• Title/Summary/Keyword: Linear current source

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Nonlinear Motion Responses for A Moored Ship beside Quay (안벽에 계류된 선박에 대한 비선형 운동응답)

  • Lee, Ho-Yooung;Lim, Choon-Gyu;Lew, Jae-Moon;Chun, In-Sik
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.05a
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    • pp.172-178
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    • 2003
  • As a typoon gets into harbour, a moored ships shows erratic motions and even mooring line failures is occurred. Such troubles may be caused by harbour resonance phenomena, result in large motion amplitudes at law frequency, which is closed to the natural frequency of the moored ship. The nonlinear motions of a moored ship beside quay are simulated under external forces due to wave, current including mooring forces in time domain. The forces due to waves are obtained from source and dipole distribution method in the frequency domain. The current forces are calculated by using slow motion maneuvering equation in the horizontal plane. The wind forces are calculated from emperical formula of ABS and the mooring forces of ropes and fenders are modeled as linear spring.

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Optimal Design for Hybrid Active Power Filter Using Particle Swarm Optimization

  • Alloui, Nada;Fetha, Cherif
    • Transactions on Electrical and Electronic Materials
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    • v.18 no.3
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    • pp.129-135
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    • 2017
  • This paper introduces a design and a simulation of a hybrid active power filter (HAPF) for harmonics reduction given an ideal supply source. The synchronous reference frame method has been used here to identify the reference currents. The proposed HAPF uses a new artificial- intelligence technique called Particle Swarm Optimization (PSO) for tuning the parameters of a proportional and integral controller called PI-PSO. The PI-PSO controller is used to archive optimality for the DC-link voltage of the HAPF-inverter. The hysteresis non-linear current control method is used in this approach to compare the extracted reference and the actual currents in order to generate the pulse gate required for the HAPF. Results obtained by simulations with Matlab/Simuling show that the proposed approach is very flexible and effective for eliminating harmonic currents generated by the non-linear load with the HAPF based PSO tuning.

Stability Analysis of an Accelerator-Driven Fluid-Fueled Subcritical Reactor System

  • Kim, Do-Sam;Cho, Nam-Zin
    • Proceedings of the Korean Nuclear Society Conference
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    • 1997.05a
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    • pp.90-95
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    • 1997
  • In this work, linear dynamics of a circulating fluid-fueled subcritical reactor system with temperature feedback and external neutron source was modeled and examined. In a circulating fluid-fuel system, the stable region is slightly moved by a circulation fluid effect. The effects of subcriticality and temperature feedback coefficient on the reactor stability were tested by calculating frequency response of neutron density originated from reactivity perturbation or external source oscillation of system. The amplitude transfer function has a different shape near subcritical region due to the exponential term in the transfer function. The results of the study show that at a slightly subcritical region, low frequency oscillation in accelerator current or reactivity can be amplified depending on the temperature feedback. However, as the subcriticality increases, the oscillation becomes negligible regardless of the magnitude of the temperature feedback coefficient.

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A study on behavioral analysis and efficient test algorithm for memory with resistive short and open defects (저항성 단락과 개방 결함을 갖는 메모리에 대한 동작분석과 효율적인 테스트 알고리즘에 관한 연구)

  • 김대익;배성환;이상태;이창기;전병실
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.7
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    • pp.70-79
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    • 1996
  • To increase the functionality of the memories, previous studies have deifned faults models and proposed functional testing algorithms with low complexity. Although conventional testing depended strongly on functional (voltage) testing method, it couldn't detect short and open defects caused by gate oxide short and spot defect which can afect memory reliability. Therefore, IDDQ (quiescent power supply current) testing is required to detect defects and thus can obtain high reliability. In this paper, we consider resistive shorts on gate-source, gate-drain, and drain-source as well as opens in mOS FET and observe behavior of the memory by analyzing voltage at storge nodes of the memory and IDDQ resulting from PSPICE simulation. Finally, using this behavioral analysis, we propose a linear testing algorithm of complexity O(N) which can be applicable to both functional testing and IDDQ testing simultaneously to obtain high functionality and reliability.

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A Study on the Fabrication of Polarimetric Fiber Optic Current Sensor (편광측정법에 의한 광섬유 전류 센서 제작에 관한 연구)

  • Jang, Nam-Young;Chio, Pyung-Suk;Eun, Jae-Jeong;Park, Hae-Soo
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.41 no.6
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    • pp.33-41
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    • 2004
  • In this paper, a polarimetric fiber optic current sensor(P-FOCS) is experimented and fabricated, and then a possibility to the commercial utilization of the P-FOCS is also investigated. The P-FOCS measures an applied current by a Faraday rotation linearly proportional to a magnetic field generated by the applied current. The bending-induced linear birefringence in the sensing fiber is minimized by using the low birefringent fiber. Also, all fiber-optic components are used to avoid optical losses coming from the use of bulk components. A signal processing circuit is constructed and used to eliminate the effects of intensity variations in the output signal due to losses coming from misalignments of components such as fiber connectors. Using the optical source of 632.8nm wavelength, Faraday rotation is measured by passing through the sensing fiber within the solenoid of about 1500 turns which is equivalent to a current source of about 7500A. In the range of 1000A to 7500A, the measurement error for linearity is within about 1.5%.

