Temperature Rise Prediction And Analysis Of A New DSPMVM

The permanent magnet vernier motor introduces the modulation tooth structure on the stator of the traditional permanent magnet motor to modulate different air gap magnetic fields generated by the motor,so that the motor can output more stable and more stable torque than the traditional permanent magnet motor at low rotational speed.Compared with the performance of general motor,the permanent magnet vernier motor has higher torque density,so it is widely concerned by the experts.A new double stator permanent magnet vernier motor(DSPMVM)is presented in this paper.The design of inner and outer double stators and middle rotor are adopted in the structure.The outer stator is Split-pole structure,which greatly reduces material of the motor,and is favorable for heat dissipation of the motor.The inner stator is Open-pole structure,of which manufacturing process is simple,and it can ensure the motor to output a sinusoidal anti EMF waveform.The magnetic field modulation teeth are designed respectively in the interior and exterior stators,which can modulate the inside and outside double air gap magnetic field to improve the utilization ratio of magnetic field to reduce the magnetic field loss of motor,and get more stable output torque at last.In this paper,the working principle and the schematic diagram of the design parameters and 2D and 3D structure of the motor are illustrated in detail,2D model of the motor is built in finite element software to study and analys the electromagnetic properties.The simulation results prove that the new DSPMVM has great harmonic modulation effect,and can output more stable and larger torque.When the motor is working,different kinds of loss will be produced inside the motor inevitably to reduce the performance,working efficiency and life of the motor.Based on the structure characteristics of DSPMVM,combining with the theory of circuit science and the principle of equivalent heat path,an equivalent thermal circuit simplified model with five heat sources,which are composed with armature winding of inside and outside stator,inner and outer stator core and rotor core,is built,and a detailed mathematical calculation model is given.Through the study and analysis of various losses of the motor,each heat source in DSPMVM are determined.The electromagnetic simulation software is used to study the changes of different kinds of loss with different parameters,which include the eddy current loss of the permanent magnet and core loss under different working conditions of the motor.In addition,considering the affect of change of temperature to winding,the feedback regulation link is added to the calculation model of copper loss to reflecte the bi-directional coupling relationship between winding and temperature rise.The influence of bi-directional coupling relationship on the final temperature rise is analyzed in this paper.The analysis results show the change of the armature winding with temperature rise has a great influence on result of the final temperature rise of winding.By referring to the related documents at home and abroad,the calculation models of all equivalent thermal resistance and heat capacity are given in detail.Combined with the specific size of DSPMVM,all relatived parameters of the equivalent thermal circuit model are determined.Finally,the loss simulation results under different conditions are imported into the equivalent thermal circuit model to work out the temperature rise of each part of DSPMVM under different conditions.The results show that the different temperature rises inside the motor is low while working,which satisfies the allowable temperature range of all parts of the motor,and it provides a powerful basis for the rationality of motor design.In order to verify the accuracy and reliability of thermal path method,the magnetocaloric coupling finite element temperature field simulation of DSPMVM is carried out in this paper.First,a complete three-dimensional analysis model is built,then finishing the simulation of magnetocaloric coupling finite element temperature fied.Comparing the results of different conditions between finite element method and thermal path method,it shows that the temperature rise trend are consistent and the result of temperature rise have similar accuracy,which fully verify the calculation models of equivalent thermal path and thermal parameters have certain reliability and rationality,and reach the purpose to accuratly predict the temperature rise of motor,what's more,it provides strong evidence for the feasibility and rationality of the new DSPMVM structure design.