Integrated Regenerative Braking And ABS/ASR Control Of Electrified Bus

Electric drive system is one of the most important components of electrified vehicles such as EV/HEVs. The integrated control of regenerative braking and Anti-lock Braking (ABS)/Anti Slip Regulation (ASR) belongs to the domains of advanced technologies of electrified vehicles. This paper proposed one kind of optimized compensatory control law of ABS and brake regeneration and also the united control law of ASR in electrified buses. Both of the control strategies are evaluated by using simulation tools such as Simulink and Hardware-in-loop (HIL) bench.First, the optimized compensatory control law of ABS and brake regeneration is proposed based on traditional pneumatic ABS control rules, which have been designed according to the references released from manufacturers. In this optimized control law the regenerative braking force is integrated to compensate the gap between optimal braking force and frictional braking force, targeting the acquisition of maximum surface coefficient of roads. The simulation results indicate that three control rules including traditional pneumatic ABS control rules, integrated control rule regulation regenerative braking force and frictional brake force synchronously and of course the optimal compensatory control law can ensure the security and maneuverability during emergent braking on slippery roads when ABS is activated. The best performance is obtained when using the optimized control law.Then the abovementioned three kinds of control rules are evaluated on the HIL bench including pneumatic braking system of electrified buses. The results indicate that better brake performance is obtained by utilizing optimized compensatory control law, which is similar to the results of simulations. Facing different road conditions the adaptability and maneuverability are guaranteed without wheels locking up when ABS functioning. At the same time this optimal compensatory law is beneficial to the improvement of brake distance, which also proves the validity of this kind of law.After researching the optimal compensatory control law during ABS working, four kinds of control strategies focusing on the transition process from normal regenerative braking to ABS are proposed. Utilizing the simulation environment and HIL bench, the availability of all four strategies are ensured as well as the differences are listed, from which the potential impact of regenerative brake force is analyzed comprehensively.At last the united control law of anti slip regulation is proposed by regulating electric motor drive torque and pneumatic brake torque simultaneously, both of which are regulated based on the classical threshold method. The simulation and HIL results are illustrated to prove that the united control law can ensure the dynamic performance and security on various road surfaces and prevent the radical slip of driven wheels.