Papers by Keyword: Low-Speed

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Authors: Fei Xiao, Lei Yuan, Ming Liang Chen
Abstract: This paper proposes an adaptive sliding-mode observer (SMO) for a low-speed interior permanent magnet synchronous motor (IPMSM) drive. In this paper, an adaptive SMO is employed to estimate the rotor speed and extended EMF, a soft phase locked loop (PLL) technology is used to estimate rotor position due to its strong robustness since under voltage phase unbalance or polluted and variable-frequency environment. The global asymptotic stability of the proposed adaptive SMO is verified using Lyapunov stability analysis with considering motor parameter variations. Simulation results are presented to verify the principles and to demonstrate the effectiveness of the proposed method.
536
Authors: Xiao Jing Wang, Jun Peng Shao, Guang Bin Yu
Abstract: In order to improve the low speed stationary of continuous rotary electro-hydraulic servo motor and avoid the pressure impact in the sealed cavity during the oil distributing, this paper designed the shape of buffer groove, established the mathematical model of pressure gradient, and analyzed change law of sealed cavity pressure gradient under different dimension of buffer groove. The pressure field distribution of sealed cavity was studied in certain radial and axial gap, and it is validated the dimension of buffer groove is rational, which lays foundation for structure design and experimental research of large displacement servo motor.
234
Authors: Xiu Chun Lu, Jia Wei Xu, Cai Jun Liu, He Rong Jin, Ji Fang Qu
Abstract: As a typical large rotary dual-drive device, three-car dumper is an essential and important equipment of raw materials storage and transport in the power, chemical industry, metallurgy, ports and other industries. It has some characters such as massive structure, heavy bearer, low-frequency running, frequent starting and braking and mechanical center of gravity which often shifts. The low-speed drive system has some working characteristics such as heavy loads, heavy shocks, low speed, poor working conditions, often breaking teeth and so on, so we propose a reverse design method for low-speed overloaded open gears through using design principles of reverse transformation. By using product reverse technology, we make the parameter design of low-speed and overloaded open gear pairs of Delafu dumper localization, so it extends the service life of gear pair and parts replacement period.
2407
Authors: Jun Guo Cui, Wen Sheng Xiao, Jian Bo Zhao, Jing Xi Lei, Xiao Dong Wu, Zhi Gang Wang
Abstract: To meet the demands of direct-drive petroleum equipment, developed a low-speed and high-torque permanent magnet synchronous motor. By analyzing and identifying the suitable key parameters such as permanent magnet structure parameters, air gap length, type and size of Stator Slot and so on, designed permanent magnet synchronous motor with the torque 10800 Nm, the rated speed 30 r/min and high efficiency and power factor. Obtained the flux density distribution situation and characteristic curves under no-load working condition through simulation and analysis. Manufactured the low-speed and high-torque permanent magnet synchronous motor and applied it to pumping unit. Test results show that this motor has many advantages such as wide range of speed regulation, small torque ripple, smooth operation and other characteristics. The Direct-drive Pumping Unit used this permanent magnet synchronous motor can save 20% energy than the beam pumping unit, so its social and economic benefits are significant.
888
Authors: Hua Qing Wang, Yong Wei Guo, Jian Feng Yang, Liu Yang Song, Jia Pan, Peng Chen, Hong Fang Yuan
Abstract: The fault of a bearing may cause the breakdown of a rotating machine, leading to serious consequences. A rolling element bearing is an important part of, and is widely used in rotating machinery. Therefore, fault diagnosis of rolling bearings is important for guaranteeing production efficiency and plant safety. Although many studies have been carried out with the goal of achieving fault diagnosis of a bearing, most of these works were studied for rotating machinery with a high rotating speed rather than with a low rotating speed. Fault diagnosis for bearings under a low rotating speed, is more difficult than under a high rotating speed. Because bearing faults signal is very weak under a low rotating speed. This work acquires vibration and acoustic emission signals from the rolling bearing under low speed respectively, and analyzes the both kinds of signals in time domain and frequency domain for diagnosing the typical bearing faults contrastively. This paper also discussed the advantages using the acoustic emission signal for fault diagnosis of rolling speed bearing. From the results of analysis and experiment we can find the effectiveness of acoustic emission signal is better than vibration signal for fault diagnosis of a bearing under the low speed.
