Estimatıon of Induction Motor Equivalent Circuit Parameters for Vector Controlled Drives From Manufacturer Datasheet

Son yıllarda meydana gelen endüstriyel gelişmeler gerek endüstriyel gerekse ev tipi uygulamalarda kullanılan asenkron motorların geniş bir hız aralığında kontrol edilebilmesini zorunlu kılmıştır. Vektör kontrolü algoritmaları sayesinde hız ve moment kontrolünün geniş aralıkta yüksek başarımlı bir şekilde yapılabilmesi için asenkron motorun eşdeğer devre parametrelerinin yüksek doğrulukla bilinmesi gerekir. Bu çalışmada sadece üreticilerin veri föylerinde paylaşmış olduğu kısıtlı bilgiler ile asenkron motorun eşdeğer devre parametrelerinin tahmini gerçekleştirilmiştir. Tahmin yöntemi asenkron motorun eşdeğer devresinden türetilen doğrusal olmayan denklemlerin Newton-Raphson yöntemi ile çözülmesi ilkesine dayanmaktadır. Önerilen denklem sistemi ve çözüm algoritması 20 farklı asenkron motor için test edilmiş ve deneysel olarak elde edilen eşdeğer devre parametreleri ile karşılaştırmalı olarak sunulmuştur. Dahası seçilen 4 farklı motor için deneysel olarak elde edilen hız-moment karakteristiği ve kestirilen parametreler ile hesaplanan hız-moment karakteristiği verilerek önerilen algoritmanın başarımı irdelenmiştir.In recent years, industrial developments have made it necessary to control induction motors used in both industrial and household applications in a widespeed range. Thanks to vector control algorithms, in order to control the torque in a wide speed range operations with high performance, the equivalent circuit parameters of induction motor have to be known precisely. In this study, the estimation of the equivalent circuit parameters of the induction motor is implemented only with the limited information shared by the manufacturer’s datasheets. The estimation method is based on the principle of solving nonlinear equations derived from the equivalent circuit of an induction motor by NewtonRaphson method. The proposed equation set and solution algorithm have been tested for 20 different induction motors and presented in comparison with the experimentally obtained equivalent circuit parameters. Moreover, the speed-torque characteristics obtained experimentally and calculated from estimated equivalent circuit parameters for 4 different selected motors are compared and the performance of the proposed algorithm is examined

Dijagnostička točnost sastojaka mlijeka kod dijagnostike gravidnosti u krava srednje i kasne laktacije

The aims of this study were to establish a cut-off point by evaluating the usability of the somatic cell count (SCC) and milk components (fat, fat-free dry matter (FFDM), protein, lactose, freezing point, electrical conductivity and pH) to observe the pregnancy status, and to determine the practical usage of these parameters as diagnostic biomarker of pregnancy status. In the present study, primiparous Holstein cows (n=133) were included in the mid and late lactation. Milk samples were collected in sterile tubes for SCC and milk components analysis. In each lactation period, SCC, milk yield and milk component parameters were analysed by Student\u27s t test according to pregnancy status. Receiver operating characteristic curves were used to determine the predictive threshold using SCC and milk component parameters to discriminate between pregnant and non-pregnant cows. SCC levels were similar for all cows in the mid and late-lactation. In the mid lactation, FFDM, protein, lactose and electrical conductivity were higher and milk yield, fat, freezing point and pH were lower in pregnant cows (p<0.05). In the late lactation, FFDM, protein, lactose and electrical conductivity were significantly higher and milk yield, fat and pH were significantly lower in pregnant cows (p<0.05). Furthermore, fat, FFDM, protein, lactose, freezing point, electrical conductivity, and pH were the best predictors for pregnancy diagnosis in mid-lactating cows with the AUC values of 0.840, 0.768, 0.780, 0.772, 0.693, 0.792, and 0.901 respectively. Furthermore, fat, FFDM, protein, lactose, electrical conductivity, and pH could be useful diagnostic tools for pregnancy determination in late lactating cows with the AUC values of 0.869, 0.684, 0.661, 0.689, 0.756, and 0.841 respectively. In conclusion, the milk components could be used as rapid, easily accessible, and inexpensive markers for the evaluation of the diagnosis of pregnancy status in primiparous Holstein cows.Ciljevi ove studije bili su utvrditi granične vrijednosti procjenom mogućnosti upotrebe broja somatskih stanica (SCC) i pojedinih fizikalno-kemijskih parametara mlijeka (udio masti, bezmasne suhe tvari (FFDM), proteina, laktoze, točke zamrzavanja, električne vodljivosti i pH) za promatranje statusa gravidnosti kao i u svrhu korištenja navedenih parametara kao bioloških markera u dijagnozi statusa gravidnosti. U ovu su studiju bile uključene prvotelke holstein pasmine (n=133) u srednjoj i kasnoj laktaciji. Uzorci mlijeka sakupljani su u sterilne epruvete za analizu SCC i fizikalno-kemijskih parametara. U svakom razdoblju laktacije, SCC, prinos mlijeka i fizikalno-kemijski parametri analizirani su Student t-testom u odnosu na status gravidnosti. Za određivanje prediktivnog praga korištene su krivulje odnosa specifičnosti i osjetljivosti klasifikatora (ROC), korištenjem SCC i fizikalno-kemijskih parametara mlijeka za razlikovanje gravidnih i negravidnih krava. Za sve krave u srednjoj i kasnoj laktaciji razine SCC bile su slične. Sredinom laktacije, FFDM, udjeli proteina i laktoze te električna vodljivost bili su viši, a prinos mlijeka, udio masti, točka ledišta i pH bili su niži u gravidnih krava (p<0,05). U kasnoj laktaciji, FFDM, udjeli proteina i laktoze te električna vodljivost bili su značajno viši, a prinos mlijeka, udio masti i pH bili su značajno niži u gravidnih krava (p<0,05). Udjeli masti, proteina i laktoze, FFDM, točka ledišta, električna vodljivost i pH bili su najbolji prediktori za dijagnozu gravidnosti kod krava u srednjoj laktaciji s vrijednostima površina ispod ROC krivulje (AUC) 0,840, 0,768, 0,780, 0,772, 0,693, 0,792 i 0,901. Udjeli masti, proteina i laktoze, FFDM, električna vodljivost i pH mogu biti korisni dijagnostički alati za određivanje gravidnosti kod krava u kasnoj laktaciji s AUC vrijednostima 0,869, 0,684, 0,661, 0,689, 0,756 i 0,841. Zaključno, komponente mlijeka mogu se koristiti kao brzi, lako dostupni i jeftini markeri za procjenu dijagnoze statusa gravidnosti kod prvotelki holstein krava

