Vladimir L. Kodkin
South Ural State University

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The experimental identification method of the dynamic efficiency for frequency regulation algorithms of AEDs Vladimir L. Kodkin; Aleksandr S. Anikin
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 12, No 1: March 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v12.i1.pp59-66

Abstract

The article proposes and substantiates a method for studying the dynamics of an asynchronous electric drives with frequency control from the input side of the signal for setting the speed of rotation of the electric motor. In this method, a constant speed reference signal is added to a harmonic variable frequency signal. The set of amplitude changes and phase shifts of velocity oscillations are the initial data for identifying the dynamics of the studied control method. The logic of this method is determined by the previously obtained nonlinear transfer function of the link that forms the mechanical moment in the asynchronous electric drive with frequency control. Experiments have shown the dynamic benefits of the drive with positive stator current feedback.
Stabilization of the stator and rotor flux linkage of the induction motor in the asynchronous electric drives with frequency regulation Vladimir L. Kodkin; Aleksandr Sergeevich Anikin; Aleksander Aleksandrovich Baldenkov
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 11, No 1: March 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (14.949 KB) | DOI: 10.11591/ijpeds.v11.i1.pp213-219

Abstract

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.
Performance identification of the asynchronous electric drives by the spectrum of rotor currents Vladimir L. Kodkin; Aleksandr Sergeevich Anikin; Aleksandr A. Baldenkov
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 10, No 1: March 2019
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (543.04 KB) | DOI: 10.11591/ijpeds.v10.i1.pp211-218

Abstract

The efficiency of analyzing the rotor currents of asynchronous electric drives with frequency control is substantiated in the article. To assess the quality of torque generation in the engine it is suggested to use the spectral analysis of these currents and the fundamental harmonic, as the most accurate "conformity" of slip in an asynchronous motor. The proposed method showed that "sensorless vector" control leads to the appearance of high-frequency harmonics with significant amplitude. Because of these harmonics, a non-sinusoidal electromagnetic moment is created and the performance of the drive is decreased. The most effective method of torque generation is the frequency control with positive stator current feedback. This control is dominated by pronounced harmonic components, which indicates the proximity of this structure to linear and significantly better controllability of the drives, which makes promising their use in high-tech mechanisms, in particular, in industrial robots. Simulation and experiments confirm the proposed theoretical propositions.
Experimental study of the VFD’s speed stabilization efficiency under torque disturbances Vladimir L. Kodkin; Aleksandr S. Anikin
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 12, No 1: March 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v12.i1.pp80-87

Abstract

The article presents a technique for experimental research of variable frequency drives experiencing periodic torque disturbances of variable frequency. The technique is based on the nonlinear transfer function of a link of an asynchronous electric motor, which forms an electromagnetic torque, proposed in previously published articles. The dependence of the transfer function on the frequency of the stator voltage and slip determines the research methodology. Experiments have shown the advantage of the dynamic characteristics of a drive with a positive feedback on the stator current over electric drives with traditional control methods (vector and scalar sensorless), and in terms of dynamic characteristics they also exceed drives with a vector control closed in motor speed. These advantages are retained when the frequency of change of the disturbing torque is changed from 0 to 5 Hz.
Structural correction of nonlinear dynamics of frequency-controlled induction motor drives Vladimir L. Kodkin; Aleksandr Sergeevich Anikin; Aleksandr Aleksandrovich Baldenkov
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 11, No 1: March 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (13.378 KB) | DOI: 10.11591/ijpeds.v11.i1.pp220-227

Abstract

Frequency analysis of processes in the frequency-controlled induction motor drive s, as in automatic control systems with dynamic non-linearities, are presented in this paper. For the first time, dynamic formulas of transfer functions of a torque driver in an induction motor with frequency control, taking into account the slip and frequency of the stator voltage, are proposed. Methods for constructing families of frequency characteristics of such electromechanical systems with “frozen” but different values of the frequency of the stator voltage and slip are described. The frequency characteristics corresponding to these transfer functions are constructed in the Simulink application of the MatLab software. Based on results of the analysis the structural correction methods that improve the dynamics of such nonlinear systems are proposed. The nonlinear transfer functions obtained in this work made it possible to substantiate structural solutions that linearize frequency-controlled electric drives and significantly increase their efficiency. This paper is an example of how the initial complicated (but more accurate) interpretation of nonlinearity allowed us to find a new best solution to the problem of controlling a complex dynamic object.