Research On Control Strategy Of Regenerative Braking And Hardware-in-loop System For Pure Electric Bus

With the Chinese haze weather is getting more and more serious, theenvironmental problems are also increasingly prominent, so preventing pollution andenergy conservation and emissions reduction have become what the word must firsttake into consideration. In the automotive industry, the development of new energyvehicles has been the important measures for alleviating pressure on the earth’senvironment.The development of regenerative braking system (RBS) is one of theimportant means for energy saving and emission reduction. The development ofRBS is not only beneficial to the environmental protection but also increase the rangeof electric vehicles. The RBS is mainly applied to frequent start-stop road conditions.Firstly, analysis of the brake pedal and making full use of the pedal free stroke, on thebasis of which, combining with the limiting factors the maximum regenerativebraking forces are calculated by ECE regulations, motor and battery characteristics.Then solving the problem of how to smoothly enter and exit for the regenerativebraking force under different braking intensity realizing the coordination controlbetween mechanical braking and electrical braking.This paper, pure electric bus is the research object for establishing a set ofsuitable control strategy. By using the joint simulation, Hardware-in-loop testplatform verifying the feasibility of the theory. Finally the working effect of RBSwas verified in real vehicle. In this paper, the main research work is as follows:(1) The structure of the braking system and brake mechanics of the electrical busare analyzed in detail. According to the automotive theory, this paper analyzed therelationship between front and rear axle braking force distribution, determinedsynchronous adhesion coefficient both at full-load and no-load. The utilizationadhesion coefficient and braking efficiency also have been analyzed. Both front and rear axle utilization adhesion coefficient meet the ECE regulations.(2) Analyzing the brake pedal and making full use of the pedal free stroke, on thebasis of which, combining with the limiting factors the maximum regenerativebraking forces are calculated by ECE regulations, motor and battery characteristics.Then solving the problem of how to smoothly enter and exit for the regenerativebraking force under different braking intensity. And considering the factors of speed,SOC of the battery, battery temperature. Building the control model in the tool ofMatlab/Simulink.(3) According to the specific parameters of pure electric bus, making use of theAVL-Cruise to build a pure electric vehicle model. And verify the feasibility ofbuilding model. Joint simulation test by Cruise/Simulink, regenerative brakingevaluation index is measured through specific braking and typical city cycle. On theother hand the ride comfort has been tested when the regenerative braking force entryand exit.(4) Setting up the hardware-in-loop testing system, respectively designing thehardware system and software system. Making use of the dSPACE as theHardware-in-loop testing system platform and using TTC200as the controller. Cruisevehicle model will be built by CMC (Common Model Compiler) function to generateexecutable file. And using the RTW (Real Time Workshop) which is one of thefunction of MATLAB/Simulink to generate C code to download dSPACE. Completethe system configuration, debugging module, signal correlation and function test.(5) The real vehicle testing. By the real vehicle road test,obtaining a largenumber of experimental data. In this way analyze and judge the communication of thecomponents, verify the regenerative braking control strategy in the real vehicle.