Two different carrier phase shifted space vector PWM techniques for pole phase modulation based 9-phase induction motor drive

Abstract

The pole phase-modulated induction motor (PPMIM) drives fulfils all significant requirements of high power traction applications, like extended speed-torque capabilities, higher fault tolerance and high efficiency. In the low pole high phase mode, PPMIM drive offers the high speeds for steady run application but in this mode, drive suffers from the lower DC-link utilization. In high pole low phase mode, the drive offers high torque for cruising and faster acceleration, however, the drive suffers from the higher torque pulsations. In this paper, these two limitations of 9-phase PPMIM drives are addressed by proposing a dual inverter-based multilevel inverter (MLI), where the drive is modulated with two different carrier phase shifted space vector pulse width modulation (SVPWM) schemes. For achieving the 3-level voltage across each phase the proposed inverter requires 4 DC source and 36 switches. Firstly, the DC link utilization of the proposed MLI fed 9-phase PPMIM drive is improved by 15.4%, where the drive is modulated by using 3-phase carrier-based SVPWM along with phase grouping concepts. In the high pole low phase mode, two different carrier phase shifted PWMs (CPS-PWM) are proposed for feeding the effective phase windings with multilevel voltage, which results in better torque ripple profile of PPMIM drive. In CPS-PWM1, both level shifted and phase shifted carrier PWM concepts are effectively used for modulating the proposed MLI configuration. Whereas in CPS-PWM2, phase shifted carrier PWM concept is used. The proposed MLI fed PPMIM drive with different PWMs are validated by using the Ansys Maxwell 2D as well as an experimental prototype.