• Title/Summary/Keyword: Saturation

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Active Cancellation of PMSM Torque Ripple Caused by Magnetic Saturation for EPS Applications

  • Lee, Geun-Ho
    • Journal of Power Electronics
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    • v.10 no.2
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    • pp.176-180
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    • 2010
  • This paper deals with a control method to reduce the torque ripple of a permanent magnet synchronous motor (PMSM) for electric power steering (EPS) systems. Such an application requires a very low torque ripple in order to maintain a good steering feel. However, because of spatial limitations, it cannot help having a partial saturation in the iron core of the PMSM for an EPS system, and this saturation results in a significant torque ripple. Thus, this paper analyzes the torque ripple caused by the magnetic saturation of a PMSM and proposes a method with respect to inductance measurement to verify the partial saturation. In addition, it is shown that a compensation current is needed in order to minimize the torque ripple when a PMSM is driven in the high torque region. The estimation process of the current and the torque ripple decreased by the current are presented and verified with test results.

Equivalent Circuit Analysis of Single Phase Induction Motor Considering Magnetic Saturation Characteristics (자기포화 특성을 고려한 단상유도전동기의 등가회로 해석)

  • Kim, Young Sun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.2
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    • pp.270-277
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    • 2013
  • Single phase induction motor(SPIM) is used widely because it is driven by single phase source. However, the efficiency of the motor is not good due to saturation of magnetic material. To analyze the motor accurately, the magnetic saturation characteristics should be considered in analysis of equivalent circuit. In this paper, lumped parameter of circuit are derived from multi phase induction motor using method of symmetrical coordinates. Also, we presents a method for the equivalent circuit analysis of SPIM using magnetic saturation rate. The magnetic nonlinearity is considered deriving magnetizing reactance from voltage-current saturation curve. As a results, current characteristic, torque, output and efficiency are shown through analysis of equivalent circuit. A simulation results of SPIM will be used to improve the characteristics and efficiency of motor.

Experimental Verification on Stability of Robust Saturation Controller (강인 포화 제어기의 안정성에 관한 실험적 검증)

  • Lim, Chae-Wook;Moon, Seok-Jun;Park, Young-Jin;Park, Youn-Sik
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.223-226
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    • 2005
  • In previous research, we proposed robust saturation controller which involves both actuator's saturation and structured real parameter uncertainties. This controller can analytically prescribed the upper and lower bounds of parameter uncertainties, and guarantee the closed-loop robust stability of the system in the presence of actuator's saturation. And the availability and the effectiveness of the proposed robust saturation controller were verified through numerical simulations. In this paper, we verify the robust stability of this controller through experimental tests. Especially, we show unstable cases of other controllers in comparison with this controller. Experimental tests are carried out in the laboratory using a two-story test structure with a hydraulic-type active mass damper.

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On a Reading Aloud to Relieve the Decrease in Blood Oxygen Saturation when Jogging

  • Tian, Zhixing;Bae, MyungJin
    • International Journal of Advanced Culture Technology
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    • v.8 no.4
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    • pp.95-100
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    • 2020
  • Recently, the problem of hypoxia caused by jogging is attracting attention. To solve this problem, this paper proposed a new solution. This paper proved that as a vocalization method of reading aloud, it is possible to increase air intake and activate lung function to exchange more air and obtain more oxygen. Then, blood oxygen saturation was used as an evaluation index for the body's oxygen content level to prove its effectiveness. A photoelectric pulse oximeter developed on the basis of different light absorption principles in blood was used to test blood oxygen saturation. Experimental results show that a certain degree of hypoxia is induced when a lot of oxygen is required due to jogging. Therefore, it was proved that the new vocal breathing method by reading books can increase the blood oxygen saturation of the body and improve the hypoxia of the body. Reading vocal breathing is a simple and efficient oxygen saturation recovery breathing method.

Determination of Ammonia Nitrogen by Color Saturation Measurement System (채도측정시스템을 이용한 암모니아성 질소의 정량방법)

  • Lee, Hyeong-Choon
    • Journal of Environmental Health Sciences
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    • v.38 no.2
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    • pp.136-141
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    • 2012
  • Objectives: The objective of this study was to investigate whether the ammonia nitrogen concentration of aqueous samples such as drinking water can be determined by measuring the saturation of the samples colored by indophenol method. Methods: A color saturation measurement system was constructed by connecting a notebook computer to an image acquisition device composed of a PC camera and a light source, and was then used to measure the saturation of samples colored by blue indophenol complex. Results: Between two available light sources, a fluorescent lamp was selected due to its demonstrating better linearity between color saturation and ammonia nitrogen concentration. Prediction by quadratic regression was more accurate than by linear regression, and prediction by quadratic regression in the concentration range of 0.1-1.0 $mg/l$ was more accurate than in the concentration range of 0.0-1.0 $mg/l$. Regression-based predictions over 0.25 $mg/l$, 0.55 $mg/l$ and 0.75 $mg/l$ concentrations were implemented both by spectrophotometric method and by measuring color saturation. In the case of 0.25 $mg/l$, the predicted concentration by spectrophotometric method was $0.256{\pm}0.0076\;mg/l$ and the predicted concentration by measuring color saturation was $0.246{\pm}0.0086\;mg/l$ (p=0.051). In the case of 0.55 $mg/l$, they were $0.561{\pm}0.0068\;mg/l$ and $0.564{\pm}0.0166\;mg/l$ (p=0.660). In the case of 0.75 $mg/l$, they were $0.755{\pm}0.0139\;mg/l$ and $0.762{\pm}0.0088\;mg/l$ (p=0.215). Conclusions: There were no statistically significant differences (p>0.05) between the data from the two methods in all three of the concentrations. Therefore, the color saturation measurement method proposed in this paper may be considered applicable for determining the ammonia nitrogen concentration of aqueous samples such as drinking water.

