REGENERATION POTENTIAL OF ELECTRIC VEHICLES

Abstract

In this paper the range extension potential of regenerative braking for electric vehicles is discussed based on computer simulation results. The analysis techniques applied to the simulation results, in particular the formulation of time and energy distributions in the speed/load plane of the motor, are shown to give the design engineer the tools necessary to assess the range effects of various regenerative braking design considerations. Three vehicles, which bracket potential weight and road load characteristics, are studied over several driving cycles, and a potential range increase of 20 to 26% is demonstrated with an ideal regenerative brake system on an urban driving schedule. The decrease in range from the maximum potential, that occurs as the limitations of an actual regenerative braking implementation are taken into account, is also quantified. The design concerns investigated are motor torque and speed limits, transmission downshifting and integrtion with the hydraulic brakes. (Author/TRRL)