Fault-Tolerant Operation of Six-Phase Energy Conversion Systems With Parallel Machine-Side Converters

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.