• Title/Summary/Keyword: induction technique

Search Result 583, Processing Time 0.027 seconds

Experimental Study on Spray Structure of a High Pressure 6-Hole Injector by Mie Scattering Technique (미산란 기법에 의한 고압 6공 연료분사기의 분무형상에 대한 실험적 연구)

  • Kim, Seong-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.32 no.11
    • /
    • pp.878-883
    • /
    • 2008
  • The spray characteristics of a high pressure 6-hole injector were examined in a single cylinder optical direct injection spark ignition (DISI) engine. The effects of injection timing, in-cylinder charge motion, fuel injection pressure and coolant temperature were investigated using the 2-dimensional Mie scattering technique. It was confirmed that the in-cylinder charge motion played a major role in the fuel spray distribution during the induction stroke while the propagation of fuel spray was restrained during the compression stroke by the increasing pressure and the upward moving piston. In additions, it was confirmed that the liquid fuel droplets existing at the sprays edges were vaporized by the increase of the coolant temperature.

Input Filter for Direct Matrix Converter with Stepless Current Commutation Technique (스텝리스 전류 커뮤테이션 기법이 적용된 직접형 매트릭스 컨버터를 위한 입력 필터)

  • Han, Sanghun;Kwon, Soyeon;Cho, Younghoon
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.25 no.2
    • /
    • pp.152-155
    • /
    • 2020
  • This study proposes an input filter for a gallium-nitride-based direct matrix converter with a stepless current commutation technique. Various current commutation strategies have been adopted for reliable operation of switches. These strategies are complex to be implemented and require additional components. The stepless current commutation technique is simple to operate but causes overcurrent issues due to the occurrence of short circuit on input sources. In this study, to restrict the short circuit current, we utilized GaN devices with fast switching properties and modified the input filter. The proposed input filter was verified by experimental results of induction motor drive.

Traumatic Tricuspid Regurgitation Treated by the Minimally Invasive Double Orifice Technique

  • Lee, Chan Kyu;Jang, Jae Hoon;Lee, Na Hyeon;Song, Seunghwan
    • Journal of Chest Surgery
    • /
    • v.54 no.1
    • /
    • pp.68-71
    • /
    • 2021
  • A 37-year-old man was transferred to our level I trauma center after a road traffic accident, presenting with right acetabular fracture, multiple rib fractures, epidural hemorrhage, and liver contusion. Severe traumatic tricuspid regurgitation was also discovered during the work-up for surgery. Our initial attempt at acetabular surgery failed when the patient experienced near cardiac arrest during anesthetic induction. It was hence decided that tricuspid valve repair should precede orthopedic surgery. Minimally invasive tricuspid valve repair using the double orifice technique was successfully performed. Subsequently, acetabular surgery was performed and he was discharged 35 days post-trauma without any complications.

Low Speed Drive of Induction Motor using Direct Toque Control (DTC를 이용한 유도전동기의 저속 영역운전)

  • Song, Ho-Bin;Lee, Chun-Sang;Seo, Young-Soo
    • Proceedings of the KIEE Conference
    • /
    • 2002.07b
    • /
    • pp.1178-1180
    • /
    • 2002
  • A control technique which utilizes the stator flux components as control variables has been applied to a speed sensorless induction motor drive. The scheme may be regarded as a development of a DTC scheme, aimed achieve constant switching frequency operation. At each sampling period the required voltage vector is calculated on the basis of the error between the reference and the estimated stator flux vector. The problems related to the VSI dead time and the stator flux estimation at low speed have been analyzed, and an efficient solution has been proposed.

  • PDF

Robust Sensorless Sliding Mode Flux Observer for DTC-SVM-based Drive with Inverter Nonlinearity Compensation

  • Aimad, Ahriche;Madjid, Kidouche;Mekhilef, Saad
    • Journal of Power Electronics
    • /
    • v.14 no.1
    • /
    • pp.125-134
    • /
    • 2014
  • This paper presents a robust and speed-sensorless stator flux estimation for induction motor direct torque control. The proposed observer is based on sliding mode approach. Stator electrical equations are used in the rotor orientation reference frame to eliminate the observer dependence on rotor speed. Lyapunov's concept for systems stability is adopted to confine the observer gain. Furthermore, the sensitivity of the observer to parameter mismatch is recovered with an adaptation technique. The nonlinearities of the pulse width modulation voltage source inverter are estimated and compensated to enhance stability at low speeds. Therefore, a new method based on the model reference adaptive system is proposed. Simulation and experimental results are shown to verify the feasibility and effectiveness of the proposed algorithms.