A Study of Seam Tracking by Arc Sensor Using Current Area Difference Method (전류 면적차를 이용한 아크 센서의 용접선 추적에 관한 연구)

  • 김용재;이세헌;엄기원
    • Journal of Welding and Joining
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    • v.14 no.6
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    • pp.131-139
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    • 1996
  • The response of the arc sensor using the welding current and/or welding voltage as its outputs has been obtained by the analysis and/or experiments of the static characteristics of arc sensor. But in order to improve the reliability of arc sensor, it is necessary to know its dynamic characteristics. So in this paper, it is presented the dynamic model of arc sensor including the power source, arc voltage, electrode burnoff rate, and wire feed rate. A numerical simulation of the dynamic model of arc sensor was implemented, computing the welding current with input of CTWD. The results of computer simulations and experiments of $CO_2$arc welding showed that a linear relationship between weaving center - weld line distance and current area difference was established. Additionally, a real-time weld seam tracking system interfaced with industrial welding robot was constructed, the result of the weld seam tracking experiment for weld line with an initial offset error of 5$^{\circ}$was good.

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A 3 Dimensional Characteristic Analysis of SLIM by the 2-D Finite Element Method (2차원 유한요소법에 의한 SLIM의 3차원적 특성 해석)

  • Cho, Yun-Hyun;Kim, Yong-Joo;Shin, Pan-Seok;Kang, Do-Hyun
    • Proceedings of the KIEE Conference
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    • 1990.11a
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    • pp.37-42
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    • 1990
  • In order to obtain optimal design criteria and operating parameters, a Single-sided Linear Induction Motor (SLIM) is analysed by using a 2-D finite element method with magnetic and current vector potential. In the analysing procedures, the governing equation is derived from Maxwell's equation combined with the magnetic vector potential. As a forcing term, 3-phase voltage source is employed using the Kirchhoff's voltage law in order to look into effects of the unbalanced 3-phase currents and air gap flux density. Also, 2ndary eddy current distribution, longitudinal end and transverse edge effects are in turns visualized by flux lines in 3 different analysing planes as functions of frequency and input power.

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Design and investigation of a shape memory alloy actuated gripper

  • Krishna Chaitanya, S.;Dhanalakshmi, K.
    • Smart Structures and Systems
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    • v.14 no.4
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    • pp.541-558
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    • 2014
  • This paper proposes a new design of shape memory alloy (SMA) wire actuated gripper for open mode operation. SMA can generate smooth muscle movements during actuation which make them potentially good contenders in designing grippers. The principle of the shape memory alloy gripper is to convert the linear displacement of the SMA wire actuator into the angular displacement of the gripping jaw. Steady state analysis is performed to design the wire diameter of the bias spring for a known SMA wire. The gripper is designed to open about an angle of $22.5^{\circ}$ when actuated using pulsating electric current from a constant current source. The safe operating power range of the gripper is determined and verified theoretically. Experimental evaluation for the uncontrolled gripper showed a rotation of $19.97^{\circ}$. Forced cooling techniques were employed to speed up the cooling process. The gripper is simple and robust in design (single movable jaw), easy to fabricate, low cost, and exhibits wide handling capabilities like longer object handling time and handling wide sizes of objects with minimum utilization of power since power is required only to grasp and release operations.

LED Driver by the Low Cost DSP (저가형 DSP를 이용한 LED 구동회로)

  • Song, Jae-Wook;Yoo, Jin-Wan;Park, Chong-Yeun
    • Journal of Industrial Technology
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    • v.32 no.A
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    • pp.103-107
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    • 2012
  • Due to improvement of the semiconductor technology, the LED replaces the conventional lighting source and LED drivers have been studied and developed. The LED is driven by the constant current control method according to its characteristics. For the constant current control method, the linear regulator and the switching regulator is used. The switching regulator is usually used to LED drivers because it has specific characteristics as the wide input dynamic range and the high efficiency. In this paper, we have described the principle and the implement of the switching regulator, using the drive IC and the low cost DSP chip. Also, both methods have been implemented and its electrical characteristics had almost same experimental results in the steady state and the transient state.

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Nonlinear Representation of Two-Stage Power-Factor-Correction AC/DC Circuits

  • Orabi Mohamed;Ninomiya Tamotsu
    • Journal of Power Electronics
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    • v.4 no.4
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    • pp.197-204
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    • 2004
  • Two-stage Power-Factor-Correction (PFC) converters are the most common circuits for drawing sinusoidal and in phase current waveforms from an ac source with a good regulated output voltage. The first stage is a boost PFC converter with average-current-mode control for achieving the near-unity power factor and the second stage is a forward converter with voltage-mode control to regulate the output voltage. Stability analysis and design methods of two-stage PFC converters have previously been discussed using linear models. Recently, new nonlinear phenomena have been detected in pre-regulator boost PFC circuits and a new nonlinear model has been proposed for pre-regulated PFC converters. Therefore, investigation of two-stage PFC converters from the nonlinear viewpoint becomes important because the second stage DC/DC converter adds more complexity to the circuit. So, this paper introduces a study of the stability of two-stage PFC converters. A novel nonlinear model of two-stage PFC converters is proposed. Then, a stability analysis is made based upon this nonlinear model. The high correspondence between the simulated and experimental results confirms our analysis.