Study On Regenerative Brake Control Strategy For HEV Bus Based On Brake Condition

Regenerative braking system is becoming a hot area of research in HEV key technologiesas one of the most important measure to increase the mileage and save energy. While theregenerative brake control strategy is one of the most important factors of work effort ofregenerative braking system. And when building the regenerative brake control strategy thereare many factors should be considered, especially like ECE laws, vehicle configuration,drive conditions and the characteristics of brake system. This paper built a functionalregenerative brake control strategy for an HEV bus which was developed by CHANA FAWGROUP CORPORATION R&D CENTER based on above background. The researchobjectives of this paper are building a functional regenerative brake control strategy withconsidered of ECE laws, vehicle configuration, drive conditions and the characteristics ofbrake system based on different brake condition and the regenerative brake control strategywas verified by simulation and vehicle test combining with project and company needs.Firstly, the Chang Chun Urban Drive Cycles was analyzed. Analysis result shows that thecharacteristics of Drive Cycles are benefit the regenerative brake with low velocity, heavyload and high frequency brake. It is possible to add a slide regenerative brake control modulein the regenerative brake control strategy with the relatively low level average brakedeceleration of the Chang Chun Urban Drive Cycles. A torque control system is needed witha low coefficient of road adhesion in the winter. According to the analysis result of ChangChun Urban Drive Cycles, based on the analysis result of ECE laws, vehicle configuration,drive conditions and the characteristics of brake system, this paper built a functionalregenerative brake control strategy with different brake conditions which includeconventional brake condition, slide brake condition and drive slide condition.This paper is to build a functional regenerative brake control strategy based on differentbrake conditions. There are mainly four parts of works are researched:1. As the theoretical basis of building regenerative brake control strategy, the ECE laws,vehicle configuration, drive conditions and brake system characteristics were analyzed. 2. Based on the analysis result of above description, a functional regenerative brakecontrol strategy with different brake conditions which include conventional brake condition,slide brake condition and drive slide condition was built.3. Vehicle model and brake system model were built in AMESim software. And also theregenerative brake control strategy was built in MATLAB/Simulink software. Finally theoff-line simulation was done in MATLAB/Simulink software.4. Finally, the regenerative brake control strategy was tested and verified on a parallelhybrid electric bus. The tests included summer high coefficient of road adhesion test andwinter low coefficient of road adhesion test.The test result shows that the regenerative brake control strategy built in system can adeptto different brake conditions and the control effect is obvious. The regenerative brake controlstrategy has a relatively good practical value. Motor brake torque can control coordinatelywith the pneumatic brake torque in conventional brake condition. Motor brake torque canwell analog the drag torque from engine in slide brake condition. The drive slide controlmodule can effectively reduce the slip rate of drive wheel and improve the accelerationability in low coefficient of adhesion road.