• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.3
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• pp.159-166
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• 2021

This study compares the maximum power point tracking (MPPT) control methods of a thermoelectric generator on vehicles. The researchers conduct comparisons on five different MPPT methods, including a fractional open circuit voltage method, a perturbation and observation (P&O) method, an incremental conductance method, a linear extrapolation-based MPPT (LEMPPT) method, and a LEMPPT/P&O hybrid method. These five MPPT methods are theoretically analyzed in detail, and the comparisons are conducted through MATLAB/Simulink simulation results. The comparison outcomes reveal that linear MPPT methods, including LEMPPT and LEMPPT/P&O hybrid methods, are more suitable for a thermoelectric generator on vehicles than the other MPPT methods examined in this work.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.620-627
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• 2004

As h-bridge multilevel inverter is connected with series of single phase power cell, so it obtain high voltage using low voltage power semi-conductor and output voltage similar to sine wave. In this topology, the number of power cell increases in proportion to the output voltage level. Therefore, there are drawbacks that are responsibility against operating ability of main controller and signal wire increase. However, we can overcome this problems by the substitution of serial communication for the PWM signal in power cell control. Additionally, it has merits of reliability and maintenance. This paper deals with the synchronization and phase-shift method of power cell PWM using CAN(Controller Area Network) communication interrupt in H-bridge multilevel inverter. The advantages of proposed method are signal-line simplification using serial communication between main controller and cell controller, burden reduction in main controller, modularization of power cell, easy protection of each power cell, expandability improvement and reliability increase of control signal and power cell. This paper establishes propriety and reliability of proposed method through experiment of 13-level H-bridge multilevel inverter.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.634-636
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• 2008

This paper proposes a frequency detection method based on an advanced zero-crossing technique. Zero-crossing method for detecting frequency is one of the most widely used methods today. Although it is simple to apply, it requires extra hardware in implementation due to its limitations in accuracy. The proposed method models the error generated during zero crossing linearization and compensated for it in real time which makes it simple and accurate. The validity of the method and its applicability in anti-islanding detection of distributed generators was confirmed through simulation.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.2
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• pp.55-59
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• 2002

Parallel processing is able to be used effectively on computationally intense power system problems. But this technology is not still available is not only parallel computer but also parallel processing scheme. Testing these algorithms to ensure accuracy, and evaluation of their performance is also an issue. Although a significant amount of parallel algorithms of power system problem have been developed in last decade, actual testing on parallel computer architectures lies in the beginning stages because no clear cut paths. This paper presents Jacobian modeling method to supply the base being able to treat power flow by newton's method by the computer. This method is to assign and to compute teared blocks of sparse matrix at each parallel processors. The testing to insure accuracy of developed method have been done on serial computer by trying to simulate a parallel environment.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1437-1439
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• 1999

This paper describes test method though low voltage power system implementation for high impedance fault relay test before its operation in real power system. Through this test, relay tested its function and algorithm. In this paper, we will provides test method using low voltage power system and its results.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.171-173
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• 2002

This paper presents a power system decomposition technique for digital simulation of large power system. To decompose power system, distributed transmission line model is used. But this model can be used only for long transmission lines. In this paper, capacitor compensation method is proposed to use distributed transmission line model for short transmission line. And case study shows proposed method can be used for effective power system decompositon in digital simulation of large power system.

• Journal of Electrical Engineering and Technology
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• v.7 no.5
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• pp.689-697
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• 2012

This paper proposes a new coordinated voltage control scheme between STATCOM (Static Synchronous Compensator) and reactive power compensation devices, such as shunt elements(shunt capacitor and shunt reactor) and ULTC(Under-Load Tap Changer) transformer in a local substation. If STATCOM and reactive power compensators are cooperatively used with well designed control algorithm, the target of the voltage control can be achieved in a suddenly changed power system. Also, keeping reactive power reserve in a STATCOM during steady-state operation is always needed to provide reactive power requirements during emergencies. This paper describes the coordinative voltage control method to keep or control the voltage of power system in an allowable range of steady-state and securing method of momentary reactive power reserve using PSS/E with Python. In the proposed method of this paper, the voltage reference of STATCOM is adjusted to keep the voltage of the most sensitive bus to the change of loads and other reactive power compensators also are settled to supply the reactive power shortage in out range of STATCOM to cope with the change of loads. As the result of simulation, it is possible to keep the load bus voltage in limited range and secure the momentary reactive power reserve in spite of broad load range condition.

• Journal of the Korean Magnetics Society
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• v.22 no.3
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• pp.97-102
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• 2012

In this paper, a non-contact power transferring has been performed. Power Transferring by using an electromagnetic inductive coupling is more suitable for high power transmission than by using a magnetic resonance method. Power transferring system has been designed with Loading Distribution Method to divide the electric and magnetic loading for designing the magnetic core and electric coil. To design optimum shapes of magnetic yoke, 3D finite element analysis has been performed. Experimental results show good agreement with numerical ones. So, it could be adopted in the electric power transferring system for a short-distance wireless electric power transferring machine.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.527-534
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• 2019

Although ground investigation had carried out prior to the construction, many problems have arisen during the civil-engineering works because of the presence of the unexpected underground utility lines or anomalies. In this study, a new geophysical exploration method was developed to solve those problems by improving and supplementing the existing methods. This new method was based on the difference of electrical resistance values between anomalies and surrounding ground medium. A theoretical expression was suggested to define the characteristics of the anomalies such as location, size and direction, by applying the electric field analysis. An inverse analysis algorithm was also developed to solve the theoretical expression using the measured electrical resistance values which were generated by the voltage flowing the subsurface medium. To verify the developed method, field applications were conducted at the sites under construction or planned. From the results of the field tests, it was found that not only the new method was more predictive than the existing methods, but its results were good agreed with the measured ones. Therefore, it is expected that application of the new exploration method reduces the unexpected accidents caused by the underground uncertainties during the underground construction works.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.4
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• pp.390-396
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• 2004

Recently, there have been Increasing demands for high power factor and low harmonic distortion in the current drawn from utility. The harmonic limits imposed by international standards. It need the PFC techniques in order to reduce line current harmonics and comply with the standards. The average current control method that is the most proper PFC control method in a switching power supply of middle and high power has been used mostly to PFC control method. However, the switching device of PFC circuit has frequently destructed at power return after instantaneous power interrupt. Therefore, this paper have verified the cause of this problems and proposed the solution through simulation and experiment