• Journal of Power Electronics
• /
• v.18 no.4
• /
• pp.1099-1110
• /
• 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.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.26 no.5
• /
• pp.364-371
• /
• 2021

A magnetic flux saturation model of Synchronous Reluctance Motors (SynRMs) and a parameter estimation method are proposed at standstill. The proposed magnetic flux model includes the nonlinear relationship between the current and the magnetic flux for self-saturation and cross-saturation. Voltage is injected at standstill to estimate the magnetic flux saturation model. Voltages are injected into the d-axis and q-axis to obtain data on self-saturation. Subsequently, voltages are simultaneously injected into the d-q axis to obtain data on cross-saturation. On the basis of the measured current and the calculated magnetic flux, the parameters of the proposed model are estimated using the least square method (LSM). Simulation and experiment were performed on a 1.5-kW SynRM to verify the proposed method. The proposed model can be used to create a high-efficiency operation table, a sensorless algorithm, and a current controller to improve the control performance of a motor.

• Journal of Magnetics
• /
• v.20 no.3
• /
• pp.284-289
• /
• 2015

This paper discusses general methods of modelling magnetic saturation in steady-state, two-axis (d & q) frame models of dual stator induction generators (DSIG). In particular, the important role of the magnetic coupling between the d-q axes (cross-magnetizing phenomenon) is demonstrated, with and without cross-saturation. For that purpose, two distinct models of DSIGs, with and without cross-saturation, are specified. These two models are verified by an application that is sensitive to the presence of cross-saturation, to prove the validity of these final methods and the equivalence between all developed models. Advantages of some of the models over the existing ones and their applicability are discussed. In addition, an alternative is given to evaluate all saturation factors (static and dynamic) by just calculating the static magnetizing inductance which is simply the magnitude of the ratio of the magnetizing flux to the current. The comparison between the simulation results of the proposed model with experimental results gives a good correspondence, especially at startup.

• Geomechanics and Engineering
• /
• v.25 no.4
• /
• pp.295-302
• /
• 2021

Cross-borehole electrical resistivity tomography (ERT) is an effective groundwater detection tool in geophysical investigations. In this paper, an artificial water injection test was conducted on a small clay sample, where the high-resolution cross-borehole ERT was used to investigate the moisture migration law over time. The moisture migration path can be two-dimensionally imaged based on the relationship between resistivity and saturation. The hydraulic conductivity was estimated, and the magnitude ranged from 10^-11 m/s to 10^-9 m/s according to the comparison between the simulation flow and the saturation distribution inferred from ERT. The results indicate that cross-borehole ERT could help determine the resistivity distribution of small size clay samples. Finally, the cross-borehole ERT technique has been applied to investigate the self-sealing characteristics of clay.

• Journal of Electrical Engineering and Technology
• /
• v.1 no.4
• /
• pp.482-489
• /
• 2006

This paper presents the generalized dynamic modeling of self-excited induction generator (SEIG) using state-space approach. The proposed dynamic model consists of induction generator; self-excitation capacitance and load model are expressed in stationary d-q reference frame with the actual saturation curve of the machine. An artificial neural network model is implemented to estimate the machine magnetizing inductance based on the knowledge of magnetizing current. The dynamic performance of SEIG is investigated under no load, with the load, perturbation of load, short circuit at stator terminals, and variation of prime mover speed, variation of capacitance value by considering the effect of main and cross-flux saturation. During voltage buildup the variation in magnetizing inductance is taken into consideration. The performance of SEIG system under various conditions as mentioned above is simulated using MATLAB/SIMULINK and the simulation results demonstrates the feasibility of the proposed system.

• Current Optics and Photonics
• /
• v.2 no.6
• /
• pp.563-567
• /
• 2018

We propose and experimentally demonstrate a simple tunable photonic microwave band-pass filter with high resolution using a reflective semiconductor optical amplifier (RSOA) and an optical time-delay line. The RSOA is used as a gain medium for generating cross-gain modulation (XGM) effect as well as an optical source. The optical source provides narrow spectral width by self-injection locking the RSOA in conjunction with a partial reflection filter with specific center wavelength. Then, when the RSOA is operated in the saturation region and the modulated recursive signal is injected into the RSOA, the recursive signal is inversely copied to the injection locked optical source due to the XGM effect. Also, the tunability of the passband of the proposed microwave filter is shown by controlling an optical time-delay line in a recursive loop.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.305-305
• /
• 2012

The organic-inorganic hybrid polymer thin films were deposited using the gas phase method which known as molecular layer deposition (MLD). Titaniumchloride (TiCl4) and 1,4-phenylenediamine (PD) were used as monomers to deposit hybrid polymer. Self-terminating nature of TiCl4 and PD reaction were demonstrated by growth rate saturation versus precursors dosing time. Infrared spectroscopic and X-ray photoelectron spectroscopy were employed to determine the chemical composition and state of hybrid polymer thin films. Layer by layer growth was showed by increasing UV-VIS absorption peak of hybrid polymer thin films.

