Pole-phase Modulated Open-End Winding Induction Motor Drive with Gradual Pole Changing Technique for EV Application

This paper proposes an inverter topology that implements pole-phase modulation (PPM) with gradual pole changing technique for an open-end winding-induction motor drive (OEW-IMD) in electrical vehicle applications. The PPM is popular in changing poles in IMD which can covers a wide range of speed-torque characteristics. However, in implementation of PPM in IMD from low-pole mode exists lower order space harmonics. These harmonics are attributed to common mode voltage (CMV) of the inverter that is fed to the motor. Aside to that, during pole transition there exists circulating current as there is sudden flux transition. This is due to sudden change of supply feeding to IMD from 3-φ to 9-φ and vice-versa. Consequently, this flux in stator of IMD is distorted. Subsequently, the IMD performance is affected by producing an unforeseen torque and successively speed disturbances. The paper proposes a nine-phase reconfigurable-inverter to OEW-IMD which aims to solve the above said issue during transfer from one mode to other by a progressive approach. In addition, the proposed inverter for OEW-IMD is able to operate in two combinations of voltages: one with a common DC source (battery) and other by isolated two DC sources with minimum switch combinations. By the single source operation, the proposed topology gives provision to charge the other and keep that as backup. The proposed inverter configuration amends the all above said issues and improves system performance in EV application. The proposed reconfigurable-inverter is implemented and its performance is validated by a designed 5HP, 3-φ, 12-pole OEW-IMD in Ansys simulation environment.