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1

Application of Spectral and Wavelet Analysis of Stator Current to Detect Angular Misalignment in PMSM Drive Systems

Pietrzak Przemysław, Wolkiewicz Marcin

Power Electronics and Drives

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2021

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Vol. 6 (41)

42--60

EN

This paper deals with the selected methods of detecting angular misalignment in drive systems with a permanent magnet synchronous motor (PMSM), which are based on the analysis of the stator phase current signal, as well as their experimental verification and comparison. The proposed and compared methods are spectral analysis and wavelet analysis of the stator current, stator current envelope, stator current space vector module. Furthermore, the influence of power supply frequency and load torque on the performance of the proposed diagnostic methods is also discussed. The experimental tests were carried out for an undamaged motor and for two levels of angular misalignment. The article discusses the question of exactly what damage symptoms can be extracted from each of the methods. In the case of spectral analyses, it is demonstrated which multiplicities of the failure frequency are the most sensitive to misalignment and the least sensitive to changes in motor operating condition, which may be considered novel in the case of drive systems with permanent magnet motors. It is also proven that discrete wavelet transform (DWT) of the envelope and monitoring of the value of the relevant components allows the detection of misalignment with the availability of measuring current only in one phase in various motor operating conditions.

2

Infulence of Geometry Imperfections on Flexural-Torsional Vibrations in Rotating Systems

Łazarz B., Matyja T.

Machine Dynamics Research

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2015

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Vol. 39, No. 2

97-110

EN

In paper we investigated the influence of geometry imperfections on coupled flexural-torsional vibrations in the transient states, at start-up, in rotating systems. Consideration was given to two types of errors: the permanent deflection of a shaft in place of rotors installation (shaft bow) and inclination of a rotor plane with respect to the designed axis of rotation of the machine (angular misalignment). Used was the specialist Simulink library developed by the authors.

3

Analiza dynamiki wentylatora promieniowego w warunkach niewspółosiowości wałów wirnika i silnika

Zachwieja J.

Diagnostyka

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2010

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nr 1(53)

61-70

PL

Istotnym problemem jaki występuje w diagnozowaniu maszyn wirnikowych jest poprawna identyfikacja symptomów ich uszkodzeń. W przypadku grupy maszyn przepływowych, do której należą przemysłowe wentylatory promieniowe, najczęściej występującymi uszkodzeniami są: niewyważenie wirnika, defekty łożysk oraz niewspółosiowość wałów. Tryb pracy ciągłej urządzeń powoduje, że często niemożliwe jest wyłączenie maszyny i bezpośredni pomiar wartości równoległego przesunięcia i względnego kąta obrotu osi wałów. Dlatego rzeczą istotną staje się poszukiwanie symptomów tego typu uszkodzenia metodami pośrednimi, dającymi duży stopień pewności w przewidywaniu wpływu niewspółosiowości wałów na dynamikę pracy wentylatora. Zagadnienia te zostały omówione w artykule.

EN

An important problem connected with turbomachine diagnostics is identifying its failure symptoms. In case of the fluid-flow machines, which include industrial centrifugal fans, the most common failures are: a rotor's unbalance, bearings defect and a shaft misalignment. Continuous operation mode results in a fact that it is often impossible to disengage the machine and take a direct measurement of the translation and shaft axes' angle of relative revolution. Therefore an important thing is to determine the symptoms of a failure using indirect methods and a possibility to predict the influence of shafts misalignment on fan operation dynamics. These problems were discussed in this article.