Study On Regenerative Braking Coordinated Control Algorithm Of Hybrid Electric Bus Based On EBS

With the increasingly serious problems of energy depletion and environmentaldegradation, the hybrid electric car has gradually become an important option for theroad traffic, especially the urban road traffic. Compared with the traditional cars,hybrid cars can recover the braking energy during braking by regenerative brakingsystem. How to distribute the pneumatic braking force and motor braking force is thekey problem of regenerative braking control strategy. As a new type of electronicallycontrolled pneumatic brake system, electronic brake system can not only shorten theresponse time of pneumatic braking system, but can also distribute the frontaxle and real axle’s braking force properly. It makes great sense to improving theregenerative braking energy recovery rate and braking comfort.Based on the provincial and ministerial project "Research on Braking ForceDistribution and Regenerative Braking Control of Hybrid Electric Bus", theregenerative braking coordinated control algorithm of hybrid electric bus wasdeveloped. The models were built based on TruckSim and Matlab/Simulink combinedplatform, and the regenerative braking control algorithm was verified by softwaresimulations and hardware-in-the-loop tests. The main research works are as follows:(1)A hybrid electric bus model was built by using modular modeling methodbased on the TruckSim and Matlab/Simulink combined platform. It includes thevehicle model, motor model and battery model. The model was used to verify theregenerative braking coordinated control algorithm in software simulations andhardware-in-the-loop tests.(2)A braking force predistribution algorithm was built. The regenerativebraking control algorithm was divided into braking force predistribution algorithmand coordinated control algorithm. The braking force predistribution algorithm includes the front and rear axle braking force distribution and the rear axle brakingforce distribution. In order to recover the braking energy as much as possible, thebraking force provided by motor preferentially and the rest was supplied bypneumatic braking system.(3) A regenerative braking coordinated control algorithm was built. The purposeof braking force coordination control algorithm is to ensure the braking performanceand braking comfort during the braking modes switching. Because of the influence sof the factors such as the battery SOC value, the motor speed, temperature and so on,the motor braking force isn’t a stable value. So there is a need to adopt pneumaticcompensation control. The pneumatic braking force can be adjusted by the EBSsystem. Because the front axle of the hybrid electric bus only has pneumatic brakingsystem, there is no need to adopt coordinated control. Different kinds of simulationswere used to verify the algorithm.(4)A regenerative braking control algorithm hardware-in-the-loop test benchwas built. In order to verify the algorithm, the experiment with coordinated controland the experiment without coordinated control have been compared to analysis thebraking comfort in different conditions.