Four-Axis Vector-Controlled Dual-Rotor PMSM for Plug-in Electric Vehicles

Dual-rotor permanent-magnet synchronous motors (PMSMs) offer the merits of higher efficiency, higher torque density, and inherent electric differential (ED). This paper proposes a novel four-axis vector-controlled dual-rotor PMSM drive for driving plug-in electric vehicles (PEVs). A four-axis d-q model of the dual-rotor PMSM is developed with the proposed three-phase to four-phase transformation. This transformation separately resolves the stator variables to the d-q-axes of the inner and outer rotor. Instead of applying back electromotive forces and rotor power angles, the d-axis fluxes are used for computing the displacement between the two d-q-axes, which is essential for the transformation. The proposed four-axis vector control of dual-rotor PMSM allows for the independent control of stator quantities corresponding to the inner and outer rotors. This facilitates ED and better control under parametric differences, such as rotor inertia and permanent magnet flux for the inner and outer rotors. The comparison of the dual-rotor PMSM-based PEV operation with the proposed control and two earlier reported schemes reveals that the proposed scheme offers effective ED without the loss of vehicle control. Furthermore, the proposed configuration is validated with different drive cycles, including the loss modeling, sensitivity analysis, and efficiency mapping.