Large Induction Motor Based On Dynamic Magnetic Network Method Impedance Parameters And Performance Calculation

The skin effect and saturation effect exist in the starting process of large induction motor,so it is the key to calculate the starting performance of the motor accurately to calculate the saturation effect and saturation effect.Firstly,this dissertation takes a 6500 k W large induction motor as the research object.According to the distribution of magnetic field lines,specific structure and material properties during the operation of the large induction motor,a dynamic magnetic network model is established considering the air gap permeability changes caused by rotor rotation.The node magnetic potential equation is derived and the specific solution process is determined.Then,the skin effect of rotor guide strip caused by the change of motor speed in the process of motor starting is analyzed.Based on this,a calculation method of dynamic inductance parameters considering the skin effect and saturation effect is proposed.Considering the particularity of rotor groove,skin effect model of rotor guide strip was established by stratification method,and skin effect coefficient was obtained.The inductance parameters were modified and calculated by combining dynamic magnetic network model,and the results were compared and analyzed with the finite element results to verify the correctness of the proposed method.Moreover,on the premise of ensuring accuracy,Greatly reduce the modeling difficulty and calculation time of the model.Finally,the dynamic mathematical model of large induction motor based on rotor multi-loop method was derived and established.The dynamic mathematical model,magnetic network model and skin effect model were coupled to solve,and the resistance and inductance parameters in the dynamic mathematical model were modified to achieve the calculation of motor starting characteristics taking into account skin effect and saturation effect.The current of the motor under different operating conditions,the electromagnetic torque,speed and the current density values of each layer of the rotor guide strip of the motor under different slip rates are obtained.The calculated results are compared with the finite element results.The calculated results are similar to the calculated results of the algorithm proposed in this dissertation.