• Title, Summary, Keyword: Synchronous

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A Study on Counter Design using Sequential Systems based on Synchronous Techniques

  • Park, Chun-Myoung
    • Journal of information and communication convergence engineering
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    • v.8 no.4
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    • pp.421-426
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    • 2010
  • This paper presents a method of design the counter using sequential system based on synchronous techniques. For the design the counter, first of all, we derive switching algebras and their operations. Also, we obtain the next-state functions, flip-flop excitations and their input functions from the flip-flop. Then, we propose the algorithm which is a method of implementation of the synchronous sequential digital logic circuits. Finally, we apply proposed the sequential logic based on synchronous techniques to counter.

An Improved Stationary Frame-based Digital Current Control Scheme for a PM Synchronous Motor

  • Kim, Kyeong-Hwa;Young, Myung-Joong
    • Journal of Power Electronics
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    • v.1 no.2
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    • pp.88-98
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    • 2001
  • An improved stationary frame-based digital current control technique for a permanent magnet(PM) synchronous motor is presented. Generally, the stationary frame current controller is known to provide the advantage of a simple implementation. However, there are some unavoidable limitations such as a steady-state error and a phase delay in the steady-state. On the other hand, in the synchronous frame current regulator the regulated currents are dc quantities and a zero steady-state error can be obtained through the integral control. However, the need to transform the signals between the stationary and synchronous frames makes the implementation of a synchronous frame regulator complex. Although the PI controller in the stationary frame gives a steady-state error and a phase delay, the control performance can be greatly improved by employing the exact decoupling control inputs for the back EMF., resulting in an ideal steady-state control characteristics irrespective of an operating condition as in the synchronous PI decoupling controller. However, its steady-state response may be degraded due to the inexact cancellation inputs under the parameter variations. To improve the control performance in the stationary frame, the disturbance is estimated using the time delay control. The proposed scheme is implemented on a PM synchronous motor using DSP TMS320C31 and the effectiveness is verified through the comparative simulations and experiments.

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An Improved Stationary Frame-based Digital Current Control Scheme for a PM Synchronous Motor

  • Kim Kyeong-Hwa;Youn Myung-Joong
    • Proceedings of the KIPE Conference
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    • pp.174-178
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    • 2001
  • An improved stationary frame-based digital current control technique for a permanent magnet (PM) synchronous motor is presented. Generally, the stationary frame current controller is known to provide the advantage of a simple implementation. However, there are some unavoidable limitations such as a steady-state error and a phase delay in the steady-state. On the other hand, in the synchronous frame current regulator, the regulated currents are dc quantities and a zero steady-state error can be obtained through the integral control. However, the need to transform the signals between the stationary and synchronous frames makes the implementation of a synchronous frame regulator complex. Although the PI controller in the stationary frame gives a steady-state error and a phase delay, the control performance can be greatly improved by employing the exact decoupling control inputs for the back EMF, resulting in an ideal steady-state control characteristics irrespective of an operating condition as in the synchronous PI decoupling controller. However, its steady-state response may be degraded due to the inexact cancellation inputs under the parameter variations. To improve the control performance in the stationary frame, the disturbance is estimated using the time delay control. The proposed scheme is implemented on a PM synchronous motor using DSP TMS320C31 and the effectiveness is verified through the comparative simulations and experiments.

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Fixed Time Synchronous IPC in Zephyr Kernel (Zephyr 커널에서 고정 시간 동기식 IPC 구현)