1020
Authors: Hua Qing Wang, Yong Wei Guo, Jin Ji Gao, Feng Wang
Abstract: Bearing faults signal is very weak under a low rotating speed, and therefore fault diagnosis for bearings under a low rotating speed, is more difficult than under a high rotating speed. The wavelet analysis technique is adopted for fault diagnosis of rolling element bearing under low rotating speed. This work also acquired vibration signals and acoustic emission signals from the rolling bearing under low speed respectively, and analyzed the both kinds of signals for diagnosing the typical bearing faults contrastively.
2006
Authors: Wen Yu Zhang, Jing Zhuo Shi
Abstract: PWM technology has been widely used in motor drive systems today. To avoid the short-circuit condition, dead-time must be inserted to the PWM driving pulses. The addition of dead-time increases the harmonic of output voltage, makes the waveform of winding current more badly. The ripple of motor torque and speed is also increased by the addition of dead-time. The influence of dead-time is more remarkable while the motor speed is low, and so, greatly influence the low-speed working ability. This paper analyzes the influence of dead-time for low-speed motor drive in detail. The nonlinear phenomena in the motion of output voltage-vector, which affects the motor’s low-speed performance directly, is also indicate
1518
Authors: Wen Qing Yang, Bi Feng Song, Wen Ping Song, Zhan Ke Li, Ya Feng Zhang
Abstract: A numerical simulation method is presented in this paper for 3D low speed micro flapping-wing with complex kinematics. The main characteristics for the numerical simulation of Flapping-wing Micro Air Vehicle (FMAV) include: low speed, big range of wing motion, and complex kinematics. The low speed problem is solved by preconditioning method. The big range of wing motion problem is solved by chimera grid system. The problem of complex kinematics is solved by decomposed into three main motions, i.e. plunging, pitching, and swing respectively. The numerical method is solving the Reynolds Averaged Navier-Stokes equations for the viscous flow over micro flapping-wing. The numerical method of this paper is validated by good accordance with experimental results of reference. This method can used to simulate the aerodynamic performance of micro flapping-wing with complex kinematics in low speed and is helpful to the FMAV designers as a design tool.
332
Authors: Min Zhang, Li Jun Wang, Chun Fei Guo
Abstract: Numerical simulation on low-speed magnetic flux leakage inspection to heat exchanger pipes is described. Statistics suggest that 90% of defects in ferromagnetic heat exchanger pipes occur under the retaining plate or nearby, making it a key monitoring area. This paper illustrates influence of different velocities, defect depth and position on the characteristic of flux leakage signals. Result of the numerical simulation provides theoretical principle for application of Magnetic flux leakage (MFL) technique to inspection of heat exchanger pipes. It possesses great significance to enhance the possibility for defect inspection as well.
355
Authors: Xiao Jing Wang, Xiao Dong Yang, Jun Peng Shao, Ji Hai Jiang
Abstract: In order to improve the low speed stationary of continuous rotary electro-hydraulic servo motor and avoid the pressure impact in the sealed cavity during the oil distribution, based on fluid and solid interaction theory, this paper adopted ADINA to analyze the pressure field distribution of sealed cavity in certain radial and axial gap, the computed model of the motor was established, and the pressure change of sealed cavity under the given dimension of the buffer groove was analyzed. The result shows that the pressure changes stably and buffer groove’s dimension is reasonable, which lays foundation for the structure design and experimental research of large displacement servo motor and improve the low speed performance of continuous rotary electro-hydraulic servo motor.
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