• Title/Summary/Keyword: Low-speed Power Loss

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Analysis of the Power for a Decanter-Type Centrifuge (II) - Total Power and the Power-Transmission Mechanism - (Decanter형 원심분리기의 동력 계산 (II) - 총동력과 동력전달 기구 -)

  • Suh, Yong-Kweon;Han, Geun-Jo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.7
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    • pp.938-947
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    • 2003
  • In this paper, we derived the formula for estimating the power of the electric motors needed to operate the Decanter-type centrifuge. In the derivation of the formula the sludge-removal torque is to be supplied from the formula derived in the first paper. The intricate nature of the transmission mechanism in the planetary gear trains of the sludge-removal power and torque has been clarified in this second paper. In particular we considered two-motor system, where the main motor drives the machine while the differential-speed control motor plays the role of braking in adjusting the differential speed. Sample calculation for the specific design treated in the first paper showed that the selection criterion for the main motor depends on the lower limit of the differential speed; when the lower limit is set low, it should be selected based on the steadily operating power, while it should be selected based on the starting power when the lower limit is set high. The total power required by both the main motor and the differential-speed control motor increases as the differential speed is decreased. It is suggested that the power loss in the differential-speed control motor could be minimized by attaching an electric generator to it.

Prediction of the Occurring Time of Stall for a Booster Fan in a Power Plant Combusting Low Quality Coal through Draft Loss (저품위탄 연소시 탈황용 승압송풍기 실속시점 예측)

  • Kim, Yeong-Gyun;Lee, Jae-Heon
    • Plant Journal
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    • v.8 no.4
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    • pp.34-39
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    • 2012
  • This study presents how low quality coal combustion affects the desulfurizer draft system by correlating of draft loss in a coal-fired thermal power plant and predicts the stall occurrence time of a booster fan. In case of low quality coal, a lot of coal is needed to generate equivalent output power, thereby the rating of increasing draft loss was faster than designed amount of coal. We surely confirmed that draft loss affects the specific energy of a booster fan strongly. On this basis, it is possible to predict the occurring time of stall for a booster fan from current operation specific energy to stall limit specific energy. This study suggests increasing speed of draft loss in each caloric value and the impact of specific energy at a booster fan, it expects to help safe operating in a thermal power plant.

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Electromagnetic Field Analysis of 230 kW-class Low Wind Speed Medium Wind Turbine for Island-area Application (도서지역 적용을 위한 230 kW급 저풍속 중형 풍력발전기의 전자장해석)

  • Choi, Mansoo;Choi, Hyewon;Lee, Changmin;Choi, Hyenjun
    • New & Renewable Energy
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    • v.16 no.2
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    • pp.14-19
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    • 2020
  • Recently, a project to build a carbon zero island with no carbon emissions has been carried out by replacing diesel generators with renewable energy sources in island areas where diesel generators supplied local loads as independent systems. To minimize damage to the lives of islanders, low noise wind generators should be installed by adjusting the rated speed. In islands with low loads, wind turbines that are more efficient than medium-sized wind turbines should be installed. In this study, the generator field analysis and characteristics were analyzed to develop 230 kW-class low wind medium-wind turbine technology. The electromagnetic field analysis program used Maxwell. As a result, the cogging torque was reduced, and the initial maneuver wind speed and loss value were lowered. Hence, the output amount was increased with high efficiency.

Loss Minimization Control for Induction Generators in Wind Power Systems Using Support Vector Regression

  • Abo-Khalil, Ahmed G.;Lee, Dong-Choon
    • Proceedings of the KIEE Conference
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    • 2006.04b
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    • pp.344-346
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    • 2006
  • In this paper, a novel algorithm for increasing the steady state efficiency during light load operation of the induction generator that integrated with a wind power generation system is presented. The proposed algorithm based on the flux level reduction, where the flux level is estimated using Support-Vector -Machines for regression (SVR) for the optimum d-axis current of the generator. SVR is trained off-line to estimate the unknown mapping between the system's inputs and outputs, and then is used online to calculate the optimum d-axis current for minimizing generator loss. The experimental results show that SVR can define the flux-power loss accurately and determine the optimum d-axis current value precisely. The loss minimization process is more effective at low wind speed and the percent of power saving can approach to 40%.