Estimation of Induction Motor Equivalent Circuit Parameters from Manufacturer’s Datasheet by Particle Swarm Optimization Algorithm for Variable Frequency Drives

In recent years, industrial developments have made it necessary to control induction motors, used in both industrial and household applications, over a wide range of speeds. Thanks to vector-control algorithms, in order to control the torque in high-performance operations over wide-ranging speeds, the equivalent circuit parameters of the induction motor have to be known precisely. In this study, the equivalent circuit parameters of the induction motor are estimated only with the limited information shared by the manufacturer’s datasheets. The estimation method is based on the principle of solving nonlinear equations derived from the equivalent circuit of an induction motor by the particle swarm optimization algorithm. The proposed equation set and the algorithmic solution have been tested for 20 different induction motors and presented in comparison with the experimentally obtained equivalent circuit parameters. Moreover, the speed–torque characteristics obtained experimentally and calculated from the estimated equivalent circuit parameters for ten different selected motors are compared and the performance of the proposed algorithm is examined

Sensorless Scalar Speed Control of Induction Motor Wıth Flux and Slip Frequency Estimation

Bu çalışma, asenkron motorun hız kontrolü için algılayıcısız bir skaler denetim algoritması ortaya koymaktadır. İlk olarak, motor gerilimleri ve akımları ölçülerek stator akısı tahmin edilmiş ardından asenkron motorun matematiksel modeline göre kayma frekansı hesaplanmış ve uygulanması gereken gerilim değeri kayma frekansının değerine göre yeniden hesaplanmıştır. Stator direncinin üzerindeki düşen gerilimi kompanze etmek için otomatik gerilim yükseltme kontrolörü tasarlanmıştır. Kontrolör parametreleri doğadan ilham alan optimizasyon algoritmalarından olan genetik algoritma ile hesaplanmıştır. Son olarak, önerilen kontrol algoritmasının başarımını irdelemek için, 18 kW'lık bir asenkron motorda geniş bir hız aralığında benzetim sonuçları verilmiştir.This study presents a sensorless scalar control algorithm for speed control of induction motor. Firstly, the stator flux was estimated by measuring the motor voltages and currents, then the slip frequency was calculated according to the mathematical model of the induction motor and the voltage value to be applied was recalculated according to the value of the slip frequency. An auto-voltage boost controller is designed to compensate for the dropping voltage on the stator resistor. Controller parameters were calculated with a genetic algorithm, which is one of the nature-inspired optimization algorithms. Finally, simulation results over a wide speed range are given for an 18 kW induction motor to examine the performance of the proposed control algorithm

Ultrasound in labor admission to predict need for emergency cesarean section: a prospective, blinded cohort study

