• Title, Summary, Keyword: Switching

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Comparison Study of EMI and Switching Loss Reductions of Unipolar and Improved Limited Unipolar Switching Circuits

  • Fujimoto, Takashi;Park, Kyihwan
    • 제어로봇시스템학회:학술대회논문집
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    • pp.152.2-152
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    • 2001
  • This paper investigates the effect of the conducted EMI Electromagnetic Interference and the switching loss which occurs from the switching devices in the switching period of the unipolar and limited unipolar switching circuits. The three main sources of conducted EMI and switching loss in the unipolar and limited unipolar switching circuit come from the switching devices, the number of switching times in the switching period and their switching waveform. In this paper, these three parameters are used to determine the conducted EMI which generated from the unipolar and limited unipolar switching circuits and to improve the limited unipolar switching circuit which uses the power MOSFET´s as the switching devices. The significant reduction of Ire conducted EMI ...

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What are the Individual's Real Cares to Switch Personal Cloud Services?

  • Luo, Weiyi;Lee, Young-Chan
    • The Journal of Information Systems
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    • v.23 no.2
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    • pp.109-137
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    • 2014
  • As the fast development of information technology (IT), abundant attractive alternatives have showed up and challenged to the traditional information technology (IT). Cloud services, the hottest representative among these alternatives, has attracted the attention from all walks of life. Considering the diversity of cloud services, this study attempts to find out the important factors affected on individual's switching intention from incumbent IT to cloud services mainly based on two-factor theory (switching enablers and switching inhibitors) and explore the direct influences of these factors on individual's switching intention. According to our findings, individual's switching intention to cloud services is not only positively influenced by switching enablers but also negatively influenced by switching inhibitors. All the switching enablers in this study (perceived omnipresence, perceived collaboration support and perceived compatibility of cloud services) have positively significant influences on individual's switching intention as well as the switching inhibitors (usage habit of incumbent IT and perceived risk of cloud services) have negatively significant influences on individual's switching intention. It's noteworthy that satisfaction of incumbent IT has insignificant influence on individual's switching intention in this study. Moreover, as we expected, both social influence and personal innovativeness have significant influences on the generation of individual's switching intention.

A study on Three-Phase AC-DC Boost Converter using A Soft-Switching for discontinuous Mode (소프트 스윗치를 이용한 불연속 모드 3상 AC-DC 부스터 컨버터에 관한 연구)

  • Chun, J.H.;Kwak, D.G.;Kim, C.S.;Suh, K.Y.;Kwon, S.K.;Lee, H.W.
    • Proceedings of the KIEE Conference
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    • pp.188-190
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    • 1995
  • This paper describes a soft switching using discontinuous inductor current. The soft switching snubber circuit provides ZCS and ZVS for main switch. For high power applications, the input ractifier is fed from a three-phase ac source. The Conventional switching method is hard switching technics, because of the device turn off is ocurred in maximum reactor current. In this time, switching losses are maximised by the hard switching. In generally, soft switching technique has been adjusted with the snubber condenser in order to compensates for this losses. So, it was compared hard switching with soft switching which has proposed in this paper for switching losses, distortion factor by the simulation.

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Automatic Protection Switching Schemesfor Network Survivability in ATM-PON Networks (ATM-PON망에서 망 생존성을 위한 자동보호절체)

  • 김영구
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.9A
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    • pp.1441-1451
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    • 2000
  • There are two types of protection switching : a) automatic switching and b) forced switching. The switching mechanism is generally realised by OAM functions, therefore, the required OAM information field should be reserved in the PLOAM cells. This paper proposes an unidirectional and a bidirectional protection switching method and potential advantages. The unidirectional protection switching method can be faster than the bidirectional method because the unidirectional method does not require an APS protocol for protection switching. The bidirectional protection switching method uses APS K1 byte and K2 byte, which is included in octets of a PST message through downstream or upstream PLOAM cells, for protection switching. As making comparisons between the unidirectional and the bidirectional protection. switching method, this paper proposes an effective constructing method for ATM-PON network.

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ISDN 교환기

  • Lee, Heon
    • ETRI Journal
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    • v.9 no.4
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    • pp.26-35
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    • 1987
  • Switching system can be regarded as the key node of Integrated Services Digital Networks(ISDN) because it plays the Important role in realization of ISDN. As ISDN is evolved from the telephony Integrated Digital Network(IDN), the switching system for ISDN will be evolved from the function and structure of telephony digital switching system. At near future, ISDN switching system is expected to implement the integrated access and transparent switching functions for both voice and data. As final goals of switching system, advanced switching methods for information having various traffic characteristics such as voice, data, text and image should be considered. This paper considered. This paper will show some of the fundamental design challenges and architectural trends in ISDN switching system.

