Direct Torque Control of an Axial Field Switched-Flux Permanent Magnet Machine

Axial field switched-flux permanent magnet (PM) (AFSFPM) machine is a stator-PM axial-flux machine, which exhibits many merits including simple and robust structure, short axial length, and high power/torque density. In this paper, a kind of direct torque control (DTC) method with flux-weakening strategy implementation, for the AFSFPM machine, is investigated. According to the stage control schemes, a given method with self-adaption for the flux-linkage, by remaining direct-axis is zero, is achieved in constant toque region. A flux-weakening control strategy is implemented in constant power region. On the basis of the DTC method, the performance of the drive system in the entire operating region is investigated. The results indicate that the proposed control strategy reduces the direct-axis component of armature current while increases the efficiency. Moreover, the constant power operating range is broaden. The effectiveness of the proposed method and the characteristics of the AFSFPM machine are verified. Therefore, the machine is very interesting in electrical vehicles (EV) or hybrid EVs (HEVs) application.