Rotor Regionalization Design and Investigation of Direct-Drive Hub PM Motor With Active-Balancing Between Torque and Flux Regulation Ability

In this article, through a newly proposed rotor regionalization design method, a direct-drive hub permanent magnet (DD-HPM) motor is designed for electric vehicles. The key of the research is to achieve active-balancing between torque and flux regulation ability by the targeted design of the three regions of the rotor. First, according to the regionalized magnetic circuit, the torque and flux regulation ability can be deduced to be represented by the three regional magnetic fluxes, respectively, achieving the performance decoupling. Then, combined with the reluctance and magnetic motive force (MMF) design of the torque-flux regulation public region, the required flux regulation ability can be obtained. Further, targeted to the reluctance and MMF of the torque capability region and the flux regulation ability region, the key parameters are selected. And the relationship between the parameters is derived, to satisfy the flux regulation ability design based on the freezing concept. Consequently, within an invariable flux regulation ability, the torque is effectively maximized. Finally, the performance including output torque, flux regulation ability, and speed regulation range are evaluated. The results show the effectiveness of the rotor regionalization design method, and high-torque output capability as well as the wide speed range of the proposed DD-HPM motor.