Loss Calculation And Temperature Characteristic Analysis Of Pure Electric Vehicle Drive Motor

Permanent magnet synchronous motor(PMSM)has the advantages of small volume,high power density,but at the same time,it has the disadvantages of large loss density,relatively closed workin g environment and poor heat dissipation.High temperature brought many adverse effects to the performance and reliability of the motor,so it is important to accurately calculate the motor loss and temperature field distribution within the various componen ts,rational design the cooling system,and control the motor operating temperature in a safe range.In this paper,based on the water-cooled permanent magnet synchronous motor used for electric vehicle,The loss calculation and temperature characteristics of the main components of the motor are researched deeply.It is necessary to accurately calculate the loss of the components within the motor for the calculation of the motor temperature rise.Accordin g to the theoretical basis of electromagnetic,the two-dimensional finite element model of prototype is established.Based on the electromagnetic loss generation mechanism,combined with numerical methods and finite element method,the core loss,winding copper loss and eddy current loss of permanent magnet under rated condition are analyzed and calculated,which lays the foundation for the follow-up motor temperature field simulation.According to the basic idea of computational fluid dynamics,based on the theory of fluid mechanics and heat transfer,the physical model and mathematical model of the temperature field are simplified,and the corresponding boundary conditions are given.The steady-state and transient temperature distribution of the motor under rated operating condition is simulated,and the temperature distribution of the motor is obtained.The purpose and method of motor temperature rise test is introduced,the test platform is built to test the temperature rise of the motor,which verifies the rationality of the theoretical calculation and the simulation of the temperature field.Convective heat transfer coefficient is an important factor which affects the heat transfer and temperature distri bution of the motor.Combined with the theoretical analysis of the pressure loss calculation and the convection heat transfer coefficient solution,The influence of the structural parameters such as the water cooling structure and the number of channels on the flow field and temperature field is calculated;The influence of the physical parameters such as the flow rate of the coolant flow from 2 to 20 ml and the different concentration of glycol solution in the cooling medium on the flow field and temperature field of the motor is analyzed;The influence of the assembly gap between the motor shell and the stator core on the temperature rise of the motor is investigated,which can provide reference for the design of the following motor cooling system.