Research On Compound Braking Control Strategy And Braking Stability Of Pure Electric Vehicle

As environmental pollution and the consumption of non-renewable resources become intensifying,energy conservation and environmental protection have become the focus of various industries in China.In the automotive industry,new energy vehicles have become the direction of industrial change because of their great advantages in power control,energy saving,and chassis layout.At present,there are still many problems with electric vehicles in terms of power control and endurance.Especially after problems such as increasing the energy density of batteries have encountered bottlenecks,how to strengthen the use of energy in energy storage systems and further increase the mileage of electric vehicles is a core issue in the field of modern vehicles.Regenerative braking technology is a type of technology that can recycle the kinetic energy consumed into electricity when the car slows down,so that it can be used when the vehicle is running.In urban conditions with more braking,regenerative braking technology is used in conjunction with traditional hydraulic braking.The composite braking system can effectively improve the energy utilization rate of the vehicle’s power battery and the mileage of the vehicle,while reducing the loss of the mechanical braking system,so this technology has important research significance.The research object of this paper is a four-wheel drive pure electric vehicle.Firstly,it summarizes the current progress of regenerative braking and the difficulties still existing in the current research.Afterwards,this paper expounds the mechanism of regenerative braking technology and analyzes the power control and energy transfer in deceleration.In view of the problem of dividing the proportion of braking force in conventional braking,the paper summarizes and studies a variety of braking force distribution strategies that have been applied at present.Considering the critical factors,a multi-factor constraint braking under conventional braking is proposed,which can realize stable braking and improve the level of energy recovery.For stable braking in a variety of complex road conditions,this paper presents an ABS anti-lock braking system which combines regenerative braking force and mechanical braking force.The slip rate of the automobile wheels is introduced as the control target.First,it is proposed a method for estimating road information using a sliding mode observer,and then a sliding mode controller for controlling the slip rate is designed to ensure that the compound brake ABS system can adapt to various complex road conditions.Through the joint simulation of Matlab and Carsim,it is proved that the system can simultaneously guarantee high energy recovery utilization rate and braking stability during braking.