Advanced vehicles with dynamically reconfigurable number of stator turns

This paper presents technical justification for implementing the capability to change automatically the effective number of turns in the stator of propulsion motors while they run, adapting to changes in speed and load of the vehicle. Our simulation studies show significant potential benefits on efficiency and battery size in a typical electrically propelled vehicle when the stator of its IPM motor is modified to be able to switch between its standard and twice the number of turns, as it operates. Along eight different standard driving cycles, the reference vehicle with a motor modified to switch between 9 and 18 stator-turns showed better utilization of the available voltage, lower stator currents, better efficiency in the motor, power electronics, battery, and cabling as well as higher overall vehicle system efficiency, than an identical vehicle with an unmodified motor having 9 fixed stator turns. In addition, the size and cost of the battery with the switching-capable motor can potentially be reduced and the need for voltage boosting to meet the power demand in some of the driving cycles can potentially be eliminated. For a fully electric EV configuration, the vehicle with the reconfigurable turn motor consumed between 4% and 27% less energy and required between 5% and 20% less peak power than the vehicle with the conventional 9-turn motor, depending on the driving cycle. For a hybrid, HEV configuration, the vehicle with the reconfigurable turn motor consumed between 13% and 23% less electrical energy and required between 16% and 39% less electric power than the vehicle with the conventional 9-turn motor, depending on the driving cycle.