Research On Design Method Of Synchronous Motor Using Permanent Magnet-Reluctance-Cage Bar Combined Rotor

Permanent magnet assisted synchronous reluctance motor is a motor with less permanent magnet structure,which has significant advantages such as low cost,high efficiency,high power density and small size.In recent years,as the price of permanent magnets continues to rise,highperformance motors with less permanent magnets have better economic factors and application prospects.Therefore,in this thesis,on the basis of the rotor structure of the permanent magnetassisted synchronous reluctance motor,a “circle” type cage bar is slotted,and permanent magnet-reluctance-cage synchronous motor(PMRCSyn M)is proposed.Due to the complexity of the rotor mechanism of the motor,it takes too long to calculate the torque by finite element method in the initial stage of design.Thus,it is devoted to the design and research of the magnetic circuit structure,rotor structure design parameters,and magnetic field analytical modeling of this kind of motor.The main research contents of this paper are given as follows:Firstly,by consulting a large number of domestic and foreign references,the development status of permanent magnet synchronous motors,synchronous reluctance motors and permanent magnet-assisted synchronous reluctance motors are briefly described and further studied.A new type of rotor structure is designed,and a mathematical model is established for the rotor structure of PMRCSyn M.Besides,under the operating characteristics of no-load and load,the mathematical model of quadrature axis and direct axis flux is established in line with the magnetic circuit model of the motor.Secondly,the finite element method is used to compare and analyze the main structural parameters of the motor.Among them,the parametric analysis is realized in the position of the magnetic barrier,the width of the magnetic isolation bridge,the distance between two adjacent magnetic barriers and the ratio of permanent magnets,from which the law of direct-axis inductance and quadrature axis inductance,salient pole ratio,no-load back potential,cogging torque,and electromagnetic torque varies with the change of parameters is obtained;Compared with the traditional permanent magnet auxiliary synchronous reluctance motor,the salient pole ratio increases by 17.1% and the torque increases by 19.8%,which provides a theoretical basis for the design of PMRCSyn M.Finally,the equivalent magnetic network model of PMRCSyn M is established under the two conditions of armature current alone and permanent magnet alone.In accordance with the established magnetic network model,the main parameters of the no-load and load air gap flux density,no-load flux linkage and no-load back electromotive force of the motor are analyzed and calculated respectively.In addition,the finite element calculation results are used to verify the analytical calculation results,and it is concluded that the error of air gap magnetic density waveform is within 3%,and the error of torque average is within 10%.Ultimately,the correctness and accuracy of the analytical calculation model is verified.