Research On Dual-motor Drive Control And Brake Energy Recovery Of Pure Electric Logistics Vehicle

With the increasingly severe energy and environmental issues,pure electric vehicles with high efficiency and cleanliness are attracting more and more attention.However,the technical level of existing commercial vehicles is far lower than that of passenger products,with insufficient power redundancy and high power consumption.Their configuration and control strategies need to be improved urgently.In order to improve the braking energy recovery rate of a pure electric logistics vehicle,this paper rematches the electric drive system of the vehicle,and studies the vehicle drive control and braking energy recovery strategies.The main research work of this paper is as follows:(1)Using Cruise software to build a simulation model of the original vehicle model,a dynamic and economic simulation was carried out,and a real vehicle road test was carried out.Comparing dynamic and economic simulation and test results,the error is within 2.4%,which verifies the accuracy of the simulation model.At the same time,the simulation shows that the mileage increase brought by the energy recovery of the original model is about 5%.(2)Improved design of electric drive system.The design process of the power transmission system was formulated.According to the basic performance requirements of the target model,the required power of the vehicle was calculated,the structure of the power system of the pure electric vehicle was analyzed,and the improved configuration was determined to be the front and rear dual-motor four-wheel drive.The main parameters and selection of the two motors are determined by statistical analysis of the original vehicle’s multi-condition driving power.The simulation analysis shows that the improved design is under the condition that the total rated power is reduced by 6.7% and the total peak power is increased by 16.7%,the maximum vehicle speed is basically unchanged,the 0-50 acceleration time is reduced by 15.1%,the maximum gradeability is increased by 29.57%,and the vehicle power Significantly improved.(3)Research on dual-motor drive control strategy.Construct a mathematical model of vehicle driving efficiency,analyze common optimization algorithms,and select particle swarm optimization to perform optimization.According to the efficiency map of the two motors,the driving control model is determined based on the principle of the highest total efficiency.A drive strategy control model was established,and through simulation analysis,it was concluded that while improving power performance,the dual-motor optimized drive energy consumption was about 4.5% lower than that of the original vehicle.(4)Design the integrated brake scheme.In order to achieve a better energy recovery effect,a fully decoupled braking system solution is introduced through the analysis of different decoupling levels of braking systems.Determine the hydraulic schematic diagram of the 1-box configuration and the composition of the main components,analyze the brake fluid flow direction and the opening and closing of the corresponding solenoid valve in a typical working mode.Parameter matching of key components such as booster motor,master cylinder and servo cylinder is carried out to ensure that each component meets the requirements of the vehicle braking system.(5)Research on the control strategy of braking energy recovery.In order to improve the braking energy recovery rate,the basic principles,main influencing factors and typical braking force distribution are analyzed.For the original single-motor model and the improved dual-motor model equipped with fully decoupling brakes,a recovery strategy was developed respectively.And double-motor recovery,particle swarm optimization with efficiency as the goal.Simulink is used to establish three models of single-motor improved recovery strategy,dual-motor ideal braking force distribution recovery strategy,and dual-motor recovery total efficiency optimization strategy.The simulation calculation is carried out in conjunction with Cruise,and the result analysis shows that the two dual-motor control strategies can be reduced The SOC drops,the SOC drop value of the dual-motor recovery total efficiency optimization strategy can be reduced by 1.41%,and the battery’s recovered energy is increased by 1884.08.The combined use of the drive optimization control strategy and the dual-motor recovery total efficiency optimization strategy can increase the battery life by 8% to 18.88% compared to the original car’s single-motor improvement scheme.