Performance identification of the asynchronous electric drives by the spectrum of rotor currents (original) (raw)
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The dynamics identification of asynchronous electric drives via frequency response
International Journal of Power Electronics and Drive System (IJPEDS), 2019
The article substantiates the necessity of identifying the dynamics of asynchronous electric drives with frequency control. It is proposed to use nonlinear transfer functions and the formula of a family of frequency responses of an electric drive, depending on the frequency of the stator voltage and slip. Experiments and simulations confirming theoretical conclusions are presented. The frequency responses of the drive of the stand calculated by the proposed method allowed to explain those problems of frequency control that were not explained by traditional methods - analytical, vector diagrams, substitution schemes, etc. This same technique allowed us to formulate a structural correction of the asynchronous electric drives. In contrast to the previously published research materials of asynchronous electric drives, a detailed qualitative analysis of the obtained nonlinear frequency responses and the interrelation of these characteristics with experimental results is shown for the first time in the article.
International Journal of Power Electronics and Drive System (IJPEDS) , 2020
The article is a continuation of the authors' work in research, mainly experimental, asynchronous electric drives with frequency regulation (AED FR) of hoisting-and-transport mechanisms, in which for constructive, operational and other reasons it is difficult to install additional sensors, for example encoders. The results of the analysis of the dynamics of AED FR with two types of sensorless control: vector and scalar are presented in this article. The study was conducted by mathematical modeling in the Simulink application of the MatLab software using standard control system models. The processes of sequential acceleration of the engine to fixed speeds with overload and load shedding on each of them were simulated. At the same time, the speed and effective values of the flux linkages of the rotor and stator and the stator current were monitored, by which the dynamics and efficiency of each type of control were evaluated. As in experimental studies, the dynamic and efficiency of a more stable scalar control was significantly improved by the use of dynamic positive feedback on stator current.
International Journal of Engineering Research and Technology (IJERT), 2012
https://www.ijert.org/investigation-of-effect-of-harmonicson-air-gap-flux-density-and-torque-performance-of-asynchronous-machine-invariable-speed-drive-systems https://www.ijert.org/research/investigation-of-effect-of-harmonicson-air-gap-flux-density-and-torque-performance-of-asynchronous-machine-invariable-speed-drive-systems-IJERTV1IS10035.pdf Application of Variable speed drives in industrial applications has reached to highest percentage in the global industry sector. Even though many analytical and digital techniques available till today, still there is need for improvement of VSD system performance along with protection of supply voltage and current profiles. Theeffect of harmonics on air gap flux density of rotating machine and itsfurther effect on torque performance, harmonics injected by power electronic switching converters intothe rotating magnetic devices are investigated in this paperby considering generalized model of electrical machine [1] as a prerequisite for later work on optimization of Variable Speed Drive (VSD) system. Investigation of harmonics carried out on Induction Motor fed by ac-dc-ac converter system and fed by pure sinusoidal ac supply system. The special harmonic analyzer [5, 6] proposed by the authors comprises of investigation of harmonics using FFT analysis used for harmonic analysis of both converter and induction motor. The aim of proposed work is to investigate converter level harmonics and its effects on air gap flux density and further torque performance issues. The MATLAB Simulink models of Induction Motor is used for analysis and machine with typical parameters used for the purpose of practical measurements. A general switching converter circuit along with PWM inverter is in the induction motor drive. The results obtained from these methods show good agreement with the practical methods.
Mechanical Systems and Signal Processing, 2014
In the paper dynamic electromechanical interaction between the rotating machine drive system and the electric driving motor is considered. The investigations are performed by means of the circuit model of the asynchronous motor as well as using an advanced structural hybrid model of the drive system. Using the analytical solutions applied for the electrical and the mechanical systems the electromagnetic stiffness and coefficient of damping, both generated by the electric motor rotationally interacting with the mechanical system of the given dynamic properties, were determined. By means of experimentally validated computational responses obtained for torsional harmonic excitation induced by the driven machine working tool, a modification of dynamic properties of the mechanical system by the electromagnetic flux between the stator and the rotor has been studied.