  • Jung, Jooyoung;Kim, Eunyoung;Shin, Dongha
    • IEMEK Journal of Embedded Systems and Applications
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    • v.12 no.4
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    • pp.205-212
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    • 2017
  • Linux Foundation has announced a real-time kernel, called Zephyr, for IoT applications recently. Zephyr kernel provides synchronous and asynchronous IPC for data communication between threads. Synchronous IPC is useful for programming multi-threads that need to be executed synchronously, since the sender thread is blocked until the data is delivered to the receiver thread and the completion of data transfer can be known to two threads. In general, 'IPC execution time' is defined as the time duration between the sender thread sends data and the receiver thread receives the data sent. Especially, it is important that 'IPC execution time' in the synchronous IPC should be fixed in real-time kernel like Zephyr. However, we have found that the execution time of the synchronous IPC in Zephyr kernel increases in proportion to the number of threads executing in the kernel. In this paper, we propose a method to implement a fixed time synchronous IPC in Zephyr kernel using Direct Thread Switching(DTS) technique. Using the technique, the receiver thread executes directly after the sender thread sends a data during the remaining time slice of the sender thread and we can archive a fixed IPC execution time even when the number of threads executing in the kernel increases. In this paper, we implemented synchronous IPC using DTS in the Zephyr kernel and found the IPC execution time of the IPC is always 389 cycle that is relatively small and fixed.

A Study on Synchronous Rectification of Push-Pull Converter for Efficiency Improvement (효율개선을 위한 Push-Pull Converter의 동기정류에 관한 연구)

  • 김영규;김동중;김이훈;원충연;김규식;최세완
    • The Transactions of the Korean Institute of Power Electronics
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    • v.9 no.2
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    • pp.134-141
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    • 2004
  • This paper presents a method of synchronous rectifier(SR) for improving the efficiency in DC/DC converter. The proposed method is used push-pull topology on primary as a single winding self driven synchronous rectification(SWSDSR). Specially, this method can improve efficiency to turn on SR switch during dead time. Finally, the simulation and experimental results will be given to show comparison and analysis on the efficiency between self driven synchronous rectification(SDSR) and SWSDSR method.

An acoustical analysis of synchronous English speech using automatic intonation contour extraction (영어 동시발화의 자동 억양궤적 추출을 통한 음향 분석)

  • Yi, So Pae
    • Phonetics and Speech Sciences
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    • v.7 no.1
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    • pp.97-105
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    • 2015
  • This research mainly focuses on intonational characteristics of synchronous English speech. Intonation contours were extracted from 1,848 utterances produced in two different speaking modes (solo vs. synchronous) by 28 (12 women and 16 men) native speakers of English. Synchronous speech is found to be slower than solo speech. Women are found to speak slower than men. The effect size of speech rate caused by different speaking modes is greater than gender differences. However, there is no interaction between the two factors (speaking modes vs. gender differences) in terms of speech rate. Analysis of pitch point features has it that synchronous speech has smaller Pt (pitch point movement time), Pr (pitch point pitch range), Ps (pitch point slope) and Pd (pitch point distance) than solo speech. There is no interaction between the two factors (speaking modes vs. gender differences) in terms of pitch point features. Analysis of sentence level features reveals that synchronous speech has smaller Sr (sentence level pitch range), Ss (sentence slope), MaxNr (normalized maximum pitch) and MinNr (normalized minimum pitch) but greater Min (minimum pitch) and Sd (sentence duration) than solo speech. It is also shown that the higher the Mid (median pitch), the MaxNr and the MinNr in solo speaking mode, the more they are reduced in synchronous speaking mode. Max, Min and Mid show greater speaker discriminability than other features.

Steady-State Characteristic Analysis of Single-Phase Line-Start Permanent Magnet Synchronous Motor (단상 영구자석형 유도동기기의 정상상태 특성해석)

  • Kang, Gyu-Hong;Nam, Hyuk;Hong, Jung-Pyo
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.52 no.2
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    • pp.53-60
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    • 2003
  • This paper deals with steady-state analysis of a single-phase line-start permanent magnet synchronous motor. In order to analyze the steady-state characteristics, the asymmetric single-phase line-start synchronous motor is converted to the symmetric two-phase synchronous motor, that is, the asymmetric magnetic field is separated from the positive and the negative symmetric components using symmetrical-component theory. The analysis method of the synchronous motor on the d-q axis coordinates is used for the positive component and the equivalent circuit of the induction motor is applied for the negative component analysis. Moreover, d-q axis inductance considering current phase angle is applied to positive component analysis for precise characteristic analysis. In order to validate the proposed analysis method, the analysis results are compared with the experimental results.