Objective: To assess whether assessment with ultrasound could improve the detection of emergency cesarean section (ECS) in laboring women. Methods: Women who presented with symptoms of active labor or women in need of labor induction were invited to participate in the study. Women included in the study were evaluated with ultrasonography for fetal biometry and vaginal examinations for Bishop score assessment. The main aim in this study was determining factors associated with ECS due to fetal distress and obstructed labor. Results: No fetal biometry variable was associated with ECS due to any indication (fetal distress and obstructed labor combined) in the univariate analysis. In multivariate analyses, biometry variables were adjusted for Bishop score at admission and only abdominal circumference percentile showed a significant association with the odds of ECS due to any indication (OR:1.02, 95% CI: 1.01-1.03). Biparietal diameter and abdominal circumference variables were associated with the odds of ECS due to obstructed labor in both univariate and multivariate analyses (p < .05 for all). However, the predictive accuracy of biparietal diameter percentile (area under the curve (AUC): 0.55, 95% CI: 0.46-0.63) and abdominal circumference percentile (AUC: 0.56, 95% CI: 0.48-0.64) without adjunct variables were poor. Moreover, the addition of fetal biometry parameters to Bishop score did not improve the predictive accuracy of Bishop score. Conclusion: Ultrasound assessment at admission, in addition to Bishop score assessment, did not significantly improve the prediction of ECS. Also, the fetal biometry alone had poor predictive capability for ECS. Routine ultrasound assessment at labor admission appears to be ineffective for predicting ECS. Precis Fetal biparietal diameter and abdominal circumference showed an association with emergency cesarean due to obstructed labor but the predictive accuracy of fetal biometry was low. Routine ultrasound examination at admission, in addition to Bishop score assessment, may not useful for assessing the risk of emergency section in unselected populations

Novel intraoperative strategies significantly reduce transfusion requirements in liver transplantation

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Two Different Bifurcation Lesion Techniques In The Same Patient After Acute Coronary Syndrome.

13th International Congress of Update in Cardiology and Cardiovascular Surgery (UCCVS) -- MAR 23-26, 2017 -- Cesme, TURKEYWOS: 000407309200080

Depression, anxiety, sleep problems and suicidal behavior among medical students: A cross-sectional comparison study between first and sixth year students

Y Objective: The aim of our study is to determine the frequeny of depression/anxiety, suicidal behaviour and sleep problems in the first and sixth year medical students and to compare the both groups in terms of specified parametres and evaluate the possible change during the course. Method: This cross-sectional study included 205 first year and 81 sixth year medical students between January 2020 and March 2020 at a faculty of medicine. Data were collected using self-report questionnaire consist of sociodemographic data form, Hospital Anxiety Depression Scale and Pittsburg Sleep Quality Index. Results: While there was no significant difference in anxiety scores, depression scores of sixth year students were significantly higher. Among all students, the percentage of higher cut off depression and anxiety scores were 40% and 36%, respectively. Suicidal ideation and suicide plan were significantly higher in students with high depression score. Use of sleep medication and daytime dysfunction scores were higher in the sixth year. During the last year among all students, 3.5% (n = 10) had self-harm behavior, 9.2% (n = 26) had serious suicidal thoughts, 9.5% (n=27) had suicide plans and 1.1% (n = 3) of students had suicide attempt. There were no significant differences between the groups in terms of self-harm behavior, suicidal ideation, suicide plan and suicide attempt. Discussion: Our findings suggest that medical school students is at risk for mood disorders, suicide and sleep problems. This risk, which is higher than the general population, appears to increase in the later years of education

Efficacy of carbetocin in the prevention of postpartum hemorrhage: a systematic review and Bayesian meta-analysis of randomized trials

Objectives: To evaluate the efficacy of carbetocin for the prevention of postpartum hemorrhage (PPH) and related events after vaginal or cesarean delivery. Methods: Medline, Scopus, Embase, and the Cochrane Library were searched in February 2018 using combinations of the relevant MeSH terms, keywords. Randomized studies, comparing carbetocin to any other uterotonic agent, in the management of cesarean and vaginal deliveries, were conducted. Two reviewers independently extracted the data. A random-effects meta-analysis was used for quantitative synthesis. Also, Bayesian random-effect metaregression was used to estimate the posterior probabilities (PP) for benefits of carbetocin use. Results: After the full-text review, 30 trials were included in the meta-analysis. Compared to oxytocin, carbetocin was associated with a reduced need for additional uterotonic use in women undergoing cesarean delivery (RR 0.43, 95% CI 0.30-0.59, I-2 = 71%, 3216 women, PP > 99.9%). Women at high risk of PPH delivering vaginally also had a reduced need for additional uterotonic use with carbetocin compared to oxytocin (RR 0.56, 95% CI 0.34-0.94, I-2 = 38%, 789 women, PP = 81.2%). The risk of postpartum blood transfusion (RR 0.57, 95% CI 0.33-0.96, I-2 = 0%, 1991 women, PP = 97.9%) was also less with carbetocin compared to oxytocin in high-risk women undergoing cesarean delivery. The risk of PPH was similar between carbetocin and other uterotonic agents for both cesarean (RR 0.69, 95% CI 0.45-1.05, I-2 = 27%, 2926 women, PP = 96.3%) and vaginal deliveries (RR 0.61, 95% CI 0.32-1.14, I-2 = 35%, 1515 women, PP = 88.9%). Conclusions: Carbetocin is effective in reducing the need for additional uterotonic use and postpartum blood transfusion in women at increased risk of PPH undergoing cesarean delivery. There is still a need for high-quality trials on its effectiveness in preventing PPH in high-risk women. Precis Carbetocin is effective in reducing the need for additional uterotonic use and postpartum blood transfusion in high-risk women undergoing Cesarean delivery