Braking Force Distribution and Coordinated Control Algorithm for Hybrid Electric Bus based on EBS

In order to improve the braking energy recovery and ensure the braking comfort, a new type of regenerative braking coordinated control algorithm is designed in this paper. The hierarchical control theory is used to the regenerative braking control algorithm. First, the front axle braking force and rear axle braking force are distributed. Then the rear axle motor braking force and mechanical braking force are distributed. Finally, the dynamic coordinated control strategy is designed to control pneumatic braking system and motor braking system. Aimed at keeping the fluctuation of the total braking force of friction and the regenerative braking force small during braking modes switch, a coordinated controller was designed to control the pneumatic braking system to compensate the error of the motor braking force. Based on Matlab/Simulink platform, a parallel hybrid electric bus simulation model with electric braking system (EBS) was established. Then the simulation in different operating conditions was used to analyze the braking energy utilization and the braking performance based on the simulation model. Simulation results show that the proposed coordination regenerative braking control algorithm can effectively reduce the vehicle braking force error and improve the vehicle braking comfort. At the same time, the breaking energy recovered by the coordination regenerative braking control algorithm is nearly identical with the energy recovered by the biggest energy recovery control strategy.