Implementation and performance evaluation of a regenerative braking system coupled to ultracapacitors for a brushless DC hub motor driven electric tricycle

Research related to electrical vehicles is gaining importance due to the energy crisis. An electric vehicle itself is far ahead of an internal combustion engine based vehicle due to its efficiency. Using regenerative braking when braking, improves the efficiency of an electric vehicle as it recovers energy that could go to waste if mechanical brakes were used. A novel regenerative braking system for neighborhood electric vehicles was designed, prototyped and tested. The proposed system utilizes an ultracapacitor bank to capture energy where as the conventional systems regenerate to the batteries. The switching frequency of the current plays a key role in controlling the negative torque applied by the motor while capturing energy. The user has direct control over the amount of current regenerated and hence the amount of negative torque applied for braking. The research has shown that the proposed regenerative braking system is significantly better in recovering energy and slowing the vehicle compared to a commercially available regenerative braking system.