Study On Performance Analysis And Control Strategies Of Regenerative Brake Ystem For HEV Bus

As energy and environmental pressure increases, hybrid cars of low energyconsumption and low emission become the trend of the development of the car.Regenerative braking is an important technology to improve a hybrid car fueleconomy and extended trip mileage. In the braking process, motor used as a generatorproduces braking force for the drive wheels, and the recovery of the form of energy isstored in battery. Regenerative braking force will definitely affect distribution of thebraking force of original air brake system. Therefore, a kind of suitable regenerativebraking control strategy was put forward to ensure safety and achieve the purpose ofenergy recovery.In this paper, combining the commercial software development platform andfuzzy control theory, performance analysis and regenerative braking control strategiesof the hybrid braking system.The main work and innovative points of the paper are asfollows:(1)The dynamic response characteristics of the motor brake and the air brakewere analyzed based on the rank of the front and the rear axle braking force ratiounder the regulations of the ECE.The result showed that the dynamic response time ofthe motor braking and the air braking were not at the same level, so the braking torqueof these two should be dynamic distribution.(2) The software of the Simulink and the Advisor were used to model thedynamics and the regenerative braking system of the bus. The main models were asfollows: The vehicle dynamic model, Dynamic distribution model, Brake model,Motor model, Battery model and Brake demand model, then the simulation platformof the regenerative braking strategies was formed. Performance of the model was metthe simulation requirements after the test.(3) The hierarchical control was used in the distribution of power system. Thefirst level was adopted the fuzzy PID which based on the target of sliding rate torealize the adjustment of the total braking torque. With target of the change of thetotal braking torque and the SOC of the battery to realize the dynamic distribution ofthe braking torque on the motor brake and the air brake, recycling braking energy asmuch as possible on the condition of safety. The simulation results show that afer thecontrol strategies raised in the paper is applied, the braking stability and energyrecovery effect are both satisfying under various braking strength.