• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.152.1-152
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• 2001

This paper presents a high performance and cost effective way by using an FPGA circuit to implement torque controller so that the SRM can operate at high speed. In order to increase the operating speed, we need to implement both the torque and the current controllers by using an FPGA. However, it is difficult to implement all of the torque controller in the FPGA. Moreover, implementation of a time critical part is sufficient for improving the performance. One of the time critical part is the switching angle control. In this study, torque controller which calculate the switching on and commutation angles is implemented in PC because these angle are a function of rotor velocity which is varied slowly, and switching angle controller ...

• 한국정보컨버전스학회:학술대회논문집
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• 한국정보컨버전스학회 2008년도 International conference on information convergence
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• pp.131-134
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• 2008

A Mobile Ad hoc NETwork(MANET) is a system of wireless mobile nodes that dynamically self-organize in arbitrary and temporary network topologies. In the highly dynamic environment of MANET, energy efficiency is an important performance measure since it directly affects the network lifetime. The failure of energy severely impacts a communications system in crucial communications environments, such as disasters salvage. In this study, we propose a new packet switching routing that can increase the durability of the energy resource and therefore, the lifetime of the mobile nodes and MANET. The performance of the packet switching routing on the node-disjoint multipath and that of AODV are compared by NS2 simulation. The simulation results indicate that this new switching routing can extend the lifetime of a MANET.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.1354-1357
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• 1993

This paper proposes that the best reasoning(i.e. rule evaluation) method which should be used in a fuzzy system significantly depends on the reasoning environment. It is shown that allowing for dynamic switching of reasoning methods leads to better performance, even when only two different reasoning methods are considered. This paper discusses DSFS (Dynamic Switching Fuzzy System) which dynamically switches and finds the best reasoning method (from among 80 different possible reasoning methods) to use depending on the reasoning situation. To overcome the reasoning speed and memory problem of DSFS due to its computational requirements, the DSFS Switching Reasoning Table method is proposed and its higher performance as compared to a conventional fuzzy system is shown. Finally, efforts to obtain general relationships between the characteristics of different reasoning methods and the actual control surface/environment is discussed.

• 한국군사과학기술학회지
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• 제10권3호
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• pp.129-138
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• 2007

Recently, Direction Finding(DF) System is using switching DF algorithm to reduce system-weight by eliminating RF cable as much as possible. Also, Correlation Vector Direction Finding(CVDF) algorithms is being used for Fast Direction finding in tactical environment. In this paper, I will give you burst error elimination algorithms and compare the performance in case we use switching CVDF algorithm. Although antenna array is not working, we will successfully perform direction finding when we use this burst error elimination algorithms. Also, we will be completely capable of DF mission despite of meeting the unwanted situation that the monitoring signal disappear in case we use Switching Direction Finding algorithms. That situation frequently occurs under the Frequency Hopping signal circumstances.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.45-47
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• 2001

This paper studies the relationship between output and vibration characteristics of Switched Reluctance Motor(SRM) according to switch-on and off angles. Acceleration and motor performance are measured by changing switching angles and the magnetic forces are analyzed by Finite Element Analysis. A proper switching angle from theoretical and several experimental results are presented for satisfying power, efficiency and low vibration.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.364-369
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• 2002

Presently, a high frequency switching technique is used for a converter design to reduce its size and weight. However an increased switching frequency introduces a high switching loss. To the reduce switching loss, soft switching techniques using ZVS and ZCS are applied. It is very important to improve efficiency. However In general to develop new converter circuits, the efficiency and other performance parameters can be determined after design, implementation and experiments. The idea in this paper is to determine and predict efficiency and other operating characteristics without realization and experiments. Thereby a complex design and implementation can be avoided. PSPICE is used as a simulation tool. This is verified by comparing simulation and experiments results of the two different soft switching converters.

• Journal of Power Electronics
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• 제18권4호
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• pp.1255-1267
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• 2018

Parasitic parameters have a larger influence on Silicon Carbide (SiC) devices with an increase of the switching frequency. This limits full utilization of the performance advantages of the low switching losses in high frequency applications. By combining a theoretical analysis with a experimental parametric study, a mathematic model considering the parasitic inductance and parasitic capacitance is developed for the basic switching circuit of a SiC MOSFET. The main factors affecting the switching characteristics are explored. Moreover, a fast-switching double pulse test platform is built to measure the individual influences of each parasitic parameters on the switching characteristics. In addition, guidelines are revealed through experimental results. Due to the limits of the practical layout in the high-speed switching circuits of SiC devices, the matching relations are developed and an optimized layout design method for the parasitic inductance is proposed under a constant length of the switching loop. The design criteria are concluded based on the impact of the parasitic parameters. This provides guidelines for layout design considerations of SiC-based high-speed switching circuits.

• 한국정보시스템학회지:정보시스템연구
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• 제8권1호
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• pp.93-108
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• 1999

The switching system is designed and developed to satisfy the performance design objectives recommended by ITU for call processing capacity and quality of service(QOS), etc. When the results by actual measurement at the system testing phase do not satisfy the performance design objectives, however, an effort is required to improve the performance. This paper presents a method for improving QOS by modifying the application programs for the switching system. In the proposed method, the sequence chart related to a delay time for call connection is modelled using PERT(Program Evaluation and Review Technique) network. Then, the criticality index of a message is calculated using Monte Carlo simulation to evaluate which message's processing time to decrease in order to decrease the delay time and thus to improve QOS. The criticality index of a block is also calculated to identify those software blocks that significantly contribute to the delay time.

• Journal of Power Electronics
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• 제13권6호
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• pp.1016-1023
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• 2013

Predictive current control offers the potential for achieving more precise current control with a minimum of distortion and harmonic noise. However, the predictive method is difficult to implement and has a greater computational burden. This paper introduces a theoretical analysis and experimental verification for an improved predictive current control technique applied to single phase grid connected voltage source inverters (VSI). The proposed technique has simple calculations. An ATmega1280 microcontroller board is used to implement the proposed technique for a simpler and cheaper control system. To enhance the current performance and to obtain a minimum of current THD, an improved tri-level PWM switching strategy is proposed. The proposed switching strategy uses six operation modes instead of four as in the traditional strategy. Simulation results are presented to demonstrate the system performance with the improved switching strategy and its effect on current performance. The presented experimental results verify that the proposed technique can be implemented using fixed point 8-bit microcontroller to obtain excellent results.

• 한국통신학회논문지
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• 제18권12호
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• pp.2001-2012
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• 1993

기존의 전전자교환기에 ISDN 기능을 부가하게 되면 가입자 모듈의 구조적인 변화가 따르게 되어 시스팀의 성능에 영향을 미치게 된다. 따라서 이러한 성능의 변화가 발생하지 않도록 시스팀을 설계하는 것이 중요하다. 본 논문은 음성급 전전자교환기인 TDX-LB 시스템에 ISDN기능을 추가 개발함에 따라 예상되는 디지틀 가입자 모듈의 성능을 평가하기 위하여 해석적인 방법으로 목표만을 확인하고, 개발된 시스팀의 성능을 측정하여 기존의 음성 시스팀과 비교함으로서 ISDN 가입자 정합 기술이 시스팀 성능에 미친 영향을 분석 하였다.