Regenerative Braking Strategy Research Based on Multi-factor Input Fuzzy Control

Abstract

Most of the regenerative braking strategies only considered the stability on the braking direction and ignored the braking efficiency constancy, thus these researches may have defect under the ideal braking condition. A front driving electric vehicle was studied with the object to obtaining good braking and maximizing energy recovery rate. A regenerative braking strategy based on the multi-factor input fuzzy control was also proposed. Using the passage vehicle model, the front and rear axle braking force distribution was first set up according to the braking stability and ECE regulations. The front axle braking force was tried to be kept at the maximum at the same time. Second, the dynamic friction coefficient was used to predict the mechanical braking performance factor. Third, the battery state of charge, the braking strength and the estimated mechanical brake efficiency factor were introduced to the fuzzy controller. Finally, the distribution of regenerative braking force was obtained, and thus energy recovery was finished. The results show that with the new method, the braking performance constancy is improved in the frequent and constant intensity braking conditions. The braking energy recovery rate is increased by 18.5%. In the urban road condition with battery full power to zero, the energy recovery rate is increased by 5.3%.

Keywords: regenerative braking,  braking performance,  fuzzy control,  predict,  braking efficiency factor