• Title/Summary/Keyword: low-speed

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Improvement of Control Performance of PMSM in the low Speed Range (영구자석형 동기전동기의 저속도 영역에서 제어 성능 개선)

  • Won, Chung-Yuen;Yu, Jae-Sung;Jun, Bum-Su;Hwang, Sun-Mo;Kim, Yuen-Chung;Lee, Song-Seok
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.1
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    • pp.70-79
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    • 2005
  • In this paper, improvement method of control performance by a full-order observer using reduced-order state equation is proposed in the low speed range. Full-order observer using reduced-order state equation is the motor speed and the disturbance torque observer. The proposed algorithm is very stable in the low speed range about 1.9[rpm]. The disturbance torque in the motor drive system degrades speed control performance in the low speed range. The proposed algorithm estimated both motor speed and disturbance torque. The estimated disturbance torque is used as a feedforward value in output of the speed controller, As a result, it improves the response of load torque in the low speed range(1.9rpm).

Design of Vehicle Low speed Drive Assistant System with Laser Scanner (레이저스캐너를 이용한 차량저속운전보조장치의 설계)

  • Moon, Hee-Chang;Son, Young-Jin;Kim, Jung-Ha
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.8
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    • pp.856-864
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    • 2008
  • This paper describes a vehicle low speed driving assistant (VLDA) system that is composed of laser scanner. This vehicle is designed for following lead vehicle (LV) without driver's operation. The system is made up several component systems that are based on unmanned ground vehicle (UGV). Each component system is applied to use advanced safety vehicle developed to complete UGV system. VLDA system was divided into vehicle control system and obstacle detecting system. The obstacle detecting system calculate distance and angle of LV and transmit these data to vehicle control system using front, left and right laser scanners. Vehicle control system makes vehicle control values such as steering angle, acceleration and brake position and control vehicle's movement with steering, acceleration and brake actuators. In this research, we designed VLDA system like as low speed cruise control system and test it on real road environments.

Numerical Design and Performance Prediction of Low Specific Speed Centrifugal Pump Impeller

  • Yongxue, Zhang;Xin, Zhou;Zhongli, Ji;Cuiwei, Jiang
    • International Journal of Fluid Machinery and Systems
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    • v.4 no.1
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    • pp.133-139
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    • 2011
  • In this paper, Based on Two-dimensional Flow Theory, adopting quasi-orthogonal method and point-by-point integration method to design the impeller of the low specific speed centrifugal pump by code, and using RANS (Reynolds Averaged N-S) Equation with a standard k-${\varepsilon}$ two-equation turbulence model and log-law wall function to solve 3D turbulent flow field in the impeller of the low specific speed pump. An analysis of the influences of the blade profile on velocity distributions, pressure distributions and pump performance and the investigation of the flow regulation pattern in the impeller of the centrifugal pump are presented. And the result shows that this method can be used as a new way in low speed centrifugal pump impeller design.

Improved Performance of Sensorless PMSM in Low Speed Range Using Variable Link Voltage (가변 링크전압에 의한 센서리스 PMSM의 저속운전 성능개선)

  • Lee, Dong-Hee;Kwon, Young-Ahn
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.10
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    • pp.708-711
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    • 2000
  • Sensorless PMSM is much studied for the industrial applications and home appliances because a mechanical sensor reduce reliability and increase cost. Most of sensorless algorithms are based on motor equations, and so the magnitude of phase voltage and current should be exactly obtained. However, the inverter output voltage applied to PMSM has relatively large error in the low speed range, and a relatively poor response is shown in the low speed range. This paper investigates the improved performance of sensorless PMSM in the low speed range. This paper proposes the error reduction of inverter output voltage which is realized through the variable link voltage. The proposed algorithm is verified through simulation and experiment.

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Sensorless Control for Surface Mounted Permanent Magnet Synchronous Machines at Low Speed

  • An, Lu;Franck, David;Hameyer, Kay
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.4
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    • pp.429-435
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    • 2013
  • This paper proposes a sensorless speed control based on a novel extension of the torque producing flux (active flux) observer for the surface mounted permanent magnet synchronous machines (SPMSM) without additional high frequency signal injection. From the estimated torque producing flux, the rotor position and speed can be calculated at low speed due to their independency. Therefore, no rotor position sensor is required. Two approaches of the torque producing flux observer are presented and compared. The results show the stability and robustness of the expansion of the torque producing flux observer at low speed for the SPMSM.

