Gradual Pole Changing Technique for Elimination of Circulating Current in Pole-Phase Modulated Induction Motor Drive during Transition

This paper proposes a methodology for the smooth pole phase change in induction motor drive (IMD) for electrical vehicle applications. The pole phase modulation technique improves the performance of IMD by extending its speed-torque ranges. However, during the pole-phase transition in IMD from low pole to high pole mode or vice-versa, there exist a circulating current in IMD. These circulating currents are due to the flux of stator periphery tries to change its nature suddenly during pole change. Nevertheless, this change of flux can’t be carried suddenly. Thus, this results in flux distortion in IMD in-turn effecting performance of the IMD by creating abrupt torque and subsequent speed disturbances. The paper proposes a control strategy that provides a solution based on gradual pole change approach. In the given approach, the winding of IMD is excited by both 3-φ and 9-φ voltages, with one gradually decreasing and other gradually ramping up during pole transition. The proposed gradual pole changing technique emends the above issues and further improves performance in the pole phase-modulated induction motor (IM). This proposed method of pole changing technique is implemented on a designed 5HP 3-φ, 12-pole IM model in Ansys software, and the results are realized in MATLAB/Simulink environment.