• Title, Summary, Keyword: Speed

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Improvement of Speed Ripple in Low Speed Range for PMSM using Observer (관측자를 이용한 영구자석형 동기모터의 저속영역 속도리플 개선)

  • 김정태;노철원;최종률
    • Proceedings of the KIPE Conference
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    • pp.65-69
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    • 1997
  • Generally, we often use a speed sensor based on a rotary encoder and we can obtain a speed information by counting the increased or decreased number of encoder pulses in a sampling period. However, these speed measurement systems do not inherently produce a true, instantaneous speed information and them the speed ripple is generated by speed measurement errors. In order to overcome this problem, speed observer is used for the accurate speed measurement and improvement of speed ripple for Permanent Magnet Synchronous Motor (PMSM) in this paper. Speed observer estimates the instantaneous speed at each sampling instant. This estimated speed signal is then used as the speed feedback signal for the speed loop control. The proposed speed observer system is proved simulation using SABER simulation S/W.

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Speed Control of an Induction Motor using Intelligent Speed Estimator (지능형 속도 추정기를 이용한 유도전동기 속도 제어)

  • Kim Lark-Kyo;Choi Sung-Dae
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.7
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    • pp.437-442
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    • 2005
  • In order to realize the speed control of an induction motor, the information of the rotor speed is needed. So the speed sensor as an encoder or a pulse generator is used to obtain it. But the use of speed sensor occur the some problems in the control system of an induction motor. To solve the problems, the appropriate speed estimation algorithm is used instead of the speed sensor. Also there is the limitation to improve the speed control performance of an induction motor using the existing speed estimation algorithm. Therefore, in this paper, intelligent speed estimator using Fuzzy-Neural systems as adaptive laws in Model Reference Adaptive System is proposed so as to improve the existing estimation algorithm and ,using the rotor speed estimated by the Proposed estimator, the speed control of an induction motor without speed sensor is performed. The computer simulation and the experiment is executed to prove the performance of the speed control system usinu the proposed speed estimator.

A Experimental Study on Train Speed and Wave Propagation Speed of Contact Wire according to the Speed-up (속도향상에 따른 열차속도와 전차선 파동전파속도에 대한 실험적 연구)

  • Lee, Kiwon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.12
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    • pp.1820-1823
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    • 2013
  • An overhead catenary system is the one of the main subjects for increasing speed in electric railway. When a vehicle increases the speed over 350km/h, vibrations and wave propagation reflections occur severely. Therefore, the system suitable for the speed are needed. A wave propagation speed of contact wire is the main criteria to determine the tension for the system. Therefore, a train speed is restricted below 70% of wave propagation speed of it in European railway code. In this study, we measured a strain and uplift of contact wire while HEMU-430X tain is operated for the speed-up trial test in Kyungbu high-speed railway. The measured strain and uplift are analyzed with wave propagation speed according to the speed-up. The more a train speed reaches to a propagation speed, the more measured strain is high. Through the study, an experimental approach is performed about the code which a train speed is restricted below 70% of wave propagation speed of it.

Low Speed Control of Induction Machine by Instantaneous Speed Estimation (순시 속도 추정에 의한 유도 전동기의 저속 운전)

  • Kwon, Bong-Hyun;Hyun, Dong-Seok
    • Proceedings of the KIEE Conference
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    • pp.100-102
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    • 1993
  • This paper proposes a control method of induction machine at a low speed range. When an encoder is used for speed detection, we usually obtain speed information from the increased pulse number. At low speed range, however, we can get only average speed between encoder pulses and it makes speed controller unstable. By using a disturbance observer and torque current, it is possible to estimate accurate speed information. The simulation and experiment show that the stable speed control is performed at a low speed with proposed algorithm.

