Minimum Torque Dip Pole Transition in Variable Phase-Pole Machines With Voltage Limitation

Abstract

Induction machine-based multiphase electrical machines combine the robustness and reliability of well-known induction machines with the benefits of additional degrees of freedom, such as potential higher torque density and true fault tolerance. The subcategory of variable phase-pole machines allows extending the operational torque and speed range with the same voltage and current limits by changing the number of magnetic poles through control without hardware reconfiguration. Maintaining the torque throughout the operation is vital for many applications. The question of maintaining torque during a pole transition still needs to be answered, especially concerning the electric limitations. This paper's proposed pole transition strategy minimizes the torque dip during the pole transition. Field weakening is added to the control scheme to accommodate the voltage limitation. Experimentally controlled, loaded, and scheduled pole transitions demonstrate the capabilities of the proposed strategy with and without voltage limitation.