• Title/Summary/Keyword: Load mode

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Crack Growth Behavior by Fatigue Load under Mixed Mode(I+II) (혼합모드(I+II)에서 피로 하중에 의한 균열진전 거동)

  • Gong, B.C.;Choi, S.D.
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.2
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    • pp.276-282
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    • 2012
  • This study looked for Mode status of each for fatigue crack growth behavior about the repeat load of mode I and the static load of mode II. The experiment was performed in the state of the repetition frequency of the sine wave 10Hz, the stress ratio 0.1, maximum load 300kg.f, a static load 0, 100, 200, 300kg.f, As the experimental results, in mode of static load, while the load value increases, the crack growth rate is slower as the energy of a crack mixing grows. Mode I and the power mode II get an influence each other in the direction of crack propagation path, but as they eventually get closer to the breaking point of the crack growth, it is dominated by the mode I.

Current Sliding Mode Control with a Load Sliding Mode Observer for Permanent Magnet Synchronous Machines

  • Jin, Ningzhi;Wang, Xudong;Wu, Xiaogang
    • Journal of Power Electronics
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    • v.14 no.1
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    • pp.105-114
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    • 2014
  • The sliding mode control (SMC) strategy is applied to a permanent magnet synchronous machine vector control system in this study to improve system robustness amid parameter changes and disturbances. In view of the intrinsic chattering of SMC, a current sliding mode control method with a load sliding mode observer is proposed. In this method, a current sliding mode control law based on variable exponent reaching law is deduced to overcome the disadvantage of the regular exponent reaching law being incapable of approaching the origin. A load torque-sliding mode observer with an adaptive switching gain is introduced to observe load disturbance and increase the minimum switching gain with the increase in the range of load disturbance, which intensifies system chattering. The load disturbance observed value is then applied to the output side of the current sliding mode controller as feed-forward compensation. Simulation and experimental results show that the designed method enhances system robustness amid load disturbance and effectively alleviates system chattering.

The Effect of Behavior Fatigue Crack Propagation on 2-Axle Load Frequency (2축 하중주파수가 피로균열진전거동에 미치는 영향)

  • Kim, Sang-Hee;Li, Jing-Hua;Choi, Seong-Dae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.14 no.1
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    • pp.78-84
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    • 2015
  • The stress state acting on mechanical parts and structures is generally mixed stress. This complex stress state, which is subject to changes in the environment, will produce many. Cars running on roads with different road conditions will subject the automotive parts to combined stress state. In the x direction and the y direction, a different amplitude and frequency of the fatigue load can be present. However, the load amplitude for Mode I and Mode II in a 2-axis fatigue test is limited to a constant ratio; the load frequency is always the same for any mode. In this paper, it is verified how the variation of the load frequency for mode II affects the behavior of fatigue crack propagation under mixed mode.

Part-load Performance Characteristics of a Solid Oxide Fuel Cell/Gas Turbine Hybrid Power System Operating with Various Load-following Operation Modes (부하추종 운전방법에 따른 고체산화물 연료전지/가스터빈 하이브리드 동력 시스템의 부분부하 성능특성)

  • Kim Jae-Hoon;Yang Jin-Sik;Ro Sung-Tack;Sohn Jeong-Lak
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.3 s.246
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    • pp.193-200
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    • 2006
  • The purpose of this study is to compare the part-load performance of a SOFC/GT hybrid power system with three different kinds of load-following operation modes. The primary mode for the part load operation of a hybrid power system is the reduction of supplied fuel (e.g., fuel control mode) to the hybrid system. The other two options, i.e., variable speed and VIGV controls, are related to the reduction of supplied air simultaneously with the reduction of supplied fuel to the system. With the performance analysis of a SOFC/GT hybrid power system, it is concluded that the variable speed con佐ol mode Provides the best performance for the part-load operations. It is also found that the VIGV control mode, with its better performance behavior than the fuel control mode, can be used as an important option for the part-load operation especially in case that the variable speed control mode can not be adopted.

A Mode Selector for Operation with Linear and Switching Regulator (선형방식과 스위칭 방식의 레귤레이터를 함께 구동하기 위한 Mode Selector)

  • Cho, Han-Hee;Park, Kyeong-Hyeon;Jung, Jun-Mo;Koo, Yong-Seo
    • Journal of IKEEE
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    • v.19 no.2
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    • pp.260-264
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    • 2015
  • In this paper, we propose mode selector for operating a switching system and regulator of linear system to detect the load current. The proposed mode selector can be a mode switching of linear system and switching system, and it has been proposed to compensate for the disadvantages of regulator of switching system with low efficiency in light load conditions. At light load conditions, the mode selector is possible to provide a high efficiency in light load condition by switching the mode to the regulator of linear system. The mode selector was designed to using a Dongbu Hitek $0.18{\mu}m$ CMOS process.

