A novel pole‐changing method with multiple three‐phase inverters

This paper presents a new pole‐changing method with multiple three‐phase inverters. Since the number of controllable current phases is much larger than that in conventional methods, a higher winding factor can be obtained in both high‐ and low‐pole driving modes. To evaluate the magnetic characteristics of the proposed method, magnetomotive force analysis is conducted based on Fourier series expansion and finite element method (FEM). Moreover, mutual inductance is compared between high‐ and low‐pole drives using FEM. To validate the effectiveness, an efficiency map is evaluated by using a prototype induction motor. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.