Online full range copper loss minimization for single-phase short-circuit fault tolerant control in five-phase PMSM

Five-phase machines are increasingly adopted in high-reliability applications because of their fault-tolerant characteristics. In this framework, single-phase short-circuits (SC) fault tolerant control has drawn increasing interest. One issue with fault-tolerant control is the increased copper loss that a machine experiences in post-fault operations. This study adopts not only the full-range minimum copper loss (FRML) SC fault application but also its online tuning process. To achieve the online FRML strategy, the contact resistance and motor speed are considered as factors to first analyze the uncontrollable SC current. Furthermore, after eliminating the multiple effects of SC faults, a load torque observation is built to provide an accurate online load torque estimation. The experimental results show that the maximum remaining phase current can be limited to the rated current by the online FRML method. Additionally, the advantages of the FRML strategy in SC faults, that is, high torque output, and low copper loss, are also simultaneously verified by experiments.