• Journal of Power Electronics
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• 제12권6호
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• pp.925-934
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• 2012

Three-phase controlled converters have many applications in the utility interfacing of renewable energy sources and adjustable speed drives as a rectifier or inverter. The utility line currents of these converters have a high harmonic distortion, which is more than the harmonic standards. This paper introduces a new technique for circulating the third harmonic currents from the dc-link to the line currents to reduce their harmonic contents. The proposed system uses a single-phase PWM converter to control the angle and amplitude of the injection current for each of the firing angle of a three-phase converter. A detailed analysis is introduced to achieve a relationship between the firing angle of the three-phase controlled converter and the power angle of the PWM converter. In addition, a detailed design for the other injection path components is introduced. A simulation and experimental work is introduced to prove the mathematical derivations. Analysis, simulation and experimental results prove the superiority of the proposed technique.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 B
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• pp.247-249
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• 2000

Transient phenomena cause delay in control response and must be studied and eliminated, if possible, suppressed. The difficulty in analyzing transient phenomena in ac machines comes from the large number of windings involved. But, it is possible that only one phase is used to represent three phases of the induction motor as called phase segregation method. The phase segregation method provides equivalent circuits for both the steady and transient states of induction motor. In this paper, analysis of the torque transient of the induction motor be carried out the phase segregation method and confirmed in the possibility of transientless torque control.

• 전기학회논문지
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• 제62권2호
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• pp.184-189
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• 2013

Compared to a multiphase SRM, a single-phase SRM has some advantages, such as lower number of switches and power converter size, which leads to gradually increasing in the household appliances and industrial applications. But the torque dead zone is existed in the single-phase SRM which decreases the starting capability of the motor and increases the torque ripple. In order to solve the aforementioned problems, a single-phase hybrid SRM with commercial ferrite permanent magnet is proposed in this paper. Basic design principle for the proposed structure is described. To verify the proposed structure, FEM is employed to get the characteristics of the proposed structure. Based on the analysis, a prototype is designed and manufactured. And, the experimental system is also constructed. The validity of the proposed structure is verified by the experimental results.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2001년도 추계학술대회 논문집
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• pp.50-54
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• 2001

Information systems development entails planning, analysis, design and construction phases. The analysis phase identifying user requirements is the most important of these phases. Since unidentified defects in the early phase causes increased work and costs as development proceeds, the quality of analysis results affects the quality of the resultant system. Major tasks in the analysis phase are data modeling and process modeling. Research on building a knowledge-based system for data modeling have been conducted much, however, not sufficiently for process modeling. As a system environment with high user interaction increases, research on process modeling methods and knowledge- based systems considering such environment are required. In this research, a process modeling framework for information systems with high user interaction is suggested and a knowledge-based system for supporting the suggested framework is implemented. A proposed model consists of the following tasks: event analysis, process analysis, and event/process interaction analysis. Event analysis identifies business events and their responses. Process analysis break down the processes of an enterprise into progressively increasing details. Decomposition begins at the function level and ends when the elementary process level is reached. Event/process interaction analysis verifies the results of process analysis and event analysis. A knowledge-based system for supporting a proposed process modeling framework is implemented in a web-based environment.

• 전기학회논문지
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• 제66권3호
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• pp.587-592
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• 2017

In the three-phase four-wire low-voltage power distribution equipment, single-phase and three-phase load have been used mainly mixed. Also linear and nonlinear loads have been used together in the same conditions. In a three-phase four-wire distribution line, the current distribution of three-phase linear load is almost constant in each phase during driving or stopping, but the single-phase load is different from each other for each phase in accordance with the operation and stop. So that the voltage unbalance is caused by the current difference of each phase. In the three-phase four-wire distribution system, non-linear load is used with linear load. The presence of single-phase nonlinear loads can produce an increase in harmonic currents in three-phase and neutral line. It can also cause voltage unbalance. In the present study, we analyzed for the voltage unbalance fluctuations by the operation pattern of the single and three-phase linear and non-linear load in three-phase four-wire low voltage distribution system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.536-539
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• 1997

This paper presents a three dimensional modeling and a trajectory generation for minimized impact walking of the biped robot. Inverse dynamic analysis and forward dynamic analysis are performed considering impact force between the foot and ground for determining the actuator capacity and for simulating the proposed biped walking robot. Double support phase walking is considered for close to human's with adding the kinematic constraints on the one of the single support phase.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.222-227
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• 1997

Unbalanced source voltages due to unbalanced loads in the 3-phase power system is decomposed into positive, negative and zero sequence components. Also, assuming there is no neutural path in the system, the zero sequence component is not shown. Therefore, it is possible to compensate unbalanced source voltage by canceling the negative sequency component of the voltages of the source. In this paper, an algorithm compensating unbalanced source voltages by canceling the negative sequence component is presented and analysis of instantaneous voltage compensator using 3-phase PWM inverter is carried out through computer simulation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.400-403
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• 2002

This paper presents a shearographic technique for measuring in-plane strains. During the measurement, the test object is illuminated alternately with two laser beams, symmetrically with respect to the viewing direction. Employing a phase shift technique, the phase distributions due to object deformation for each beam are obtained separately. The difference of the two phase distributions depicts the derivative of in-plane surface displacements. The technique is equivalent to a system of many strain gages.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.517-520
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• 2000

This paper deals with the statistical analysis of an autocalibration procedure for the gain and phase imbalances between the in-phase (I) and quadrature (Q) components in quadrature receivers. In real implementation, the imbalances of the gain and phase exist and degrade the performance of the receiver. In this paper we investigate the statistical characteristic of the estimates in an on-line imbalance estimation method for the receiver under the assumption of an additive white Gaussian noise environment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.1147-1149
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• 1998

This paper presents the result of an analysis on effects of phase compensation on power system stability in the PSS parameter tuning. Synchronizing and damping coefficients are induced from lineal model for generator with PSS. Synchronizing and damping coefficients corresponding to time constants of phase compensation control block are calculated on a single machine, infinite bus test system. The Parameter tuning concepts, basic function, structural elements and performance criteria of PSS are introduced.