Analysis for Electrical Fire Possibility Using Fuzzy Logic with Input Variables of Overcurrent and Saturation Time in the Indoor Wiring (전기배선에서 과전류와 포화시간을 입력변수로 갖는 퍼지기반 전기화재가능성 분석)

  • Kim, Eun-Jin;Kim, Doo-Hyun;Kim, Sung-Chul
    • Journal of the Korean Society of Safety
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    • v.30 no.6
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    • pp.34-39
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    • 2015
  • The study is aimed to develop fuzzy logic system that has overcurrent and saturation time as input variable and possibility of electrical fire as output variable by making bad conductor area with physical damage to indoor wiring. Most previous studies focused on thermal characteristics depending on the current size and no study considered the current size and saturation time at the same time. Therefore, the paper made into account current value and saturation time together. To this end, it created bad conductor area half the size of IV conductor (1.6 mm) on purpose and transmit electrical current from 10A to 60A by unit of 2A to find out the thermal characteristics and saturation time for current. Based on the data that came out, the study applied fuzzy logic and established the current and saturation time as input variable and chance of fire as output variable. As a result, the center of area of the system that depended only on the existing current value was 75 while the system that applied both current and saturation time presented the chance of fire at 92. It is found that the chance of bad conductor area and deteriorated insulation of electrical wire had current and saturation time as important variables. The data can be used as basic data like deteriorated wire insulation or operation features of circuit breaker in investigating the cause of electrical fire.

Calcium Carbonate Saturation State in the Ulleung Basin, East Sea (동해 울릉분지의 탄산칼슘 포화상태)

  • KIM, SO-YUN;JEONG, SEONGHEE;LEE, TONGSUP
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.24 no.3
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    • pp.389-399
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    • 2019
  • The calcium carbonate saturation state in the Ulleung Basin of East Sea was calculated using bottle data set of pH, dissolved inorganic carbon and total alkalinity obtained from the year 1999, 2014, 2017, and 2018 cruise. In the 2010s calcium carbonate saturation state was significantly lowered at all depth compared to the 1999 reference state. Accordingly calcite saturation horizon and aragonite saturation horizon shoaled to 500 m and 200 m, respectively. A key chemical species for the calcium carbonate saturation state, carbonate ion showed distinctive profile between upper and deep waters: it is moderately high (${\sim}175{\mu}mol\;kg^{-1}$) in upper waters and very low (< ${\sim}50{\mu}mol\;kg^{-1}$) in the deep waters. However the decreasing trend of carbonate ion concentration was pronounced in the upper water than deep waters, suggesting atmospheric $CO_2$ penetration is largely confined to the upper waters in the 2000s.

Color Saturation Improvement using the Maximum Color Difference Table (최대색차신호 표를 이용한 컬러 채도 향상)

  • Kim, Sun-Jung;Hong, Sung-Hoon
    • Journal of Korea Multimedia Society
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    • v.16 no.2
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    • pp.119-130
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    • 2013
  • In this paper, we propose a new color image enhancement method to improve the color saturation as well as luminance contrast in the YCbCr color space. The proposed method uses the maximum color difference table to compensate the perceived saturation changes due to luminance contrast changes. To improve the color saturation, the method first calculates the weighting factor by using the maximum color difference table and then multiplies the weighting factor to the input color difference signals. In this step, it maps color difference signals to proper color region to prevent the color distortion by considering the correlation of color saturations depending on the luminance and hue. The experimental results show that our method effectively improves color saturation compared to the conventional methods.

System-Level Saturation Modeling of Thermal Imager (열상장비의 포화 현상에 대한 시스템 모델링)

  • Han, Seungoh;Park, Seung-Man
    • Journal of the Korea Institute of Military Science and Technology
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    • v.19 no.6
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    • pp.698-702
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    • 2016
  • Thermal imager is now regarded as one of the key observation devices for ISR activities and getting important more and more. As other detectors, however, the thermal detectors also have maximum input and therefore they will be saturated if the input IR energy exceeds the allowed range. The saturation in the thermal detector makes it impossible to distinguish the target from background, as a result, the thermal imager does not perform its own mission anymore. In order to get an insight related with the image saturation, this paper develops a saturation model for a thermal imaging system, not a thermal detector. The proposed modeling starts from analyzing the specification of a thermal imager. Coupled with the characteristic parameters of the object, the saturation model can be used to predict the distance on which the detector is saturated. The proposed saturation model prove its validity by applying it for the case of observing a flash-bang.

Experimental Verification on the Availability of Robust Saturation Controller for the Active Vibration Control of Building using AMD (AMD를 이용한 건물의 능동 진동 제어를 위한 강인 포화 제어기의 유용성에 관한 실험적 검증)

  • Lim, Chae-Wook;Moon, Seok-Jun;Park, Youn-Gjin
    • Journal of the Earthquake Engineering Society of Korea
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    • v.10 no.2 s.48
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    • pp.83-90
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    • 2006
  • In active vibration control of building, controller design considering both control input saturation of controller and parameter uncertainties of building is needed. In our previous research, we proposed a robust saturation controller which guarantees robust stability and control performance of the uncertain linear time-invariant system in the presence of control input saturation. In this paper, the availability of the robust saturation controller for the building with an active mass damper (AMD) system is verified through experimental tests. Experimental tests are carried oui using a two-story building model with a hydraulic-type AMD.