• Journal of Nutrition and Health
• /
• v.35 no.1
• /
• pp.90-101
• /
• 2002

This study was undertaken to investigate the nutrient intake, dietary behavior, perception of body image and iron deficiency of high school adolescent girls. The subjects were 463 high school girls in Inchon. This cross-sectional survey was conducted by questionnaires and data were analysed by SAS program. Nutrient intakes collected from 3 day-retails were analyzed by the Computer Aided Nutritional Analysis Program. The following anthropometric measurements were made on all participants height, weight, body fat (%), skinfold thirkness, subscapular skinfold thickness, mid-upper arm circumference and waist-hip circumference. Blood samples were obtained and analyzed for iron nutritional status. The mean obesity index of rural students were highest among students. However, over 18% of the urban and rural students belonged to the low-weight group. Proportions of skipping meals were most high in urban vocational students and the main reason was lack of time for meal. Most nutrient intakes of the students were below the RDA, in particular calcium, iron, vitamin A and vitamin B$_2$. Most of the students were concerned with body image and weight control. Also they were not satisfied with their body image. The mean fell hemoglobin and transferrin saturation of rural students were lowest among students. The total binding capacity of urban vocational student\ulcorner were Invest among students. Prevalence of iron deficiency was most high in urban general students when judged by Hb, MCV and serum ferritin. In conclusion, this study indicates that nutrient intake in the female high school students was considerably lower than RDA. They should also be notified that severe weight control is very harmful for health. And they had lower self -satisfaction for their body image and undesirable flood habits. Therefore, prefer nutrition education is required to maintain desirable flood habits and improve their iron status in female high school students.

• Proceedings of the KSCN Conference
• /
• 2003.11a
• /
• pp.1048-1048
• /
• 2003

The purpose of this study was to investigate dietary behaviors, body image, hematological index and nutrient intake of female athletes in Incheon. The subjects were 112 female athletes (field and track: n=32, firing: n=27, fencing: n=29, swimming: n=14, badminton: n=10) from middle and high schools in Incheon. This cross-sectional study was conducted by a self-administered questionnaire. Fasting blood samples were obtained and analyzed for hemoglobin (Hb), hematocrit(Hct), ferritin, serum iron, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), unsaturated iron binding capacity (UBC), total iron binding capacity (TIBC) and transferrin saturation (TS). Nutrient intakes collected from 3 day-recalls were analyzed by the Computer Aided Nutritional Analysis Program. Statistical analysis was conducted using SPSS 10.0 program. The results are summarized as follows: Average age of field and track athletes, firing, fencer and swimmer was 14 years and that of badmintoner was 17 years. Most of female athletes had dietary problems such as unbalanced meals, skipping meals, and preference of processed foods. More than 60% of female athletes skipped breakfast. As for perception of body image, most of female athletes perceived themselves fatter compared to normal body image. Especially, field and track athletes were more significantly experienced weight control compared to the other athletes (p<0.05). As for physical burden during exercise, 56.3% of swimmer and 31.3% of field and track athletes answered “very hard”, which showed a significant difference (p<0.001) More than 80% of female athletes had experienced a vertigo during exercise (p<0.01). Also, more than 50% of female athletes except badmintoner had experienced an irregular menstruation (p<0.05). Average serum iron level (p<0.05) and TS (p<0.05) of field and track athletes were significantly lower compared to the other athletes. Serum ferritin of badmintoner, field and track athletes and fencer was significantly lower compared to firing and swimmer (p<0.05). Nutrient intakes of female athletes except vitamin B6, niacin and phosphorus were lower than the Korean RDA. Especially, calcium and iron intakes of female athletes were under the 50% of the Korean RDA. Therefore, proper nutrition education and supplementation are required for female athletes to encourage desirable food habits as well as to improve their nutritional status and exercise performance.

• Korean Journal of Community Nutrition
• /
• v.8 no.6
• /
• pp.951-963
• /
• 2003

The purpose of this study was to investigate the eating behaviors, the self-perception of body images, the hematological indices and the nutrient intake of adolescent female athletes in Incheon. The subjects were 112 female athletes(track and fleld: n=32, target shooting: n=27, fencing n=29, swimming: n=14, badminton: n=10) from middle and high schools in Incheon. This cross-sectional study was conducted by means of a sol(-administered questionnaire. Fasting blood samples were obtained and analyzed for hemoglobin (Hb), hematocrit (Hct), ferritin, serum iron, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration(MCHC), unsaturated iron binding capacity (UIBC), total iron binding capacity (TIBC) and transferrin saturation (TS). Nutrient intakes obtained by means of the 3 day-recall method were analyzed using the Computer Aided Nutritional Analysis Program. Statistical analysis was conducted using the SPSS 10.0 program. Most of the female athletes had dietary problems such as eating unbalanced meals, skipping meals, and preferences for processed foods. More than 60% of the female athletes skipped breakfast. As for perception of their body images, track and field athletes in particular, controlled their weights significantly better than the other athletes (p<0.05). With regard to their physical exertion during exercise, 56.3% of the swimmers and 31.3% of the track and field athletes answered “very hard”, which was a significant difference (p< 0.001). More than 80% of the female athletes experienced vertigo during exercise (p< 0.01). Also more than 50% of the female athletes, with the exception of the badminton players, had experienced irregular menstruation (p<0.05). The average serum iron levels (p<0.05), the serum ferritin levels (p<0.05) and TS (p<0.05) of the track and field athletes was significantly lower as compared to that of the other athletes. The nutrient intakes of the female athletes, with the exception of Vitamin B$_{6}$, niacin and phosphorus were lower than the Korean Recommended Daily Allowances (RDA). In particular, the calcium and iron intakes of the female athletes were under 50% of the Korean RDA. Therefore, proper nutritional education and supplementation are required for female athletes to encourage desirable eating habits, as well as to improve their nutritional status and exercise performances.s.