Optimal Fault-Tolerant Control of Six-Phase Induction Motor Drives With Parallel Converters

Multiphase drives and parallel converters have been recently proposed in low-voltage high-power applications. The fault-tolerant capability provided by multiphase drives is then extended with parallel converters, increasing their suitability for safety-critical and renewable uses. This advantageous feature, compared with standard three-phase drives, has been analyzed in the event of open-phase faults. However, when using parallel converters, a converter fault does not necessarily imply an open-phase condition, but usually just a limited phase current capability. This paper analyzes the fault-tolerant capability of six-phase drives with parallel converter supply. Different scenarios considering up to three faults for single and two neutral configurations are examined, optimizing offline the postfault currents and modifying accordingly the control strategies. Experimental results confirm the smooth transition from prefault to postfault situation and the enhanced postfault torque capability.