Open-circuit fault detection of asymmetrical six-phase induction motor fed from Z-source inverter

Recently, asymmetrical six-phase induction motors have proved their performance and easiness of design and control over many other types of multiphase machines. On the other hand, it is well-known that the key feature of any type of multiphase machines is their fault tolerant capability with no additional hardware. To ensure performing of the post-fault control strategy immediately after the fault occurrence, fast fault detection method is a necessity or more devices will be damaged. On the other hand, despite of the multiple features of ZSI in healthy state, the impedance network is expected to delay the fault detection time. The vector space decomposition fault detection (VSDFD) method has proved its high velocity and robustness in fault detection for six-phase machine fed by sinusoidal supply and for a five-phase machine fed by VSI. Therefore, this method is tested in this paper for an asymmetrical six-phase induction machine fed by ZSI. A simulation is performed to test the performance of the VSDFD method under three different types of fault and transient states also. Some of the suggested parameters for this method in the other literatures is adjusted to ensure it is adequate with the new machine and inverter type with a final recommendation for choosing the parameters. Finally, the simulation results show fast detection of all types of fault which ensures the reliabilty and robustness of this method.