• Title, Summary, Keyword: Saturation

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Loss Minimization Control of Interior Permanent Magnet Synchronous Motors Considering Self-Saturation and Cross-Saturation

  • Pairo, Hamidreza;Khanzade, Mohammad;Shoulaie, Abbas
    • Journal of Power Electronics
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    • v.18 no.4
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    • pp.1099-1110
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    • 2018
  • In this paper, a loss minimization control method for interior permanent magnet synchronous motors is presented with considering self-saturation and cross saturation. According to variation of the d-axis and q-axis inductances by different values of the d-axis and q-axis components of currents, it is necessary to consider self-saturation and cross saturation in the loss minimization control method. In addition, the iron loss resistance variation due to frequency variation is considered in the condition of loss minimization. Furthermore, the loss minimization control method is compared with maximum torque per ampere (MTPA), unity power factor (UPF) and $i_d=0$ control methods. Experimental results verify the performance and proper dynamic response of the loss minimization control method with considering self-saturation and cross saturation.

Adaptive Saturation Enhancement Algorithm on Normalized YCbCr color space (Normalized YCbCr 색 공간에서의 적응적 채도 향상 방법)

  • 옥현욱;최원희;김창용
    • Proceedings of the IEEK Conference
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    • pp.385-388
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    • 2003
  • In this paper, we propose a new saturation enhancement algorithm which is processed on the new color space, called Normalized YCbCr(NYCbCr). The algorithm consists of two processing unit. One is color space conversion from YCbCr to NYCbCr, and the other is using adaptive saturation mapping function(ASMF). NYCbCr color space is designed to prevent shortcomings such as luminance and hue shift of YCbCr color space and by saturation enhancement. ASMF is effective to enhance saturation properly for each image and to protect low saturation regions of color images from over-saturation. we verified our method using several color images. Experimental results show that the proposed method enhance the saturation with minimizing Luminance and Hue shift.

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Autotuning of A PID Controller Using a Saturation function Having a Memory

  • Oh, Seung-Rohk
    • Journal of IKEEE
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    • v.11 no.4
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    • pp.193-197
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    • 2007
  • We use a saturation function with memory instead of a pure saturation function to generate a limit cycle in order to find one point information of a plant in the frequency domain. The saturation function with memory is useful in the presence of noise and/or a short duration of short duration of external disturbances. We analyze the error caused by the approximation that the saturation function with memory treated as a pure saturation function. We propose a new tuning formula for PID controller which can be applied a saturation function having memory with an arbitrary memory size. We show that the proposed method is more accurate than that of the approximation method via an example.

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Saturation Prediction for Crowdsensing Based Smart Parking System

  • Kim, Mihui;Yun, Junhyeok
    • Journal of Information Processing Systems
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    • v.15 no.6
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    • pp.1335-1349
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    • 2019
  • Crowdsensing technologies can improve the efficiency of smart parking system in comparison with present sensor based smart parking system because of low install price and no restriction caused by sensor installation. A lot of sensing data is necessary to predict parking lot saturation in real-time. However in real world, it is hard to reach the required number of sensing data. In this paper, we model a saturation predication combining a time-based prediction model and a sensing data-based prediction model. The time-based model predicts saturation in aspects of parking lot location and time. The sensing data-based model predicts the degree of saturation of the parking lot with high accuracy based on the degree of saturation predicted from the first model, the saturation information in the sensing data, and the number of parking spaces in the sensing data. We perform prediction model learning with real sensing data gathered from a specific parking lot. We also evaluate the performance of the predictive model and show its efficiency and feasibility.

Comparison of oxygen saturation, heart rate of cerebral palsy and normal child between the pre-ambulation and post-ambulation (뇌성마비아동과 정상아동의 보행전후 산소포화도 및 심박수 비교에 관한 연구)

  • Hwang, Joo-Moon;Lee, Wan-Hee
    • Journal of Korean Physical Therapy Science
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    • v.10 no.1
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    • pp.38-46
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    • 2003
  • Since the current tendencies show us the increasing number of cerebral palsy children and the standard longevity, we need to find out more research about the following various problems. Therefore I have tried to figure out the difference of oxygen saturation and heart rate between before ambulation and after. Objects chosen are 17 C.P children on the process of treatment those who were able to walk and 8 normal children in Ah-San hospital, Gang-Nung. They haven't had either any operation or suffered heart disease and I measured their oxygen saturation and heart rate by using pulse-oximeter and are analyzed by SPSS (10.07 version). Results are the followings; 1. There was no difference of oxygen saturation and heart rate between pre-ambulation and post-ambulation of normal and spastic hemiplegia children. 2. There showed the significant statistic difference of oxygen saturation, heart rate between pre-ambulates and post-ambulation of normal and spastic diplegia(p<.05). 3. There was no difference of oxygen saturation, heart rate in C.P between(p>.05), but shows the significant statistic difference in heart rate(p<.05). As I compared the oxygen saturation and heart rate of spastic and normal children on between pre-ambulation and post-ambulation, theres is significant statistic difference on both items (p<.05). However there was no difference of oxygen saturation among hemiplegia, normal and diplegia children while the pulse rate showed the significant difference(p<.05). According to this clinical research, CP children's oxygen saturation and heart rate had no change between pre and post compared to normal children. But there was difference in diplegia. This is why we need to invest time to study these kinds of research about various analysis and comparison of oxygen saturation and heart rate, and furthermore making use of pulse-oxymetry in physical therapy room for the children involved would be beneficial to calculate in accuracy without any discomfort for the patient as well.

