电励磁同步发电机损耗的分析研究

【作者】 张磊；

【导师】 吴新振；

【作者基本信息】 青岛大学 ， 电气工程， 2020， 硕士

【摘要】 现代使用的交流电能几乎全由同步发电机产生,三相同步发电机具有供电品质好、带载能力强等优点,广泛应用于大容量电力系统或独立电力系统中,随供电量的不断提高,开发高效发电机显得尤为重要。同步发电机运行中存在多种损耗,这些损耗会导致电机发热,若局部过热严重,则会影响发电机性能,降低电机使用寿命,因而准确计算同步发电机损耗对提高电机效率与估算其使用寿命具有重要意义,本文从理论分析与数值计算两方面研究同步发电机的损耗,并探究降耗的措施。研究电磁现象的主要依据麦克斯韦方程组,分别介绍四个定律及电磁场有限元求解步骤。基于麦克斯韦方程组建立同步发电机空载及负载下的有限元模型,为电机损耗的计算打下基础。分别介绍了基本铁耗、空载/负载情况下转子附加损耗、铜耗的理论及计算方法。考虑电机齿槽效应,得到计及谐波的铁耗分离模型,分别采用解析法与有限元法计算电机空载/负载下定子基本铁耗,对比分析两个方法下的计算结果。基于建立的空载/负载模型,通过瞬态场计算得到所研究样机两种工况下转子附加损耗。利用解析公式计算电机的定、转子相电阻,进而求得定、转子铜耗。采用控制变量的方法分别研究磁性槽楔、定子槽口宽度、定子导体股数、股线换位等参数对电机损耗的影响。探讨槽楔取不同相对磁导率情况下电机气隙系数、磁场、定子槽漏抗、损耗的变化情况。利用有限元法得到定子铁耗随定子槽口宽度的变化关系。给出定子导体不同股数下电阻增加系数公式,得到定子附加铜耗与定子导体股数的变化关系。介绍计算股线换位的漏感电势法与多截面场路耦合法,对比两方法下不足换位的股线漏感电势、电流及损耗,验证漏感电势法在样机损耗计算中的有效性。本文所做的工作可对同步发电机设计与优化提供理论指导。更多还原

【Abstract】 The AC power used in modern times is almost entirely generated by synchronous generators.Three-phase synchronous generators have the advantages of good power supply quality and strong load capacity.They are widely used in large-capacity power systems or independent power systems.With the continuous increase of power supply,The development of efficient generators is particularly important.There are various losses in the operation of the synchronous generator.These losses will cause the motor to heat up.If the local overheating is severe,it will affect the performance of the generator and reduce the service life of the motor.Therefore,accurately calculating the loss of the synchronous generator will improve the efficiency of the motor and estimate its service life It is of great significance.This paper studies the loss of synchronous generators from theoretical analysis and numerical calculation,and explores measures to reduce consumption.The main study of electromagnetic phenomena is based on Maxwell’s equations,introducing four laws and the steps of solving electromagnetic field finite element.Based on Maxwell’s equations,the finite element model of the synchronous generator under no-load and load is established to lay the foundation for the calculation of motor losses.The theories and calculation methods of basic iron loss,rotor additional loss and copper loss under no-load / load conditions are introduced respectively.Considering the cogging effect of the motor,the iron loss separation model considering harmonics is obtained.The analytical method and the finite element method are used to calculate the basic iron loss of the stator under no-load / load of the motor.Based on the established no-load / load model,the additional loss of the rotor under the two working conditions of the prototype under study is calculated by the transient field.Use the analytical formula to calculate the stator and rotor phase resistance of the motor,and then obtain the stator and rotor copper consumption.The influence of parameters such as magnetic slot wedge,stator slot width,stator conductor strands,strand transposition,etc.on the motor loss was studied by using control variables.Discuss the changes of air gap coefficient,magnetic field,stator slot leakage reactance and loss under different relative permeability of slot wedge.The finite element method is used to obtain the relationship between the stator iron loss and the stator slot width.The formula of the resistance increase coefficient under different strands of the stator conductor is given to obtain the relationship between the additional copper loss of the stator and the number of strands of the stator conductor.Introduce the leakage inductance potential method and the multi-section field-circuit coupling method for calculating strand transposition.Compare the leakage inductance potential,current and loss of strands under transposition under the two methods to verify the effectiveness of the leakage inductance potential method in the calculation of prototype loss.The work done in this paper can provide theoretical guidance for the design and optimization of synchronous generators.更多还原