Design Of Low-Speed Electric Vehicle Drive System

In recent years,new energy vehicles have been developing rapidly in China.Whether it is low-speed micro electric vehicles,commercial large-scale passenger cars and trucks,or passenger car market,all show a phenomenon of blooming.The main task of this paper is to research and design the drive system of low-speed electric vehicle.First of all,the paper briefly introduces the composition of the electric vehicle power system and the calculation process of its power system matching;analyzes and derives the theoretical calculation formula and equation of the electric vehicle power system design,mainly including the matching calculation of motor speed,power and torque,transmission ratio and battery matching;according to the demand of mainstream low-speed electric vehicles in the market and According to the above formula,the performance parameters of the matching drive system are calculated.Then,the paper analyzes and calculates the performance requirements of the drive system.Motor is one of the main parts of drive system.This paper introduces the structure and basic operation principle of permanent magnet synchronous motor,analyzes its steady-state operation state,and introduces its mathematical model in the calculation process.The design of the drive motor mainly includes two parts:theoretical calculation and finite element analysis.In the part of theoretical calculation,the selection of main dimensions of stator and rotor,the influence of pole slot matching on performance,the characteristics of different winding forms and the optimization analysis of rotor topology structure are analyzed and studied.Finally,the design parameters of the motor are determined.In the finite element calculation part,according to the motor parameters obtained by theoretical calculation,the model is analyzed in the finite element software,Then the performance calculation is carried out,mainly from the external characteristics,temperature distribution,efficiency map,demagnetization check,rotor structure strength check,NVH analysis,control model building and control strategy analysis,etc.at the same time,according to the vehicle parameters,the whole vehicle model is built,and the driving system is simulated to verify its dynamic performance and endurance performance.Finally,the prototype is made and the experimental platform is built.The design results are verified by experimental tests.The data of key operating points are compared,and the measured results are basically consistent with the simulation results.At the same time,the NVH test of the prototype is carried out on the whole vehicle,and the influence of different pole groove matching on NVH is compared.