• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권2호
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• pp.116-122
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• 2000

In the high speed range for salient type synchronous reluctance motor, the effect of iron loss can not be negligible. We have investigated the voltage equations including iron loss from the model that is added the equivalent iron loss in the equivalent inductance in series. In this paper, we derive Ld linear approximate equation from saturation range of Ld, Lq vs applied voltage characteristics and obtain equations including saturation and iron loss related to maximum torque control using Ld. The effect of saturation and iron loss is investigated under maximum torque control. And we show that the proposed maximum torque control scheme achieves the desired performances through experimental results.

• 한국전기전자재료학회논문지
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• 제22권12호
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• pp.1073-1077
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• 2009

The iron core, which comprises the superconducting fault current limiter (SFCL) using magnetic coupling of coils, can be operated in the saturation region, especially at the initial fault period. This operation of the iron core in the saturation region deteriorates the fault current limiting operation of the SFCL. To solve the saturation problem of the SFCL using magnetic coupling of coils, the iron core with two magnetic paths, which has an air-gap in one of them, was adopted. In this paper, the hysteresis characteristics of SFCL using magnetic coupling of coils, which were wound in the iron core with two magnetic paths, were analyzed. Through comparative analysis on the hysteresis characteristics of the iron core comprising SFCL, the hysteresis characteristics of the iron core with two magnetic paths were confirmed to be kept in the non-saturation region during the fault period and thus, the effective fault current limiting operation of the SFCL using the magnetic coupling of coils could be performed.

• Journal of Magnetics
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• 제17권4호
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• pp.280-284
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• 2012

This paper presents a method for evaluating interior permanent magnet synchronous motor (IPMSM) performance over the entire operation region. Using a d-q axis equivalent circuit model consisting of motor parameters such as the permanent magnetic flux, copper resistance, core loss resistance, and d-q axis inductance, a conventional mathematical model of an IPMSM has been developed. It is well understood that in IPMSMs, magnetic operating conditions cause cross saturation and that the iron loss resistance - upon which core losses depend - changes according to the motor speed; for the sake of convenience, however, d-q axis machine models usually neglect the influence of magnetic cross saturation and assume that the iron loss resistance is constant. This paper proposes an analysis method based on considering a magnetic cross saturation and estimating a core loss resistance that changes with the operating conditions and speed. The proposed method is then verified by means of a comparison between the computed and the experimental results.

• 한국전기전자재료학회논문지
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• 제20권11호
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• pp.995-999
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• 2007

We investigated the characteristics of a flux-lock type superconducting fault current limiter(SFCL) considering magnetization characteristic of iron core. The flux-lock type SFCL, like other types of SFCLs using the iron core, undergoes the saturation of the iron core during the initial fault time. Therefore, if the design to prevent the saturation of the iron core is considered, the effective fault current limiting operation can be achieved. Through the analysis for its equivalent circuit including the magnetization characteristic of the iron core, the limiting impedance of the flux-lock type SFCL was drawn. The magnetization currents and the limited currents of SFCL, which were dependent on the winding direction and the turns' ratio between two coils, were investigated from the short circuit experiment. It was confirmed that their experimental results agreed with the analysis ones.

• Journal of Electrical Engineering and Technology
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• 제2권2호
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• pp.241-248
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• 2007

The accuracy of all the schemes that belong to vector controlled induction machine drives is strongly affected by parameter variations. The aim of this paper is to examine iron losses and magnetic saturation effect in sensorless vector control of induction machines. At first, an approach to induction machine modelling and vector control scheme, which account for both iron loss and saturation, is presented. Then, a model reference adaptive system (MRAS) based speed estimator is developed. The speed estimation is modified in such a way that iron losses and the variation in the saturation level are compensated. Thus by substituting an artificial neural network flux estimator into the MRAS speed estimator. Experimental results are presented to verify the effectiveness of the proposed approach.

• Journal of Nutrition and Health
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• 제3권3호
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• pp.141-147
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• 1970

Nutritional anemias are an important nutritional problem affecting large population groups in most developing countries. Many reports on investigations of nutritional anemias have been published and there is good evidence that prevalence of iron deficiency anemias in vulnerable groups is high in many areas of the world. However, there is a general lack of accurate data on its prevalence throughout the world. Methods used to measure different factors have been variable and often of poor quality. Furthermore recent comparison of values obtained in different laboratories have shown a much greater discrepancy in iron binding capacity measurements as compared with serum iron determinations. Since the major cause of these differences appears related to the technique employed, the efforts of the central laboratory will be directed initially to standardization of methodology. My laboratory has been joined interlaboratory comparison of WHO studies of iron standardization. The determination of serum iron, iron-binding capacity and transferrin saturation was done on healthy adults, 79 males and 20 females, who visited hospital for health certificate from January to July 1970. The serum iron was determined by the method of modification of Bothwell and Mallett and total iron blinding capacity by Ramsay method and Bothwell and Mallett method. The results of this study are as follows; 1) The serum iron concentration of seventy nine adult male by the method presented is $131.5{\pm}37.3{\mu}g/100ml\;(range\;52.5{\sim}225.0{\mu}g/100ml)$ and of twenty female adult is $108.5{\pm}40.2{\mu}g/100ml\;(range\;45.0{\sim}202.5{\mu}g/100ml)$. 2) The adult male level of serum iron-binding capacity is $330.9{\pm}48.9{\mu}g/100ml\;and\;adult\;female\;is\;291.2{\pm}55.2{\mu}g/100ml$. 3) The transferring saturation of healthy male is $35.6{\pm}12.8%\;(range\;15.1{\sim}18.0%)\;and\;of\;female\;as\;25.4{\pm}12.4%\;(range\;10.1{\sim}60.0)$.

