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Jo, Gwon-Jae,Choi, Jong-Woo The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.1
Flux estimator (FE) is critical for achieving high-performance sensorless drive of induction motors. A voltage model (VM) is an excellent candidate for a FE since it does not require speed information and has a simple structure. A VM using a closed-loop style has excellent sensorless drive capability over a wide speed range. However, it is limited by the uncertainties such as offset and parameter mismatch. This paper presents an improved a closed-loop style FE. To overcome the problems inherent in the conventional FE, a hybrid strategy for the changeover between control modes is applied. In the setting of the FE's cutoff frequency (CF), the influences of the offset and parameter mismatch are analyzed. The phase distortion and acquisition of the back electromotive force are also analyzed. From this analysis, a vector compensation strategy for the flux linkage is applied. This strategy facilitates the CF setting, which improves the robustness against both the offset and parameter mismatch. Finally, the effectiveness of the proposed FE in a sensorless driven induction motor is verified using simulations and experiments under various conditions.
Jo, Gwon-Jae,Choi, Jong-Woo The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2
In the rotor-flux oriented control used in induction motors, the electrical parameters of the motors should be identified. Among these parameters, the mutual inductance and rotor resistance should be accurately tuned for better operations. However, they are more difficult to identify than the stator resistance and stator transient inductance. The rotor resistance and mutual inductance can change in operations due to flux saturation and heat generation. When detuning of these parameters occurs, the performance of the control is degenerated. In this paper, a novel method for the concurrent identification of the two parameters is proposed based on recursive least square estimation and model reference adaptive control.
Gwon-Jae Jo,Jong-Woo Choi 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2
In the rotor-flux oriented control used in induction motors, the electrical parameters of the motors should be identified. Among these parameters, the mutual inductance and rotor resistance should be accurately tuned for better operations. However, they are more difficult to identify than the stator resistance and stator transient inductance. The rotor resistance and mutual inductance can change in operations due to flux saturation and heat generation. When detuning of these parameters occurs, the performance of the control is degenerated. In this paper, a novel method for the concurrent identification of the two parameters is proposed based on recursive least square estimation and model reference adaptive control.
다중선형회귀분석 기반 건설장비 이산화탄소 배출량 예측모델 개발
권재민 ( Gwon Jae-min ),이재학 ( Lee Jae-hak ),조민도 ( Jo Min-do ),최영준 ( Choi Young-jun ),한승우 ( Han Seung-woo ) 한국건축시공학회 2019 한국건축시공학회 학술발표대회 논문집 Vol.19 No.2
Environmental problems caused by GHG emitted by various industries are emerging around the world, and accordingly, relevant regulations are being applied by countries around the world. Korea is operating a carbon credit system that trades GHG in industry for money, which is expected to be applied to the construction industry. In addition, construction equipment using fossil fuels accounts for the largest portion of CO<sub>2</sub> emissions in the construction industry, and the importance of CO<sub>2</sub> reduction and prediction is increasing. However, there is a lack of data on the directly measured CO<sub>2</sub> emissions of construction equipment and there is no accurate methodology for measuring methods. Therefore, in this study, independent variables were derived based on the CO<sub>2</sub> emission data. In addition, multiple linear regression is performed for each independent variable to derive a predictive model of carbon dioxide emission by work type of construction equipment. It is expected that the construction process plan based on environmental factors in the construction industry can be established in the future.
유도전동기의 폐루프 고피나스 자속 관측기를 이용한 전압 모델 자속 관측기의 구현
조권재(Gwon-Jae Jo),최종우(Jong-Woo Choi) 대한전기학회 2015 대한전기학회 학술대회 논문집 Vol.2015 No.10
Accurate estimation of rotor flux is very important to implement direct vector control of induction motors. In case that error of rotor parameters (such as rotor resistance and mutual inductance) of induction motors exists, voltage model among various flux observers shows superb performance because this observer is robust with respect to error of these parameters. However, it is difficult to realize the voltage model flux observer because of the effect of voltage offset which occurs from PWM inverter and by others. This paper proposes realization of the voltage model flux observer by using the conventional closed-loop Gopinath flux observer and analyzing of characteristic function of that.
