Current Imbalance Detection Method based on Vector Space Decomposition Approach for Five-Phase Induction Motor Drives

The inherent fault-tolerant capability against open-phase faults (OPFs) of multiphase machines is an appreciated advantage in applications where high-reliability is a main concern. This desirable feature has usually required fault localization and post-fault control reconfiguration to provide a suitable performance in this anomaly situation. However, recent model predictive control (MPC) based on virtual voltage vectors (VVs) has validated the multiphase machine fault-tolerant capability without post-fault control reconfiguration. This fact allows to relax some of the OPF detection methods requirements. On the other hand, incipient faults or damaged connections can generate resistance dissymmetry (RD) situations that produces overheating and control degradation. Although the origin of OPFs and RDs can be of a different nature, the symptoms of both anomalies are common: a current imbalance that generates non-null x-y currents appears. Focusing on this approach, this work suggests new settings for an OPF detection method based on the vector space decomposition (VSD) in order to make it universally valid both in OPF and RD situations. The proposed current imbalance detection (CID) method is implemented together with a natural fault-tolerant direct torque control (DTC) for five-phase induction motor drives. Experimental results are employed to verify the goodness of the proposed method.