Experience derived from the conversion of a conventional car to a hybrid electric vehicle -analysis of the powertrain

This paper deals with the experience gained from the conversion of a conventional vehicle to a hybrid electric vehicle (HEV).The resulting concept vehicle is a hybrid SUV that features an additional electric drivetrain, which is composed of a three – phase asynchronous motor, a battery pack, the power converters and the transmission system. The placement of the electric and the conventional propulsion system forms a parallel topology. The operation of the electric drive system is characterized by two opposite directions of power flow, during the acceleration and the deceleration of the vehicle (regenerative braking). The energy management is achieved by two electronic power converters; a bidirectional DC/DC Boost/Buck converter and a three-phase DC/AC inverter, both of which have been designed and constructed at the laboratory. The motor control is carried out by a microcontroller according to Direct Torque Control technique. Finally, some characteristic experimental results of the constructed system are presented.