• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.89-94
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• 2003

Recently many kinds of power transducers have been commercially used to increase the energy efficiency. However, those devices unavoidably produce the harmonics having an integral frequency of fundamental waves. The harmonics should be removed since they have negative effects on the other devices based on fundamental sine waves. As the current information technology makes the PCs more widespread, it is essential to study the harmonics that they produce. In this paper the harmonic generation of a PC has been measured and analyzed. Additionally, the most efficient way of reducing the harmonics has been proposed.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.439-442
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• 2000

An adaptive nonlinear control of a brushless direct drive motor(BLDDM) is proposed. Comparing to the traditional PMSM the direct drive motor has smaller number of per pole and per phase slots to provide higher torque in low speed. This generic construction generates flux harmonics and finally results in unwanted torque harmonics. To control the speed a feedback linearization method is applied by choosing the $i_{ds}$ and $\omega_{m}$ as the output variables. The control of the flux harmonics is provided by using a flux observer with MRAC technique. As shown in the simula-tion results the proposed nonlinear speed controller has a good speed response in the steady state and robust to the flux variation

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.3
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• pp.81-87
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• 2000

The increasing use of non-linear loads such as power electronics draw highly distorted currents from the utility system. High harmonics currents and voltages will cause equipment damage and disturb the plant operation. The common solution to harmonics problem is to use harmonics filters. In this paper simulation results used the EDSA harmonics analysis program verifying the effects of the single-tuned filter for harmonic elimination are presented.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.8
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• pp.441-448
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• 2002

Harmonics studies have been an important aspect of power conversion system analysis and design in recent years. Harmonics using power conversion device, have a harmful effect on power qualify. Nonlinear load such as converter causes harmonic and effects self & other system. There are linear and nonlinear loads in the end-user application. For filter design to reduce harmonics, it is important to understand how loads interact with each other. In this paper, effects on the power conversion system at the low voltage local bus are discussed.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.252-254
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• 2000

For many years, electric utility has used sustained interruption rates as a reliability index. Today, however, many electricity consumers are adversely affected by more subtle voltage disturbances such as harmonic distortion. This paper deals with observations of events that occur in the Dimmer circuits and phase control which could affect harmonics problem to the commercial power system. In order to reduce the effect of harmonics and design filters, Solid State Relay Dimmer(SCRs or TRIACs) and Noise Filter are described, and the effects of harmonics is also analyzed. IGBT Dimmer which is appropriate method to reduce harmonics and improve efficiency is introduced.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.149-158
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• 2015

This paper proposes a subband filtering technique to the MUSIC and the ESPRIT algorithm for estimating the magnitude and frequency of the harmonics of power signal. In proposed method, the input power signal is decomposed to the odd harmonics and the even harmonics respectively by the filter bank system. The amplitude and the frequency estimation of the decomposed harmonics are carried out using the MUSIC and the ESPRIT method. Subband filtering can reduce the autocorrelation matrix size of input data, and spectrum leakage between adjacent harmonics. Therefore, this subband technique has advantage in computational cost and estimation accuracy compared to fullband MUSIC and ESPRIT. To demonstrate the performance of the method, computer simulations are performed to the synthesized input signal, and experiment results are compared in subband and fullband cases.

• Journal of Magnetics
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• v.18 no.2
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• pp.216-219
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• 2013

In this paper, the influence of inverter switching harmonics on iron loss and PM loss of Permanent Magnet Synchronous Motor (PMSM) is numerically investigated by Finite Element Method (FEM). In particular, nonlinear FEM is applied for a multi-layered PM Synchronous Motors (PMSMs), Interior buried PMSM (IPMSM) and PM assisted Synchronous Reluctance Motor (PMa-SynRM), which are adoptively designed and compared for Electric Vehicle (EV) propulsion. In particular, iron loss and PM eddy-current loss under the real current waveform including the carrier harmonics from inverter switching are numerically analyzed with nonlinear FEM by considering the skewed stator structure employed for minimizing spatial harmonics.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.359-361
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• 1987

It is known that the reactive component of AC power in the Power system gives no energy to outside and causes enlargement of power apparatus, voltage fluctuation and unstability of power system. The power conversion system and control system which are composed of power semiconductor devices such as Thyrisor, transistor, GTO and so on have been appeared as new sources of Harmonics. So the reduction of harmonics in power semiconductor system is one of impending problems on the point of energy conservation and improvement of power factor. This paper treates the fundamental review of the harmonics reduction by Current type PWM-Inverter. This Inverter-detects not only the fundamental wave but also that of all harmonics created in the power semiconductor system and is scheduled to control by sampled value.

• Journal of Magnetics
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• v.3 no.4
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• pp.120-122
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• 1998

The higher order harmonic components of magnetostriction during ac magnetization in 3% SiFe are measured as a function of the magnetizing angle respect to [001] axis using a constructed laser interferometry. The magnetostriction with magnetizing angle from [001] axis agrees ith the calculation based on domain reorientation. The relative amplitudes of odd and even harmonics respectively for magnetic induction and magnetostriction decrease with the order of harmonics, accompanying the contraction of the amplitudes. The contraction of harmonics order of magnetostriction harmonics is shown to be the even number times of that of magnetic induction.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.131-133
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• 2005

Recently the harmonic generation has declined electricity quality and has bad influence on the electrical installation including OA(Office Automation), FA(Factory Automation), IT(Information Telecommuni-cation) devices and so on. The study of harmonics be greatly interested in diagnosis accident with harmonics was not merely guesswork but clarify the cause by experimental data at these days. Therefore, it is necessary development of AC power source for correct experiment with reliable data. In this paper, we realized the AC power source that can produce and compose harmonics for analysis of accident with harmonics.