Innovative Fault-Tolerant Three-Phase SPMSM Drive Without Split Capacitors, Auxiliary Legs, or TRIACs

摘要

The existing fault-tolerant three-phase ac drives need split capacitors, auxiliary legs, and triode for alternating current (TRIACs) upon a standard three-phase two-level voltage source inverter (VSI) to obtain the self-healing ability toward open-phase faults (OPFs). In order to reduce the cost, volume, and weight, this article proposes a novel fault-tolerant three-phase surface-mounted permanent magnet synchronous machine (SPMSM) drive without split capacitors, auxiliary legs, or TRIACs. The proposed drive is still built upon a three-phase two-level VSI, whereas its dc-source is directly connected to the neutral point of the motor. First, mathematical model and equivalent circuit are established to reveal the existence of an equivalent dc/dc boost converter in the drive system. Second, the brand-new d-0 axes current references are proposed in order to preserve the motor's performance when an OPF occurs. In this case, both i(d) and i(0) are nonconstant. Third, an overall control strategy including the healthy and fault-tolerant modes is presented. In the fault-tolerant mode, a deadbeat current controller is developed to track the nonconstant current references. Finally, experiments are carried out on an SPMSM test-bench to verify the effectiveness of the proposed scheme.