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Driving Characteristic of Passive Converter for Single Phase SRM
Jianing Liang,석승훈(Seung-Hun Seok),이동희(Dong-Hee Lee),안진우(Jin-Woo Ahn) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.4
At the high speed operation, the high demagnetization voltage can reduce the negative torque, so the output power and efficiency can be improved. In this paper, a novel power converter for single phase SRM with high demagnetization voltage is proposed. A simple passive capacitor circuit is added in the front-end, which consists of three diodes and one capacitor. Based on this passive network, the two capacitors can be connected in series and parallel, so the phase winding of SRM obtains general dc-link voltage in excitation mode and the double de-link voltage in demagnetization mode. The operation modes of the proposed converter are analyzed in detail. Some computer simulation results is done to verify the performance of proposed converter.
Effect of Heat Treatment on the Lipophillic Pigments of Fresh Green Tea Liquor
Jian-Liang Lu,Zhan-Bo Dong,Shun-Shun Pan,Chen Lin,Xin-Qiang Zheng,Borthakur Devajit,Yue-Rong Liang 한국식품과학회 2009 Food Science and Biotechnology Vol.18 No.3
Changes in lipophillic pigments concentration and its relation to color of fresh green tea liquor during heat treatment were studied. The results showed liquor greenness decreased markedly with extension of incubation time at 55℃, while the brightness and yellowness changed a little. Significant increase in ‘a’ and ‘b’ values of tea liquor was observed at 95℃. Color change of liquor at 55℃ was accompanied by a decrease in the level of chlorophylls, lutein and neoxanthin, and an increase in the pheophytins and β-carotene levels. However, all pigments except β-carotene decreased with time extension at 95℃. Significant correlation was found between pigments and color difference index. The browning of fresh green tea liquor was attributed to vicissitudes of lipophillic pigments during heat treatment, especially to the change of chlorophylls/pheophytins ratio. Result also showed addition of Zn²? at 1.6 μ㏖/ℓ could partially alleviate the decrease in greenness during heat treatment.
A Novel Direct Instantaneous Pressure Control of Hydraulic Pump System with SR Drive
Jianing-Liang,Tae-Hyoung Kim,Dong-Hee Lee,Jin-Woo Ahn 전력전자학회 2007 전력전자학술대회 논문집 Vol.- No.-
This paper proposes a novel direct instantaneous pressure control(DIPC) of hydraulic pump system with SR drive. And it has very simple control structure, because it doesn’t use any speed and torque control for adjusting pump pressure. The hysteresis band of pressure and proper switching rules can make the actual pump pressure to be constant with fast dynamic response. Therefore, the proposed DIPC method can control of hydraulic pump pressure steadily with fast dynamic response.
A Novel Direct Instantaneous Pressure Control of Hydraulic Pump System with SRM Drive
Jianing Liang,Dong-Hee Lee,Jin-Woo Ahn,Young-Joo An 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-
A novel direct instantaneous pressure control of hydraulic pump system with SRM drive is presented in this paper. The proposed hydraulic pump system embeds pressure controller and direct instantaneous torque control (DITC) controller. DITC controller can reduce inherent torque ripple of SRM, and develop a smooth torque, which can increase stability. The proposed hydraulic pump system has also fast step response and load response. At last the proposed hydraulic pump system is verified by computer simulation and experimental results.
Improvement of DITC SRM with a Novel 4-level Converter
Jianing Liang,이진국(Zhen-Guo Lee),이동희(Dong-Hee Lee),안진우(Jin-Woo Ahn) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7
This paper presents a direct instantaneous torque control (DITC) of Switched Reluctance Motor (SRM) with a novel 4-1evel converter to obtain smooth torque and dynamic performance improvement. The DITC method can reduce the high inherent torque ripple of SRM drive system, but driving efficiency and dynamic performance are somewhat low due to the slow excitation current build-up. Since the 4-level converter can obtain a addition high voltage to get fast excitation current and demagnetization current, so, it can improve dynamic performance easily. As a high performance SRM drive system with low torque ripple and high dynamic performance can be implemented. The validity of proposed method is verified by some computer simulations and comparative experiments.
DITC of SRM using 4-Level Converter
Jianing Liang,Zhen-Guo Lee(이진국),Dong-Hee Lee(이동희),Jin-Woo Ahn(안진우) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.4
This paper proposes a DITC(Direct Instantaneous Torque Control) of SRM (Switched Reluctance Motor) using a novel 4-level converter for smooth torque control and high efficiency. DITC of SRM is very useful for smooth torque control, but the driving efficiency is low due to advanced current that does not produce torque. For the high efficiency control of SRM, fast excitation and demagnetization of phase current are required. A novel 4-level converter and a new control scheme are present to improve the driving efficiency. The proposed DITC of SRM using 4-1evel converter is verified by computer simulation.
Series-Parallel Type Passive Boost Converter for 3-phase SRM
Jianing Liang,Seung-Hun Seok,Dong-Hee Lee,Jin-Woo Ahn 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.1
This paper presents a novel series-parallel type passive boost converter for 3-phase SRM. The proposed simple passive circuit added three diodes and one capacitor in the front-end of conventional asymmetric converter in order to obtain high negative bias. Based on this passive power network, the terminal voltage of the converter side is general dc-link voltage level in parallel mode and is u to double dc-link voltage level in series mode. So it can suppress the negative torque generation from the tail current and improve the output power. Combining passive circuit with 3-phase asymmetric converter, without the phase current overlap, the phase winding obtains the dc-link voltage in the demagnetization mode. With the phase current overlap, the dc-link voltage or double dc-link voltage is dependent on the overlap current. The operation modes of the proposed converter are analyzed with a 3-phase SR motor in detail. The compared simulation and experiments for conventional and proposed converter have been executed. And the results verify the performance of proposed converter.
Jianing Liang,김태형(Tae-Hyoung Kim),안진우(Jin-Woo Ahn),안영주(Young-Joo An) 전력전자학회 2005 전력전자학술대회 논문집 Vol.- No.-
This paper presents dynamic characteristics of super high speed SRM and it's drive. The nonlinear model of super high speed SRM is implement by Matlab/simulink and the simulation results show that the prototypeSRM can operate up 20,000[rpm]with stable performance.