Natural Fault Tolerance of a Nine-Phase Induction Motor Drive Operating at Variable Frequency and Switched Supply Sequence

The paper presents tests of fault tolerance of a regulated drive with a multi-phase squirrel-cage induction motor. The drive was controlled using variable frequency with switching the output voltage sequence of the inverter. The damages were mainly caused by break of one or several motor phase currents. The reason was bad inverter operation or phase connection interruption. Additionally, the effect of blocking a single transistor of the inverter half bridge was investigated. The faulty drive was to perform the same task of speed regulation as the healthy drive. The permissible extent of damage has been determined. The research was carried out in Simulink using the developed multi-harmonic model of a multi-phase induction motor.