Design of Sliding-mode Observer for Robust Speed Sensorless Induction Motor Drive

  • Son, Young-Dae;Lee, Jong-Nyun
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2004.08a
    • /
    • pp.488-492
    • /
    • 2004
  • In this paper, the design of a speed sensorless vector control system for induction motor is performed by using a new sliding mode technique based on current model flux observer. A current and flux observer based on the current estimation error is constructed. The proposed current observer includes a sliding mode function, which is derivative of the flux. That is, sliding mode observer which allows the estimation of both the rotor speed and flux based on the measurement of motor terminal quantities, would be proposed. And, a synergetic speed controller using the estimated speed signal is designed to stabilize the speed loop. Simulation results are presented to confirm the theoretical analysis, and to show the system performance with different observer gains and the influence of the motor parameter.

  • PDF

Optimum Design of SCR Inverter for High-Frequency Induction Heating (SCR Inverter 고주파유도가열장치의 최적설계에 관한 연구)

  • 박성규;김주홍
    • Journal of the Korean Institute of Telematics and Electronics
    • /
    • v.14 no.1
    • /
    • pp.23-28
    • /
    • 1977
  • This paper describes the practical design of a SCR inverter which is suposed to be very much suitable for high frequency induction heating power source. In this design an optimum control technique was applied to maintain constant output power and constant power factor to various heating load by the use of frequency control. Some appreciable characteristics was obtained for some design guide of large ndstrial heating power sources by the test of the 3KHz, 3KW inverter which was designed in this study.

  • PDF

A Fuzzy Current Controller using General Purposed Fuzzy Control Software Tool (범용 퍼지 지원 도구를 이용한 퍼지 전류제어기)

  • Min, Seong-Sik;Lee, Kyu-Chan;Song, Jhong-Whan;Cho, Kyu-Bok
    • Proceedings of the KIEE Conference
    • /
    • 1991.11a
    • /
    • pp.341-344
    • /
    • 1991
  • Current controlled pulse width modulation(PWM) for voltage source inverter(VSI) is one of the control method which controls the current directly so that we can perform vector control because it reduces the orders of differential equations of the induction machine. This paper propose a Fuzzy current controlled PWM which properly minimize a current ripple using Fuzzy theory in a constant switching frequency. This technique is applied to an electrical drive system with an induction machine(IM) by simulation. By comparison with the known classical method such as ramp comparison, hysteresis band method, our contribution shows the better performances.

  • PDF

Nonlinear Sensorless Control of Induction Motor by using Feedback Linearization and Current Error

  • Seo Kang-Sung;Choi Youn-Ok;Cho Geum-Bae;Baek Hyung-Lae;Jeong Sam-Yong
    • Proceedings of the KIPE Conference
    • /
    • 2001.10a
    • /
    • pp.448-452
    • /
    • 2001
  • This paper describes the nonlinear sensorless control of induction motor by using feedback linearization and current error; the feedback linearization technique and the current error are applied for independent between rotor flux and electric torque and for speed estimation. The dynamic characteristics of the proposed nonlinear control algorithm involving field weakening area are verified by simulation and experiment.

  • PDF

Implementation of Self-Tuning Fuzzy Control System for Speed Control of an Induction Motor

  • Shin, Song-Ho;Jin, Shim-Young;Lee, Oh-Keol;Lee, Joon-Tark
    • Proceedings of the Korean Institute of Intelligent Systems Conference
    • /
    • 1998.06a
    • /
    • pp.449-452
    • /
    • 1998
  • In this paper, we implemented the variable fuzzy speed controller of an IM(induction motor) using the fuzzy control algorithms. Specially, we proposed a self-tuning technique of scale factors which could make easily the fuzzy speed controller optimize. Comparing with the conventional PI speed controller, the dynamic performances of a proposed fuzzy controller such as the reaching time, the maximum overshoot and the robustness against load disturbance were substantially improved.

  • PDF