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RISS 인기검색어
- 검색키워드
- 저자 : Yasushi Amano (검색결과 3 건)
- 무료
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A Novel Seamless Direct Torque Control for Electric Drive Vehicles
Ghaderi, Ahmad,Umeno, Takaji,Amano, Yasushi,Masaru, Sugai The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.4
Electric drive vehicles (EDV) have received much attention recently because of their environmental and energy benefits. In an EDV, the motor drive system directly influences the performance of the propulsion system. However, the available DC voltage is limited, which limits the maximum speed of the motors. At high speeds, the inverter voltage increases if the square wave (SW) voltage (six-step operation) is used. Although conventional direct torque control (DTC) has several advantages, it cannot work in the six-step mode required in high-speed applications. In this paper, a single-mode seamless DTC for AC motors is proposed. In this scheme, the trajectory of the reference flux changes continuously between circular and hexagonal paths. Therefore, the armature voltage changes smoothly from a high-frequency switching pattern to a square wave pattern without torque discontinuity. In addition, because multi-mode controllers are not used, implementation is more straightforward. Simulation results show the voltage pattern changes smoothly when the motor speed changes, and consequently, torque control without torque discontinuity is possible in the field weakening area even with a six-step voltage pattern.
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A Novel Seamless Direct Torque Control for Electric Drive Vehicles
Ahmad Ghaderi,Takaji Umeno,Yasushi Amano,Sugai Masaru 전력전자학회 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.4
Electric drive vehicles (EDV) have received much attention recently because of their environmental and energy benefits. In an EDV, the motor drive system directly influences the performance of the propulsion system. However, the available DC voltage is limited, which limits the maximum speed of the motors. At high speeds, the inverter voltage increases if the square wave (SW) voltage (six-step operation) is used. Although conventional direct torque control (DTC) has several advantages, it cannot work in the six-step mode required in high-speed applications. In this paper, a single-mode seamless DTC for AC motors is proposed. In this scheme, the trajectory of the reference flux changes continuously between circular and hexagonal paths. Therefore, the armature voltage changes smoothly from a high-frequency switching pattern to a square wave pattern without torque discontinuity. In addition, because multi-mode controllers are not used, implementation is more straightforward. Simulation results show the voltage pattern changes smoothly when the motor speed changes, and consequently, torque control without torque discontinuity is possible in the field weakening area even with a six-step voltage pattern.
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Ryota Sagami,Kenji Hayasaka,Tetsuro Ujihara,Ryotaro Nakahara,Daisuke Murakami,Tomoyuki Iwaki,Satoshi Suehiro,Yasushi Katsuyama,Hideaki Harada,Yuji Amano 대한소화기내시경학회 2020 Clinical Endoscopy Vol.53 No.2
Background/Aims: Endoscopic transpapillary gallbladder drainage (ETGBD) is useful for the treatment of acute cholecystitis; however,the technique is diffcult to perform. When intraductal ultrasonography (IDUS) is combined with ETGBD, the orifice of the cystic ductin the common bile duct may be more easily detected in the cannulation procedure. The aim of this study was to evaluate the effcacy ofETGBD with IDUS compared with that of ETGBD alone. Methods: A total of 100 consecutive patients with acute cholecystitis requiring ETGBD were retrospectively recruited. The first 50consecutive patients were treated using ETGBD without IDUS, and the next 50 patients were treated using ETGBD with IDUS. Through propensity score matching analysis, we compared the clinical outcomes between the groups. The primary outcome was thetechnical success rate. Results: The technical success rate of ETGBD with IDUS was significantly higher than that of ETGBD without IDUS (92.0% vs. 76.0%, p=0.044). There was no significant difference in procedure length between the two groups (74.0 min vs. 66.7 min, p=0.310). Thecomplication rate of ETGBD with IDUS was significantly higher than that of ETGBD without IDUS (6.0% vs. 0%, p<0.001); however,only one case showed an IDUS technique-related complication (pancreatitis). Conclusions: The assistance of IDUS may be useful in ETGBD.
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