Coordinated optimization control strategy for composite braking considering braking comfort and energy recovery
摘要
A Regenerative braking system (RBS) has a greater energy recovery potential for four-wheel drive electric vehicles (FWDEVs). Ensuring brake comfort while maximizing energy recovery is undoubtedly a key issue. The strategy of distribution before coordination is usually adopted, but the post-coordination will affect the regenerative braking distribution ratio, which is not conducive to maximum energy recovery. This paper proposes a control strategy of first coordination and then optimization for FWDEVs, considering the loss of battery energy, and gives full play to the energy recovery potential of FWDEV. Firstly, the composite braking torque is distributed coordinately based on feedback control to guarantee the stability of the whole vehicle’s braking force. Then, particle swarm optimization (PSO) is used to optimize the allocation of front and rear axles’ braking torque, aiming for braking stability and reducing energy loss. The weights can be adjusted adaptively by fuzzy control. Finally, through co-simulation verification, compared to the I curve allocation strategy without coordinated control, the proposed strategy increases energy recovery by 2.3% under WLTC cycles, and the braking impact during the EMB intervention stage and RBS withdrawal stage is reduced by more than 35% and 60%, respectively, in the middle and high braking intensity scenarios. Compared with the traditional coordination control strategy, energy recovery has increased by 5.8% under high-speed and high-braking conditions.