风电一体化齿轮-发电机系统机电-刚柔耦合动态特性

DYNAMIC CHARACTERISTICS OF ELECTROMECHANICAL-RIGID-FLEXIBLE COUPLING OF WIND TURBINE GEARBOX-GENERATOR INTEGRATED SYSTEM

考虑齿轮的时变啮合刚度、啮合相位以及轴、壳体的柔性等因素,同时计入永磁体的磁饱和特性、电磁力波以及空间谐波等非线性因素,该文构建了8 MW风力发电机一体化齿轮-发电机系统的机电-刚柔耦合动力学模型,并通过实验验证了建模方法的准确性,分析了永磁发电机电磁激励对齿轮-发电机系统机电耦合动态特性的影响,同时采用升速分析法,结合模态振型矢量分布,讨论从切入风速至额定风速运行过程中的潜在共振转速和危险构件。研究发现:对于一体化齿轮-发电机系统而言,电磁力是系统主要的内激励,对齿轮系统振动特性影响显著。同时,机械系统与电气系统存在强耦合特性,机械系统振动信号中存在电磁激励频率,发电机电磁转矩与电流信号中出现了齿轮系统的各级啮合频率。系统共振的产生条件为激励频率接近某阶固有频率,同时激励源和该阶模态下的主要振动构件处于传动链中的同一位置。

Considering the time-varying meshing stiffness and meshing phase,flexible shaft and housing,as well as the nonlinear factors of generator such as magnetic saturation characteristics,electromagnetic waves and space harmonics,the rigid-flexible electromechanical coupling dynamics model for the integrated gear-generator system of 8 MW wind turbine is established.The modeling method is verified by experiment.The influence of electromagnetic excitation on the dynamic characteristics of the integrated system is studied.Speed-sweep analysis method,combined with modal vector distribution principle,are proposed to predict the potential resonance speed and search the dangerous components,during the operation process from start-up wind speed to rated wind speed.It is demonstrated that electromagnetic force is the main internal excitation for the integrated gear-generator system,which has a significant influence on the system vibration characteristics.There is a strong coupling effect between the mechanical system and the electrical system.Gear systems are affected by electromagnetic excitation,and the excitation frequency of the gear system also appears in the generator current and electromagnetic torque signal.The system resonance only happens,when the excitation frequency is close to a certain order natural frequency,and the excitation source and main vibration component in this order mode are in the same position as well.