Common mode voltage elimination scheme for dual-inverter fed five phase AC drives with open-end stator windings

Abstract

This paper proposes a PWM scheme for common-mode voltage elimination of a five-phase inverter fed AC drive with open-end stator windings. Alternating common mode voltages are eliminated from the inverter poles as well as phase voltages thereby mitigating all the problems due to common mode voltages usually encountered in PWM inverter-fed drives, considered to be one of the main reasons for mechanical failures of the motor. In addition, the elimination of common mode voltages facilitates the use of single DC source for feeding both ends of the windings through two five-phase, two-level inverters. A carrier based technique without involving any dwell time calculations or sector identification is proposed for implementation of the PWM scheme. The proposed PWM scheme is validated by extensive simulation on a Matlab/Simulink platform and then verified experimentally on a laboratory prototype.