本文選題：感應電機　切入點：軸承　出處：《大連海事大學》2017年碩士論文　論文類型：學位論文

【摘要】：三相感應電機因其具有結構簡單、運行可靠等優(yōu)點,在工業(yè)生產(chǎn)的各個領域發(fā)揮著重要作用。軸承故障作為發(fā)生概率最高的一種故障形式,很容易導致電機出現(xiàn)不可修復的損壞。因此,對電機軸承故障進行早期故障診斷的研究具有重要的意義。本文針對Blodt提出的軸承故障模型在電機定子電流診斷中的不足,從動力學角度研究軸承故障時的振動表現(xiàn)形式。基于軸承故障引起的轉子重心偏移從而導致的恢復力變化情況,在充分考慮軸承運動過程中負荷分布和受力變化的前提下,搭建了軸承外圈單點故障下的動力學模型。通過模型仿真和解析計算,分析了軸承故障下的振動特性,推導了軸承故障的振動形式、振動頻率、衰減系數(shù)的關系式,最終求得了軸承單點故障時摩擦力矩表達式,給出了軸承故障轉矩變化的新模型。在新模型的基礎上,重新推導了軸承故障時電機定子電流特征頻率的表達式,得到定子電流中各個特征邊頻的幅值隨著故障寬度和電機轉速變化的規(guī)律。通過仿真研究,對不同故障寬度下和不同轉速下的電流頻譜進行比對分析,仿真結果初步驗證了上述結論的正確性。利用軸承動態(tài)摩擦力矩測試臺,實際測試了軸承故障時的摩擦力矩變化情況,驗證了動力學模型的準確性。針對感應電機實際檢測中,軸承故障的弱特征信號易被淹沒在電源基頻附近的高噪聲背景中,不利于軸承故障檢測的情況,設計了諧波注入感應電機軸承故障實驗平臺,把軸承故障特征頻率與注入的較高頻率的諧波相調(diào)制,提高故障特征的可識別性。實驗結果驗證了上述的結論,在結論對正確判斷軸承故障以及故障的嚴重程度提供了有效的理論依據(jù)。
[Abstract]:Because of its simple structure and reliable operation, three-phase induction motor plays an important role in various fields of industrial production. It is easy to cause irreparable damage to the motor. Therefore, it is of great significance to study the early fault diagnosis of the motor bearing fault. This paper aims at the deficiency of the bearing fault model proposed by Blodt in the stator current diagnosis of the motor. Based on the change of the restoring force caused by the rotor center of gravity deviation caused by the bearing fault, the load distribution and the force change in the course of bearing motion are fully considered. The dynamic model of bearing outer ring under single point fault is built. The vibration characteristics of bearing fault are analyzed by model simulation and analytical calculation, and the relationship between vibration form, vibration frequency and attenuation coefficient of bearing fault is deduced. Finally, the expression of friction torque of bearing at single point fault is obtained, and a new model of bearing fault torque change is given. On the basis of the new model, the characteristic frequency expression of stator current of motor under bearing fault is derived again. The amplitude of each characteristic side frequency in stator current varies with the fault width and motor speed. Through simulation, the current spectrum under different fault width and different rotating speed is compared and analyzed. The simulation results preliminarily verify the correctness of the above conclusions. By using the bearing dynamic friction torque test bench, the variation of the friction torque during the bearing failure is tested, and the accuracy of the dynamic model is verified. The weak characteristic signal of bearing fault is easily submerged in the high noise background near the basic frequency of power supply, which is not conducive to bearing fault detection. A bearing fault test platform for harmonic injection induction motor is designed. The characteristic frequency of bearing fault is modulated with the harmonic wave of higher frequency injection to improve the identifiability of the fault feature. The experimental results verify the above conclusion. The conclusion provides an effective theoretical basis for correctly judging the bearing fault and the severity of the fault.
【學位授予單位】：大連海事大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TM346

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本文編號：1643048