Fault-Tolerant Symmetrical Six-phase Induction Motor Drive Based on Feed-forward Voltage Compensation

Fault-tolerant multiphase drives have received plenty of attention from the research community over the past two decades due to the increased emphasis on reliability of power electronics and drives systems. Among different types of fault, open circuit or open phase faults have been well studied and different fault-tolerant control approaches have been proposed in the past. While fault-tolerant control based on closed-loop approach have been shown to give good performance, it is possible to tolerate open-phase fault using just simple feed-forward voltage compensation. In this paper, the operation of a multiphase induction machine during open phase fault is examined, and the fundamental factors affecting its performance are discussed. Based on the analytical discussion, it is demonstrated that by calculating x-y voltages and adding to the control voltage in feed-forward manner, torque oscillations due to open phase fault can be easily compensated. Compared to the closed-loop approach, the feed-forward method is superior is terms of simplicity and transient response.