• 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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• 2000.07a
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• pp.739-743
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• 2000

With significant development of power electronics technology the proliferation of nonlinear loads such as such as static power converters has deteriorated power quality in power transmission distribution systems. Notably voltage harmonics resulting from current harmonies produced by the nonlinear loads have become a serious problem in many systems Moreover momentary interruptions and voltage sags are responsible for many of the power quality problems found in typical industrial plants. Int his paper proposed 3 phase hybrid series active power filter is not only for harmonic compensation but also for harmonic isolation between supply and load and for voltage regulation and imbalance compensation Through computer simulations we have verified the effectiveness of the proposed system.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1074-1076
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• 1992

By using nonlinear loads in power line, reactive power and harmonics are occured. In this thesis, on the basis of the instantaneous reactive power theory, the calculation method of compensation current commands and the current control characteristics of active power filter using voltage source PWM converter are presented. The calculation of compensation current is performed by DSP within 50 usec. And the Pl control of current is performed by analog devices. The compensations of harmonic current in rectifier loads and unbalance currents are proved by experiments.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.605_606
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• 2009

Generally, series reactor is connected to the power capacitor in series to attenuate the distortion of voltage waveform and to reduce an inrush current of power capacitor. Also, harmonic current of power capacitor is highly dependent on the series reactor because it is operated with the power capacitor as a passive filter against nonlinear loads. In this paper, harmonic current of power capacitor from nonlinear loads is analyzed by the computer simulation and is experimentally verified.

• Journal of Electrical Engineering and Technology
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• v.3 no.1
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• pp.94-100
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• 2008

This paper presents a new control method of single-phase active power filter (APF) for the compensation of harmonic current components in nonlinear loads. To facilitate the possibility of complex calculation for harmonic current detection of the single phase, a single-phase system that has two phases was constructed by including an imaginary second-phase giving time delay to the load current. The imaginary phase, which lagged the load current T/4 (Here T is the fundamental cycle) is used in the conventional method. But in this proposed method, the new signal as the second phase is delayed by the filter. Because this control method is applied to a single-phase system, an instantaneous calculation was developed by using the rotating reference frames synchronized to source-frequency rather than by applying instantaneous reactive power theory that uses the conventional fixed reference frames. The control scheme of single-phase APF for the current source with R-L loads is applied to a laboratory prototype to verify the proposed control method.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.68-75
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• 2012

This study aims at the structural analysis of vibration and fatigue according to the tie rod configuration. The maximum displacement amplitude is happened at 156Hz by harmonic vibration analysis, this tie rod model can be broken as the weakest state. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sine wave' becomes most stable. In case of 'Sine wave' with the average stress of 0MPa and the amplitude stress of 570MPa, the possibility of maximum damage becomes 70%. This stress state can be shown with 140 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The structural result of this study can be effectively utilized with the design on tie rod by investigating prevention and durability against its damage.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.5
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• pp.65-71
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• 2011

This study analyzes about front axle through the analyses of stress, fatigue and vibration. Maximum equivalent stress is shown with the frequency of 60Hz in case of the harmonic vibration analysis applied with force. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'Sample history' with the average stress of 0 to $-2{\times}10^5MPa$ and the amplitude stress of 0 to $-2{\times}10^5MPa$, the possibility of maximum damage becomes 3%. This stress state can be shown with 6 times more than the damage possibility of 'SAE Bracket history' or 'SAE transmission'. The structural result of this study can be effectively utilized with the design of front axle by investigating prevention and durability against its damage.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.239-244
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• 2011

This study analyzes the behaviors on stress, fatigue and vibration about bulldozer in operation. Maximum equivalent stress is shown with the frequency of 100 Hz in case of the harmonic vibration analysis applied with force. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'Sample history' with the average stress of 0 to -105MPa and the amplitude stress of 0 to $1.617{\times}105MPa$, the possibility of maximum damage becomes 3.23%. This stress state can be shown with 5 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The structural result of this study can be effectively utilized with the design of bulldozer by investigating prevention and durability against its damage.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.2
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• pp.29-37
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• 2006

Heavy chemical industries have nonlinear loads including elecrolyzers. AC-DC converters are the most widely used in an elecrolysis in a chemical plant. The electrolysis consists of AC-DC converter groups connected in parallel at the DC side. The converter operations cause harmonic currents and create distortions on the sinusoidal voltage of the AC power system. This paper provides an in depth analysis on harmonics field measurement for the electrolyzer loads and harmonics assessment by the international harmonic standards IEC 61000-3-6 and IEEE 519-1992.

• Journal of Power Electronics
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• v.17 no.3
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• pp.716-724
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• 2017

The output voltage of an off-grid inverter is influenced by load current, and the voltage harmonics especially the 5th and 7th are increased with nonlinear loads. In this paper, to attenuate the output voltage harmonics of off-grid inverters with nonlinear loads nearby, a load current feedforward is proposed. It is introduced to a voltage control loop based on the Positive and Negative Sequence Harmonic Regulator (PNSHR) compensation to modify the output impedance at selective frequencies. The parameters of the PNSHR are revised with the output impedance of the off-grid inverter, which minimizes the output impedance of the off-grid inverter. Experimental results verify the proposed method, showing that the output voltage harmonics caused by nonlinear loads can be effectively suppressed.