Electro-Mechanical EV Powertrain With Reduced Volt-Ampere Rating

Transmotor-based flywheel energy exchange is a low-cost yet highly efficient method of energy transfer between vehicle wheels and a lightweight flywheel. This method utilizes one dual-rotor electric machine that enables us to overcome some of the shortcomings of the conventional electric kinetic energy recovery systems (KERS). The proposed system is capable of capturing far more mechanical power than its electrical power ratings. Furthermore, since a significant part of the energy exchange takes place in mechanical form, only a small fraction of the initial kinetic energy needs to be processed by the electrical energy storage device and the power electronic drive system. In this paper, the proposed Transmotor-based KERS has been compared with the conventional electric KERS. Mathematical modeling and simulations were performed using a space vector modeling method for both conventional electric KERS and the proposed system. Results show that the proposed system is capable of capturing a great part of kinetic energy of a vehicle during deceleration and storing it in a lightweight flywheel to be used for the next acceleration while keeping the electrical ratings of the KERS relatively low. Experimental results are also presented for the proof of the concept.