Regenerative Braking Strategy for an Unaltered Mechanical Braking System of a Conventional Vehicle Converted into a Hybrid Vehicle

Regenerative braking has become one of the major features for a hybrid vehicle as it converts brake energy into electrical energy storable into battery and leads to an increase in overall fuel efficiency of the vehicle. Traditional regenerative braking systems are designed such that the mechanical braking force from the friction brakes is varied in order to get maximum electric braking. This is the optimum method; however, such a system calls from electronics (Anti-lock Braking System) for regulation of mechanical braking leading to an increased cost.

In this paper, the authors present a new strategy for implementing a regenerative brake strategy without changing the mechanical brake system of a conventional vehicle converted to a hybrid vehicle. The electric motor that serves as the traction motor or the Integrated Starter Generator (ISG) system, is used for regenerative braking also. There is no change in the other vehicle specifications as compared to the conventional vehicle. The electric braking force is additional to the mechanical braking force applied by friction brakes.

The strategy has been simulated for various typical city drive cycles and the results have been presented in this paper. The benefits of this strategy over classical mechanical braking have been evaluated in this paper. This paper discusses the methodology developed for the amount of regeneration possible and also used to predict the motor/generator size for such type of hybrid vehicles.