Fault-Tolerant Six-Phase Motor Drive Topology and Control Technique for Short-Circuit Failure

Fault-tolerant operation capability of a motor drive system has become an important issue as application rapidly expands towards electrified transportation as well as distributed energy resources (DERs). These applications often require high- level of fault-tolerant capability, which means rated torque or output power of a system should not be compromised in post-fault conditions. Among different types of faults in electric drives, a short-circuit fault condition generally causes more catastrophic consequences than open-circuit faults, such as overheating, saturation, demagnetization, and an excessive amount of ripple and dragging torque, which can permanently damage the electric drives. In this paper, different types of short-circuit faults in a surface permanent magnet machine and motor drive are investigated, and new fault compensation strategies (i.e., multiphase motor drive and control technique) are proposed to eliminate dragging and ripple torque in post-fault operation. This paper proposes a new fault-tolerant six-phase motor drive topology using multiple two-phase inverter modules, which can provide an unprecedently high-level of fault-tolerant capability due to the presence of both phase and parallel redundancies in post-fault conditions. The proposed drive can tolerate a short- circuit fault, and the post-fault operation with a short-circuit failure is validated through simulation and experiment.