Controllability and Performance of a Nine-Phase FSPM Motor Under Severe Five Open-Phase Fault Conditions

Fault-tolerant controllability for a nine-phase flux-switching permanent magnet (NP-FSPM) machine under severe five open-phase fault is presented in this paper. First, combinations of additional degrees of freedom are derived to prove the high fault tolerance in the nine-phase drive system. Second, angles between the adjacent healthy phases are used to categorize the five open-phase fault cases, and stator-flux-oriented fault-tolerant control with harmonic current injection is developed to ensure the disturbance-free operation of the NP-FSPM machine drive. The main contribution is the investigation on the effect of the reconstructed harmonic current components on the machine phase currents and the dynamic performance under various switch transients. Also, some practical hints are given for implementation, such as the control degree of freedom, drive derating, and current control scheme. Experimental results are presented to validate the effectiveness of the sinusoidal current excitation and the high dynamic performance of the NP-FSPM machine drive system.