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A Study on the Variations of Runing Speed Characteristics by Automated Speed Enforcement System (속도위반단속시스템에 의한 주행속도 특성 변화에 관한 연구)

  • Kim, Wan-Ki;Ryu, Boo-Hyung
    • Journal of the Korean Society of Safety
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    • v.25 no.2
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    • pp.78-83
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    • 2010
  • An installation of automated speed enforcement system(ASES) was known for traffic safety and accident preventive effects that traffic characteristics transmute by speed distribution stabilizing. This study is verified the variations of average speed, 85% speed, speed distribution and dispersion as traffic characteristics depend on enforcement system influences in the road. We tested selected 5 areas. By and large, it has a little differences depend on road geometric structure and traffic environment but that is not too much. After all, after automated speed enforcement system installed in all of test areas, average speed, 85% accumulated speed, speed distribution and dispersion characteristics were declined and equalized. The speed dispersion was smaller than before installed the ASES. The speed dispersion value of each case that is the limited speed has been 70Km/h, 80Km/h at flat and straight, 80Km/h at downhill and straight or downhill and left-curved area was 77.3%, 65.2%, 68.7% and 54.1%. Each of the data was declined. We could analyze that average speed distributed depletion factor was declined rapidly by 66.3% in test area.

Quality of Fresh Vegetable and Fruit Juice produced with Low-Speed and High-Speed Juicers (저속 압착 방식의 착즙기와 고속 파쇄 방식의 블랜더를 사용한 주스의 품질 변화에 대한 연구)

  • Kim, Youngsung
    • The Korean Journal of Food And Nutrition
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    • v.30 no.3
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    • pp.568-577
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    • 2017
  • Vegetables and fruits contain a great deal of vitamins, minerals, dietary fiber and phytochemicals. Therefore, healthconcious consumer prefer beverage made from fresh fruits and vegetables due to their health benefits. This study was conducted to investigate differences in nutritional composition and sensory characteristics of juices depending on the apparatus used: either a low-speed juicer or high-speed blender. All ingredients could be made into juice without addition of water using the low speed juicer. However, addition of water was necessary to produce juice with the high-speed blender. Phenol and flavonoid content, were higher in juice made with the low-speed juicer than that produced with the high-speed blender and were correlated with DPPH radical scavenging ability. Protease activity of pineapples juices was not significantly different for the two methods, but protease activity of kiwi juice was about 8 times higher in juice made with low-speed juicer than that made with the high-speed blender. SOD activity also tended to be higher in the juice made with low-speed juicer. The concentration of dissolved oxygen in the juice made with high-speed blender was higher than that of juice made with a low-speed juicer and was correlated with color change. In addition, the high-speed blender caused an increase juice temperature, but temperature was not changed during use of the low-speed juicer. The noise level of the low-speed juicer was low, but the high-speed blender had high noise intensity comparable to that of railway or aircraft noise. In the sensory evaluation of juice, juice made with the low-speed juicer was preferred over juice made with the high-speed blender. As a result, the overall quality of the juice produced using the low-speed juicer was superior.

New Speed Adjustment Factor for Analyzing Level of Service at Multi-Lane Highway (다차로도로의 서비스수준 분석을 위한 속도보정계수 개선에 관한 연구)

  • Kim, Wongil;Kang, Woneui;Noh, Chang-Gyun;Park, Bumjin
    • International Journal of Highway Engineering
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    • v.14 no.6
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    • pp.167-173
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    • 2012
  • PURPOSES : This study is to develop speed correction factor for more realistic Level-of-Service(LOS) at multilane highway. METHODS : In this study, we compared speed difference the degree of speed reductions in actual multilane road conditions with speed reduction considering speed correction factor presented in highway capacity manual using statistical techniques. And also we presents new speed correction factor analyzing collected data at national highway No.1 (Goyang~Wolrung). RESULTS : The result of analyzing and comparing new suggested speed correction factor with speed correction factor in Korea Highway Capacity Manual (KHCM) shows RMSE (Root Mean Square Error) in new speed correction factor (RMSE 1.5) is much lower than existing speed correction factor (RMSE 13.4). New suggested speed correction can be used for analyzing Level-of-Service at multilane highway. And also we suggests improvements for analysis procedure in analyzing Level-of-Service at multilane highway CONCLUSIONS : As a result of comparing differences, we draw the causes that effect the differences in speed and suggest new speed correction factor that consider traffic volumes. It can be more rational because it uses speed correction factor which can consider more realistic traffic conditions, etc.

