| Electric motor is the core component of new energy vehicles.With the development of new energy vehicles,electric motor has attracted more and more attention.Switched reluctance motor(SRM)has the advantages of large operating torque,low loss,high efficiency and wide range of speed regulation.Compared with other types of motors,SRM has a great potential advantage in the field of electric vehicles.However,due to the small cooling area of its winding and serious temperature rise problems,it is necessary to analyze its cooling performance.In this paper,liquid-cooled switched reluctance motor is taken as the research object,and the influence of inlet/outlet position on parallel channel heat dissipation performance is analyzed.Aiming at the deficiency of liquid-cooled heat dissipation structure,liquid-cooled compound heat dissipation structure is proposed,and its heat dissipation performance is studied.Firstly,the motor cooling schemes at home and abroad are summarized,and the common motor cooling methods such as forced air cooling and liquid cooling are described.Based on the basic knowledge of electromechanics,heat transfer and fluid mechanics,the basic theory for thermal analysis of liquid-cooled switched reluctance motor is introduced,including the structure and working principle of the motor,heat conduction,convection heat transfer,supplementary conditions for heat transfer and the governing equation of fluid mechanics.Follow,the two-dimensional electromagnetic model of the motor was established in Ansoft Maxwell software,and the thermal physical property parameters of each component material of the motor were assigned to the model.The distribution of magnetic field lines and magnetic flux density at different positions at rated speed was analyzed.Combined with the empirical formula,the loss values of the motor and the heat generation rate of the stator,rotor and winding of the heat source parts were obtained.Then,the thermal conductivity and heat transfer coefficient of the corresponding part of the motor are calculated.Liquid cooled motor three-dimensional simplified model is established to ethylene glycol solution volume concentration,environment temperature,fluid flow as impact factors,the highest temperature in motor,flow pressure difference as evaluation index,the contrast research of three parallel port structure heat dissipation performance,and analyzes the influence factors of motor cooling and flow pressure difference,considering the cooling performance and flow pressure difference,Optimized the inlet/outlet position,fluid medium and fluid flow rate of parallel flow channel.Finally,in view of the deficiency of liquid-cooled heat dissipation structure,based on the parallel flow channel structure,a liquid-cooled composite motor heat dissipation structure is proposed by filling the stator and the end of the winding with heat-conducting silica gel.Before and after considering the end cover and the air field conditions,a 3 d surface composite motor were established on the simplified model,and the thermal conductivity silica gel model,initial temperature,thermal conductivity silicone fluid position as influencing factors,the orthogonal experiment was designed in the stator windings and the highest temperature as test index,the motor is obtained under different test temperature,and the simulation results are very poor and variance analysis,The fluctuation degree of the test index and the optimal combination of the factor level are obtained. |
