Regenerative Braking Concepts for Electric Vehicles - A Primer

Battery electric propulsion presents opportunities to regeneratively recover vehicle kinetic energy and provide: unique integrated regenerative braking options singly and/or in combinations; to further improve vehicle energy economy by methods which are not inherently applicable to the conventional internal combustion powered automobile. There are three basic modes to be considered in the design of regenerative braking systems for battery electric vehicles: service braking, programmable deceleration, and emergency braking. Furthermore, the type of traction motor, the driving schedule, and charging characteristics of the associated battery pack are essential considerations involved in designing regenerative braking systems for optimal recovery of vehicle kinetic energy and optimizing battery pack life.

This paper presents a mathematical model of a regenerative braking system as a primer and shows how some design choices for regenerative braking systems can be affected by the newly disclosed high performance high power level battery electric vehicles (1, 2, 3, 4 and 5) and the type of driving schedules encountered. Also examined, as a function of two hypothetical driving schedules, is a regenerative braking control concept which can be programed to automatically optimize energy recovery and/or battery life. However, the scope of this review is limited to illustrating some effects of design parameters selected for battery electric vehicles. Specific circuit design and algorithm details are not presented.