Asymmetrical six-phase induction motor drives based on Z-Source inverters: modulation, design, fault detection and tolerance

Multiphase machines are becoming one of the mainstream research topics during the last decade, especially in high-reliability based systems. Among the different configurations of the multiphase machines, Asymmetrical Six-Phase Induction Motor (ASPIM) with a spatial displacement of 30° is popular as it has a better magnetomotive force (MMF) distribution. This paper therefore concerns with detecting and mitigating the operation of ASPIM during healthy and faulty modes. Recently, the Z-source Inverter (ZSI) technology has attracted great concerns of the researchers. The key idea of this paper is to combine together the technologies of ASPIM and ZSI. This combination produces a very high reliable drive system. Traditional modulation methods associated with the ZSI are modified in this paper to be convenient for ASPIM drives. Besides, the impedance network design procedures are introduced. Moreover, the Vector Space Decomposition Fault Detection (VSDFD) method has been applied to detect open-circuit faults and used to select the proper post-fault operation. An experimental setup has been established in the laboratory to validate the proposed ideas. Finally, the actual machine parameters are measured and used to investigate the system performance via simulation and experimental results in both healthy and faulty conditions.