Comparative study of current vector control performance of alternate fault tolerant inverter topologies for three-phase PM brushless ac machine with one phase open - circuit fault

Reliability and fault tolerance of drive systems has received renewed research interest over last decade with several fault tolerant drive topologies and control schemes having been proposed and investigated. In this paper, the performance of hysteresis current vector control methodologies when applied to three common fault tolerant drive topologies has been investigated and compared theoretically and experimentally. Their advantages and limitations in terms of current value, current and torque ripples, and operating speed range etc. are considered and verified by both simulated and measured results. It is proven that by simply modifying the hysteresis current control methodology, the maximum torque per ampere (MTPA) can still be achieved in post-fault operation, albeit with potentially increased current value, low frequency current and torque ripples, and compromised speed operating range.