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Direct torque control (DTC) has been recently used for the development of high-performance five-phase induction motor (IM) drives, where normal operation of the system has been usually considered and the ability of DTC to manage the situation has been analyzed in comparison with different rotor-field-oriented control (RFOC) strategies. The exploitation of fault-tolerant capabilities is also an interesting issue in multiphase machines, where the utility of RFOC controllers has been stated when the open-phase fault operation is considered. In this paper, the performance of DTC and RFOC controllers based on proportional resonant regulators and predictive control techniques is compared when an open-phase fault appears in a five-phase IM drive. Experimental tests are provided to compare the performance of the system using these control alternatives. [ABSTRACT FROM PUBLISHER]

The fault tolerance provided by multiphase machines is one of the most attractive features for industry applications where a high degree of reliability is required. Aiming to take advantage of such postfault operating capability, some newly designed full-power energy conversion systems are selecting machines with more than three phases. Although the use of parallel converters is usual in high-power three-phase electrical drives, the fault tolerance of multiphase machines has been mainly considered with single supply from a multiphase converter. This study addresses the fault-tolerant capability of six-phase energy conversion systems supplied with parallel converters, deriving the current references and control strategy that need to be utilized to maximize torque/power production. Experimental results show that it is possible to increase the postfault rating of the system if some degree of imbalance in the current sharing between the two sets of three-phase windings is permitted. [ABSTRACT FROM PUBLISHER]

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. [ABSTRACT FROM AUTHOR]