不同故障情况对并网型半直驱永磁风力发电机影响的研究

发布时间：2018-05-13 17:54

本文选题：半直驱永磁风力发电机 + 断路故障　；参考：《北京交通大学》2016年硕士论文

【摘要】：风力发电是新能源发电的一个重要组成部分,目前,我国风力发电机的装机容量是世界上新增装机容量和累计装机容量最多的国家。半直驱永磁风力发电机综合了双馈风力发电机和直驱永磁风力发电机的优点,是未来风电发展的主要发展趋势之一。作为风电并网的核心部件,半直驱永磁风力发电机在运行过程中受到高温、振动等影响,易发生断路、失磁或短路等故障情况,同时由于风能的随机性和间歇性,发电机经常在不同风速下运行,因此对不同风速运行时故障后特征量的准确计算可以为半直驱永磁风力发电机在线监测和故障诊断提供参考依据,具有十分重要的现实意义。本文以一台1.5MW、32极半直驱永磁风力发电机为研究对象,基于电磁场理论,建立了半直驱永磁风力发电机二维场—路耦合数学模型,基于该模型对发电机断路、短路及失磁故障后的特征量进行了研究。首先,计算了发电机额定风速运行时的支路断路故障和单相断路故障,重点分析了故障前后的发电机相电压、相电流和气隙磁场；在此基础上,研究了不同风速发电机运行时,断路故障对发电机电磁场的影响。其次,建立了发电机额定风速运行时的三相短路故障、接地短路故障模型,研究了短路故障时发电机的相电流和转矩；并分析了不同风速下发电机三相短路故障对发电机相电流的影响。再次,重点研究了发电机额定风速运行时的一个单元结构内不同位置永磁体失磁故障,计算了发电机失磁故障的支路电流、漏磁系数、极弧系数等参数；同时以相邻两块永磁体失磁故障为例,分析了发电机在不同风速下运行时该故障对发电机电磁场的影响。最后,考虑发电机在发生失磁故障后,继电装置未切除发电机的情况下,可能出现的失磁断路复合故障和失磁短路复合故障,以失磁断路复合故障、失磁三相短路复合故障、失磁接地短路复合故障为例,研究了复合故障对发电机电流的影响。为了验证失磁故障计算方法的准确性,本文用该方法对一台相似结构的小型永磁风力发电机单块永磁体失磁故障进行仿真计算,并将计算结果和实验结果对比,误差在合理范围内。通过对上述各故障的研究,可得到不同故障情况对发电机电流、电压、电磁转矩等参数的影响，为永磁风力发电机在线监测和故障诊断提供了参考依据。
[Abstract]:Wind power generation is an important part of new energy generation. At present, the installed capacity of wind turbines in China is the largest in the world. The semi-direct-drive permanent magnet wind turbine integrates the advantages of doubly-fed wind turbine and direct-drive permanent magnet wind generator, and is one of the main development trends of wind power in the future. As the core component of wind power grid connection, the semi-direct-drive permanent magnet wind turbine is affected by high temperature, vibration and so on during its operation. It is prone to break the circuit, lose magnetic field or short circuit, and because of the randomness and intermittency of wind energy, Generators often operate under different wind speeds. Therefore, the accurate calculation of fault characteristics for semi-direct-drive permanent magnet wind turbines can provide a reference for on-line monitoring and fault diagnosis of semi-direct-drive permanent magnet wind turbines, which is of great practical significance. In this paper, a 1.5MW-32 pole semi-direct-drive permanent magnet wind turbine is taken as the research object. Based on the theory of electromagnetic field, a two-dimensional field-circuit coupling mathematical model of semi-direct-drive permanent magnet wind turbine is established, based on which the generator is cut off. The characteristics of short-circuit and lost-excitation fault are studied. First of all, the branch and single-phase fault of generator with rated wind speed are calculated, and the phase voltage, phase current and gap magnetic field of generator before and after the fault are analyzed, and on the basis of this, the operation of generator with different wind speed is studied. The effect of Breaking Fault on electromagnetic Field of Generator. Secondly, the three-phase short-circuit fault and grounding short-circuit fault model of generator with rated wind speed are established, and the phase current and torque of generator under short-circuit fault are studied. The effect of three-phase short-circuit fault on generator phase current under different wind speed is analyzed. Thirdly, the failure of permanent magnet in different positions in one unit structure is studied, and the parameters of the fault, such as branch current, flux leakage coefficient and pole arc coefficient, are calculated. At the same time, taking two adjacent permanent magnets as an example, the effect of the faults on the electromagnetic field of generators under different wind speeds is analyzed. Finally, when the generator has lost its magnetic field and the relay device has not excised the generator, the compound fault of the lost magnetic circuit and the composite fault of the lost magnetic circuit are considered, so that the compound fault of the lost magnetic circuit and the three-phase short circuit of the lost excitation are taken into account. The influence of compound fault on generator current is studied. In order to verify the accuracy of the calculation method for the loss of magnetic field, this paper uses this method to simulate the failure of a single permanent magnet of a small permanent magnet wind generator with similar structure, and compares the calculated results with the experimental results. The error is within a reasonable range. Through the study of the above faults, the influence of different fault conditions on the generator current, voltage, electromagnetic torque and other parameters can be obtained, which provides a reference for the on-line monitoring and fault diagnosis of permanent magnet wind turbine generator.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM315

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