Design And Analysis Of MW-level High Voltage Line-start Permanent Magnet Synchronous Motor

With the rapid development of modern economy and industry,the contemporary ecological environment has encountered more and more problems.We are facing the crisis that natural resources are constantly being consumed and exhausted.Energy conservation is an urgent task,and energy conservation and consumption reduction are the current solutions to energy problems.For China 's motor industry,the development of high-efficiency motors can achieve the purpose of energy saving.At present,in industrial and agricultural production,production machinery such as fans and pumps need to run continuously at a constant speed,often driven by several hundred kilowatts and megawatt-level induction motors,However,induction motors have the disadvantages of generally low efficiency and power factor,and a narrow economic operating range,which will cause a lot of waste of electrical energy in practical applications.As a linestart permanent magnet synchronous motor that combines the structural characteristics of permanent magnet motors and induction motors,it does not require a frequency conversion adjustment system,and it has the advantages of high-power factor,high efficiency,and wide economic operating range.The development prospect is good,but at the same time permanent magnet synchronous motors also have problems such as higher starting current and large cogging torque.This paper designs a 6kV,1120 kW line-start permanent magnet synchronous motor according to the rated parameters and performance requirements of the motor.The main work contents are as follows:Firstly,consult the relevant domestic and foreign literature of the subject,explain the background,significance and research status of the subject of this article,and then complete the design of the line-start permanent magnet motor based on the rated parameters and performance requirements of the motor,including: the determination of the main size of the motor design of stator and rotor blanks,selection of stator windings,determination of permanent magnet size and placement form.Secondly,for the problem of excessive cogging torque of permanent magnet synchronous motors,analyze the cause of cogging torque and use analytical method to get the analytic expression of cogging torque.The finite element method is used to analyze the influence of the magnetic slot wedge,stator skew slot and uneven air gap structure on the cogging torque,and measures are given to effectively weaken the cogging torque.Then,analyze the starting process of the motor,and use the Taguchi method to study the influence of the four variables of rotor slot number,rotor slot height,rotor slot width and bridge arch height on the motor starting performance and steady state torque ripple,by processing and analyzing the simulation data,the influence proportion of variables on the optimization target is obtained,and then the optimal rotor slot parameters are obtained,and the no-load and load simulation analysis of the motor by finite element is performed to verify the rationality of the designed motor.Finally,the three-dimensional temperature field simulation model of the motor is established,the motor is cooled by forced air cooling,and calculate the thermal conductivity,heat dissipation coefficient and heat generation rate of each part of the motor.Perform finite element analysis on the steady-state temperature field of the high-voltage line-start permanent magnet synchronous motor,summarize the temperature rise law of each part of the motor,the overall temperature rise of the motor is within a reasonable range.