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36 results on '"Hong, Jin Su"'

3. Single-Sided Compensation Network Design Method for Capacitive Power Transfer System Considering Coupling Variation

Author

Choi, Sunghyuk, Chung, Euihoon, Lim, Gyu Cheol, Hong, Jin-Su, Choe, Gyu-Yeong, and Ha, Jung-Ik

Abstract

In capacitive power transfer systems, coupling variation inevitably occurs due to air gap variation and coupler misalignment. This paper presents a single-sided compensation network design method for capacitive power transfer systems considering coupling variation. The proposed method adopts a single-sided compensation network to reduce the volume and weight of the receiver side circuit. The proposed compensation network, within a preselected narrow operational frequency range, effectively transforms the variable load impedance into a single resistive point, resulting in constant output power and zero-phase angle operation under coupling variation. The proposed method employs the impedance matching network design based on a two-port network analysis. The validity of the proposed design method is confirmed with a simulation and a 1.2 kW small air gap capacitive power transfer system prototype. The experimental prototype system achieved a maximum efficiency of 91.2% under no misalignment and a minimum efficiency of 89.9% under a maximum 40% area displacement in coupling conductor plates, with a near-constant output power and zero-phase angle operation.

Published
2024
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4. Modulation Method of Series-Resonant Dual-Active Half-Bridge Converter for ZVS and Minimum RMS Current

Author

Hong, Jin-Su, Choi, Sunghyuk, and Ha, Jung-Ik

Abstract

This article presents a modulation method for the series-resonant dual-active half-bridge (SR-DAHB) converter. The proposed method employs four control degrees of freedom: primary- and secondary-side duty ratios, voltage phase shift angle, and switching frequency. The proposed modulation method minimizes the rms current of the resonant tank while achieving complete zero-voltage switching of all primary and secondary switches for all operational ranges. Time-domain analysis of the SR-DAHB converter, which takes into account every harmonic, has been performed to obtain control value sets. Accurate steady-state values, such as half-bridge inverter switching current/voltage, output current, and rms current of the resonant tank, are derived in closed-form expressions. The derived expressions are utilized in numerical optimization algorithms to calculate optimal control value sets. Since closed-form equations are used, the computational burden of the numerical solver is relieved. The effectiveness of the proposed modulation method is verified through simulations and experiments on a 9.0 kW, 600 V full-SiC converter prototype. Compared to existing modulation methods, it is advantageous when primary- and secondary-side dc-link voltages have a large voltage difference. Particularly, in 0.25 voltage conversion ratio operation, the proposed modulation method presents an efficiency boost of up to 2% compared to the existing modulation methods.

Published
2024
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12. Effects of different creep feed types on pre-weaning and post-weaning performance and gut development

Author

Heo, Pil Seung, Kim, Dong Hyuk, Jang, Jae Cheol, Hong, Jin Su, and Kim, Yoo Yong

Subjects
0301 basic medicine, lcsh:Animal biochemistry, Biology, Body weight, Article, 03 medical and health sciences, Animal science, Weaning, lcsh:QP501-801, lcsh:SF1-1100, Creep Feed Quality, 0402 animal and dairy science, Nonruminant Nutrition and Feed Processing, 04 agricultural and veterinary sciences, 040201 dairy & animal science, Creep feeding, 030104 developmental biology, Creep, Post weaning, Animal Science and Zoology, Weaning diet, Weaning Pig, Creep Feed, lcsh:Animal culture, Suckling Piglet, Food Science
Abstract

Objective This experiment was carried out to determine the effects of different creep feed types on suckling performance and further adjustments to solid feed after weaning. Methods A total of 24 multiparous sows and their litters were allotted to one of three treatment groups: i) provided highly digestible creep feed (Creep), ii) provided a pig weaning diet (Weaner), and iii) provided sow feed (Sow) as creep feed until weaning. After weaning, a total of 96 piglets were selected for evaluation of post-weaning performance. Results For pre-weaning performance, the Creep treatment led to a significantly higher feed intake from 14 to 28 d (p

Published
2018
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13. Effects of cashew nut testa levels as an alternative to wheat bran in gestating sow diets

Author

Fang, Lin Hu, Hong, Young Gi, Hong, Jin Su, Jeong, Jae Hark, Han, Young Geol, Kwon, In Hyuk, and Kim, Yoo Yong

