Gearless Powertrain for Electric Vehicles

Abstract

Electrical Machines are driving the modern world in one way or the other. The modern world is moving towards the sustainability of ecological systems and greener modes of transportation to stabilize the environmental conditions for future generations. For this, the multiphase machines have risen as efficient solutions over traditional 3-phase electrical machines. In this project, a Pole Phase Modulated (PPM) multiphase induction motor drive is developed for gearless electric vehicle applications. With the help of conventional pole changing techniques (like using multiple auxiliary windings or dual stator windings) variable speed and torques can be achieved but the poor copper utilization, de-energization of the windings, and multiple auxiliary windings are the major limitations. In this project, a novel single stator winding multiphase induction motor is developed that is capable of delivering variable speed-torques by varying the number of phases as well as poles simultaneously using novel multiphase power converter topologies. Moreover, the proposed drive offers high fault-tolerant capability, the ability to handle high power with reduced voltage ratings of power electronic devices, better torque/power distribution, and improved efficiency with a lesser magnitude of space harmonics, etc. The proposed drive gives similar speed torque characteristics of conventional IC-based conventional vehicles, which helps in the elimination of the gearbox system in the EVs. This minimizes the cost, size, weight, and volume of the vehicle. Two-level inverters and multilevel inverters with carrier phase shifted space vector PWM are developed for achieving the better performance of the PPM-based MIM drive w.r.t. efficiency, torque ripple and DC link utilization. Fault-tolerant operation of the drive with respect to inverter switch or source failures is also developed as a part of the project and presented. To operate the PPM-based MIM drive smoothly in different pole phase combinations, the indirect field-oriented vector control is developed and presented.