Research On The Controller And Control Strategy Of Electric Vehicle Based On Simulink

With the aggravation of environmental pollution,China's demand for new energy is gradually increasing.As an application of new energy,electric vehicles have obvious advantages in energy saving and simplicity,while the advantages and disadvantages of energy management strategies of electric vehicles directly affect the performance of vehicle power system.In this paper,a vehicle controller(VCU)is developed for a pure electric logistics vehicle,and its control strategy is studied.The working mode of the whole vehicle is divided,and the start stop control strategy of the vehicle is formulated.Based on the fuzzy control theory,taking the vehicle economy as the design goal,taking the vehicle speed and the accelerator pedal opening as the input signals,the reference torque is obtained.Taking the power compensation as the design goal,taking the vehicle speed,the accelerator pedal opening and the change rate of the accelerator pedal opening as the input signals,the compensation torque under the dynamic condition is obtained.Taking the maximum torque,the maximum vehicle speed and the residual capacity of the power battery as the input signals.The allowable output power of the battery and the fault condition of the whole vehicle are the constraints to determine the final output torque.Based on the SOC of battery pack and motor speed,the control strategy of braking energy recovery is established.The hardware of the whole vehicle controller is developed with Freescale xep100 as the main chip.The hardware system includes switch data acquisition,analog data acquisition,drive output,can bus communication,RS485 communication,data storage and other modules.The bottom code and application layer function library of the vehicle controller are compiled.The bootloader program writing function is developed based on CAN bus.The real vehicle test management system with real-time monitoring and data storage function is developed.The hardware in the loop simulation platform of the pure electric vehicle controller is built.Based on the Simulink platform,the forward simulation model of the whole vehicle is established,including driver model,motor model,battery model,vehicle dynamics model,etc.The hardware in the loop simulation of the pure electric vehicle controller is carried out to verify the effectiveness of the hardware function and control strategy of the controller.The performance of the device meets the design requirements.Compared with the traditional torque control strategy,the developed vehicle energy management strategy has better dynamic performance.Compared with the standard torque control strategy,it has better economic performance and acceleration performance at low speed.In order to verify the effectiveness of the developed vehicle controller,10 cycles of tests are conducted on the hub test-bed based on NEDC condition and the original vehicle controller of the sample vehicle.The results show that the 100 km energy consumption of the developed controller is about 18.3%lower than that of the original controller.The acceleration test of 0-50km/h and 50-80km/h and the climbing and parking test of 20%gradient are carried out in the real vehicle road test.The results show that the developed vehicle controller meets the design requirements.