Subjects
0301 basic medicine, Litter (animal), animal diseases, Birth weight, Gestating Sow, lcsh:Animal biochemistry, Biology, Article, 03 medical and health sciences, Animal science, Lactation, medicine, Weaning, lcsh:QP501-801, lcsh:SF1-1100, Animal fat, Meal, Bran, Reproductive Performance, 0402 animal and dairy science, food and beverages, Nonruminant Nutrition and Feed Processing, 04 agricultural and veterinary sciences, 040201 dairy & animal science, 030104 developmental biology, medicine.anatomical_structure, Wheat Bran, Animal Science and Zoology, Composition (visual arts), lcsh:Animal culture, Lactating Sow, Cashew Nut Testa, Food Science
Abstract

Objective This study was conducted to evaluate the effects of dietary cashew nut testa (CNT) as an alternative feed ingredient to wheat bran on reproductive performance, litter performance, milk composition, and blood profiles of gestating sows. Methods Forth multiparous sows (Yorkshire×Landrace) were fed experimental diets starting at 35 days of pregnancy and an initial average body weight (BW) of 211.53±8.86 kg. Each sow was assigned to a treatment based on BW, backfat thickness (BF) and parity with 10 sows per treatment. Treatments were as follows: i) corn-soybean meal based diet with 6% of wheat bran (C0); ii) basal diet with 2% of CNT and 4% of wheat bran (C2); iii) basal diet with 4% of CNT and 2% of wheat bran (C4); and iv) basal diet with 6% of CNT (C6). Results There were no statistically significant differences in BW and BF of gestating sows throughout the experimental period. However, changes in BF (p = 0.09) and the daily feed intake of sows (p = 0.09) tended to linearly increase during the lactation period. The weaning to estrus interval (WEI) showed a quadratic response to CNT treatment (p = 0.02), and the C2 diet showed the shortest WEI. Litter birth weight (p = 0.04) and piglet birth weight (p = 0.06) were linearly decreased with increase in CNT. Furthermore, there had no significant differences in piglet weight and litter weight in 21 day. Insulin concentration at day 70 of gestation was linearly reduced with increasing CNT level in diets (p = 0.03). Conclusion When 6% CNT replaced wheat bran in gestating sow diets, there were no negative effects on sow performance, but litter birth weight and piglet birth weight were decreased when CNT level increased in gestating sow diets.

Published
2018
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36. Effects of dietary energy and crude protein levels on growth performance, blood profiles, and nutrient digestibility in weaning pigs.

Author

Fang LH, Jin YH, Do SH, Hong JS, Kim BO, Han TH, and Kim YY

Abstract

Objective: This experiment was conducted to investigate the effect of reducing dietary metabolic energy (ME) and crude protein (CP) levels on growth performance, blood profiles, and nutrient digestibility in weaning pigs., Methods: A total of 240 crossbred pigs (Duroc×[Landrace×Yorkshire]) with an average body weight of 8.67±1.13 kg were used for a 6-week feeding trial. Experimental pigs were allotted to a 2×3 factorial arrangement using a randomized complete block design. The first factor was two levels of dietary ME density (low ME level, 13.40 MJ/kg or high ME level, 13.82 MJ/kg) and the second factor was three dietary CP levels based on subdivision of early and late weaning phases (low CP level, 19.7%/16.9%; middle CP level, 21.7%/18.9%; or high CP level, 23.7%/20.9%)., Results: Over the entire experimental period, there were no significant difference in body weight among groups, but a decrease in diet energy level was associated with an increase in average daily feed intake (p = 0.02) and decrease in gain-feed ratio (G:F) ratio (p<0.01). Decreased CP levels in the diet were associated with a linear increase in average daily gain (p< 0.05) and quadratic increase in G:F ratio (p<0.05). In the early weaning period, blood urea nitrogen concentration tended to increase when ME in the diet decreased and decrease when CP level in the diet decreased (p = 0.09, p<0.01, respectively). Total protein concentration tended to increase when CP level was reduced (p = 0.08). In the late weaning period, blood urea nitrogen concentration decreased linearly as CP level decreased (p<0.01). The CP and crude fat digestibility decreased when ME was decreased by 0.42 MJ/kg (p = 0.05, p = 0.01, respectively). The CP digestibility increased linearly as CP level decreased (p = 0.01)., Conclusion: A weaning pig diet containing high ME level (13.82 MJ/kg) and low CP level (19.7%/16.9%) can improve pig growth performance and nutrient digestibility.

Published
2019
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