【摘要】：永磁同步發(fā)電機是目前風(fēng)力發(fā)電系統(tǒng)中廣泛采用的形式之一。變流器產(chǎn)生的共模電壓會通過電機內(nèi)部雜散電容形成的耦合通路,在電機轉(zhuǎn)軸上產(chǎn)生軸電壓和軸電流,繼而引起軸承早期失效,造成風(fēng)電機組停機、燒毀,帶來巨大損失。同時高頻共模電壓產(chǎn)生的共模電流經(jīng)過定子機殼流入大地,也將帶來諧波干擾。因此對永磁同步風(fēng)力發(fā)電機軸電流問題進行分析并開展共模電流抑制方法的研究具有重要意義。本文首先計算了永磁同步發(fā)電機內(nèi)部的雜散電容參數(shù)。分別給出了表貼式和內(nèi)置式兩種永磁同步發(fā)電機雜散電容的解析計算公式,并根據(jù)多導(dǎo)體系統(tǒng)部分電容理論采用有限元法對雜散電容進行了求解�；谏鲜鰞煞N方法,本文對2.1MW表貼式和內(nèi)置式永磁同步發(fā)電機進行了計算,結(jié)果表明內(nèi)置式電機雜散電容的解析和有限元計算結(jié)果相近,而表貼式電機差別較大,同時分析了誤差產(chǎn)生的原因。其次建立了永磁同步發(fā)電機軸電流等效電路并進行了仿真分析。分別給出了表貼式和內(nèi)置式發(fā)電機軸承分壓比的計算公式,算例表明,相同容量時兩種電機的軸承分壓比相同,且介于變頻電動機和雙饋異步風(fēng)力發(fā)電機之間。隨后本文提出了表貼式永磁同步發(fā)電機的簡化軸電流模型并驗證了其有效性。為了解電機中各電容參數(shù)對軸電壓的影響,文章還對永磁同步發(fā)電機的軸承分壓比進行了靈敏度分析。在MATLAB中建立變流器-永磁同步發(fā)電機系統(tǒng)的仿真模型,預(yù)測了共模電壓、共模電流、軸電壓和軸電流,同時分析了兩種軸電流抑制措施對共模電流的影響,結(jié)果表明軸電流的抑制措施并不能有效地抑制共模電流。然后針對共模電流抑制問題圍繞共模磁環(huán)的電感參數(shù)計算、設(shè)計方案和抑制效果展開研究。綜合考慮共模電壓、電路參數(shù)、電纜線徑、共模電流峰值范圍和磁環(huán)材料特性給出了磁環(huán)設(shè)計方案,針對永磁同步風(fēng)力發(fā)電機進行了磁環(huán)設(shè)計并就抑制效果展開了仿真分析,結(jié)果證明磁環(huán)能夠有效地抑制共模電流。最后本文對軸承等效電氣參數(shù)進行了實驗研究。通過設(shè)計軸承電氣參數(shù)測量實驗方案,分析電機軸承等效電容和擊穿電阻與電機轉(zhuǎn)速和軸承溫度之間的關(guān)系。實驗結(jié)果表明,軸承等效電容與電機轉(zhuǎn)速成反比,與軸承溫度成正比。軸承等效電阻與電機轉(zhuǎn)速成正比,與軸承溫度成反比。
[Abstract]:Permanent magnet synchronous generator (PMSM) is one of the most widely used forms in wind power generation system. The common mode voltage generated by the converter will generate shaft voltage and shaft current on the motor shaft through the coupling path formed by stray capacitors in the motor, which will cause the early failure of the bearing, resulting in the shutdown and burning of the wind turbine, resulting in huge losses. At the same time, the common mode current generated by high frequency common mode voltage flows into the earth through the stator housing, which will also bring harmonic interference. Therefore, it is of great significance to analyze the shaft current of permanent magnet synchronous wind turbine and to study the common-mode current suppression method. In this paper, the stray capacitance parameters of permanent magnet synchronous generator (PMSM) are calculated. The analytical formulas for calculating the stray capacitance of two kinds of permanent magnet synchronous generator (PMSM) are given respectively, and the stray capacitance is solved by finite element method according to the partial capacitance theory of multi-conductor system. Based on the above two methods, the 2.1MW meter-mounted and built-in permanent magnet synchronous generators are calculated in this paper. the results show that the analytical and finite element calculation results of the stray capacitance of the built-in motor are similar to those of the finite element method, but the difference of the table-mounted motor is great. At the same time, the causes of errors are analyzed. Secondly, the shaft current equivalent circuit of permanent magnet synchronous generator is established and simulated. The formulas for calculating the bearing partial pressure ratio of the table type generator and the built-in generator are given respectively. the numerical examples show that the bearing partial pressure ratio of the two kinds of motors is the same at the same capacity, and is between the variable frequency motor and the doubly-fed asynchronous wind turbine. Then, a simplified axial current model of table-mounted permanent magnet synchronous generator (PMSM) is proposed and its effectiveness is verified. In order to understand the influence of capacitance parameters on shaft voltage, the sensitivity analysis of bearing partial voltage ratio of permanent magnet synchronous generator (PMSM) is also carried out in this paper. The simulation model of converter-permanent magnet synchronous generator system is established in MATLAB. The common-mode voltage, common-mode current, axial voltage and axial current are predicted. At the same time, the effects of two kinds of axial current suppression measures on the common-mode current are analyzed. The results show that the suppression measures of axial current can not effectively suppress the common mode current. Then, aiming at the problem of common-mode current suppression, the inductance parameters of the common-mode magnetic ring are calculated, the design scheme and the suppression effect are studied. Considering the common mode voltage, circuit parameters, cable diameter, peak range of common mode current and the material characteristics of magnetic ring, the design scheme of magnetic ring is given. The magnetic ring design of permanent magnet synchronous wind turbine is carried out and the suppression effect is simulated and analyzed. The results show that the magnetic ring can effectively suppress the common mode current. Finally, the equivalent electrical parameters of the bearing are studied experimentally. By designing the experimental scheme of bearing electrical parameter measurement, the relationship between equivalent capacitance and breakdown resistance of motor bearing and motor speed and bearing temperature is analyzed. The experimental results show that the equivalent capacitance of the bearing is inversely proportional to the speed of the motor and proportional to the bearing temperature. The equivalent resistance of the bearing is proportional to the speed of the motor and inversely proportional to the bearing temperature.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TM315

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本文編號：2476771