An Open-Phase Fault-Tolerant Algorithm for Symmetric Dual Three-Phase Interior Permanent Magnet Synchronous Motor

This paper proposes an open-phase fault-tolerant algorithm for a Dual Three Phase Interior Permanent Magnet Synchronous Motor with$0^\circ$displacement between the three-phase winding sets (DTP0 IPMSM). The algorithm considers the necessary conditions to extract both Lorentz and reluctance torques. The operating points are calculated by taking into account all possible combinations of the phase currents and thereby selecting the one pertaining to minimum copper losses. The operation of the fault-tolerant DTP0 IPMSM is extended above base speed with a reduced torque capability using a voltage-constrained technique presented in this paper. One of the key features of this technique is its simplicity in implementation, as it does not demand any change in the control architecture in the fault-tolerant mode. For the prototype DTP0 IPMSM considered in this study, the proposed fault-tolerant technique is compared against existing methods, including single-inverter operation. The results are benchmarked against the healthy operation of the machine. It is observed that the proposed method achieves approximately 78% of the rated torque under fault conditions, while incurring lower total losses compared to existing fault-tolerant strategies. The proposed concepts are validated on a 2.5 kW DTP0 IPMSM, and the results align with the presented theory.