scholarly journals Correction of the static characteristic of a frequency converter to reduce the amplitudes of resonance vibrations of the vibrating table

2021 ◽  
Vol 29 (2) ◽  
pp. 117-128
Author(s):  
Alexander S. Vedernikov ◽  
Dmitry I. Dunaev
Keyword(s):  
Output Voltage ◽  
Frequency Control ◽  
Frequency Converter ◽  
Equations Of Motion ◽  
Effective Means ◽  
Control Object ◽  
Static Characteristic ◽  
Static Characteristics ◽  
Acceleration And Deceleration ◽  
Vibrating Table

It is known that vibration systems of directional vibrations based on asynchronous vibration motors are currently widely used in practice, but at the same time they have a significant drawback - a sharp increase in vibration amplitudes when passing through the resonance zone at the time of acceleration and deceleration of vibration motors, which negatively affects their operation. The article discusses a vibration table with two unbalanced asynchronous vibration motors. The calculation scheme and equations of motion of such a vibration system are presented. It is shown that the vibration table as a control object is an oscillatory link with a pronounced resonant frequency. The equations of motion of asynchronous vibration motors with scalar frequency control are given. A structural diagram of a vibration table with unbalanced exciters has been developed, the modeling of which made it possible to determine the amplitudes of resonant oscillations. It is proposed to apply correction of the static characteristics of the frequency converter, which connects the effective value of the output voltage with the frequency, to reduce the resonance amplitudes. Equations of the desired static characteristics of the inverter and analytical dependences for calculating the necessary coefficients for its implementation are given. A computational model has been developed that makes it possible to take into account the effect of the corrected static characteristic of the frequency converter on the operation of the vibrating table at the stages of acceleration and deceleration. The results of computer simulation are given, convincingly showing that the correction of the static characteristics of the inverter is an effective means of reducing the amplitudes of resonant oscillations. It is shown that modern frequency converters have functionality that makes it easy to correct the dependence of the effective value of the output voltage on the frequency. The need to adjust the static characteristics of the inverter for a specific type of product tested on the vibration table is noted.

FREQUENCY CONVERTER WITH THE REDUCED THD OF THE OUTPUT VOLTAGE

2016 ◽  
Vol 2016 (5) ◽  
pp. 14-16 ◽  
Author(s):  
G.V. Pavlov ◽  
◽  
I.L. Vinnichenko ◽  
A.V. Obrubov ◽  
◽  
...  
Keyword(s):  
Output Voltage ◽  
Frequency Converter

Study on the "Phase Hopping" AC-AC Frequency Conversion Method with Approximately Continuous Frequencies

2020 ◽  
Vol 13 (8) ◽  
pp. 1217-1226
Author(s):  
Zhengwang Xu ◽  
Guozhuang Jiang ◽  
Ke Kun ◽  
Yuchun Yi
Keyword(s):  
Output Voltage ◽  
Frequency Conversion ◽  
Frequency Control ◽  
Actual Application ◽  
Power Frequency ◽  
Voltage Frequency ◽  
The Law ◽  
Large Cycle ◽  
Selection Of ◽  
Conversion Technology

Background: The output voltage frequency for the previously proposed "phase hopping" AC-AC frequency conversion technology is determined by the law that the number of output voltage cycles is reduced by one relative to the power frequency in a large cycle containing six jumps. According to the law, only a limited number of output frequencies, such as 37.5 Hz, 42.86 Hz and 45 Hz are found. Due to the large spacing between the output frequencies, the "phase hopping" frequency conversion technology is difficult to put into practical use. Methods: In this paper, the law of the output frequency control is generalized so that the number of output cycles in a large cycle is reduced by n relative to the power frequency. The analysis shows that the appropriate selection of large cycles, including the number of power frequency cycles and the value of n, can find more frequencies to be used. Reducing the interval between the output frequencies within 1Hz. Results: The analysis results were verified in simulation by MATLAB, and the harmonics and the feasibility of the actual application were analyzed. Conclusion: Finally, an experimental platform was built and an experimental analysis was carried out. The experimental results show that the theoretical and simulation analyses are correct.

scholarly journals Analysis and Implementation of a Frequency Control DC–DC Converter for Light Electric Vehicle Applications

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1623
Author(s):  
Bor-Ren Lin
Keyword(s):  
Electric Vehicles ◽  
Output Voltage ◽  
Frequency Control ◽  
Input Voltage ◽  
Pulse Frequency ◽  
Switching Frequency ◽  
Battery Charger ◽  
Dc Microgrid ◽  
Load Voltage ◽  
Transportation Vehicle

