Research On Power System Structure Of New Range Extended Electric Vehicle

In recent years,petroleum resources have been depleted,and automobile exhaust has caused serious pollution to the air,making the improvement of the ecological environment facing huge challenges.Electric vehicles have zero exhaust emissions,and national policies strongly support the rapid development of electric vehicles.Therefore,the development of the electric vehicle industry has also become the technical route of the automotive industry in my country and even the world.As the current power battery technology still has bottlenecks,leading to shortcomings such as insufficient range of electric vehicles and high battery costs,these technical bottlenecks cannot be broken in the short term of power batteries.Therefore,extended-range electric vehicles take into account the long range of traditional gasoline vehicles and have pure electric vehicles.The advantages of no exhaust gas pollution have attracted wide attention.Traditional extended-range electric vehicles have problems such as energy loss during charging and discharging of power batteries and high capacity of power converters.Therefore,this paper proposes a new type of power system structure for extended-range electric vehicles,which uses double-fed motor power generation,asynchronous traction motor drive,and generator power generation to directly drive the power system of the traction motor.Through the power system structure,the energy loss caused during the charging and discharging process of the power battery can be effectively avoided,and the capacity of the power converter can be reduced.Therefore,the power system structure has broad application prospects.This paper conducts an in-depth study on the direct drive system for power generation.The main research contents are as follows:Investigate the advantages of electric vehicles and the current problems,which leads to the background and significance of the research of this topic;in order to solve the problems of current extended-range electric vehicles,this paper proposes a new type of extended-range electric vehicle power system structure.According to the current development trend of range-extended vehicles,a research plan for the power system of a new range-extended electric vehicle is determined.According to the research plan of the extended-range electric vehicle power system,the speed distribution and the doubly-fed induction generator involved are analyzed in detail,and the Ackerman steering model and the mathematical model of the doubly-fed induction generator are established.The control of program electric vehicle power system lays the theoretical foundation.During the operation of the vehicle,in order to ensure the safe and stable driving of the vehicle,it is necessary to control the speed of the stator and rotor side converter of the doubly-fed induction generator and the asynchronous traction motor.The voltage-oriented vector control technology is adopted for the stator side of the doubly-fed generator,and the stator flux-oriented vector control calculation is adopted for the rotor side.And on the upper layer of the doubly-fed induction generator,closed-loop control of the asynchronous traction motor speed is adopted to ensure that the actual wheel speed of the vehicle runs at the given wheel speed.In order to verify the safety and stability of the vehicle power system,this paper uses simulation to verify the extended-range electric vehicle power system model,and the simulation software used is Matlab.The performance indicators of asynchronous traction motor,doubly-fed generator and power system are simulated and verified under the vehicle’s straight-line driving and steering driving conditions.The simulation results verify that the power system can ensure the stable operation of the vehicle and can also reduce back-to-back converters.The capacity is not higher than 20%of the capacity of the doubly-fed generator.