Research And Design Of Battery Electric Vehicle Drive Controller

As the main direction for the future development of automobiles,battery electric vehicles are widely studied and developed due to energy conservation and environmental protection.For the normal driving of the car,the drive control technology becomes a key factor to improve the car's performance.This article focuses on the research and design of the drive controller for electric vehicles to maximize the performance of the car.Based on the thorough analysis of the running state,working principle and key technologies of pure electric vehicles,the frame structure of the main circuit is given,including bidirectional DC/DC converter and three-phase inverter circuit.In order to meet the actual driving demand of automobiles,the bidirectional DC/DC converters are selected to use a staggered parallel connection technology.The operating modes of the converter and the Buck mode are analyzed in detail.Voltage and current dual closed-loop PI controllers are designed to reduce the input and output respectively.The voltage and current ripple and the increase of the dynamic response speed of the converter are verified by plotting Bode plots of the corresponding controllers;the DC output of the bidirectional DC/DC converter is provided by the three-phase inverter to the electric vehicle.Phase-to-phase AC voltage,using SVPWM technology to control the three-phase inverter circuit,in-depth study of the SVPWM control algorithm,and the mathematical model of the three-phase inverter circuit is transformed into the analysis of the synchronous coordinate system,and the inner loop of the inductor current and the outer loop of the output voltage are designed.Double closed loop controller.Using MATLAB software to model the circuit of bi-directional DC/DC converter and three-phase inverter,built a double closed-loop subsystem module,SVPWM sector judgment module and switch point calculation module,and verified feasibility of the circuit controller design through system simulation.The simulation waveforms and analysis results show that when the bi-directional DC/DC converter operates in the Buck mode,the output current ripple rate is 0.5% and the output voltage ripple rate is 4.1% when the two-phase interleaving and parallel connection technology is used;when operating in the Boost mode,The response time of the converter to abrupt load adjustment is 0.5ms;in the three-phase inverter circuit controlled by double closed-loop SVPWM,the output time of the three-phase AC reaches the steady state value is 5ms,and the output voltage THD is 0.7%,which meets the basic performance index.