A novel power-train using coaxial magnetic gear for power-split hybrid electric vehicles

This paper proposes a novel power-train for power-split hybrid electric vehicles (HEVs). The key is to integrate two permanent magnet motor/generators (M/Gs) together with a coaxial magnetic gear (CMG). By designing the modulating ring of the CMG to be rotatable, this integrated machine can achieve both power splitting and mixing, and therefore, can seamlessly match the vehicle road load to the engine optimal operating region. With the one-side-in and one-side-out structure and the non-contact transmission of the CMG, all the drawbacks aroused by the mechanical gears and chain existing in the traditional power-train system can be overcome. Moreover, the proposed power-train possesses the merits of small size and light weight, which are vitally important for extending the full-electric drive range of HEVs. The working principle and the design details are elaborated. By using the finite element method, the electromagnetic characteristics are analyzed. Finally, system modeling and simulation are conducted to evaluate the proposed system.