Design of synchronous VHDL Code Generator from Synchronous SpecCharts (Synchronous SpecCharts로부터 Synchronous VHDL 코드 생성기 설계)

  • 윤성조;안성용;이정아
    • Proceedings of the Korean Information Science Society Conference
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    • pp.54-56
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    • 1999
  • 현재 많은 내장형 시스템을 구현하기 위한 방법론으로 가상 프로토타입(VP)을 이용하고 있다. 본 논문에서는 가상 프로토타입을 이용하여 내장형 시스템의 설계 및 구현을 위해 사용되는 시스템 명세 언어인 SpecCharts로 명세된 시스템을 동기적 의미론에 만족하는 SpecCharts의 Subset을 규명하여 동기화 형태로 해당명세를 변환시키고 이로부터 synchronous VHDL 코드로 생성할 수 있는 방법을 설계하였다. 동기적 의미론을 만족시키기 위하여 비결정적인 추상적인 모델(NDAM)을 이용하여 SpecCharts로부터 VHDL ?로 변환하는 방법을 제시하고, 변환된 VHDL 코드를 동기적 VHDL 코드로 변환하기 위하여 W. Baker에 의해 규명된 동기적 VHDL subset 적용하여 synchronous VHDL 코드를 생성하는 방법을 제안한다.

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Phase Shift Controlled GM ZVS-MRC with Synchronous Rectifier (동기 정류기를 이용한 위상 변위 제어 클램프 모드 포워드 다중 공진형 컨버터)

  • Song, Jong-Hwa;Kim, Chang-Sun;Kim, Hee-Jun
    • Proceedings of the KIEE Conference
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    • pp.2016-2019
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    • 1997
  • To solve the low efficiency problem of low-voltage power supplies, it has been studied to replace the schottky barrier diode with the MOSFET synchronous rectifier. In this paper, Phase Shift-Controlled Clamp Mode Zero Voltage Switching-Multi Resonant Converter with Synchronous Rectifier (PSC CM ZVS-MRC with SR) is presented to achieve high efficiency in low-voltage power supplies. The characteristics analysis of synchronous rectifier is established by using the MOSFET equivalent circuit and efficiency comparison is established between the Synchronous Rectifier and the schottky barrier diode. To verify the validity of the analysis, 33W(3.3V, 10A) PSC CM ZVS-MRC with self-driven synchronous rectifier at switching frequency of 1MHz is designed and tested. And it is confirmed that the experimental results are well consistent with the theoretical results. The maximum efficiency of the converter is 83.4% at full load, which is 3.3% higher than conventional schottky diode rectification.

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A New Type of CPPM Machine with Stator Axial Magnetic Ring

  • Xie, Kun;Li, Xinhua;Ma, Jimin;Wu, Xiaojiang;Yi, Hong;Hu, Gangyi
    • Journal of Electrical Engineering and Technology
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    • v.13 no.3
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    • pp.1285-1293
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    • 2018
  • This paper proposes a new type of consequent-pole permanent-magnet (CPPM) machine with stator axial magnetic ring that increases torque capability over a wide speed range and enhances efficiency for the built-in rare-earth permanent magnet synchronous machine used in new energy vehicles. The excitation winding of the CPPM hybrid excitation synchronous machine in the stator is replaced by ferrite magnetic ring to simplify the structure and manufacturing process of the machine. The basic structure and magnetic regulation principle of the proposed machine are introduced and compared with the traditional interior rare-earth permanent magnet synchronous machine and CPPM hybrid excitation synchronous machine. Finally, experimental results of a new type of CPPM synchronous motor prototype with axial magnetic ring are introduced in the paper.