Laboratory-based examination of the effect of rotational inertia on energy recuperation in the regenerative braking process

Abstract

Dynamic energy recovery in electric and hybrid electric vehicles can assist in restoring kinetic energy during descending and braking operations. The recouped energy can be stored in various storage units, such as a flywheel energy storage (FES) units, ultra-capacitors (UCs) or batteries, thus conserving energy for later use during acceleration condition. The FES is used in a variety of modern applications; for instance, it tends to be associated with the motor shaft to assist in starting the vehicle from rest. Several different components have been utilized to execute the motoring and braking mechanism in a structured test rig. However, there is an urgent need to represent this application within the limits of the laboratory facilities while being able to simulate the natural system. Consequently, this paper will examine the effect of rotating inertia at a different rotating speed in the drive system on propelled energy. It will also evaluate the stored energy in the UC storage unit and the braking time in the regenerative braking (RB) process. Moreover, it will demonstrate the experimental probing and mathematical modeling of the motor/flywheel (lumped into an equivalent inertial mass), which is used in different drive cycle schemes to simulate real system behavior. The analysis is accomplished with experimental verification, highlights the advantage of the new approach for evaluating storage capacity. Also, it gives the static and dynamic (time dependency) equations to show an accurate system representation as a ready-made (black box) models, which will be used to determine the overall system performance.