Diagnostics of an asynchronous motor powered from a self-commutated voltage inverter

International Conference on Mechanical Engineering, Automation and Control Systems 2018

Zhukovskiy, Y.L.^1 ; Korolev, N.A.^1 ; Koteleva, N.I.^1

St. Petersburg Mining University, 2, 21 Line of Vasilyevsky Island, St. Petersburg

199106, Russia^1

关键词: Amplitude of oscillation;    Autonomous inverters;    Current consumption;    Electrical parameter;    Incomplete information;    Low and medium power;    Non-sinusoidal voltage;    Technical conditions;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/560/1/012171/pdf
DOI  :  10.1088/1757-899X/560/1/012171

来源: IOP

【 摘 要 】

The presented research is focused on two issues. The first one is finding additional parameters that characterize the technical condition of an electric machine according to the current consumption. The second one is increasing of the informativeness of diagnostic methods in conditions of limited access to equipment and incomplete information. The paper discusses a method for diagnosing low and medium power asynchronous electric motors by electrical parameters. It is shown that asynchronous electric motors powered from a self-commutated voltage inverter have contained higher harmonic components in addition to the main harmonic. The non-sinusoidal voltage leads to the emerging of the highest current components in the stator winding of the motor. This is the reason for occurring of a pulsating component of the torque on the motor shaft. Therefore, there are two types of ripple: the one caused by the power supply from the self-commutated inverter and the one caused by defects. The moments' coincidence of these ripples leads to increasing in the amplitude of oscillations. However, significant noise due to the presence of an autonomous inverter does not allow using the current spectrum to diagnose damage. Analysis of the hodographs of the Park's vector of the stator current and voltage allows one to exclude harmonic components that were formed by the carrier frequency (and multiple of it). At the same time, analyzing the modulus of the Park's vector and its spectrum, one can note pulsations of the amplitude values of the vector modulus corresponding to certain damage.