In order to realize emission-free solutions and clean transportation alternatives, this paper presents a new DC converter with pulse frequency control for a battery charger in electric vehicles (EVs) or light electric vehicles (LEVs). The circuit configuration includes a resonant tank on the high-voltage side and two variable winding sets on the output side to achieve wide output voltage operation for a universal LEV battery charger. The input terminal of the presented converter is a from DC microgrid with voltage levels of 380, 760, or 1500 V for house, industry plant, or DC transportation vehicle demands, respectively. To reduce voltage stresses on active devices, a cascade circuit structure with less voltage rating on power semiconductors is used on the primary side. Two resonant capacitors were selected on the resonant tank, not only to achieve the two input voltage balance problem but also to realize the resonant operation to control load voltage. By using the variable switching frequency approach to regulate load voltage, active switches are turned on with soft switching operation to improve converter efficiency. In order to achieve wide output voltage capability for universal battery charger demands such as scooters, electric motorbikes, Li-ion e-trikes, golf carts, luxury golf cars, and quad applications, two variable winding sets were selected to have a wide voltage output (50~160 V). Finally, experiments with a 1 kW rated prototype were demonstrated to validate the performance and benefits of presented converter.

scholarly journals Modeling and Analysis of Static and Dynamic Characteristics of Nonlinear Seat Suspension for Off-Road Vehicles

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Zhenhua Yan ◽  
Bing Zhu ◽  
Xuefei Li ◽  
Guoqiang Wang
Keyword(s):  
Vibration Isolation ◽  
Characteristic Curve ◽  
Real Zero ◽  
Low Frequency ◽  
Static Characteristic ◽  
Static Characteristics ◽  
Weight Changes ◽  
Road Vehicles ◽  
Seat Suspension ◽  
Performance Reduction

Low-frequency vibrations (0.5–5 Hz) that harm drivers occur in off-road vehicles. Thus, researchers have focused on finding methods to effectively isolate or control low-frequency vibrations. A novel nonlinear seat suspension structure for off-road vehicles is designed, whose static characteristics and seat-human system dynamic response are modeled and analyzed, and experiments are conducted to verify the theoretical solutions. Results show that the stiffness of this nonlinear seat suspension could achieve real zero stiffness through well-matched parameters, and precompression of the main spring could change the nonlinear seat suspension performance when a driver’s weight changes. The displacement transmissibility curve corresponds with the static characteristic curve of nonlinear suspension, where the middle part of the static characteristic curve is gentler and the resonance frequency of the displacement transmissibility curve and the isolation minimum frequency are lower. Damping should correspond with static characteristics, in which the corresponding suspension damping value should be smaller given a flatter static characteristic curve to prevent vibration isolation performance reduction.

Dynamic Analysis of One-Link Robot Arm Driven by Stepping Motor Using Microstep Drive and Harmonic Reduction Gear

2007 ◽  
Vol 1 (1) ◽  
pp. 20-26
Author(s):  
Hiroyuki Kojima ◽  
◽  
Kengo Motomura ◽  
Yoshifumi Kuwano ◽  
Keiichi Abe ◽  
...  
Keyword(s):  
Equations Of Motion ◽  
Reduction Gear ◽  
Robot Arm ◽  
Stepping Motor ◽  
Transient Vibration ◽  
Two Phase ◽  
Trajectory Tracking Control ◽  
Harmonic Reduction ◽  
Acceleration And Deceleration ◽  
The One

In this paper, first, taking into consideration stepping motor torque and harmonic reduction gear flexibility, the equations of motion of a one-link robot arm driven by a harmonic reduction gear and a hybrid stepping motor using a microstep drive are derived. The stepping motor is excited by two-phase excitation. Then, the numerical simulations of the one-link robot arm's dynamic response for four-division microstep and full-step drives have been carried out, and it is confirmed theoretically that the amplitudes of the vibrating torque of the stepping motor for the microstep drive are considerably smaller than that for the full-step drive, and the transient vibrations of the stepping motor in acceleration and deceleration periods can be reduced using microstep drive. Furthermore, the experiments of the trajectory tracking control of the one-link robot arm have been carried out, and the effects of the microstep drive on the transient vibration reduction of the stepping motor are demonstrated.

Desired Signal Planning of Flexible Arm for Reduction Control of Residual Vibration

2001 ◽  
Vol 13 (1) ◽  
pp. 12-16
Author(s):  
Hiroyuki Kojima ◽  
Keyword(s):  
Control System ◽  
Joint Angle ◽  
Equations Of Motion ◽  
Equation Of Motion ◽  
Pd Controller ◽  
Flexible Link ◽  
Residual Vibration ◽  
Flexible Arm ◽  
Acceleration And Deceleration ◽  
Nonlinear Equations Of Motion

In this paper, first, the nonlinear equations of motion of a horizontal one-link flexible arm are obtained by use of mode functions of a cantilever beam with a mass. Then, the algorithm of the desired signal planning of the joint angle for the purpose of reducing control of residual vibration of the flexible arm is derived by using the initial and final conditions of the flexural displacement of the flexible link and the constraint conditions of the desired signal of the joint angle during the acceleration and deceleration terms as well as the linearized equation of motion of the flexible arm. The rotation control system of the flexible arm is constructed with the desired signal planning for the joint angle and the PD controller. Furthermore, numerical simulations of the rotation control of the flexible arm have been carried out, and it is confirmed that residual vibration of the flexible arm can be effectively reduced by the present desired signal planning for the joint angle.