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Nano-scale Inter-lamellar Structure of Metal Powder Composites for High Performance Power Inductor and Motor Applications

  • Kim, Hakkwan;An, Sung Yong
    • Journal of Magnetics
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    • v.20 no.2
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    • pp.138-147
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    • 2015
  • The unique nano-scale inter-lamellar microstructure and unparalleled heat treatment process give our developed metal powder composite its outstanding magnetic property for power inductor & motor applications. Compared to the conventional polycrystalline Fe or amorphous Fe-Cr-Si-B alloys, our unique designed inter-lamellar microstructure strongly decreases the intra-particle eddy current loss at high frequencies by blocking the mutual eddy currents. The combination of optimum permeability, magnetic flux and extremely low core loss makes this powder composite suitable for high frequency applications well above 10 MHz. Moreover, it can be also possible to SMC core for high speed motor applications in order to increase the motor efficiency by decreasing the core loss.

Performance Evaluation of GaN-Based Synchronous Boost Converter under Various Output Voltage, Load Current, and Switching Frequency Operations

  • Han, Di;Sarlioglu, Bulent
    • Journal of Power Electronics
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    • v.15 no.6
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    • pp.1489-1498
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    • 2015
  • Gallium nitride (GaN)-based power switching devices, such as high-electron-mobility transistors (HEMT), provide significant performance improvements in terms of faster switching speed, zero reverse recovery, and lower on-state resistance compared with conventional silicon (Si) metal-oxide-semiconductor field-effect transistors (MOSFET). These benefits of GaN HEMTs further lead to low loss, high switching frequency, and high power density converters. Through simulation and experimentation, this research thoroughly contributes to the understanding of performance characterization including the efficiency, loss distribution, and thermal behavior of a 160-W GaN-based synchronous boost converter under various output voltage, load current, and switching frequency operations, as compared with the state-of-the-art Si technology. Original suggestions on design considerations to optimize the GaN converter performance are also provided.

Application of Foil Gas Bearing to the 38kW, 100000 RPM Class High Speed Motor (38kW, 100000 RPM 고속모터에 대한 포일 가스 베어링 응용 개발)

  • Kim, Kyeong-Su;Park, Ki-Cheol;Kim, Seung-Woo;Lee, In
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.127-131
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    • 2003
  • Foil gas bearing is a noncontact bearing operated by coupled interaction between hydrodynamic pressure of viscous fluid and elastic deformation of foil structure. It has valuable advantages, such as low power loss, long life, oilless environment and low vibration, over conventional bearings for the high speed applications. A high speed BLDC motor adopting the foil bearing has been developed. It is designed to have 38㎾ power at 100,000 RPM for a cryogenic cooler whose operating fluid is neon. In this paper, structural development details especially for the foil gas bearing and rotordynamics are presented.

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Improvement of Processing Speed of the Doppler Filter in a Low Power Radar (저 출력 레이더의 도플러필터의 처리속도 개선)

  • Park, Jeong-Ho;Jeong, Hong
    • Proceedings of the IEEK Conference
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    • 2001.06d
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    • pp.167-170
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    • 2001
  • A low power pulse Doppler radar should integrate a large number of data to provide a required maximum detectable distance. Doppler filter needs a window that has good out-of-bard rejection level to maintain high dynamic range. From these facts, we can apply decimation and presumming to increase the speed of Doppler processing. This Paper investigates the efficiencies of several decimation methods and the loss of presumming. And I propose a method to increase processing speed but to maintain the maximum detectable distance.

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Analytical and Experimental Validation of Parasitic Components Influence in SiC MOSFET Three-Phase Grid-connected Inverter

  • Liu, Yitao;Song, Zhendong;Yin, Shan;Peng, Jianchun;Jiang, Hui
    • Journal of Power Electronics
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    • v.19 no.2
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    • pp.591-601
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    • 2019
  • With the development of renewable energy, grid-connected inverter technology has become an important research area. When compared with traditional silicon IGBT power devices, the silicon carbide (SiC) MOSFET shows obvious advantages in terms of its high-power density, low power loss and high-efficiency power supply system. It is suggested that this technology is highly suitable for three-phase AC motors, renewable energy vehicles, aerospace and military power supplies, etc. This paper focuses on the SiC MOSFET behaviors that concern the parasitic component influence throughout the whole working process, which is based on a three-phase grid-connected inverter. A high-speed model of power switch devices is built and theoretically analyzed. Then the power loss is determined through experimental validation.

A Low-Power ECC Check Bit Generator Implementation in DRAMs

  • Cha, Sang-Uhn;Lee, Yun-Sang;Yoon, Hong-Il
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.6 no.4
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    • pp.252-256
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    • 2006
  • A low-power ECC check bit generator is presented with competent DRAM implementation with minimal speed loss, area overhead and power consumption. The ECC used in the proposed scheme is a variant form of the minimum weight column code. The spatial and temporal correlations of input data are analyzed and the input paths of the check bit generator are ordered for the on-line adaptable power savings up to 24.4% in the benchmarked cases. The chip size overhead is estimated to be under 0.3% for a 80nm 1Gb DRAM implementation.