Current Issue : October-December Volume : 2021 Issue Number : 4 Articles : 5 Articles
)e aim of this study is to make a general exploration of the dynamic characteristics of the permanent magnet synchronous motor (PMSM) with parametric or external perturbation. )e pitchfork, fold, and Hopf bifurcations are derived by using bifurcation theory. Simulation results not only confirm the theoretical analysis results but also show the Bogdanov–Takens bifurcation of the equilibrium. Dynamic behaviors, such as period three and chaotic motion of PMSM, are analyzed by using bifurcation diagram and phase portraits. )e symmetric fold/fold bursting oscillation as well as two kinds of delayed pitchfork bursting oscillations is obtained, and different mechanisms are presented....
*is study performs a dynamic modeling and analysis of the axial uniform demagnetization rotor of a motor to investigate the demagnetization peculiar for permanent magnet synchronous motor (PMSM). First, the air-gap change in the motor is analyzed by constructing a dual coordinate system of stator and rotor, and the unbalanced magnetic pull (UMP) model under uniform demagnetization and eccentricity is constructed. Second, combined with theUMPand the self-gravity, a dynamic model of the rotor under a uniform demagnetization and eccentricity is established. Lastly, the accuracy of the mathematical model of UMP under uniform demagnetization and eccentricity is confirmed by the mutual corroboration of Maxwell simulation and MATLAB calculation; and based on the dynamics model, the dynamic characteristics of the rotor system under different degrees of uniform demagnetization are studied. *is study provides a theoretical basis for the accurate demagnetization fault diagnosis and vibration control of PMSMs in the future....
This paper presents a novel idea of utilizing the reactional torque of the conventional electric motor as a linear output for propulsion in addition to the conventional torque output of the rotor. The idea is demonstrated by a theoretical proposal of linearizing the stator of one of the most used motors in Electrical Vehicles and Hybrid Vehicles. The proposed Linear Stator Motor is a simple modification without involving any functional change of the conventional motor. Though theoretical, the indicated possible input energy saving of more than 75% as compared to the conventional motor is no surprise, as by linearizing the stator, an almost equal linear propulsion output is added to the conventional rotor output. In addition to this remarkable saving in input energy, the proposed Linear Stator Motor that suits all types of vehicles, can maintain propulsion without the need for a mechanical transmission system. Also, in the case of watercraft and aircraft vehicles, no external mechanical propulsion drive system is required. It is just an internal force that can push the vehicle forward, backward, or laterally, while the conventional rotor output can be utilized for energy recovery by driving a DC generator....
The article presents a new method of counteracting shaft voltages and currents in AC electrical machines. It is based on the use of an auxiliary winding located in the stator of the machine. The design of a test stand adapted to the measurement of shaft voltages of the machine, based on the prototype of a synchronous machine with permanent magnets, has been presented. The model was used to conduct a number of laboratory tests aimed at confirming the functionality of the auxiliary winding in various operating states of the machine (including no-load and load condition during generator operation). The article focuses on demonstrating the beneficial effect of the auxiliary winding on the level of induced shaft voltages in an electric machine. In order to confirm the close dependence of the circular flux in the stator yoke on the shaft voltage, shaft voltage measurement results for various cases of external power supply of auxiliary winding forcing a circular flux are presented. Regardless of the laboratory tests, a simulation model of a synchronous machine with permanent magnets, on which calculations were carried out to analyze the work of the auxiliary winding located in the stator yoke, was developed. The article is supplemented by a review of damage to electrical machines with a detailed description of bearing defects, as well as a brief de-scription of issues related to the mechanism of generating shaft voltages and currents in electrical machines and methods of counteracting them....
The vibration signal of rotating machinery compound faults acquired in actual fields has the characteristics of complex noise sources, the strong background noise, and the nonlinearity, causing the traditional blind source separation algorithm not be suitable for the blind separation of rotating machinery coupling fault. According to these problems, an extraction method of multisource fault signals based on wavelet packet analysis (WPA) and fast independent component analysis (FastICA) was proposed. Firstly, according to the characteristic of the vibration signal of rotating machinery, an effective denoising method of wavelet packet based on average threshold is presented and described to reduce the vibration signal noise. In the method, the thresholds of every node of the best wavelet packet basis are acquired and averaged, and then the average value is used as a global threshold to quantize the decomposition coefficient of every node. Secondly, the mixed signals were separated by using the improved FastICA algorithm. Finally, the results of simulations and real rotating machinery vibration signals analysis show that the method can extract the rotating machinery fault characteristics, verifying the effectiveness of the proposed algorithm....
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