• 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 Power Electronics
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• v.10 no.4
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• pp.428-433
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• 2010

This paper proposes a harmonics reduction technique for the input currents of three phase PWM converters. The quality of the phase angle information on the utility voltage connected to the PWM converters affects their control performance. Under a distorted utility voltage, the extracted phase angle based on the synchronous reference frame PLL method is distorted. This causes large harmonics in the input currents of a PWM converter. In this paper, a harmonics reduction method that makes the input currents in the PWM converter sinusoidal even under distorted utility conditions is proposed. By the proposed method, without additional hardware, the THD (Total Harmonic Distortion) of the input currents can be readily limited to below 5% which is the harmonic current requirements of IEEE std. 519. Its validity is verified by simulations and experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.508-511
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• 1997

Recently the development of motor speed control systems with both good dynamic performance and simple implementation has been required. The vector control scheme considering flux harmonics for the permanent-magnet AC servo motor having low inertia, low weight, and high efficiency is proposed. To reduce the torque harmonics, current harmonics is employed. The vector control strategy is verified through digital simulation.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2629-2632
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• 2003

This paper presents the harmonics rejection technique and the simulation of a active power filter using power operational amplifier. The proposed active power filter consists of CT(current transformer), harmonics detector and harmonics amplifier. The harmonics detector is a high pass filter using a GIC(Generalized Impedance Converter). The harmonics amplifier consists of a power operational amplifier and passive filters. The simulation has been implemented by OR-CAD program. It is examined whether the proposed active power filter can be realized or not through simple experiments.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.4
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• pp.62-70
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• 2005

This paper presents the actual conditions and reform measures of voltage and current harmonics being made in low-voltage power systems supplying various loads. The measurements were carried out at the secondary output terminals of 22.9[kV]/380[V]220[V] customer's transformers, and the results were discussed on the basis of the comparison with IEEE and IEC harmonics control standards. The voltage THDs of the power systems employed in this survey were less than $5[\%]$ that is considered to be acceptable. On the contrary, the current distortions were significantly greater than the voltage distortions, and the current THDs were distributed over the wide-range from 15.7 to $60.4[\%]$. In particular, the current distortion on the low voltage power lines of office buildings in which many PC and fluorescent lamps are used is remarkably more serious than that of factory facilities. As a result, the voltage distortion factors are observed within the range of its allowable level or less than the limits, but the current distortion factors are significantly greater than the limits of IEEE and IEC standards.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.5
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• pp.440-448
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• 2017

This paper proposes a controller design of a distributed source inverter in stand-alone mode or grid-connected mode to compensate the current or voltage harmonics caused by local nonlinear load. The PR-based multi loop controller has been used to improve the dynamic performance of the system and to compensate the output voltage or grid current harmonics. The multi-loop controller consists of an outer current controller and an inner voltage controller for the output voltage control in stand-alone mode. In grid-connected mode, an outer current controller is added to the output voltage controller for the grid current control. The design performance of each controller is described through the Root locus and Bode plot of the transfer functions. The validity of the proposed control algorithm and design parameters has been verified through the PSiM simulation and experimental results.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.1
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• pp.1-5
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• 2019

The overhead contact line (OCL) is a key piece of equipment for transmitting electrical energy to the pantograph of rail cars. Recently, a 400 km/h OCL was applied to the Honam high-speed line, and its performance was examined by running HEMU-430X. For the study, we analyzed the current of catenary wire concurrently while running HEMU-430X in the Honam high-speed line. Specifically, this study recorded the currents for each speed during operation of the railway vehicle. The analysis of the frequency of line current showed generation of third-harmonics, 15th-harmonics, 17th-harmonics, and 19th-harmonics. The current of catenary wire is a basic technology assessment used to determine the electrical safety of electric railway systems, and it can be used as a technology for analyzing circulating currents generated in the current configuration, as well as for analyzing electric fatigue of the OCL components.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1100-1103
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• 2004

The paper presents the results of using the fundamental and the low frequency harmonic components of leakage current to study aging of EPDM insulator for contaminated condition by kaolin. The largeer the leakage current during 200ms, the higher harmonic component at 60hz. The harmonic component at 60hz and the odd order harmonics is increase relation without Kaolin Conent. Arcing on the surface was always associated with distortion in the leakage current; hence the low frequency components of the leakage currnent can be used as a means to evaluate the surface degration. Both the fundamental and 3rd & 5th harmonics increase dry-band activity.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.2
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• pp.144-149
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• 2016

This paper presents a power control method of high-speed single-phase BLDC motor. Most electric appliances require a power factor corrector (PFC) to mitigate grid current harmonics. However, the reactive components and power semiconductors in the PFC increase system cost and dimension. In this paper, a new motor drive system for a high-speed single-phase BLDC motor is proposed, which can decrease grid current harmonics without PFC by directly manipulating motor power and eliminating bulky electrolytic dc-link capacitor. Given that the proposed motor power control method does not require motor current controller, no current sensor is necessary. Moreover, the proposed algorithms can be easily implemented using a low-cost micro-controller. The effectiveness of the proposed power control method is verified by experiments.

• Journal of Power Electronics
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• v.13 no.1
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• pp.77-85
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• 2013

This paper proposes a new dead time compensation method of independent six-phase permanent magnet synchronous motors (IS-PMSM). The current of the independent phase machines contains odd-numbered harmonics because of the dead time and the nonlinear characteristics of the switching devices. By using the d-q-n three-dimensional vector analysis, these harmonics can be extracted at the n-axis current. Thus, the current distortion can be compensated by controlling the n-axis current of the IS-PMSM to zero. The proposed method is simple and can be easily implemented without additional hardware setup. The validity of the proposed compensation method is verified with simulations and several experiments.