Design And Analysis Of A High Speed Permanent Magnet Synchronous Machine

High speed motor has many advantages: high power density,less material consumption and low cost,which improves the efficiency of transmission and reduces noise pollution.All these advantages make it very promising in some applications such as refrigeration system,high-speed grinder,mechanical textile and so on.At the same time,these advantages also bring many technical problems,which are very different from the ordinary motor in the design scheme.In this paper,a high-speed permanent magnet synchronous motor with a rated power of 300 kW and a rated speed of 15000r/min is used as the research object,and its electromagnetic design,rotor strength,loss calculation and temperature field calculation are carried out Analysis.The main research contents are as follows:(1)The characteristics of high speed permanent magnet synchronous motor are described,and the structure of stator and rotor of the motor is designed.According to its characteristics,the stator and rotor of the motor are designed,including the determination of the inner and outer diameter of the stator and rotor,the selection of the length of the core,the selection of the permanent magnet material,the coordination of the pole slot of the permanent magnet motor,the selection of the stator core material and the design of the stator winding.ANSOFT software is used to analyze the no-load characteristics and load characteristics of 300 kW and 15000r/min high speed permanent magnet synchronous motors.The reasonableness of the motor design is demonstrated.(2)Theoretical analysis and introduction are given to the stress of each part of the rotor,and the two-dimensional analysis model of rotor stress is established by using finite element software.After calculating and analyzing the stress of different parts of the permanent magnet and different parts of the rotor,the best solution is obtained.Finally,the variation trend of rotor stress under different temperature,speed,interference and sheath thickness is calculated and analyzed.(3)The loss of high speed motor mainly includes stator iron loss,stator winding copper consumption,eddy current loss and wind friction loss.The influence of the current harmonics and the rotating magnetization of the magnetic field on the iron consumption of the stator is very great,so the influence of the iron consumption should be considered.The calculation of the copper consumption of the stator winding needs to be solved by the formula method.Eddy current losses are greatly influenced by harmonics,and eddy current losses are calculated by establishing the finite element method of harmonic currents.As the speed of the high-speed motor is much higher than that of the ordinary motor,the wind friction of the rotor becomes more and more negligible with the increase of the speed.A fluid simulation model is established.The finite element method is used to calculate and analyze the friction friction of the rotor.(4)On the basis of learning the theory of fluid motion,the cooling system of the motor is analyzed and designed,a reasonable simplified model of the motor is set up and the corresponding boundary conditions are set up.The temperature distribution of the motor with different sheath is calculated by ANSYS software.Finally,the influence of cooling wind speed and inlet air temperature on the temperature rise of the motor is analyzed.