Fault-Tolerant Control and Common-Mode Voltage Reduction for Dual Three-Phase CSIs Fed Motor Drives

In this article, a new topology of dual three-phase current-source inverter (DTP-CSI) fed motor drive has been proposed for improving the fault-tolerant capability while reducing the common-mode voltage (CMV). In the proposed configuration, six common switches are shared between the dual three-phase CSI modules instead of the six inner-side switches in conventional configuration. The more control dimensions and redundancies enable the proposed configuration potentials for improved operation performance and better fault-tolerant capability. The modulation strategies and control schemes have been designed for both normal operation and fault-tolerant operation of the proposed motor drive. For normal operation, the CMV reduction method is proposed by optimally selecting and sorting the current vectors of the DTP-CSI, which facilitates mitigating the common-mode electromagnetic interference issue. For fault-tolerant operation, the proposed scheme guarantees complete current vectors for the DTP-CSI even one common switch fails in open-circuit fault. Thus, the symmetric phase currents can be maintained without increasing the current amplitudes. The better fault-tolerant capability can be offered compared to the conventional configuration, which suffers from the asymmetrical phase currents under open-circuit fault in inner-side switches. A laboratory prototype has been developed to verify the effectiveness of the proposed topology, CMV reduction method, and fault-tolerant operation strategy experimentally.