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Correlation between regional tissue perfusion saturation and lactate level during cardiopulmonary bypass

  • Lee, Yoon-sook;Kim, Woon Young;Yoo, Ji Won;Jung, Hyun Don;Min, Too Jae
    • Korean Journal of Anesthesiology
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    • v.71 no.5
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    • pp.361-367
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    • 2018
  • Background: Cardiopulmonary bypass (CPB) can cause systemic hypoperfusion, which remains undetected by routine monitoring of physiological parameters. Noninvasive tissue perfusion monitoring offers a clinical benefit by detecting low systemic perfusion. In this study, we tried to evaluate whether regional tissue perfusion saturation reflects systemic hypoperfusion during CPB. Methods: This retrospective study included 29 patients with American Society of Anesthesiologists physical status II-III, who required cardiac surgery with CPB. We evaluated the correlations of serum lactate and delivery oxygen with organ perfusion values of peripheral tissue oxygen saturation and cerebral oxygen saturation. Data were recorded at different stages of CPB: T1 (pre-CPB), T2 (cooling), T3 (hypothermia), T4 (rewarming), and T5 (post-CPB). Results: Lactate levels were elevated after CPB and up to weaning (P < 0.05). The levels of peripheral and tissue oxygen saturation decreased after the start of CPB (P < 0.05). Lactate levels were negatively correlated with peripheral tissue oxygen saturation levels at T4 (R = -0.384) and T5 (R = -0.370) and positively correlated with cerebral oxygen saturation at T3 (R = 0.445). Additionally, delivery oxygen was positively correlated with peripheral tissue oxygen saturation at T4 (R = 0.466). Conclusions: In this study, we demonstrated that peripheral tissue oxygen saturation can be a reliable tool for monitoring systemic hypoperfusion during CPB period. We also believe that peripheral tissue oxygen saturation is a valuable marker for detecting early stages of hypoperfusion during cardiac surgery.

Stabilization of Saturation Nonlinearity System using Describing Functions (기술함수를 사용한 포화 비선형성 시스템의 안정화)

  • Song, Ja-Youn
    • Proceedings of the KIEE Conference
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    • pp.2043-2045
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    • 2002
  • When the input is small, increase of the input leads to a corresponding increase of output, but when the input reaches a certain level, its further increase does produces little or no increase of the output. When this phenomenon happens, the device is said to be in saturation. Occurence of saturation amounts to reducing the gain of the device as the input signals are increased. An extreme case of saturation is the on-off or relay nonlinearity. On-off nonlinearitics have effects similar to those of saturation nonlinearities. Furthermore they can lead to "chattering" in the physical systems doc to their discontinuous nature. This paper presents stabilization method of saturation nonlinearity system using deadzone describing function etc.. And computer simulation results show that saturation nonlinearity can be eliminated due to deadzone nonlinearity.

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An Algorithm for Detecting CT Saturation (변류기 2차전류의 포화 여부 판단 알고리즘)

  • Gang, Yong-Cheol;Ok, Seung-Hun;Gang, Sang-Hui
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.50 no.6
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    • pp.275-278
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    • 2001
  • This paper presents an algorithm for detecting current transformer (CT) saturation. At the instants of beginning (or end) of saturation, as a magnetizing inductance of the core is changed significantly, the shapes of the secondary current are also changed significantly though secondary currents are continuous the instants. At the instants, the second-order of third-order difference of the secondary current has big values. Thus, the third difference of the current is used to detect the beginning/end of CT saturation in this paper. If the magnitude of third-order difference of the secondary current is larger than a threshold value, the CT begins of ends saturation at the instants. The proposed detection method is unaffected by the amount of residual flux. The results of various tests with residual flux from -80% to +80% indicate satisfactory performance of the method.

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Anti-Windup Controller Design for the Ship with the Rudder Saturation (Rudder 엑츄에이터 포화특성을 고려한 Anti-Windup 제어계의 설계)

  • 김영복;최명수
    • Journal of Ocean Engineering and Technology
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    • v.16 no.4
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    • pp.61-69
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    • 2002
  • In the actual control systems, there exist many kinds of restrictions or nonlinearities. However, due to the nonlinearities in actuators and sensors, the designed controller may not be applicable in some practical situations. One such nonlinearity is amplitude saturation in actuators. Although sometimes it may be ignored, in other cases failure to consider actuator saturation may severely degrade closed-loop system performance and even lead to instability. On the other hand, limiting the controller gain to avoid saturation sacrifices control effort and may lead to loss of performance. Consequently, in some cases, the actuator saturation must be explicitly taken into account to ensure desired performance. However, in this paper, an anti-windup control system design method is introduced to suppress the windup due to the amplitude saturation of the actuator. The proposed control system has very simple design process and guarantees the good control performance. The validity of the proposed control system will be shown by comparing with the results of a reported paper.

Robust Saturation Controller for the Stable LTI System with Structured Real Parameter Uncertainties (구조적 파라미터 불확실성을 갖는 안정한 선형계에 대한 강인 포화 제어기)

  • Lim Chae-Wook;Park Young-Jin;Moon Seok-Jun;Park Youn-Sik
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.6
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    • pp.517-523
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    • 2006
  • This paper is focused on a robust saturation controller for the stable linear time-invariant (LTI) system involving both actuator's saturation and structured real parameter uncertainties. Based on affine quadratic stability and multi-convexity concept, a robust saturation controller is newly proposed and the linear matrix inequality (LMI)-based sufficient existence conditions for this controller are presented. The controller suggested in this paper can analytically prescribe the lower and upper bounds of parameter uncertainties, and guarantee the closed-loop robust stability of the system in the presence of actuator's saturation. Through numerical simulations, it is confirmed that the proposed robust saturation controller is robustly stable with respect to parameter uncertainties over the prescribed range defined by the lower and upper bounds.