• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.9
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• pp.39-46
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• 2007

This paper presents a programmable single-phase ac power source that provides a sinusoidal output voltage with an adjustable output amplitude and frequency over a wide range as well as an arbitrary waveform. The ac power source under consideration have a linear power amplifier. The desired output values can be programmed with a personal computer. The power source operates at 220[V]/60[Hz] mains and the output voltage is isolated from the input circuit. The system consists mainly of a power converter to generate and amplify the waveform signal, a controller to control the desired output signal and measure the output parameters, and a control program to set the desired output and display the values. The prototype ac power source was constructed and tested with the results demonstrating a good performance.

• Journal of Power Electronics
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• v.12 no.2
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• pp.276-284
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• 2012

AC/AC power conversion is widely used to feed AC loads with a variable voltage and/or a variable frequency from a constant voltage constant frequency power grid or to connect critical loads to an unreliable power supply while delivering a very balanced and accurate sinusoidal voltage system of constant amplitude and frequency. The load specifications will clearly impose the requirements for the inverter stage of the power converter, while wider ranges of choices are available for the rectifier. This paper investigates the utilization of a buck-type current source rectifier as the active front-end stage of an AC/AC converter for applications that require an adjustable DC-link voltage as well as elimination of the low-frequency common mode voltage. The proposed solution is to utilize a combination of two or more zero current vectors in the Space Vector Modulation (SVM) technique for Current Sources Rectifiers (CSR).

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.365-366
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• 2015

Shunt active power filter is a complete current source which can provide an effective and adjustable solution for elimination of harmonic currents in power system. Its performance depends on strategy employed in reference current generation, control technique and topology of converter used in the design.[1-2]. In this paper Three Phase Six switch Z-source rectifier with active power filtering capability based on instantaneous reactive power theory is described. Thanking to the theory power factor and THD value are significantly improved. Experiment results and conclusions are presented.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.125-126
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• 2013

ESS(Energy Storage System) for Improve the quality of the power grid, supply reliability, system stability and the efficient operation method of power is drawing attention. According to changes in the load of the power system frequency will be adjustable in real time in response to changes in the frequency of the grid, so thermal power output is mainly controlled in order to keep the grid frequency stable. ESS for adjusting the frequency of the grid when the frequency rises to grid and charge the energy storage device. If the frequency drops to discharge the battery power to the grid and the future is expected to replace the thermal power plant. This paper describes 4MW ESS for the frequency regulation and find out about the characteristics through the PSCAD/EMTDC.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.385-390
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• 2000

This paper deals with the design and simulation of the hybrid power filter to compensate reactive power and harmonic components of nonlinear load. Control target is a 3-phase diode full bridge rectifier with L-R-C nonlinear load, this load is assumed adjustable speed driver(ASD). The hybrid filter consists of a shunt active filter, shunt passive filters and series inductors. Control algorithm is based on instantaneous power compensation theory proposed by H.Akagi and etc. The result from simulation shows the hybrid filter is superior than other filters on the point of compensation performance and low cost. The PSCAD/EMTDC 3.0 is used as simulation tools.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.11
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• pp.724-729
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• 1999

We developed the correlated color temperature (CCT) control technique for electrodeless sulfur lamp (ESL) by adding a few milligrams of NaI into sulfur discharge bulb. Nal produces intense Na D-line that changes the CCT of the ESL. We can adjustthe CCT in the range of 8,400 K to 3,600 K. Color rendering index can be maintained between 79 and 90 for the adjustable range of the CCT. the NaI helps the ESL dischargeable at below 0.5 kW of forward microwave power into the bulb. We have shown that this technique did not cause reduction of luminance compared to electrodeless elemental sulfur lamp.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.162-168
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• 2014

Use of nonlinear loads, such as power converters, fluorescent lamps and adjustable speed motor drives, is expected to grow rapidly. All of these loads inject harmonic currents. This paper presents the active filtering of the harmonic distortion generated by the compact fluorescent lamps (CFL). The Instantaneous active and reactive power theory (the p-q Theory) is used to design the control of parallel active filter. The control scheme has been verified using Matlab/Simulink with SimPower Systems through a set of simulation tests under different load conditions. Also, the tuning of the active power filter is performed to improve the quality of the electrical power supply.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.236-241
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• 2001

This paper presents a novel prototype of active voltage-clamping capacitor-assisted edge resonant soft switching PWM inverter operating at a constant frequency variable power (VPCF) regulation scheme, which is suitable for consumer high-power induction-heating cooking appliances. New generation IGBT with a trench gate is particularly improved in order to reduce conduction loss due to its lowered saturation voltage characteristics. The soft switching load resonant and quasi-resonant inverter designed distinctively using the latest IGBTs is evaluated from an experimental point of view.

• Journal of Power Electronics
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• v.11 no.5
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• pp.655-661
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• 2011

This paper presents two topologies for single-stage single-phase double-buck type PFC converters, designed to operate at high power factor, near sinusoidal input currents and adjustable output voltage. Unlike the known buck type PFC topologies, in which the output voltage is always lower than the maximum input voltage, the proposed converters can operate at output voltages higher than the ac input peak voltage. A reduced number of switches on the main path of the current are another characteristic of the two proposed topologies. To shape the input line currents, a fast and robust controller based on a sliding mode approach is proposed. This active non-linear control strategy, applied to these converters allows high quality input currents. A Proportional Integral (PI) controller is adopted to regulate the output voltage of the converters. This external voltage controller modulates the amplitude of the sinusoidal input current references. The performances of the presented rectifiers are verified with experimental results.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.51-54
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• 2005

Generator efficiency optimization is important for economic saving and environmental pollution reduction. In general, the machine loss can be reduced by the decreasing the flux level, resulting in the significant reduction of the core loss. This paper proposesan model-based controller is used to decrement the excitation current component on the basis of measured stator current and machine parameters and the q-axis current component controls the generator torque, by which the speed of the induction generator iscontrolled according to the variation of the wind speed in order to produce the maximum output power. The generator reference speed is adjusted according to the optimum tip-speed ratio. The generated power flows into the utility grid through the back-to-back PWM converter. The grid-side converter controls the dc link voltage and the line-side power factor by the q-axis and the d-axis current control, respectively. Experimental results are shown to verify the validity of the proposed scheme.