永磁同步风力发电机轴电流与共模电流的分析与抑制
发布时间：2019-05-14 13:58
【摘要】：永磁同步发电机是目前风力发电系统中广泛采用的形式之一。变流器产生的共模电压会通过电机内部杂散电容形成的耦合通路,在电机转轴上产生轴电压和轴电流,继而引起轴承早期失效,造成风电机组停机、烧毁,带来巨大损失。同时高频共模电压产生的共模电流经过定子机壳流入大地,也将带来谐波干扰。因此对永磁同步风力发电机轴电流问题进行分析并开展共模电流抑制方法的研究具有重要意义。本文首先计算了永磁同步发电机内部的杂散电容参数。分别给出了表贴式和内置式两种永磁同步发电机杂散电容的解析计算公式,并根据多导体系统部分电容理论采用有限元法对杂散电容进行了求解。基于上述两种方法,本文对2.1MW表贴式和内置式永磁同步发电机进行了计算,结果表明内置式电机杂散电容的解析和有限元计算结果相近,而表贴式电机差别较大,同时分析了误差产生的原因。其次建立了永磁同步发电机轴电流等效电路并进行了仿真分析。分别给出了表贴式和内置式发电机轴承分压比的计算公式,算例表明,相同容量时两种电机的轴承分压比相同,且介于变频电动机和双馈异步风力发电机之间。随后本文提出了表贴式永磁同步发电机的简化轴电流模型并验证了其有效性。为了解电机中各电容参数对轴电压的影响,文章还对永磁同步发电机的轴承分压比进行了灵敏度分析。在MATLAB中建立变流器-永磁同步发电机系统的仿真模型,预测了共模电压、共模电流、轴电压和轴电流,同时分析了两种轴电流抑制措施对共模电流的影响,结果表明轴电流的抑制措施并不能有效地抑制共模电流。然后针对共模电流抑制问题围绕共模磁环的电感参数计算、设计方案和抑制效果展开研究。综合考虑共模电压、电路参数、电缆线径、共模电流峰值范围和磁环材料特性给出了磁环设计方案,针对永磁同步风力发电机进行了磁环设计并就抑制效果展开了仿真分析,结果证明磁环能够有效地抑制共模电流。最后本文对轴承等效电气参数进行了实验研究。通过设计轴承电气参数测量实验方案,分析电机轴承等效电容和击穿电阻与电机转速和轴承温度之间的关系。实验结果表明,轴承等效电容与电机转速成反比,与轴承温度成正比。轴承等效电阻与电机转速成正比,与轴承温度成反比。
[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.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM315
[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.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM315
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