Gwon, Kihak,Jo, Eun-Jung,Sahu, Abhishek,Lee, Jae Young,Kim, Min-Gon,Tae, Giyoong Elsevier 2018 Materials science & engineering. C, Materials for Vol.90 No.-
<P><B>Abstract</B></P> <P> <I>In situ</I> hydrogel synthesis based on photopolymerization has been recognized as a promising strategy that can be used for tissue augmentation. In this study, we developed an efficient <I>in situ</I> gelation method to prepare bulk hydrogels <I>via</I> near infrared (NIR)-mediated photopolymerization using acrylated polyethylene glycol and diacrylated Pluronic F127-coated upconversion nanoparticles (UCNPs). In our system, upon 980-nm laser irradiation, UCNPs transmit visible light, which triggers the activation of eosin Y to initiate polymerization. We found that the UCNPs coated with diacrylated Pluronic F127 can enhance the photopolymerization efficiency and thus enable the production of bulk hydrogel with requirement of a lower NIR light power compared to that required with the bare UCNPs. This photopolymerization approach will be beneficial to achieve <I>in situ</I> polymerization <I>in vivo</I> for various biomedical applications such as cell/drug delivery and construction of tissue augments.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We developed an efficient bulk-sized <I>in situ</I> gelation method via NIR-mediated photopolymerization using UCNPs. </LI> <LI> UCNPs convert NIR irradiation into visible light to activate the initiator. </LI> <LI> Diacrylated Pluronic F127-coated UCNPs can enhance photopolymerization efficiency. </LI> <LI> This NIR-mediated <I>in situ</I>-forming hydrogels have the potential for biomedical applications. </LI> </UL> </P>
Young Gwon Kim,Prashant Shinde,Jae Yong Choi,Myung Sang Kwon,Byung Jo Chae 강원대학교 동물생명과학연구소(구 강원대학교 동물자원공동연구소) 2007 동물자원연구 Vol.18 No.-
In this study 300 weaned pigs (Landrace × Yorkshire × Duroc, 23±3 d of age, 5.56± 1.21 kg initial body weight) were used to study the effect of fungal (Aspergillus oryzae, FSP-A) and fungal + bacteria (Aspergillus oryzae + Bacillus subtilis, FSP-B) fermented soya proteins on their blood hematology, enzymes and immune cell populations. Pigs were allotted to 5 treatments, each comprising of 4 pens with 15 pigs. Basal diets consisted of 15% soyabean meal (Control diet) while for treatment diets SBM was replaced with 3 and 6% of each FSP-A and FSP-B, respectively. The experimental diets were fed from 0 to 14 day after weaning and then a common commercial diet was fed from 15 to 35 day. Blood was collected on 14 and 35 day of experiment and analyzed for hematology, aspartate transaminase (AST), alanine transaminase (ALT) and immune cell populations. At d 14, lower RBC count, Hb and HCT values and higher AST values were noted in pigs fed FSP-A diets when compared with Control and FSP-B fed pigs.Also at d 14 pigs fed 6% FSP-A had lower NE (P<0.05) when compared with those fed 6% FSP-B. The level of FSP influenced the RDW on d 14 and MCHC, MO and MPV on d 35. In addition on d 35, pigs fed 3% FSP-A had lesser NE than those fed 6% FSP -A and Control diet, while pigs fed 6% FSP-B had the highest number of MO compared to other treatments. But there were no differences in the plasma AST and ALT values on d 35. Thus it may be concluded that the FSP either by fungal or fungal + bacterial sources had an influence on the blood hematological status and the populations of immune cells.
서승조,조태호,백남권,김성규,박강은,정인재 晋州敎育大學校 科學敎育硏究所 2001 科學敎育硏究 Vol.27 No.-
This research compared and analyzed the content ratio of the STS (Science-Technology-Society) Education and subjects and types of learning activities to determine the characteristics of STS education in science classes of elementary schools. In the 5th curriculum, the STS-related content on energy section took up 6.6% , in the 6th curriculum, compared with that of the 5th, the STS content ratio on the energy section increased 7.9% and the STS content on the energy section in the 7th curriculum showed an increased 20.8% proportion. Comparing the main subjects of the STS in the energy section for the science class according to curriculum in the 5th, they obviously have influenced technological development, energy, the development of space studies, and sociology of science, in that order. In the 6th curriculum. compared with that of the 5th, the energy section decreased and the sociology of science increased much. There were no significant changes in other subjects. In the 7th, the STS elements were distributed evenly but the extent of the STS main subjects reduced compared to that of the 6th. The STS education activities represented in science textbooks of elementary schools were mainly executed through discussion, research activities, and actual activities. Other activities such as role-playing, simulation tests, problem solving and decision making, data analysis, research design, case studies, etc. were hardly made.
Young Gwon Kim,Prashant Shinde,Jae Yong Choi,Myung Sang Kwon,Byung Jo Chae 강원대학교 동물생명과학연구소(구 강원대학교 동물자원공동연구소) 2007 동물자원연구 Vol.18 No.-
A total of 240 weaned pigs (Landrace ×Yorkshire × Duroc, 22±3 d of age, 5.16±0.90 kg initial body weight) were used to study the effect of feeding level of microbial fermented soya protein on their blood hematology, enzymes and immune cell populations. The microbial (Aspergillus oryzae + Bacillus subtilis) fermented soya protein (FSP) was used. Pigs were allotted to four dietary treatments, each comprising of 4 pens with 15 pigs. Basal diets consisted of 15% soya bean meal (Control diet); while for treatment diets SBM was replaced with 3, 6 and 9% FSP. The experimental diets were fed from 0 to 14 day after weaning and then a common commercial diet was fed from 15 to 35 day. Blood was collected on 14 and 35 day of experiment and analyzed for hematology, plasma aspartate transaminase (AST), plasma alanine transaminase (ALT) and immune cell populations. Increasing the level of FSP in the diet of pigs linearly decreased distribution of red blood cells (P<0.01), MPV (P<0.05), MO (P<0.05), EO (P<0.05) and BA (P<0.05) on d 14. Linear and quadratic decrease in the RBC (P<0.05), Hb (P<0.05), HCT (P<0.01), PLT (P<0.001) and EO (P<0.05) and linear increase in the MCHC (P<0.001), MPV (P<0.05), WBC (P<0.05) and NE (P<0.05) on d 35 was noted. Pigs fed with 6% FSP had lower (P<0.05) levels of AST and ALT on d 14, while the levels of ALT and AST on d 35 did not differ among the dietary treatments. Thus the results suggest that microbial fermented soya protein affected the hematological indices, immune cell populations and plasma enzymes in weaned pigs.