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1998.06a
• /
• pp.527-533
• /
• 1998

An optimized PWM switching strategy for an induction motor voltage control is developed and demonstrated. Space vector modulation in voltage source inverter offers improved DC-bus utilization and reduced commutation losses, and has been therefor recognizedas the perfered PWM method, especially in the case of digital implementation. Three-phase invertor voltage control by space vector modulation consists of switching between the two active and one zero voltage vector by using the proposed optimal PWM algorithm. The prefered switching sequence is defined as a function of the modulation index and period of a carrier wave. The sequence is selected by suing the inverter switching losses and the current ripple as the criteria. For low and medium power application, the experimental results indicate that good dynamic response and reduced harmonic distortion can be achieved by increasing switching frequency.

• Proceedings of the KIEE Conference
• /
• 1999.07a
• /
• pp.58-60
• /
• 1999

This paper presents dynamic performance prediction using Matlab / simulink after parameter estimation of synchronous reluctance motor considering iron loss. Test motor is 3 phase SynRM with the segmental rotor, rating power is 0.175KW. Experiment equipment is consists of testing motor, dynamometer, vector invertor dynamocontroller, and power analyser. The stator iron loss and rotor iron loss are modelled by additional windings on three-phase winding axis. These windings are transformed into d-q axis, and are represented as equivalent eddy current windings. P-Q circle diagram method and single phase standstill method are used to measure motor parameters considering iron loss.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.12 no.8
• /
• pp.717-724
• /
• 2000

It is important to investigate characteristics of flow of refrigerant/oil mixture circulating in a refrigeration system. Therefore the oil concentration in refrigerant/oil mixture should be measured exactly by the adequate measuring instrument. In this paper, the oil concentration was measured by density monitoring system(DMS) in the liquid-line of a inverter-driven heat pump. Experimental result follows ; the main factor that have an effect on oil concentration refrigerant/oil mixture circulating in a refrigeration system is the momentum and kinematic viscosity of refrigerant/oil mixture compressed by scroll compressor.

• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2268-2270
• /
• 2003

In this paper, mathematically modeled equations were derived for wind turbine under the analysis of aerodynamics. On the basis of these equations, maximum power controller is implemented by simulink in matlab. In order to achieving maximum power, variable speed control method is used for obtaining maximum power coefficient in the variable wind speed because we can have maximum changing efficiency in these coefficients. Also, the maximum power control of wind generator system uses a synchronous generator and a invertor circuit.

• Proceedings of the KIEE Conference
• /
• 2003.07b
• /
• pp.1181-1183
• /
• 2003

Cold cathode fluorescent lamp(CCFL) are widely used to illuminate the liquid crystal display(LCD). Usually, CCFL dimming methods are used to lamp current regulation or average current adjust feeding the CCFL inverter. Switching frequency of inverter is higher than resonant frequency at stabile states. In this study, design of CCFL driving circuit by half-bridge type series and parallel resonant inverter that variable frequency modulation method to control the output power. This method has advantages such as low EMI and reduced harmonics. And it is easy to dimming control use microprocessor. The validity of this study is confirmed from the simulation and experimental results.

• Proceedings of the KIPE Conference
• /
• 2001.07a
• /
• pp.58-62
• /
• 2001

Photovoltaic and wind power generation have an advantage of unlimited and unpolluted amount of energy resource. In conventional wind generation systems, since the blade rotates at low speed when the velocity of wind decreases their operations are possible only under limited conditions. Therefore they are in trouble of self-generation without the help of auxiliary generation devices outside. The system driven by the wind force in this paper consists of a generator, an invertor, batteries and sets for power storage with a spring. In this paper, the operation characteristics of system were analyzed through experiments for a trial product.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.37.1-37
• /
• 2001

Electric plating is used in various industry field. Specially, pulse plating is able to deposit material at high current density compared to conventional DC plating. For example, pulse plating can get more fine grain, can improve adhesion and metal distribution and current efficiency, can reduce internal stress and crack. Therefore, we developed bidirection pulse power supply(BPPS) which has high speed pulse current and high current density and improve deposition quality and increase plating speed in this paper. BPPS(Bidirection pulse power supply) needs high speed rising time, falling time and output current accuracy. BPPS consists of rectifier part, chopper part, invertor part, and control part. Rectifier part changes outprt current direction.