Design And Research Of High-Speed Permanent Magnet Synchronous Motor For Aeration Blower

Aeration fan is the equipment used for ventilation in sewage treatment plant.Because it has high requirements for wind speed and air volume and low requirements for torque,it usually uses high-speed permanent magnet synchronous motor as its driving equipment.High speed permanent magnet synchronous motor has the advantages of small volume,high efficiency,fast speed and direct connection with load.Because of its obvious advantages in power density and efficiency,it has gradually become the research hotspot of scholars all over the world in recent years.Taking a 75 k W,30000 r / min high-speed permanent magnet synchronous motor for aeration fan as an example,this thesis expounds the design method of high-speed permanent magnet synchronous motor;The designed motor is simulated and analyzed in electromagnetic field,stress field and temperature field to check the design scheme of the motor;Optimize the cooling system of the motor and reduce the rotor temperature rise by adding axial ventilation duct.According to the basic principle of motor electromagnetic design and the unique characteristics of high-speed permanent magnet synchronous motor,this thesis expounds the theoretical basis of electromagnetic design of high-speed permanent magnet synchronous motor,completes the preliminary design of motor stator and rotor,and preliminarily determines the electromagnetic scheme of motor.Then the finite element software is used to simulate the designed motor,deeply analyze the air and load characteristic curves,magnetic density and magnetic force line distribution of the motor,and check whether the electromagnetic design scheme of the motor has defects according to the simulation results.After adjustment,a perfect electromagnetic design scheme is given.After the electromagnetic design is completed,the rotor strength of the motor needs to be calculated.Based on the theory of elasticity,the mathematical model of rotor stress calculation is established in this thesis.Then,the stress distribution on the motor rotor is calculated by using the finite element method,and the factors affecting the rotor stress distribution and the law of the rotor stress distribution are analyzed.On this basis,the effects of the sheath thickness and interference on the motor rotor stress distribution are analyzed.The relationship curve between the interference and the stress on the rotor under different sheath thickness is given by using the parametric scanning method,The suitable thickness and interference of rotor sheath are determined by analyzing the curve.Then,the stress distribution of the motor rotor under different working conditions is analyzed to explore the influence of speed,temperature and other factors on the rotor strength,and check whether the rotor design of the motor can meet the strength requirements.The calculation of loss and temperature rise is very important for motor design.Firstly,the calculation formula of motor loss is given,and some losses are solved analytically.Then the finite element calculation models of stator iron loss,stator copper loss,rotor wind friction loss and rotor eddy current loss are established to accurately calculate the losses of each part of the motor.Then,the three-dimensional temperature field simulation model of the motor air-water cooling structure is established,the insulation and winding in the stator slot are treated equivalently,the boundary conditions of the motor in the calculation of temperature field are given,and the calculated loss is used as the heat source to simulate and analyze the threedimensional temperature field of the motor.According to the analysis results,the distribution principle and influencing factors of the temperature field in the motor are studied to test whether the temperature rise design of the motor is reasonable.Finally,the cooling structure of the motor is optimized,and the optimization effect is determined by comparing with the original design scheme in the temperature field.