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Comparative Study of Minimum Ripple Switching Loss PWM Hybrid Sequences for Two-level VSI Drives

  • Vivek, G.;Biswas, Jayanta;Nair, Meenu D.;Barai, Mukti
    • Journal of Power Electronics
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    • v.18 no.6
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    • pp.1729-1750
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    • 2018
  • Voltage source inverters (VSIs) are widely used to drive induction motors in industry applications. The quality of output waveforms depends on the switching sequences used in pulse width modulation (PWM). In this work, all existing optimal space vector pulse width modulation (SVPWM) switching strategies are studied. The performance of existing SVPWM switching strategies is optimized to realize a tradeoff between quality of output waveforms and switching losses. This study generalizes the existing optimal switching sequences for total harmonic distortions (THDs) and switching losses for different modulation indexes and reference angles with a parameter called quality factor. This factor provides a common platform in which the THDs and switching losses of different SVPWM techniques can be compared. The optimal spatial distribution of each sequence is derived on the basis of the quality factor to minimize harmonic current distortions and switching losses in a sector; the result is the minimum ripple loss SVPWM (MRSLPWM). By employing the sequences from optimized switching maps, the proposed method can simultaneously reduce THDs and switching losses. Two hybrid SVPWM techniques are proposed to reduce line current distortions and switching losses in motor drives. The proposed hybrid SVPWM strategies are MRSLPWM 30 and MRSLPWM 90. With a low-cost PIC microcontroller (PIC18F452), the proposed hybrid SVPWM techniques and the quality of output waveforms are experimentally validated on a 2 kVA VSI based on a three-phase two-level insulated gate bipolar transistor.

Study on Resonant PWM Switching Technique for $3{\phi}$ Boost AC/DC Converter with High Power Factor and Less Switching Loss (3상 승압형 AC/DC 컨버터의 고역율과 스위칭 손실 저감을 위한 공진 PWM 스위칭 기법에 관한 연구)

  • Yi, Eun-Gyu;Noh, Yung-Nam;Kim, Beung-Jin;Jeon, Hee-Jong
    • Proceedings of the KIEE Conference
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    • pp.541-543
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    • 1997
  • In this paper, a proposed resonant PWM switching technique makes the boost AC/DC converter to high input power factor and less switching loss. Also, the switching control scheme is used which minimize harmonic components employing novel PWM technique. In addition, an employment of resonant circuit for switching makes zero current switching(ZCS) and zero voltage switching(ZVS) for control switches without switching losses. The result shows that high power factor is still for varying load and switching loss is very low.

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Implement of Constant-Frequency-Controled Zero-Voltage-Switching Converter-fed DC Motor Drive for Low Power Loss (직류 전동기의 저손실 구동을 위한 일정 주파수 제어형 영전압 스위칭 변환기의 구현)

  • Ko, Moon-Ju;Park, Jin-Hong;Han, Wan-Ok;Lee, Sung-Paik
    • Proceedings of the KIEE Conference
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    • pp.2148-2150
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    • 1998
  • This paper proposes a constant frequency controlled zero voltage switching method that can reduce switching losses caused by emf on inductance in DC motor. The zero voltage switching method is used more than a zero current switching method because of reducing switching losses by capacitance of depletion region of MOSFET. To simplify the controller circuit, we propose constant frequency controlled zero voltage switching method in the paper. The control method is more stable than a variable frequency control method because it can optimize bandwidth of a closed-loop and reactances. Therefore, we construct a constant frequency controlled zero voltage switching converter and improve zero switching losses in high switching frequency. In the process, we can control low-losses in full range on variable voltage and load. We simulate the proposed converter with P-SPICE and compare results obtained through the experiment.

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An Indoor Positioning System Using Time-Synchronized Switching GPS Repeater (시각동기 스위칭 GPS 중계기를 이용한 실내측위 시스템)

  • Im Sung-Hyuck;Jee Gyu-In
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.8
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    • pp.789-797
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    • 2006
  • A new method for the GPS repeater based indoor positioning is proposed and its feasibility is verified by experiments in previous paper. But the problems how can identify switching GPS repeater's ID and when switching will be occurred are remained. To solve the problem faced with, we propose the time synchronized switching GPS repeater and the methods of the detection of switching time and the estimation of TDOA. First, switching GPS repeater retransmits the signals synchronized on GPS time, sequentially. Always, first switching time is synchronized with 1 PPS. Second, we formulate the detection of switching time and the estimation of TDOA and propose the various methods. No method is existed absolutely superior to others in any conditions but the method is existed superior to others in specific condition. Finally, feasibility of indoor positioning using time-synchronized switching GPS repeater is evaluated through experiments in anechoic chamber and general environment with multipath.

A Study on Antecedents of Customer Switching Behavior in Mobile Services (이동통신 서비스 전환행동에 영향을 미치는 요인에 관한 연구)

  • Yoon, Jung-In;Sung, Su-Jung;Lee, Jung-Woo
    • Korean Management Science Review
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    • v.26 no.3
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    • pp.169-184
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    • 2009
  • Recently, mobile telecommunication businesses contend with each other to expand their customer base by using aggressive marketing strategies. In order to determine if there strategies are effective, customer's switching behavior needs to be studied. This study identifies and analyzes direct, indirect factors that may customer switching behavior : attractiveness of alternatives, network externality, and switching cost. Results reveals that attractiveness of alternatives, network externalities have a direct impact on customer switching behavior. These two factors also have moderating effects on customer switching behavior but the switching cost does not In short, network externalities and alternatives strategically determine the success of 3.5G service. In this regard, mobile business should improve their own attractiveness of alternatives by developing specialized service in 3.5G service.