Extension of Virtual-Signal-Injection-Based MTPA Control for Five-Phase IPMSM Into Fault-Tolerant Operation

This paper introduces a novel fault-tolerant control for the maximum torque per ampere (MTPA) operation in five-phase interior permanent magnet synchronous machine (IPMSM), termed MTPA fault-tolerant control. The key of this fault-tolerant control is that the reluctance torque is considered and used by MTPA under open-circuit fault. Based on the decoupled model of five-phase IPMSM on synchronous frame and the computing method of d-axis and q-axis voltages under various open-circuit faults, the virtual signal injection control (VSIC) can be applied to realize the MTPA under the fault-tolerant operation by the post-fault field-oriented control (FOC) and carrier-based PWM (CPWM). This method is parameter independent in tracking of the MTPA points under the fault-tolerant operation. Besides, it can effectively reduce the amplitude of the fundamental current and improve efficiency compared with traditional i(d) = 0 fault-tolerant control. Moreover, it is robust to current and voltage harmonics and machine torque disturbances under the postfault operation. The proposed method is verified by experiments under various postfault operating conditions on an IPMSM prototype drive system.