• Title/Summary/Keyword: High speed rotor

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A Study on the Speed Sensorless Vector Control for Induction Motor Adaptive Control Method using a High Frequency Boost Chopper of Hybrid Type Piezoelectric Transformer (하이브리드형 압전 변압기의 고주파 승압 초퍼를 이용한 적응제어기법 유도전동기 속도 센서리스 벡터제어에 관한 연구)

  • Hwang, Lark-Hoon;Na, Seung-Kwon;Kim, Yeong-Wook;Choi, Song-Shik
    • Journal of Advanced Navigation Technology
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    • v.17 no.3
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    • pp.332-345
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    • 2013
  • In this paper, recently, it is described to the piezoelectric transformer technology develops, because it was have to favorable characteristics such as electromagnetic-noise free, compact size, higher efficiency, and superior power density, flux linkage, noiseless, etc. its resonance frequency was used to output waveform of a sine wave. A rotor speed identification method of induction motor based on the theory of flux model reference adaptive system(FMRAS). The estimator execute the rotor speed identification so that the vector control of the induction motor may be achieved. The improved auxiliary variable of the model are introduced to perform accurate rotor speed estimation. The control system is composed of the PI controller for speed control and the current controller using space voltage vector PWM techniuqe and DC-DC converter. High speed calculation and processing for vector control is carried out by digital signal one chip microprocessor. Validity of the proposed control method is verified through simulation and experimental results.

Control Law Design for a Tilt-rotor Unmanned Aerial Vehicle with a Nacelle Mounted WE (Wing Extension) (체공성능 향상을 위한 확장날개 틸트로터 무인기의 제어법칙설계)

  • Kang, Young-Shin;Park, Bum-Jin;Cho, Am;Yoo, Chang-Sun
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.11
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    • pp.1103-1111
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    • 2014
  • The results of control law design for a tilt-rotor unmanned aerial vehicle that has a nacelle mounted wing extension (WE) are presented in this paper. It consists of a control surface mixer, stability and control augmentation system (SCAS), hold mode for altitude / speed / heading, and a guidance mode for preprogram and point navigation which includes automatic take-off and landing. The conversion corridor and the control moments derivatives between the original tilt-rotor and its variant of the nacelle mounted WE were compared to show the effectiveness of the WE. The nacelle conversion of the original tilt-rotor starts when the airspeed is greater than 30 km/h but its WE variant starts at 0 km/h in order to reduce the drag caused by the high incidence angle of the WE. The stability margins of the inner loop are presented with the optimization approach. The outer loops for the hold mode are designed with trial and error methods with linear and nonlinear simulation. The main control parameter for altitude control of the helicopter mode is thrust command and it is transferred to the pitch attitude command in airplane mode. Otherwise, the control parameter for the speed of the helicopter mode is the pitch attitude command and it is transferred to the thrust command in airplane mode. Therefore the speed and altitude hold mode are coupled to each other and are engaged at the same time when an internal pilot engages any of the altitude or speed hold modes. The nonlinear simulation results of the guidance control for the preprogrammed mode and point navigation are also presented including automatic take-off and landing in order to prove the full control law.

Fabrication and Characteristics of Flat-type $L_{-}$-$B_{8}$ Mode Ultrasonic Motors (평판형 종($L_{-}$-굴곡($B_{8}$)모드 초음파 전동기의 제작과 특성)

  • U, Sang-Ho;Lee, Eun-Hak;Kim, Jin-Su
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.51 no.7
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    • pp.292-297
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    • 2002
  • In this paper, a flat-type $L_{-}$-$B_{8}$ mode Ultrasonic Motor[USM] having the size of 80 x 20 x ${1.5}mm^3$($l{\times}\omega{\times}t$) was designed and fabricated to examine the characteristics of an ultrasonic vibration. We used ANSYS simulation program based on FEM to get the optimum design of this USM. As results of experiment, the fastest speed of revolution(v), the maximum torque(T) and the efficiency(n) were 37.5cm/s, 5.0 mN.m and 1.17% when 27.9KHz, 150N, 50V were applied respectively. And this flat-type $L_{-}$-$B_{8}$ mode USM could be controlled the speed of rotor revolution by applied voltage, frequency and pre-load of rotor as well as showed the characteristics of typical drooping torque-speed, large torque and high speed. So, we think that this flat-type $L_{-}$-$B_{8}$ mode USM has characteristics of enough torque and velocity to be usable for applications in forwarding device of an electric card or a paper, etc.

Analysis of Estimated Position Error by Magnetic Saturation and Compensating Method for Sensorless Control of PMSM (자속 포화에 의한 PMSM 센서리스 위치 추정 오차 분석 및 보상 기법)

  • Park, Byung-Jun;Gu, Bon-Gwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.68 no.3
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    • pp.430-438
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    • 2019
  • For a pump or a compressor motor, a high periodic load torque variation is induced by the mechanical works, and it causes system vibration and noise. To minimize these problems, load torque compensation method, injecting periodic torque current, could be utilized. However, with the sensorless control method, which is usually utilized in the pump and compressor for low cost, the periodic torque current degrades the accuracy of the rotor position estimation owing to the inductance variation. This paper analyzes the rotor position and speed estimation error of sensorless control method with constant motor parameters under period loading. Assuming the constant speed by the accurate load torque compensation, the speed error equation is derived in frequency domain with inductance depending on the stator current. Further, it is also shown that the rotor position error could be minimized by compensating the inductance variation. The simulation and experimental results verify that the derived speed error model and the validity of the inductance compensation method.

