The Study On The Handling Characteristics Of Distributed Electric Vehicle Under The Motor Fault Condition

Compared with fuel oil vehicles,distributed electric vehicles are able to save chassis space and facilitate general arrangement of vehicles,and have good economy,strong power and high transmission efficiency,so it has become an important direction in the research field of electric vehicles.Distributed electric vehicles are powered by independently controlled driving motors.When the driving motor fails,the vehicle's handling characteristics will be affected causing potential safety hazards.Therefore,paper studies the handling characteristics of distributed electric vehicle under the motor fault condition.Firstly,the output characteristics of permanent magnet synchronous motor are analyzed by finite element simulation method.The finite element model of permanent magnet synchronous motor was built by using Ansoft software,and the typical operating conditions of the motor were selected for simulation.By comparing and analyzing the output characteristics of the motor with the actual parameters of the motor,the correctness of the motor model.Next,the above model is used to simulate the output characteristics of PMSM under fault condition.The failure mode of permanent magnet synchronous motor is analyzed.Short-circuit failure is selected as the research focus in this paper.The output characteristics of the motor under short-circuit failure types are simulated.The motor model is used to simulate the output characteristics under four short circuit failure types.By comparing the output characteristics of the motor under normal and failure,a method for estimating the output characteristics of the motor under failure is presented.Then,the mathematical model of distributed electric vehicle is established to study the vehicle handling characteristics under typical operating conditions.The force of distributed electric vehicle tires is analyzed and the non-linear Tire model of uni-tire is built.According to the mathematical model and control principle of permanent magnet synchronous motor,the model of permanent magnet synchronous motor with direct torque control is established.The force of distributed electric vehicle is analyzed,and the seven degrees of freedom model is built.On the basis of the above work,the distributed electric vehicle Simulink model is completed.The effectiveness of the vehicle model is verified through the simulation of three working conditions.Finally,the handling characteristics of the vehicle under the motor fault conditions are studied by simulation The vehicle model is used to simulate the influence of single motor failure on vehicle handling characteristics.Contrastive analysis is made on the vehicle's handling characteristics under the condition that the single motor has the above four short-circuit failure types when the vehicle is traveling in a low speed snaking line or a high speed straight line.In view of the vehicle behavior after the failure of the driving motor,the failure control strategy of the coordinated control of the driving motor speed and torque is proposed,which is of certain reference significance for the subsequent research field.