Electric Vehicle Regenerative Brake Control Method Based On Brake Pedal Opening Sensor

The development of electric vehicles was placed in an important strategic position in China.The electric vehicle industry has been booming in recent years.One of the distinguishing features of electric vehicles is the regenerative brake system,which converts kinetic energy from braking into electrical energy and could recycle it.Regenerative brake systems are generally divided into series regenerative brake systems and parallel regenerative brake systems.The front and rear axle braking force,hydraulic braking torque and motor regenerative braking torque of the series regenerative brake system can be adjusted arbitrarily.It is an advanced braking system.However,its cost is high,and the required auto parts such as high-speed solenoid valves cannot be localized,which restricts its use in actual vehicles.Parallel regenerative brake systems based on modified fuel vehicles.In parallel regenerative brake systems,motor regenerative brake torque and hydraulic brake force combined braking on the drive shaft.The original hydraulic brake structure is used on the non-drive shaft.The entire system can only adjust the motor regenerative braking force on the drive shaft.The parallel regenerative brake system is simple and the cost is low,and it is widely used by domestic original equipment manufacturers.In view of the current situation of Chinese electric vehicle industry,some research on parallel regenerative brake system has been done in this dissertation.Firstly,systematically and modularly models of a electric vehicle was built in this dissertation.A hydraulic brake system model,battery model,motor model,tire model,driver model,vehicle model were built in the co-simulation environment of MATLAB and AMESim.Secondly,The existing common parallel regenerative brake system's strategy was analyzed.A concept of braking efficiency consistency was proposed.It is quantified by statistical data such as the binary function partial derivative of the brake deceleration distribution and the brake pedal opening degrees linear correlation coefficient.This dissertation has pointed out that the existing common parallel regenerative brake system's strategy has the problem of braking efficiency consistency.By adding the variable of brake pedal opening degrees,the brake pedal correction factor was introduced to improve the braking efficiency consistency of the parallel regenerative brake system without reducing the energy recovery efficiency.Thirdly,research on the coordination problem of ABS and regenerative braking torque under emergency braking conditions has been done in this dissertation.For the hydraulic braking force,the traditional logic threshold method was used to control;For the regenerative braking torque,when the slip ratio is detected to be greater than a certain threshold,the regenerative braking torque is reduced to a certain low level threshold.And according to the wheel slip ratio and the slip ratio's derivative,fuzzy logic control method was used to control at this low level threshold.Finally,the control strategy based on the brake pedal opening sensor and the regenerative braking torque coordination control strategy based on fuzzy logic control are simulated and verified.And an experimental verification of the brake efficiency consistency was carried out for a model of Chery vehicle using a common parallel regenerative brake strategy.