High Performance On Off Angle Control of SRM Using Linear Encoder (선형 엔코더를 이용한 SRM의 고정밀 온, 오프 각 제어)

  • Lee, Yeong-Jin;Park, Seong-Jun;Park, Han-Ung;Lee, Man-Hyeong
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.12
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    • pp.61-67
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    • 2000
  • In switched reluctance motor(SRM) drive, it is necessary to synchronize the stator phase excitation with the rotor position. Therefore the rotor position information is an essential. Usually optical encoders or resolvers are used to provide the rotor position information. These sensors are expensive and are not suitable for high speed operation. In general, the accuracy of the switching angle is dependent upon the resolution of the encoder and the sampling period of the microprocessor. But the region of high speed, switching angles are fluctuated back and forth from the preset values, which are cause by the sampling period of the microprocessor. Therefore, the low cost linear encoder suitable for the practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using the simple digital logic circuit is also presented in this paper. It is verified from the experiments that the proposed encoder and logic controller can be a powerful candidate for the practical low cost SRM drive.

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Turbine Performance Experiments for the Turbopump of a Liquid Rocket Engine

  • Lee, Hanggi;Shin, Juhyun;Jeong, Eunhwan;Choi, Changho
    • International Journal of Aerospace System Engineering
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    • v.3 no.1
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    • pp.25-29
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    • 2016
  • This paper highlights the performance of an impulse turbine which is a part of turbopump in a liquid rocket first stage engine. The turbopump, currently under development at Korea Aerospace Research Institute, has an impulse type turbine with 12 nozzles and a single rotor. The impulse turbine can archive high specific power with the low gas flow rates. The supersonic impulse turbine with a single rotor can make a simple structure. High-pressure gases are converted into the dynamic energy with flows through the 12 nozzles and drive the rotor to make the power for the pumps. The turbine test was performed in the high-pressured turbine test facility with air gas instead of burned gas. A hydraulic dynamometer was used to absorb the power from the turbine and control the rotational speed and torque. The test points were at several pressure ratios with 7 different rotational speeds. Results showed the efficiency was highest at the design pressure ratio. The efficiency was insensitive to the pressure ratio variation than the rotational speed. It was a typical characteristic in an impulse turbine.

Stability analysis of pump using finite element method (유한요소법에 의한 펌프축계의 안정성해석)

  • 양보석
    • Journal of Advanced Marine Engineering and Technology
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    • v.10 no.4
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    • pp.31-40
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    • 1986
  • With the tendency toward high speed and high pressure in centrifugal pumps, the problem of sub-synchronous vibration has arisen, caused by the hydraulic forces of the working fluid, such as wearring, balance piston, impeller, etc.. These forces can drastically alter the rotor critical speeds and stability characteristics, and can be acted significant destabilizing forces. For preventing such self-excited vibration, the desing of the rotor system needs, which would secure the stability of the machine. In this paper, a procedure is presented for dynamic modeling of rotor-bearing-seal-impeller systems which consist of rigid disks, distributed parameter finite rotor elements and discrete bearings, seals and impellers. A finite element model including the effects of rotatory inertia and gyroscopic moments is developed using the consistent matrix approach. The technique of dynamic matrix reduction is applied to the shaft matrices to reduce them to a set of matrices of dynamic of significantly fewer degrees of freedom. The representation of bearing, seal and impeller elements is in term of linearized stiffness and damping matrices by reasonably small perturbations from equilibrium. The stability behavior of a typical double suction centrifugal pump is presented. Results show the influence of clearance and flow conditions on running speeds and stability characteristics.

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Development of Lorentz Force Type Integrated Motor-Bearing System in Dual Rotor Disk Configuration (두 장의 원판형 회전자를 갖는 로렌츠형 자기 베어링 내장 전동기의 개발)

  • Park, Sung-Ho;Lee, Chong-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.935-940
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    • 2005
  • In this paper, dual rotor disk configuration with a coreless stator is proposed for the Lorentz force type integrated motor bearing system. An experimental compensation for the effects of high order harmonics is performed using the digital controller of the experimental setup. The runout profile and rotor unbalance are also identified by the extended influence coefficient method. The experimental results confirm that this compensation method effectively attenuates the rotor vibration all over the operating range of rotational speed.

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Development of Lorentz Force Type Integrated Motor-bearing System in Dual Rotor Disk Configuration (두 장의 원판형 회전자를 갖는 로렌츠형 자기 베어링 내장 전동기의 개발)

  • Lee, Chong-Won;Park, Sung-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.9 s.102
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    • pp.1045-1052
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    • 2005
  • Tn this paper. dual rotor disk configuration with a coreless stator is proposed for the Lorentz force type integrated motor hearing system. An experimental compensation for the effects of high order harmonics is performed using the digital controller of the experimental setup. The runout profile and rotor unbalance are also identified by the extended influence coefficient method. The experimental results confirm that this compensation scheme effectively attenuates the rotor vibration all over the operating range of rotational speed.

Design and Performance Evaluation of a 10kW Scale Counter-Rotating Tidal Turbine (10kW급 상반전 조류터빈의 설계와 성능에 관한 연구)

  • Hoang, Anh Dung;Yang, Chang-Jo
    • The KSFM Journal of Fluid Machinery
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    • v.17 no.1
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    • pp.47-53
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    • 2014
  • This paper aims to present the design and performance evaluation of a counter-rotating tidal turbine using CFD and to compare its performance with single rotor. The device scale is 10kW and the rotating part consists of two rotors which rotate in opposite direction. Compared with conventional single rotor, the counter-rotating system shows higher power efficiency at high stream velocity but lower efficiency at low stream velocity. The added counter-rotated rotor together helps improve the energy absorption capacity but has influence on the upstream rotor that reduces its performance. In terms of power capture, the designed counter-rotating tidal turbine is more advantageous in high speed tidal condition.