Research On Operating Characteristics Of Switched Reluctance Motor For Electric Drive Engineering Vehicles

Nowadays,most of the driving motors used in large-tonnage electric drive engineering vehicles are mainly asynchronous motors and permanent magnet synchronous motors.With the national call for energy conservation and emission reduction and the increasing scarcity of rare earth resources,the application of switched reluctance motor(SRM)in electric drive engineering vehicles has gradually received attention.SRM has the characteristics of simple structure,small starting current,large starting torque,frequent start-stop and four-quadrant operation,which greatly meets the working condition requirements of large-tonnage electric drive engineering vehicles.This thesis investigates the operating characteristics of SRM in electric drive engineering vehicles.Taking the 12/8-pole SRM as the research object,the structure composition and operating principle of the motor are introduced.Based on the mathematical model,the inductance,flux linkage and electromagnetic torque of the motor are analyzed under linear conditions.From the mechanical operating characteristics of the motor,the control mode suitable for each operation area of the motor is introduced,and the influence of the control parameters on the performance of the motor is indicated,which lays the foundation for the analysis of the motor’s working conditions.According to the design specifications of the driving motor for electric drive engineering vehicles,the motor structure parameters are designed and the motor model is determined.The magnetic path splitting method is used to calculate the magnetic permeability components of each path at the coincidence and non-coincidence positions of the stator and rotor poles,the analytical formulas for the minimum and maximum inductances are obtained and the specific values of the minimum and maximum inductances of the motor are obtained by considering the effect of the end magnetic field.The analytical formula for the special position angle of the rotor under the parallel teeth is derived,and the inductance analytical curve is obtained.The analytical curve is verified by simulation to be within the allowable error range,which proves the accuracy of the analytical method,ensures the rationality of the initial structural parameters of the motor,and provides a theoretical basis for motor optimization.Through the simulation of the motor model,the electric operating characteristics such as flux linkage,efficiency and output torque are analyzed.After that,the parametric analysis of the motor structure parameters is carried out to study the influence of different structural parameters on the output torque,and a new motor size is obtained.Then the genetic algorithm is used for multi-objective optimization of the structural parameters,and the optimal solution of the genetic algorithm is determined.Finally,three different sizes of motors are compared,and the best performing motor is selected for the conduction angle parameterization,and the electric load analysis of the motor after the angle parameterization is carried out.The power generation conditions of SRM are analyzed.The power circuits under two excitation modes are studied,the external circuit model of the motor is constructed,and the torque,phase current and back electromotive force under power generation operation are analyzed.Then the change of output voltage under different parameters is studied.Finally,the variable load operation analysis is carried out.The power generation stability of the motor under sudden load reduction and sudden increase is studied,and the output characteristics of the motor under different speed and different load conditions are analyzed.