Efficient Flywheel-Based All-Wheel-Drive Electric Powertrain

All-wheel-drive (AWD) multimotor electric powertrains offer greater potential for system performance, efficiency, and reliability improvements. In this article, a new AWD electric powertrain that can increase the overall powertrain efficiency and battery lifetime is introduced. The proposed powertrain is based on a compact and efficient flywheel-based kinetic energy recovery system (KERS) that overcomes most of the shortcomings of the conventional electric KERS. Here, a significant part of the mechanical power transfer takes place without conversion to electrical power. Therefore, a selectable fraction of the recoverable kinetic energy is processed by power electronics. Thus, no energy exchange is necessary between the battery and the powertrain during acceleration and deceleration, resulting in a reduced battery power rating. This article compares the proposed powertrain with a conventional AWD electric powertrain. Mathematical modeling and simulations based on the space vector method were used for both powertrains that show the advantage of the proposed powertrain over the conventional one. The experimental data are also presented from our proof of the concept laboratory setup.