• 전기학회논문지
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• 제56권1호
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• pp.66-70
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• 2007

For the design to prevent the saturation of the iron core and the effective fault current limitation, the analysis for the operation of the flux-lock type superconducting fault current limiter (SFCL) with consideration for the hysteresis characteristics of the iron core is required. In this paper, the hysteresis characteristics of the flux-lock reactor, which is an essential component of the flux-lock type SFCL, were investigated. Under normal condition, the hysteresis loss of the iron core in the flux-lock type SFCL does not happen due to its winding structure. From the equivalent circuit for the flux-lock type SFCL and the fault current limiting experiments, the hysteresis curves could be drawn. From the analysis for both the hysteresis curves and the fault current limiting characteristics due to the number of turns for the 1st and 2nd windings, the increase of the number of turns in the 2nd winding of the flux-lock type SFCL had a role to prevent the iron core from saturation.

• Journal of Nutrition and Health
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• 제40권4호
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• pp.362-370
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• 2007

The study was designed to assess the effect of iron and cereal supplementation on children's iron nutritional status in social welfare institutions. Dietary survey was carried out methods of food weighing and record by interview (n=74). A nutritional intervention study was carried out through supplementing iron supplements and cereal for 4 weeks in 4-12 years old children. Children received daily 40 mg elemental Fe as iron protein succinylate (n=23) and 3.6 mg elemental Fe as 100 g cereal (n=24), respectively. Blood samples were drawn before and after supplementation. Nutrients which children's intake was less than two-thirds of the RDA were vitamin A, vitamin B-1, vitamin B-2, calcium and iron. The mean daily intake of iron was 5.1 mg for male and 4.9 mg for female, and 52.3% for male and 45.4% for female of Korean RDA. The proportion of children with iron depletion assessed by TIBC (> 360 ${\mu}g$/dl) and serum ferritin (< 20 ng/ml) were 56.6% and 58.7%, respectively. The proportion of children with the iron deficient erythropoiesis assessed by serum iron (< 70 ${\mu}g$/dl), Hb (< 12 g/dl), Hct (< 36%) were 76.0%, 58.7%, 64.0%, respectively. After iron supplements treatment, Hb (p<0.001), Hct(p<0.001), serum iron (p<0.001), transferrin saturation (p<0.001) and serum ferritin (p<0.Ol) increase significantly and only TIBC decreased slightly. After cereal supplementation, in anemic children, Hct (p<0.001), serum iron (p<0.001) and transferrin saturation (p<0.001) were significantly increased. The effect of iron supplements and cereal supplementation in children with iron deficient erythropoiesis were more effective to improve the iron nutritional status than children with iron depletion. It was concluded that cereal supplementation program in anemic children was also effective to improve iron nutritional status.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.55-57
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• 1998

A finite element analysis for a synchronous reluctance motor (SynRM) is presented with emphasis on the effect of saturation and iron losses. Preisachs model, which allows accurate prediction of iron losses, is adopted in this procedure to provide a nonlinear solution. This technique provide significant properties of proposed SynRM under the magnetic saturation and iron losses effect.

• Fisheries and Aquatic Sciences
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• 제7권1호
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• pp.23-28
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• 2004

Olive flounder (Paralichthys olivaceus) was exposed to waterborne iron (0.1, 0.5, 1, 5 and 10 mg/L) for 50 days. The effects of iron on blood iron status and iron binding capacity were studied. The serum iron concentration was significantly higher than in the group exposed to iron (1, 5 and 10 mg/L) in comparison to the control after 30 days of exposure to iron. A significant decrease in unsaturated iron binding capacity was found between the control and the group exposed to iron (5 and 10 mg/L, respectively) at 40 and 50 days, respectively. The total iron binding capacity of serum in the fish exposed to iron concentrations (5 and 10 mg/L) showed a significant decrease compared to that of the control at 40 days after iron exposure. Serum iron saturation values increased in the flounder exposed to iron concentration (5 and 10 mg/L) at 50 days. Our data suggest that sub-lethal exposure of waterborne iron alters the blood iron concentration and iron binding capacity, and these parameters seems to be valuable factors for screening and diagnosis of iron overload syndromes in fish.