Regenerative Braking Control of Multi-Step Series Hybrid Energy Storage System with Energy Constraint for Practical Operation

Regenerative braking plays an important role in improving the driving range of electric vehicles. To achieve accurate and efficient braking deceleration control, this research focuses on the energy recovery process with ultracapacitors (UCs). According to statistical analysis results of characteristics for typical operation, a multi-step series hybrid energy storage system(M-SHESS) is constructed to realize energy recovery with grading in the braking process. To explore accurate measurement of braking deceleration without the vehicle speed sensor in the braking force control, the relationship between energy recovered by UC modules and the braking deceleration during the braking energy recovery is analyzed, and a deceleration control method with energy constraint for braking force is proposed. Results show M-SHESS can be applicable for energy recovery processes on different operations, and can effectively improve the efficiency of energy recovery. Moreover, the deceleration control method based on energy constraint can meet the vehicle braking requirement. Research for M-SHESS provides new ideas and approaches for the development of electric vehicles and fuel cell vehicles.