A general approach of space and time harmonics interactions in induction motors
IEEE International Electric Machines and Drives Conference. IEMDC'99. Proceedings (Cat. No.99EX272), 1999
The interactions of space and time harmonics must be consideredl precisely during the design process of induction machines to achieve good motor performance. They also influence the harmonic content of the stator currents which can be used for sensorless speed detection or to monitor Internal defaults ol' the machine. In this paper, the authors are using a general representation of time and space harmonics in induction machines, to explain their mechanism of production and their interactions. A simple analytical method is derived to quantify precisely the harmonic content of the instantaneous torque, currents and flux in both stator and rotor windings, in terms of fixed parameters of the machine structure. The method is validated by field calculation and experimental tests. 0-7803-!3293-9/99 $10.00 0 1999 IEEE
Methodology for Asynchronous Motor Impedance Measurement by Using Higher Order Harmonics
Energies
The control methods of asynchronous motors have changed during past decades. In the past, asynchronous motors were connected to grid directly. Later, thyristors as switching element-based frequency converters for asynchronous motors have appeared. Today, asynchronous motors are controlled with variable speed drives that are frequency converters consisting of IGBT power modules as switching elements that form the output voltage for asynchronous motors. Because of IGBT’s high switching speed of around few kilohertz, higher order harmonics appear in the output voltage. Their influence was not analyzed in the past as the methodology of asynchronous motor winding resistance measurement was under development. In this article, a new methodology of motor resistance measurement for mass production is introduced. The resistance—compared to higher order harmonics values between the windings of benchmark and tested motors—gives an ability to faster and more accurately determine a motor’s charac...
The use of induction motor line current harmonics in drive system applications : A survey
2006
The line current spectrum of an induction motor normally contains a variety of harmonics of different magnitudes and frequencies from a variety of different sources. Signal processing techniques are used to extract the useful information contained in the line current harmonics. In this paper several different applications of induction motor line current spectrum are reviewed. First, the origin and the producing mechanism of the line current harmonics and the factors which affect these harmonics are explained. Then the applications of these harmonics from sensorless speed control to condition monitoring are explained.
Intelligent built-in torque sensor for harmonic drive systems
IEEE Transactions on Instrumentation and Measurement, 1999
The unique performance features of harmonic drives, such as highs gear ratios and high torque capacities in a compact geometry, justify their widespread industrial application especially in many electrically actuated robot manipulators. In many robotic control strategies it is assumed that the actuator is acting as a torque source, and in order to implement such algorithms it is necessary to accurately measure the transmitted torque by the harmonic drive. In this paper a built-in torque sensor for harmonic drive systems is developed and examined in detail, in which strain-gauges are directly mounted on the harmonic drive flexspline. To minimize sensing inaccuracy, four Rosette strain gauges are used employing an accurate positioning method. To cancel the torque ripples, the oscillation observed on the measured torque and caused mainly by gear teeth meshing, Kalman filter estimation is used. A simple fourth order harmonic oscillator proved to accurately model the torque ripples. Moreover, the error model is extended to incorporate any misalignment torque. By on line implementation of the Kalman filter, it has been shown that this method is a fast and accurate way to filter torque ripples and misalignment torque. Hence, the intelligent built-in torque sensor is a viable and economical way to measure the harmonic drive transmitted torque and to employ that for torque feedback strategies.
Development of a mathematical model of frequency controlled induction electric drive
Journal of Vibroengineering
A mathematical model of a frequency-controlled induction (asynchronous) electric drive is proposed, which makes it possible to study electromagnetic and electromechanical processes in an electric drive with any drive mechanism and takes into account the non-sinusoidality of the output voltage of the frequency converter. The block diagram of the algorithms of calculations performed in the "Mathcad" computer application, the results of modeling and their analysis are presented.