• Journal of Power Electronics
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• 제17권6호
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• pp.1563-1576
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• 2017

This paper presents a novel switching pattern current control (SP-CC) scheme, which is applied in three-phase voltage-source converters (VSCs). This scheme can select the optimal output switching pattern (SP) by referring the basic principle of space vector modulation (SVM). Moreover, SP-CC is a method without a carrier wave. Thus, the implementation process is concise and easy. When compared with the conventional hysteresis current control (C-HCC) and the space vector-based hysteresis current control (SV-HCC), the SP-CC has the performances of faster dynamic response of C-HCC and less switching number (SN) of SV-HCC. In addition, it has less harmonic contents in the three-phase current, along with a lower switching loss and a higher efficiency. Moreover, the hysteresis bandwidth and Clarke conversion are not required in the SP-CC. The effectiveness of the presented SP-CC is verified by simulation and experimental test results. In addition, the advantages of the SP-CC, when compared with the C-HCC and SV-HCC, are verified as well.

• 대한전자공학회논문지
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• 제11권3호
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• pp.27-31
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• 1974

Pontryagin의 최대원리의 놀라운 방식을 써서 원자로에 있어서 최적제어 switching시간과 최적제초 switching 점을 구하였다. 그리고 원자로의 초기상태에서 그의 목표상태로 출력을 변환시킬 때의 제어궤적을 시간최적제어 방식을 이용하여 주어진 원자로의 parameter 값과 piecewise constant 입력값에 따라 최적화 시켰다.

• 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.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2863-2866
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• 2003

In nonlinear control fields, for irregular nonlinear systems, control form which consists of approximate tracking control law and exact tracking control law and which switches between two laws has been proposed recently. In this thesis, we design new switching control law which connect approximate linearization control law and exact linearization control law by fuzzy rules for irregular nonlinear system, ball and beam system. Fuzzy switching controller designed by fuzzy concept is proved that designed scheme overcomes singularities of irregular system, improves unstability problem of switching procedure, and has more efficient control value through simulation. Stability of fuzzy control system proved by Lyapunov's stability theorems.

• 한국콘텐츠학회논문지
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• 제8권9호
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• pp.259-273
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• 2008

경제의 발전과 더불어 산업사회가 고도화 되면서 국민소득의 증가, 여가시간의 증가, 여성의 취업 증가 등의 변화에 따라 국민의 생활수요도 다양해지고 있다. 이러한 수요의 변화에 따라 서비스 산업은 여러 형태로 발전하면서 오늘날 현대 경제는 서비스 경제 또는 서비스 사회라고도 불리어 지고 있다. 이는 서비스 산업이 경제 전체에서 차지하는 비중이 확대되고 서비스 산업의 범위가 넓어지고 있고 현대사회에서 서비스 산업의 중요성이 크게 부각되고 있기 때문이다. 이러한 서비스 산업의 경우 최근 경쟁이 치열해지고 브랜드에 대한 충성도가 감소함에 따라 신규고객 유치와 시장점유율 확대 등의 공격적 마케팅전략 보다는 기존고객 유지의 방어적 마케팅 전략의 중요성이 커지고 있다. 특히 여행사와 항공사의 경우 많은 경쟁과 성수기, 비수기의 수요 양극화 현상 등으로 인하여 서비스전환의 용이성이 증가함에 따라 기존 고객을 유지하고 전환을 억제하는 것이 더욱 중요시되고 있는 실정이다. 이에 본 연구는 고객특성에 따른 전환장벽과 전환의도 그리고 재방문 의사의 관계에 대하여 연구하여 업계에 도움이 되는 시사점을 찾고자 하였다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제11B권4호
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• pp.185-192
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• 2001

In SRM drive, the ON·OFF angles of each phase switch should be accurately controlled in order to control the torque and speed stably. The accuracy of the switching angles is dependent upon the resolution of the encoder and the sampling period of the microprocessor, that are used to provide the information of the rotor position and to control the SRM power circuit, respectively. However, as the speed increases, the amount of the switching angle deviation from the preset values is also increased. Therefore, the low cost encoder suitable for the practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using the simple digital logic circuit is also presented in this paper, As a result, a stable high speed SRM drive can be achieved by the high resolution switching angle control and it is verified from the experiments that the proposed encoder the logic controller can be a powerful candidate for the practical low cost SRM drive.

• 제어로봇시스템학회논문지
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• 제12권5호
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• pp.425-430
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• 2006

To meet an increasing demand for high performance in gun dynamic plant, both a precise and a fast response positioning are strongly required for the gun servo system. A mode switching control(MSC) scheme, which includes a fine stabilizing controller, fast positioning one and a switching function, is widely used to meet this requirement. Stabilization is performed through PID controller, while a time optimal control method is used for target designation. In this paper, a modified PTOS(Proximate Time Optimal Servomechanism) algorithm is derived so as to accommodate the damping term in the gun plant model. Also, applying a mode switching strategy, the bumpless transfer is made possible when the controller switches from PTOS to PID. To show the effectiveness of the overall control system, simulation results are given including the gun dynamics.

• Journal of Power Electronics
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• 제14권2호
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• pp.302-314
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• 2014

Due to advancements in power electronics and inverter topologies, the current controlled multilevel voltage-source pulse width modulated (PWM) inverter is usually preferred for accurate control, quick response and high dynamic performance. A multilevel topology approach is found to be best suited for overcoming many problems arising from the use of high power converters. This paper presents a comprehensive review and comparative study of several current control (CC) techniques for multilevel inverters with a special emphasis on various approaches of the hysteresis current controller. Since the hysteresis CC technique poses a problem of variable switching frequency, a ramp-comparator controller and a predictive controller to attain constant switching frequency are described along with its quantitative comparison. Furthermore, various methods have been reviewed to achieve hysteresis current control PWM with constant switching frequency operation. This paper complies various guidelines to choose a particular method suitable for application at a given power level, switching frequency and dynamic response.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1049-1050
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• 2006

This paper is proposed to a novel DC-DC converter operated high efficiency for loss-less snubber capacitor. The general converters of high efficiency is made that the power loss of the used switching devices is minimized. To achieve the soft switching operation of the used control switches, the proposed converter is constructed by using a loss-less snubber capacitor. The proposed converter achieves the soft-switching for all switching devices without increasing their voltage and current stresses. The result is that the switching loss is very low and the efficiency of converter is high. The soft switching operation of the proposed converter is verified by digital simulation and experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.85.1-85
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• 2002

In this paper, a control strategy of position and force is proposed based on a switching algorithm. The main focus is the control of position and force in the same direction. The switching algorithm based on a fuzzy algorithm determines the weighting value of force control. First, the force control is dominant. If the position gets closer to the desire position, the weighting value of force control is closer to zero. The proposed algorithm is shown to be satisfactory to position and force control and the weighting factor is quite successful by simulation examples.