Design And Thermal Field Analysis Of A New Dual-Redundancy Permanent Magnet Motor

Based on the project of “dual-redundancy permanent magnet synchronous motor(DRPMSM)with low thermal coupling and none electromagnetic coupling between windings of each phase” which supports by National Natural Science Foundation of China,setting a permanent magnet motor with 24-slots and 20-poles as an example,electromagnetic properties,loss and characteristics of this novel DRPMSM are introduced and analyzed in this paper.The main work of this paper includes the following aspects.Firstly,referring the parameters and specification of similar motor,together with the existing motor frame of motor manufacturer,the initial model of the motor is determined.In order to obtain superior basic performance characters of the motor,as well as to provide bases for loss reduction and heat decrease of motor,the original motor structure is optimized as electromagnetic parameters such as air gap flux density,magnetic flux distribution,counter electromotive force and the cogging torque are taken as the measure criterion.Secondly,after determining the optimized model of motor,the loss of motor components can be calculated through relevant loss calculating formula and finite element simulation.Then,the heat generation rate of each component can be obtained.Considering motor heat fin,junction box,frame asymmetric shaft,slot wedge and slot insulation,three-dimensional(3D)modeling software is used to complete modeling of motor parts and assemble the parts according to actual situation.After that,heat conduction coefficients and heat transfer coefficients of new DRPMSM as well as heat conduction equation and boundary of the motor are determined by referring to related thermal theory.Finally,3D thermal analysis module is used to simulate and analyze steady-state temperature field of the motor with complete 3D model.By comparing the simulation results of the novel DRPMSM and temperature field of motor in similar type in normal state,the simulation results reflect heat transfer and dissipating path of each part of the motor,together with the influence of factors such as motor frame,heat fin and junction box have on the steady-state temperature field of such motor.At the same time,by comparing the temperature field simulating results of motor in normal state and state of only one set of winding working as the other set of winding is in fault as motor is loaded with 0.7 times of total load,the conclusion can be drawn that the design of small tooth and heat insulation board can change the direction of heat flow in motor which effectively hinder the heat exchange between the windings of each phase.Based on the simulation results of temperature field,this paper gives the optimal plan to arrange the windings in motor,which provides references and bases for temperature field analysis and practical application of such kind of motor.