Research On Modular Stator Permanent Magnet Synchronous Machine For Aircraft Electric Propulsion

In recent years,aviation field is gradually developing towards electrification.Replacing the traditional gas turbine propulsion system with an efficient and environmentally friendly electric propulsion system is a key topic in the field.The research on the electric propulsion motor of new aircraft is beneficial to broaden the design field of electric propulsion motors of aircraft and accelerate the electrification process of aviation products.In order to improve the performance of the electric propulsion drive system of aircraft,the electromagnetic and temperature rise of the modular stator permanent magnet synchronous motor(PMSM)with high fault tolerance and high-power density potential are studied in this paper.Firstly,slot-pole combination and basic size structure of the electric propulsion motor of the aircraft were determined,the constraints and rules of stator modularization were put forward,the electromagnetic performance of different modular stator PMSM models was compared,and the loss and efficiency of the modular stator PMSM were analyzed.Secondly,in order to explain the reason for the decrease of eddy-current loss of permanent magnet of modular stator PMSM from the perspective of armature magnetomotive force(MMF),the equivalent slot model of stator module is proposed.Based on the equivalent slot model,the armature MMF distribution of the modular stator motor is calculated and the spatial harmonic variation of the armature MMF is analyzed.According to the equivalent slot model,the equivalent current sheet distribution of the modular stator PMSM is calculated and the spatial harmonic distribution of the armature MMF is analyzed considering slot harmonics.Using the method of harmonic separation,the change of eddy current loss caused by each harmonic is analyzed,and the reason of eddy-current loss of permanent magnet of modular stator PMSM is analyzed.Then,in order to study the heat dissipation characteristics of modular stator PMSM in the radial heat dissipation mode,the basic theory of heat transfer is introduced,and the heat dissipation rule of modular stator PMSM under radial cooling mode is analyzed by using equivalent heat path method.The structural schemes of different cooling channels are compared and the conduction resistance is calculated according to the structural characteristics of modular stator PMSM.The relationship between the temperature rise of the modular stator PMSM and the flux gaps in radial water-cooling mode is analyzed,and the influence of the filling materials between the flux gaps on the temperature rise of the motor is analyzed.Finally,in order to study the heat dissipation characteristics of modular stator PMSM in axial heat dissipation mode,the basic theory of fluid dynamics is introduced,and the temperature field distribution of modular stator PMSM under different axial air-cooling modes is compared by using computational fluid dynamics(CFD)software,and the appropriate axial air-cooling scheme is determined.The differences of temperature field distribution and airflow trajectory of the motor before and after stator modularization were compared,and the advantages of the axial air-cooling scheme applied to the modularized stator motor were analyzed.