• 전자공학회논문지C
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• 제34C권12호
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• pp.1-8
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• 1997

In this paper, a new method of state code assignment for reduction of switching activities of state transition in asynchronous circuits is proposed. The algorithm is based on a on-hot code and modifies it to reduce switching activities. To estimate switching activities as a cost functions we introduce state transition probability (STP). AS a results, the proposed algorithm has an advantage of 60% over with the conventional code assignment in terms of switching and code length of state assignment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.1044-1046
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• 1993

This paper describes a switching strategy for variable speed control and low torque ripple of Switched Reluctance Motor(SRM). The main advantage of this strategy is simple control. Therefore it can be constructed easily. And a design principle of SRM is represented for the proposed switching strategy. The proposed switching method is tested by simulation and experiment on various SRM type. As a result, The SRM drive with the proposed scheme is effective in reducing the torque ripple and variable speed control.

• 전력전자학회논문지
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• 제18권4호
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• pp.312-321
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• 2013

In this paper, high efficiency control method for flyback inverter with synchronous rectifier(SR) based on photovoltaic AC modules is proposed. In this control method, the operation of SR is classified according to the voltage spike across main switch SP. When the voltage spike across SP is lower than the rating voltage of SP, the operation of active clamp circuit is interrupted for reducing the switching loss of auxiliary switch. In this time, the SR is operated for soft-switching of SP. When the voltage spike across Sp is higher than the rating voltage of SP, the operation of active circuit is activated for reducing the voltage spike. The SR is operated for reducing the conduction loss of secondary output diode. Thus, a switching loss of the main switch can be reduced in low power region, and weighted-efficiency can be improved. A theoretical analysis and the design principle of the proposed method are provided. And validity is confirmed through simulation and experimental results.

• 조명전기설비학회논문지
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• 제22권8호
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• pp.96-103
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• 2008

본 논문에서는 전력시스템에서의 송전선로 과부하를 해소하기 위한 민감도에 근거한 새로운 선로 스위칭 알고리즘이 제시된다. 각 선로의 임피던스 변화에 대한 과부하 선로 조류의 민감도를 통하여 과부하 선로를 해소하기 위한 여유 송전선로의 투입과 운전 중인 선로의 차단을 한꺼번에 체계적으로 수행하는 새로운 스위칭 알고리즘을 제시하고, 수많은 케이스의 스위칭 경우의 수를 대폭적으로 줄임으로써 효율적으로 선로 스위칭을 수행하여 효과적인 과부하 해소 대책을 세우는 방안을 제시한다. 제시된 민감도에 근거한 알고리즘에 따라 스위칭선로들의 순위를 결정하고 이 순위에 따라 선로 과부하가 해소될 때까지 선로 스위칭을 수행한다. 이 기법을 IEEE 39 모선 시스템에 적용하여 제시된 알고리즘의 효과를 보여준다.

• 대한전기학회논문지:전력기술부문A
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• 제54권2호
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• pp.67-72
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• 2005

In conventional small signal stability analysis, system is assumed to be invariant and the state space equations are used to calculate the eigenvalues of state matrix. However, when a system contains switching elements such as FACTS devices, it becomes non-continuous system. In this case, a mathematically rigorous approach to system small signal stability analysis is by means of eigenvalue analysis of the system periodic transition matrix based on discrete system analysis method. In this paper, RCF(Resistive Companion Form) method is used to analyse small signal stability of a non-continuous system including switching elements. Applying the RCF method to the differential and integral equations of power system, generator, controllers and FACTS devices including switching elements should be modeled in the form of state transition equations. From this state transition matrix eigenvalues which are mapped to unit circle can be calculated.

• KIEE International Transactions on Power Engineering
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• 제5A권4호
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• pp.344-349
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• 2005

In conventional small signal stability analysis, the system is assumed to be invariant and the state space equations are used to calculate the eigenvalues of the state matrix. However, when a system contains switching elements such as FACTS equipments, it becomes a non-continuous system. In this case, a mathematically rigorous approach to system small signal stability analysis is performed by means of eigenvalue analysis of the system's periodic transition matrix based on the discrete system analysis method. In this paper, the RCF (Resistive Companion Form) method is used to analyze the small signal stability of a non-continuous system including switching elements. Applying the RCF method to the differential and integral equations of the power system, generator, controllers and FACTS equipments including switching devices should be modeled in the form of state transition equations. From this state transition matrix, eigenvalues that are mapped into unit circles can be computed precisely.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.228-229
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• 2006

The RCF analysis method is used to analyze small signal stability of power systems including GTO controlled FACTS equipment such as STATCOM. To apply the RCF analysis method in power system small signal stability problems, the state transition equations of power system equipments and power systems with STATCOM are presented. In eigenvalue analysis of power systems by the RCF analysis method, the STATCOM is modelled into the equivalents voltage source model and the PWM switching circuit model. As a result of simulation, the RCF analysis method is very powerful to calculate the oscillation modes exactly after the switching operations, and useful to analyze the small signal stability of power systems with periodically operated switching device such as the STATCOM.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.230-231
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• 2006

In this paper, the RCF(Resistive Companion Form) analysis method is used to analyze small signal stability of power systems including GTO controlled FACTS equipment such as SSSC. To apply the RCF analysis method in power system small signal stability problems, state transition equations of power system equipments and power systems with SSSC are presented. In eigenvalue analysis of power systems by the RCF analysis method, SSSC is modelled into the equivalents voltage source model and PWM switching circuit model. As a result of simulation, the RCF method is very powerful to calculate the oscillation modes exactly after the switching operations, and useful to analyze the small signal stability of power systems with periodic switching device such as SSSC.

• Journal of Power Electronics
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• 제16권5호
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• pp.1791-1801
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• 2016

This paper considers a carrier based signal injection method for use in the three shunt sensing inverter (TSSI) for sensorless motor control. It also analyzes the loss according to the injection axis of the voltage signal. To remove both the phase current and rotor position sensors, a sensorless method and a phase current reconstruction method can be simultaneously considered. However, an interaction between the two methods can be incurred when both methods inject voltage signals simultaneously. In this paper, a signal injection based sensorless method with the 120° OFF Discontinuous PWM (DPWM) is implemented in a TSSI to avoid this interaction problem. Since one leg does not have a switching event for one sampling period in the 120° OFF DPWM, the switching loss is altered according to the injection axis. The switching loss in the d-axis injection case can be up to 32% larger than that in the q-axis injection case. Other losses according to the injection axis are also analyzed.

• 대한산업공학회지
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• 제42권4호
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• pp.290-295
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• 2016

This paper proposes a new method for the automatic detection of atrial fibrillation (AF), using Markov regime switching GARCH (1, 1) model. The proposed method is based on the observation that variability patterns of heart rate intervals during AF significantly differ from regular patterns. The proposed method captures the different patterns of heart rate intervals between two regimes : normal and AF states. We test the proposed method using Massachusetts Institute of Technology-Beth Israel Hospital (MIT-BIH) atrial fibrillation database, and demonstrate the effectiveness of the proposed method.