Improvement of Low Speed Operation Characteristic of DC Servo Motor Using a Fuzzy Tuning Speed Observer (퍼지동조 속도관측기를 이용한 직류서보전동기의 저속운전 특성 개선)

  • Ahn, Chang-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.57 no.3
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    • pp.244-249
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    • 2008
  • This paper deals with speed control of DC servo motor using a Fuzzy tuning observer. Speed sensor detect a speed of rotor continuously. But it have a limit as a driving speed to detect speed precisely. So it is problem to improve the performance of the driving system. To solve the problem, it is studied to detect a speed of DC motor without sensor. In particular, study on the method to estimate the speed using the observer is performed a lot. In this parer, the gain of the observer is properly set up using the fuzzy observer. The fuzzy observer has a superior transient characteristic and is easy to implement compared the existing method is designed. It estimate the derivative of the armature current directly using the armature current measured in the DC motor. It estimate the speed of the rotor using the differentiation. It is proposed speed sensorless control method using the estimated speed. Optimal gain of Luenberger observer is set up using the fuzzy observer and adapted speed control of DC servo motor low speed operation. It is proved excellence and feasibility of the presented observer from the comparison tested a case with a speed sensor and a case without a speed sensor which used a highly efficient drive and 200W DC servo motor starting system.

The Study for Speed-up of Main Line by High Speed Train (기존선의 고속전철 연계운용으로 고속화 방안)

  • 박광복
    • Proceedings of the KSR Conference
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    • pp.105-113
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    • 2001
  • This report was studied about speed-up for main line of KNR(Korea National Railroad) by High Speed Train. The maximum speed of Kyun-Pu line was recorded a 140km/h by Saemaul train in 1985 and the average speed its is a 107km/h now. For operation KTX Kyun-Pu High Speed Train and G7 Korea High Speed Train in KNR line, this report was studied about operation status of High Speed Train in advanced countries, operation situation of train in KNR line and plan of speed-up for main line.

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Development of the Speed Limit Model for Harbour and Waterway(II) - The Method of Speed Limit Decision and Application -

  • Kim, Deug-Bong;An, Kwang
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.21 no.3
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    • pp.274-282
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    • 2015
  • This research is the result on calculating the logical speed limit through certain process which some elements must be considered on selecting the speed limit of harbour and waterway. The suggested speed limit select model on this research is processed from 1~6 steps by forming a professional group of experts. Each step has its information which 1st step(water division), 2nd step(selecting the model vessel and vessel applied with speed limit.), 3rd step(selecting the maximum and minimum speed range on each section), 4th step(evaluation on the safeness of traffic), 5th step(suggesting the appropriate speed limit), 6th step(execution and evaluation.). The appropriate speed limit was decided on consideration of the safety of maritime traffic on the range of the maximum speed and the minimum speed. This model was used to derive the appropriate speed limit on the harbour water and Busan harbour entrance waterway. As the result, the harbour water was calculated to be 6.9 knots, the appropriate speed limit of Busan entrance harbour was 9.3 knots. The present calculation of the speed limit on the approaching channel area is 10 knots, inner harbour area is 7 knots, which are similar to the result of the speed limit. This research is the first research on selecting the speed limit model and has its limits on finding the perfect speed limit result. More detailed standards on the safeness of traffic evaluation must be found and additional study is necessary on discriminating consideration of the elements. This research has its value which it provides instances of aboard cases on guidelines of selecting the speed limit.