Calculation Of Loss And Temperature Field Of Double Stator Low Speed High Torque Synchronous Motor With Hybrid Rotor

Low speed high torque motors are widely used in industrial production,wind power generation,oil field exploitation and other fields.Due to its inherent characteristics,the traditional low speed high torque motor has a large diameter-to-length ratio and a large internal space in the rotor.In order to make full use of the internal space of the rotor and increase the torque density of the motor,this thesis proposes a new type of double stator low speed high torque synchronous motor with hybrid rotor.The motor consists of inner and outer stators and a hybrid rotor.One side of the hybrid rotor adopts a surface-mounted permanent magnet rotor structure,the other side adopts a reluctance rotor structure,and the middle is a magnetic isolation ring.Due to the special structure of proposed motor,the loss distribution is quite different from that of the ordinary motor,and the large loss will cause the motor to generate serious heat and affect the operating performance.Therefore,this thesis studies the loss calculation method and temperature field distribution characteristics of this motor.The main research contents are as follows :First,the stator and rotor structure of this dual stator low speed high torque synchronous motor with hybrid rotor are introduced,the operating principle of the motor is explained,a finite element analysis model of the motor is established,and the flux density distribution is analyzed,internal and external air gap magnetic density,and resonance of the motor wave is analyzed.Secondly,in view of the complex magnetic field,special structure,and loss is difficult to calculate of the double stator motor with hybrid rotor,a calculation model that simultaneously considers the influence of alternating magnetization,rotating magnetization and harmonics on iron loss is established.The flux density of the magnetic barrier is analyzed,and the iron loss of the entire motor is calculated by the principle of integration.The calculation results are compared with the finite element analysis to verify the accuracy of the iron loss calculation model.Copper loss calculation model considering the effects of temperature changes is established.the influence of different temperatures on the copper loss of the inner and outer stator windings is analyzed.The eddy current loss of the permanent magnet of the motor is analyzed by finite element method.Finally,in view of the complicated structure of the dual stator motor with hybrid rotor that makes the temperature field calculation difficult,the thermal network model of the motor is established,the thermal resistance of each part of the motor is deduced,and the thermal network equation is established.The temperature field of the motor with magneto-thermal unidirectional coupling and magneto-thermal bidirectional coupling is analyzed.By comparing and analyzing the thermal network and finite element calculation results,verify the effectiveness and feasibility of the thermal network model established for the double stator low speed large torque synchronous motor with hybrid rotor in this thesis.