Design And Research On The Starting Characteristic Of Permanent Magnet Motor For Textile Industry

In view of the problems of low efficiency and power factor of driving motors in the textile and chemical fiber industry,line-start permanent magnet synchronous motors are often used to replace the original induction motors.However,due to the general load of the textile and chemical fiber industry,the starting capacity and pullin capacity of the motor are generally required high,it is necessary to study the starting characteristics of line-start permanent magnet motors.In view of the above problems,this article mainly completed the following work.First,a 15 k W three-phase line-start permanent magnet synchronous motor for textile industry is designed in this paper.According to the load characteristics,the performance requirements of the motor are proposed.The design principles of the stator winding turns,air gap length,rotor slot,permanent magnet magnetization direction length and width,and so on of line-start permanent magnet synchronous motor for textile industry,and its impact on the motor are analyzed.The equivalent magnetic circuit method and two dimensional electromagnetic fields finite element analysis are used.The stator slots,stator windings,air gap lengths,rotor slots,and permanent magnets,and so on are optimized.The calculation and analysis results show that the prototype can meet the performance requirements and the design scheme is feasible.Secondly,the total average torque-slip curve of the prototype is obtained through analytical calculation and two-dimensional time-step finite element analysis.Based on the analysis of the starting process,two analytical calculation methods of total average torque are derived,and the calculation results are compared.Using the finite element analysis software Maxwell,the prototype was sequentially simulated and analyzed for locked-rotor torque,stable operation at each asynchronous speeds,large-rotation inertia no-load start,and minimum torque.The locked-rotor torque of the prototype was obtained through simulation;the simulation results of stable operation at each asynchronous speeds and large-rotation inertia no-load starting are processed separately to obtain more accurate total average torque curves;a simulation method for obtaining the exact value of the minimum torque is proposed.The results of the above calculation methods are compared.Finally,analytical calculation and time-step finite element simulation was used in this paper to obtain the pull-in criterion of the prototype.Through the analysis of the pull-in synchronization process,an analytical calculation method considering stray loss is derived.Through the simulation of the starting process,a simulation method to quickly and accurately judge whether the motor can be pull-in synchronization is put forward,and a more accurate pull-in criterion is obtained.The calculation results of the two methods are compared.