Current Reductions and Pulsating Torque Suppressions in Magnetization State Manipulations of Dual Three-Phase Variable Flux Memory Machines

The dynamic performances during the magnetization state (MS) manipulations of variable flux memory machines (VFMMs) are focused. Based on the segregated dual three-phase (DTP)-VFMMs, a new MS manipulation method is developed to reduce the current capacity requirements for MS regulations, as well as alleviate the pulsating torque and speed fluctuations during de-/remagnetizations. The proposed method employs two individual d-axis current pulses in sequence in a single three-phase winding set, while the other winding set is free from de-/remagnetizing currents. The theoretical analyses, simulations, and experimental validations are conducted to confirm the effectiveness of the developed method, in which the MS regulations of all permanent magnet (PM) poles can be completed step-by-step. More importantly, the dynamic characteristics during the flux regulations based on the developed and the conventional MS manipulation methods, are compared. The results reveal the benefits in the overall current capacity reduction and the torque/speed fluctuation alleviations in the developed method, thanks to the temporally distributed current pulses.