Detection of Cracks in Rotating Timoshenko Shafts Using Axial Impulses

1991 ◽  
Vol 113 (1) ◽  
pp. 74-78 ◽  
Author(s):  
K. R. Collins ◽  
R. H. Plaut ◽  
J. Wauer
Keyword(s):  
Piecewise Linear ◽  
Equations Of Motion ◽  
Crack Depth ◽  
Effective Means ◽  
Linear Equations ◽  
Free Vibrations ◽  
Frequency Spectra ◽  
Time Histories ◽  
Rotating Shafts ◽  
Linear Equations Of Motion

A rotating Timoshenko shaft with a single transverse crack is considered. The crack opens and closes during motion and is represented by generalized forces and moments. The shaft has simply supported ends, and the six coupled, piecewise-linear equations of motion (including longitudinal, transverse, and torsional displacements) are integrated numerically after application of Galerkin’s method with two-term approximations for each of the six displacements. Time histories and frequency spectra are compared for shafts with no crack and with a crack for which the crack depth is one-fifth of the shaft diameter. Free vibrations and the responses to a single axial impulse and periodic axial impulses are analyzed. The last case appears to provide an effective means for detecting cracks in rotating shafts.

Experiment on Static Characteristics of the Braking Signal Transmitter

2014 ◽  
Vol 889-890 ◽  
pp. 479-482
Author(s):  
Peng Zhang ◽  
Li Nan Zhang ◽  
Hong Zhi Liu ◽  
De Chun Fu
Keyword(s):  
Calibration Curve ◽  
Static Characteristic ◽  
Maximum Pressure ◽  
Static Characteristics ◽  
Test Bed ◽  
Source Pressure ◽  
Gas Source ◽  
Inflection Points ◽  
Test Pressure ◽  
Working Principle

The braking signal transmitter is a major component of the EBS. The structure and working principle of a braking signal transmitter were introduced. The test bed of the braking signal transmitter was designed and built. The static characteristics of the braking signal transmitter were obtained by analyzing the test data. The inflection points and the slope of each segment curve obtained by the bed test are basically identical to the static characteristic calibration curve. The pressure does not reach the maximum pressure of the static characteristic calibration curve because the gas source pressure does not reach the required test pressure. Keywords: Braking signal transmitter, EBS, static characteristics, bed test.

On Obtaining Dynamic and Static Characteristics of Heavy Load Deflection Angle Milling Head by CAE and Experiment Techniques

2010 ◽  
Vol 156-157 ◽  
pp. 771-777
Author(s):  
Li Gang Cai ◽  
Shi Ming Ma ◽  
Zhi Feng Liu ◽  
Qiang Cheng ◽  
Yong Sheng Zhao
Keyword(s):  
Dynamic Characteristics ◽  
Degrees Of Freedom ◽  
Deflection Angle ◽  
Influence Factors ◽  
Static Characteristic ◽  
Free Form ◽  
Static Characteristics ◽  
Cnc Machine ◽  
Heavy Load ◽  
Cae Analysis

The heavy load deflection angle milling head is an important functional component of 5-axis CNC machine tool, which is used for large and complex free-form surface processing. The characteristics of this kind of milling head are implementing multiple degrees of freedom motion with revolution and deflection angle simultaneously. Obtaining milling head dynamic and static characteristics is a pre-requisite problem to resolve for the development and research of heavy load deflection angle milling head independently. Dynamic characteristics are obtained through combination with CAE (Computer-aided Engineering) technique and experiment validation. For CAE analysis, the main parts of milling head are glued together considering milling head operating at a specific position. Experimental validation is carried through with initial fixing constraint style, which validates the correctness of CAE technique. Experimental and CAE analysis results are compared and analyzed. Therefore, exact dynamic characteristics of milling head and unsubstantial segments and its influence factors are gotten. Static characteristic is obtained considering milling head operating in different posture by CAE technique. The analytical method of three points at half of cutter are loaded is introduced. Calculated results indicate that the deformation of tool tip is the largest when milling head operating in 45° posture, which corresponds with the deformation situation of the milling head operating in workshop. The analytical results of dynamic and static characteristics of milling head provide theoretical and experimental support for structure optimization and improving of heavy load deflection angle milling head.

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