| The design of line-start permanent magnet synchronous motor(LSPMSM)is similar to that of induction motor,the permanent magnet motor is installed by the permanent magnet on the rotor of the induction motor and self-starting of permanent magnet motor depends on asynchronous torque generated by rotor bar.Compared with the induction motor,the LSPMSM has the advantages of high power factor,high efficiency and wide range of economic operation,and the structure of LSPMSM is various.Owing to the asymmetry of the permanent magnet motor rotor magnetic circuit,it is difficult for the traditional design theory and analysis method to analyze the permanent magnet motor effectively.Therefore,it is necessary to use other scientific theories and computer aided methods to complete the structure design and magnetic circuit design of the motor.However,there are still some problems in the application of LSPMSM,and this is mainly caused by the cogging torque of motor and the asymmetry of rotor magnetic circuit.The main research contents are as follows:(1)The working principle of LSPMSM is analyzed,including the starting characteristic,power characteristic,torque characteristic,power angle characteristic and cogging torque.The factors that influence the flux,torque,power factor and efficiency of permanent magnet motor are analyzed,which provides a theoretical basis for the following research.(2)The structure and magnetic circuit design of 5.5kW LSPMSM are presented.The structure design mainly includes the permanent magnet motor stator and rotor core,cogging,armature winding,number of slots,the length of permanent magnet,the width of permanent magnet and the choice of permanent magnetic material.The magnetic circuit design mainly includes the calculation of no-load leakage coefficient0?,air gap coefficient K?and pole arc coefficienti?.(3)Taking the minimum amount of permanent magnet as the purpose,the Ansoft simulation software is used to model the LSPMSM.Firstly,the no-load operation of W,U and V type permanent magnet motors are analyzed.According to the characteristics of magnetic field distribution,air gap magnetic flux density,magnetic flux leakage coefficient and cogging torque of permanent magnet motor,W and U type permanent magnet motor are selected.Secondly,according to the analysis of no-load operation of motor,the no-load starting and load starting characteristics of W and U type permanent magnet motors are analyzed and compared,and the W type permanent magnet motor is selected.Finally,the permanent magnet size of W type permanent magnet motor is changed and the influence of permanent magnet motor is analyzed,then taking the minimum amount of permanent magnet as the optimization target the simulation analysis are compared and the final results are obtained. |
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