Minimum Copper Loss Fault-Tolerant Control of Zero Phase Shift Dual Three-Phase SPMSM by Using Reduced-Order Transformation Matrices

For the zero phase shift dual three-phase surface-mounted permanent magnet synchronous motors, the traditional fault-tolerant control (FTC) strategy can ensure the stable operation of under open-phase fault. However, the copper loss minimization was not considered. For this reason, an FTC strategy for open-phase and open-switch faults to minimize the copper loss is proposed in this paper. First, the zero phase shift vector space decoupling matrix is given and the mathematical model of the motor is derived. Then, the relationship between the six-phase currents and dqz-axis currents is analyzed. The minimum copper loss reference currents under open-phase and open-switch faults are determined based on the relationship between the dqz-axis current and copper loss. On the other hand, since the normal transformation matrix is no longer applicable to the faulty cases, a reduced-order vector space decoupling matrix is constructed and utilized in the FTC strategy to generate independent reference voltage control quantities. Finally, the proposed FTC strategy is experimentally validated to verify the feasibility of the strategy.