Electric vehicles require high efficiency, compact and reliable, high-power drivetrains. A variable-pole induction machine (IM) offers a viable magnet-free solution with distinct advantages, such as extended speed range and improved utilization over all loading conditions when compared to fixed-pole machines. From a power electronics perspective, a higher number of switching devices is required to vary the IM pole count. This presentation proposes a generalized framework that investigates the efficiency and sizing of a generalized modular multi-phase inverter to drive a variable-pole IM. We explore how variable-pole operation benefits and limits the drive. We use an experimental GaN-based 18-leg inverter to drive a toroidally wound IM demonstrate the concepts discussed.