| Because of the high rotor speed of the high speed machine itself,the power density is large and its volume is much smaller than the same power medium speed and low speed machine,and reduce material consumption and costs;because the high speed machine can be connected directly with the load,the variable speed device is removed and the noise is reduced,and the efficiency of the drive system is improved.Due to these advantages of high speed machine,it has a good application prospect in energy storage flywheel,circulating refrigeration system,high speed grinding machine,textile and other occasions.At the same time,these characteristics of high speed machine make it compared with the traditional machine,there are some technical problems in the design process and the more factors need be considered.Based on a 100 kW,50000r/min high speed permanent magnet synchronous machine as the research object in this paper,the electromagnetic design,the strength of rotor,loss calculation and temperature field calculation of this machine are entirety analyzed.The main research contents are as follows:First of all,according to the characteristics of the high speed machine,the structure design of high speed permanent magnet machine stator and rotor is conducted,including the selection of the rotor external diameter and length,the choice of permanent magnetic material,the selection of number of poles,the selection of the stator iron core material,the determination of the stator iron core structure and the design of the stator winding be analyzed and researched.The electromagnetic design of a 100 kW,50000r/min high speed permanent magnet synchronous machine is performed by finite element software,and the size and material of each part of machine are determined.The no load and rated load characteristics of this machine are analyzed by finite element simulation,and the rationality of the design is validated.Secondly,the rotor strength is analyzed theoretically.ANSYS Workbench software is used to establish the finite element model of the rotor for rotor strength analysis,and the stress distribution of the rotor is calculated.The rotor stress distribution under different permanent magnet structure and the rotor stress distribution under different filling material are calculated,and the influences of temperature,speed,interference,protective sleeve thickness and permanent magnet pole arc coefficient on the rotor stress are analyzed.In addition,the calculation model of stator iron loss considering the effects of harmonic and rotational magnetization is established.This model is utilized to calculate the stator iron loss,and the finite element simulation is carried out to verify the correctness of this model.The stator winding copper loss of high speed machine is calculated by formula method.The calculation model of the rotor surface wind friction loss is established,and the finite element calculation of the machine rotor surface wind friction loss is carried out by utilizing this model,and the influences of rotor speed,rotor surface roughness and wind speed on the rotor surface wind friction loss are analyzed.The permanent magnet eddy current loss of high speed machine is calculated through Ansoft finite element software,and the relationship between carrier ratio and permanent magnet eddy current loss is analyzed when the power is PWM wave.Finally,a reasonable high speed machine cooling system scheme is designed,and the temperature distribution of each part of the machine under this cooling system is calculated by employing ANSYS Workbench software.The temperature of high speed machine is effectively reduced.The influences of cooling air flow rate and cooling water flow rate on machine temperature distribution are analyzed. |
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