Fractional-slot winding pattern for pole-phase modulated multiphase multi-speed induction motor drives

Abstract

Multiphase induction motor (MIM) drives are becoming popular for high-power applications because of fault tolerant capability and wide range speed-torque characteristics. Using pole-phase modulation (PPM) technique, it is able to give high-torque for faster acceleration as well as high speed during steady operation. To achieve both these features, the MIM drive requires higher number of stator slots that may increase size and weight of the drive. However, these two major constraints limit the pole phase modulated MIM (PPMMIM) drives for medium and low power applications. To address these issues, in this paper a fractional-slot multilayer winding (FSMLW) for PPMMIM drive is proposed for getting multi-speed ratios with the conventional 36 slots stator core frame. This FSMLW improves the harmonic profile in the air gap magneto-motive force (MMF) and efficiency of the PPMMIM drive. In addition, generalization of the PPM is revised by considering number of layers per slot. The proposed MIM drive operates in 15-phase 2-pole mode, 5-phase 6-pole mode and 3-phase 10-pole modes by using PPM. With these three pole-phase combinations, the drive is capable to runs at 1:3:5 speed ratios. The proposed 36-slot PPMMIM drive facilitates wider range of speed-torque characteristics with FSMLW. This can make it suitable for medium and low power applications. The effectiveness of the proposed MIM drive with FSMLW is verified by using FEM analysis using ANSYS Maxwell-2D. A two-level inverter is designed in Simplorer environment for co-simulating the proposed MIM drive.