Research On Electric Vehicle Converter And Motor Control

Electric cars use electric motors and consume electric energy,which can reduce the consumption of traditional energy.Therefore,the research and development of electric cars have gradually become hot.This research focuses on solving the control problems of electric motors and converters in the electric running state and regenerative braking state of electric vehicles.Before conducting control research,it is first necessary to analyze the structural composition of electric vehicles and understand the working principles of electric vehicles in the state of electric operation and regenerative braking.In order to make the research practical,motors and converters need to be selected with reference to the actual electric vehicles already on the market.After comprehensive consideration,the electric vehicle motor selected in this study is a three-phase AC asynchronous motor,and the converter is a bidirectional DC/DC converter.After selecting the three-phase AC asynchronous motor,in order to achieve effective control of the three-phase AC asynchronous motor,by analyzing the mathematical model of the three-phase AC asynchronous motor,it can be found that the use of SVPWM to control the three-phase AC asynchronous motor can achieve the same as the control of the DC motor It is simple and effective.In order to enable the stable operation of electric vehicles,on the basis of vector control,this study also adopts a double closed-loop control strategy of speed and current to control the speed and torque of the AC asynchronous motor.In order to analyze the control strategies of different working states of the bidirectional DC /DC converter,the state space averaging method was used to establish the mathematical model of the boost state of the bidirectional DC/DC converter Boost and the buck state of the bidirectional DC/DC converter,and then The control strategy of the two-way DC/DC converter Boost circuit working in the electric vehicle electric running state and the two-way DC/DC converter Buck circuit working in the electric vehicle regenerative braking running state is analyzed.After analyzing the above process,this study selects the classic PID control method of closed-loop voltage or current negative feedback to control the operation of the bidirectional DC/DC converter in the operation of electric vehicles.After the control research and analysis of three-phase AC asynchronous motor and bidirectional DC/DC converter are completed.Combined with the reality,set the relevant parameters of the electric vehicle motor,bidirectional DC/DC converter and battery.Then,with the help of MATLAB/Simulink simulation software,the model of the electric vehicle in the electric running state and the model of the electric vehicle in the regenerative braking running state are established.By analyzing the simulation results in the two states,the vector control of the AC asynchronous motor can be found.The stable operation has a significant effect.And under different working conditions of bidirectional DC/DC converter,the effect of classic PID control on its forward or reverse voltage and current is also obvious.It is concluded that this study has certain practicality.