Design and Analysis of Current Mode Low Temperature Polysilicon TFT Inverter/Buffer

  • Lee, Joon-Chang;Jeong, Ju-Young
    • Journal of Information Display
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    • v.6 no.4
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    • pp.11-15
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    • 2005
  • We propose a current mode logic circuit design method for LTPS TFT for enhancing circuit operating speed. Current mode inverter/buffers with passive resistive load had been designed and fabricated. Measurement results indicated that the smaller logic swing of the current mode allowed significantly faster operation than the static CMOS. In order to reduce the chip size, both all pTFT and all nTFT active load current mode inverter/buffer had been designed and analyzed by HSPICE simulation. Even though the active load current mode circuits were inferior to the passive load circuits, it was superior to static CMOS gates.

Investigation on Vibration Control of Squeeze Mode ER Mount Subjected to 200 kg of Static Load (200 kg급 압착모드형 ER 마운트의 진동제어성능 고찰)

  • 정우진;정의봉;홍성룡;최승복
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.11
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    • pp.882-889
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    • 2002
  • This paper presents vibration control performance of a squeeze mode ER mount for high static load. After experimentally investigating the field-dependent damping force under the squeeze mode motion, a squeeze mode ER mount which can support 200 kg of static load is designed and manufactured. Displacement transmissibility of the proposed ER mount is experimentally evaluated in frequency domain with respect to the intensity of the electric field, and a sky-hook control algorithm is designed to attenuate unwanted vibration. Vibration isolation capabilities of the flow mode ER mount and rubber mount are compared to those of the proposed squeeze mode ER mount.

Properties of Multiple Load Flow Solutions and Prevention of Voltage Collapse in System with Induction Motor Load (전압다적해의 특성 및 유도전동기부하를 갖는 계통에 있어서의 전압안정)

  • Park, Jong-Keun
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.34 no.1
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    • pp.19-28
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    • 1985
  • As is well known, the power equations of the N-node system have 2N-1 voltage solutions at most. The vlotage solutions are characterized by the introduction of the mode concept in this paper. There are two mode voltages at one node. One is defined as the (+) mode voltage and the other is defined as the (-) mode one. In this paper, we show that the (-) mode voltage responds to the increase of the power condenser almost adversly to the response of the (+) one. We study how to prevent the voltage collapse in the system with the induction motor load. The critical values of the gain and the time constant in case of the continuous power condenser control, and of the unit power condenser and the closing time delay in case of the discontinuous control for the prevention of the voltage collapse, are calculated. The effect of the composition ratio of the impedance load to the induction moter load on the above critical values are also investigated.

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Wide-Input Range Dual Mode PWM / Linear Buck Converter with High robustness ESD Protection Circuit

  • Song, Bo-Bae;Koo, Yong-Seo
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.2
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    • pp.292-300
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    • 2015
  • This paper proposes a high-efficiency, dual-mode PWM / linear buck converter with a wide-input range. The proposed converter was designed with a mode selector that can change the operation between PWM / linear mode by sensing a load current. The proposed converter operates in a linear mode during a light load and in PWM mode during a heavy load condition in order to ensure high efficiency. In addition, the mode selector uses a bit counter and a transmission gate designed to protect from a malfunction due to noise or a time-delay. Also, in conditions between $-40^{\circ}C$ and $140^{\circ}C$, the converter has variations in temperature of $0.5mV/^{\circ}C$ in the PWM mode and of $0.24mV/^{\circ}C$ in the linear mode. Also, to prevent malfunction and breakdown of the IC due to static electricity, the reliability of IC was improved by embedding a self-produced 8 kV-class(Chip level) ESD protection circuit of a P-substrate Triggered SCR type with high robustness characteristics.

Stable Standby-mode Implementation of Multi-output Power Supply using a New Load Current Estimation Technique with Linear Regulator (다중 출력 전원공급장치의 안정적 대기전력 구현을 위한 새로운 방식의 부하전류 측정기법 구현)

  • Lee, Jong-Hyun;Jung, An-Yeol;Kim, Dong-Joon;Park, Joung-Hu;Jeon, Hee-Jong
    • The Transactions of the Korean Institute of Power Electronics
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    • v.16 no.1
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    • pp.88-95
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    • 2011
  • In this paper, a new standby-mode control method for multiple output switching-mode power-supply is suggested, which uses the control signal of the feedback compensator of the inner loop in the linear voltage regulator located at the transformer secondary side, as the load current information. Conventional method has a problem that standby mode occurs depending only on the load condition of the main controller output, which makes the other secondary side output very inaccurate by burst mode operation. The proposed method detects all the load current information and operates in burst mode only when the all of them are light load condition. Minimum of the additional components are required for the implementation of the proposed method because the load information is obtained from the existing feedback circuit of the post-stage linear regulator. In this paper, the operating principles of the proposed standby-mode circuit are presented with an numerical analysis, and are verified by 25W hardware prototype implementation.