Hybrid Pulse Width Modulation Strategy for Wide Speed Range in IPMSM with Low Cost Drives

  • Ahn, Han-woong;Go, Sung-chul;Lee, Ju
    • Journal of Electrical Engineering and Technology
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    • v.11 no.3
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    • pp.670-674
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    • 2016
  • The control performance of hybrid PWM inverter using a phase current measurement is presented in this paper. The hybrid PWM technique consists of space vector pulse width modulation (SVPWM) and six-step voltage control operation. The SVPWM is performed to reduce the harmonic components in the low speed region, and the six-step modulation is applied to increase the maximum speed of the IPMSM in the high speed region. Therefore, it is possible to obtain a great performance in both the low speed range and high speed range. However, the six-step modulation cannot be completely implemented, since the inverter that includes the lag-shunt sensing method has an immeasurable current region. In this paper, a quasi-six-step modulation using a modified voltage vector is proposed. The validity and usefulness of the proposed PWM technique is verified by MATLAB/Simulink and experimental results.

The Improvement of low speed driving characteristics of induction motor by inertia moment identification. (관성 모멘트 동정에 의한 유도전동기의 저속운전 특성개선)

  • 이성근
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.2 no.4
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    • pp.627-634
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    • 1998
  • This paper proposes an algorithm which improves capacity of a state observer and low speed driving characteristics of a induction motor by inertia moment identification. In induction motet driving systems, it is difficult to obtain the accurate speed information by a low resolution encoder because the encoder pulses are very few in a low speed range. To improve this problem, state observer based on the Gopinath' theory which estimates speed and disturbance was designed, and disturbance rejection control was realized by application of the observer. Also, inertia moment of the motor was estimated and the nominal inertia of the observer was identified to minimize the error of estimated speed and disturbance. From the simulation and experimental results, it is showed that the proposed observer improved the transient response characteristics in low speed region below 6[rpm].

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The effect of low-speed drilling without irrigation on heat generation: an experimental study

  • Oh, Ji-Hyeon;Fang, Yiqin;Jeong, Seung-Mi;Choi, Byung-Ho
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.42 no.1
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    • pp.9-12
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    • 2016
  • Objectives: In this study we evaluated heat generation during the low-speed drilling procedure without irrigation. Materials and Methods: Ten artificial bone blocks that were similar to human D1 bone were used in this study. The baseline temperature was $37.0^{\circ}C$. We drilled into 5 artificial bone blocks 60 times at the speed of 50 rpm without irrigation. As a control group, we drilled into an additional 5 artificial bone blocks 60 times at the speed of 1,500 rpm with irrigation. The temperature changes during diameter 2 mm drilling were measured using thermocouples. Results: The mean maximum temperatures during drilling were $40.9^{\circ}C$ in the test group and $39.7^{\circ}C$ in the control group. Even though a statistically significant difference existed between the two groups, the low-speed drilling did not produce overheating. Conclusion: These findings suggest that low-speed drilling without irrigation may not lead to overheating during drilling.

A Study on the Low Cost Testing System Development of the Low Speed and High Torque Harsh Reducer (저속 고토크 가혹감속기의 저비용 테스트 시스템 개발에 관한 연구)

  • Park, Taehyun
    • Journal of the Korean Society of Industry Convergence
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    • v.25 no.3
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    • pp.379-386
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    • 2022
  • The goal of this research is to verify a performance test system for a low speed, high torque, and harsh reducer at low cost. The reducer rotates a cooling fan with a diameter of 10 meters, in a high temperature (50℃) cooling tower in a geothermal power plant. It requires about 500 kgf·m torque and 47.75 kW power to rotate the fan at a maximum power condition. An expensive dynamometer is commonly used for performance test of a motor or a reducer. In this paper, a low cost system is developed using a hydraulic pump as a load unit to generate torque instead of a dynamometer. We accurately calculated the required power, the flow meter, and the pressure of the pump, and selected to design and optimize the system at minimal cost. The system also applied another reverse reducer and a gearbox to increase the rotational speed and to reduce the torque from the low speed and high torque target reducer. This allows low-cost systems to be built using inexpensive components. The developed system was able to successfully measure the high torque and the low rotational speed of the target reducer at high temperature.

Improvement of Pump Performance and Suction Performance of a Very Low Specific Speed Centrifugal Pump (극저비속도 원심펌프의 펌프성능 및 흡입성능 향상)

  • Choi Young-Do;Kurokawa Junichi
    • The KSFM Journal of Fluid Machinery
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    • v.9 no.3 s.36
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    • pp.29-35
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    • 2006
  • There are high expectations of improving the performance of a centrifugal pump in the range of very low specific speed which has been developed recently for the use instead of a conventional positive displacement pump. However, even though elaborated studies has been done for the pump intensively, the pump performance has not increased so much. Also, it is difficult to find detailed information from published literatures for suction performance of the very low specific speed centrifugal pump. Therefore, this study is aimed to improve the pump performance more and to make clear suction performance of the very low specific speed centrifugal pump. Recircular flow stopper is installed on the pump casing wall at the region of impeller outlet to improve the pump performance and J-Groove is also installed at the inlet of the pump casing for the purpose of suppressing occurrence of cavitation as well as improving pump performance. The result suggests that the simultaneous improvement of pump performance and suction performance of the very low specific speed centrifugal pump is possible by adopting optimum configuration of the recirculation flow stopper and J-Groove.