Abstract:Multi-phase machines with single-phase open still have additional degrees of freedom and flexibility, which can improve system performance while achieving disturbance-free operation. The traditional fault-tolerant control strategy either minimizes stator copper loss or maximizes torque output capacity, and cannot take into account efficiency and torque density simultaneously. To solve this problem, the fault-tolerant performance of different control modes under fault-tolerant operation is analyzed and a compromise fault-tolerant control strategy based on the minimum copper loss and the maximum torque is proposed. In order to reduce the change of the control framework pre- and post-fault, the fault-tolerant control is realized based on the normal decoupling vector control. By injecting specific fundamental plane current components into the harmonic plane, the disturbance-free operation is realized. For the proposed fault-tolerant control strategy, an additional weight coefficient is introduced to compromise the operating efficiency and load capacity. Through analyzing the influence of the weight coefficient on the fault-tolerant performance, it can be concluded that compared with the minimum copper loss control method, the proposed fault-tolerant control strategy has stronger load capacity; compared with the maximum torque system, the proposed fault-tolerant control strategy has higher operating efficiency. That is, the proposed fault-tolerant control strategy achieves the best efficiency while improving the load capacity. Finally, the experiment on dual three-phase permanent magnet synchronous machines verifies the accuracy and effectiveness of the proposed fault-tolerant control strategy.